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  • 1. Abbasi, Arshad Mehmood
    et al.
    Khan, Mir Ajab
    Khan, Nadeem
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Shah, Munir H
    Ethnobotanical survey of medicinally important wild edible fruits species used by tribal communities of Lesser Himalayas-Pakistan2013In: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 148, no 2, 528-536 p.Article in journal (Refereed)
    Abstract [en]

    Ethnopharmacological relevance: Present survey was conducted to explore ethnomedicinal uses and cultural importance of wild edible fruits species by the inhabitants of Lesser Himalayas-Pakistan. Materials and methods: Information was obtained through informed consent semi-structured interviews, questionnaires, market survey, focus group conversation, unceremonious dialogue and village walks with key informants. Cultural significance of each species was calculated based on use report by participants at each study site. Results: A total of 35 wild edible fruits belonging to 21 genera and 17 families were used for the treatment of various ailments and consumed. Rosaceae was found dominating family with (8 spp.), followed by Moraceae (6 spp.), Rhamnaceae (5 spp.), Palmae and Vitaceae (2 spp. each) and remaining families were represented by one species each. Fruits (48%) were found highly utilized plant parts, followed by leaves (34%), bark, flowers and seeds (4% each), branches, latex and roots (2% each). Water was used as a medium for preparation while milk, ghee, oil, egg and butter are used for application. Modes of preparation were fall into seven categories like fresh parts eaten raw (38%), powder (24%), decoction (20%), extract (12 %), paste (4%), juice and latex (2% each). Based on cultural important index (CI) Morus nigra was found most significant species within top ten fruit plants followed by Morus alba, Olea ferruginea, Berberis lycium, Pyrus pashia, Ficus carica, Ficus palmata, Ziziphus mauritiana, Diospyros lotus and Ziziphus nummularia. Conclusions: Traditional uses of wild edible plant depend mainly on socio-economic factors rather than climatic conditions or wealth of flora. Use reports and citation demonstrated that there is a common cultural heritage regarding the gathered food plants. Further investigation is required for Antioxidant study, essential and toxic components, pharmacological applications; dietary requirements and biotechnological techniques to improve yields.

    (C) 2013 Elsevier Ireland Ltd. All rights reserved.

  • 2. Abraham, Edit
    et al.
    Miskolczi, Pal
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ayaydin, Ferhan
    Yu, Ping
    Kotogany, Edit
    Bako, Laszlo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Oetvoes, Krisztina
    Horvath, Gabor V.
    Dudits, Denes
    Immunodetection of retinoblastoma-related protein and its phosphorylated form in interphase and mitotic alfalfa cells2011In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 62, no 6, 2155-2168 p.Article in journal (Refereed)
    Abstract [en]

    Plant retinoblastoma-related (RBR) proteins are primarily considered as key regulators of G(1)/S phase transition, with functional roles in a variety of cellular events during plant growth and organ development. Polyclonal antibody against the C-terminal region of the Arabidopsis RBR1 protein also specifically recognizes the alfalfa 115 kDa MsRBR protein, as shown by the antigen competition assay. The MsRBR protein was detected in all cell cycle phases, with a moderate increase in samples representing G(2)/M cells. Antibody against the human phospho-pRb peptide (Ser807/811) cross-reacted with the same 115 kDa MsRBR protein and with the in vitro phosphorylated MsRBR protein C-terminal fragment. Phospho-MsRBR protein was low in G(1) cells. Its amount increased upon entry into the S phase and remained high during the G(2)/M phases. Roscovitine treatment abolished the activity of alfalfa MsCDKA1;1 and MsCDKB2;1, and the phospho-MsRBR protein level was significantly decreased in the treated cells. Colchicine block increased the detected levels of both forms of MsRBR protein. Reduced levels of the MsRBR protein in cells at stationary phase or grown in hormone-free medium can be a sign of the division-dependent presence of plant RBR proteins. Immunolocalization of the phospho-MsRBR protein indicated spots of variable number and size in the labelled interphase nuclei and high signal intensity of nuclear granules in prophase. Structures similar to phospho-MsRBR proteins cannot be recognized in later mitotic phases. Based on the presented western blot and immunolocalization data, the possible involvement of RBR proteins in G(2)/M phase regulation in plant cells is discussed.

  • 3.
    Abreu, Ilka Nacif
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ahnlund, Maria
    Moritz, Thomas
    Albrectsen, Benedicte R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    UHPLC-ESI/TOFMS Determination of Salicylate-like Phenolic Gycosides in Populus tremula Leaves2011In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 37, no 8, 857-70 p.Article in journal (Refereed)
    Abstract [en]

    Associations of salicylate-like phenolic glycosides (PGs) with biological activity have been reported in Salix and Populus trees, but only for a few compounds, and in relation to a limited number of herbivores. By considering the full diversity of PGs, we may improve our ability to recognize genotypes or chemotype groups and enhance our understanding of their ecological function. Here, we present a fast and efficient general method for salicylate determination in leaves of Eurasian aspen that uses ultra-high performance liquid chromatography-electrospray ionization/time-of-flight mass spectrometry (UHPLC-ESI/TOFMS). The time required for the liquid chromatography separations was 13.5 min per sample, compared to around 60 min per sample for most HPLC protocols. In leaf samples from identical P. tremula genotypes with diverse propagation and treatment histories, we identified nine PGs. We found the compound-specific mass chromatograms to be more informative than the UV-visible chromatograms for compound identification and when quantitating samples with large variability in PG content. Signature compounds previously reported for P. tremoloides (tremulacin, tremuloidin, salicin, and salicortin) always were present, and five PGs (2'-O-cinnamoyl-salicortin, 2'-O-acetyl-salicortin, 2'-O-acetyl-salicin, acetyl-tremulacin, and salicyloyl-salicin) were detected for the first time in P. tremula. By using information about the formic acid adduct that appeared for PGs in the LTQ-Orbitrap MS environment, novel compounds like acetyl-tremulacin could be tentatively identified without the use of standards. The novel PGs were consistently either present in genotypes regardless of propagation and damage treatment or were not detectable. In some genotypes, concentrations of 2'-O-acetyl-salicortin and 2'-O-cinnamoyl-salicortin were similar to levels of biologically active PGs in other Salicaceous trees. Our study suggests that we may expect a wide variation in PG content in aspen populations which is of interest both for studies of interactions with herbivores and for mapping population structure.

  • 4. Adam, Zach
    et al.
    Adamska, Iwona
    Nakabayashi, Kazumi
    Ostersetzer, Oren
    Haussuhl, Kirsten
    Manuell, Andrea
    Zheng, Bo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Vallon, Olivier
    Rodermel, Steven
    Shinozaki, Kazuo
    Chloroplast and mitochondrial proteases in Arabidopsis: a proposed nomenclature2001In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 125, no 4, 1912-1918 p.Article in journal (Refereed)
    Abstract [en]

    The identity and scope of chloroplast and mitochondrial proteases in higher plants has only started to become apparent in recent years. Biochemical and molecular studies suggested the existence of Clp, FtsH, and DegP proteases in chloroplasts, and a Lon protease in mitochondria, although currently the full extent of their role in organellar biogenesis and function remains poorly understood. Rapidly accumulating DNA sequence data, especially from Arabidopsis, has revealed that these proteolytic enzymes are found in plant cells in multiple isomeric forms. As a consequence, a systematic approach was taken to catalog all these isomers, to predict their intracellular location and putative processing sites, and to propose a standard nomenclature to avoid confusion and facilitate scientific communication. For the Clp protease most of the ClpP isomers are found in chloroplasts, whereas one is mitochondrial. Of the ATPase subunits, the one ClpD and two ClpC isomers are located in chloroplasts, whereas both ClpX isomers are present in mitochondria. Isomers of the Lon protease are predicted in both compartments, as are the different forms of FtsH protease. DegP, the least characterized protease in plant cells, has the most number of isomers and they are predicted to localize in several cell compartments. These predictions, along with the proposed nomenclature, will serve as a framework for future studies of all four families of proteases and their individual isomers.

  • 5. Ahad, Abdul
    et al.
    Keech, Olivier
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sjödin, Andreas
    Lindén, Pernilla
    Brouwer, Bastiaan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Stenlund, Hans
    Moritz, Thomas
    Jansson, Stefan
    Gardeström, Per
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Comparison between leaves from darkened plants and individually-darkened leaves reveals differential metabolic strategies in response to darknessManuscript (preprint) (Other academic)
  • 6. Ahad, Abdul
    et al.
    Keech, Olivier
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre.
    Sjödin, Andreas
    Stenlund, Hans
    Moritz, Thomas
    Jansson, Stefan
    Gardeström, Per
    Leaf metabolism during dark induced senescence in Arabidopsis: integrating metabolomics and transcriptomicsManuscript (Other academic)
  • 7.
    Ahad, Abdul
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nick, Peter
    Actin is bundled in activation-tagged tobacco mutants that tolerate aluminum2007In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 225, no 2, 451-468 p.Article in journal (Refereed)
    Abstract [en]

    A panel of aluminum-tolerant (AlRes) mutants was isolated by protoplast-based T-DNA activation tagging in the tobacco cultivar SR1. The mutants fell into two phenotypic classes: a minority of the mutants were fertile and developed similarly to the wild type (type I), the majority was male-sterile and grew as semi-dwarfs (type II). These traits, along with the aluminum tolerance, were inherited in a monogenic dominant manner. Both types of mutants were characterized by excessive bundling of actin microfilaments and by a strongly increased abundance of actin, a phenotype that could be partially phenocopied in the wild type by treatment with aluminum chloride. The actin bundles could be dissociated into finer strands by addition of exogenous auxin in both types of mutants. However, actin microfilaments and leaf expansion were sensitive to blockers of actin assembly in the wild type and in the mutants of type I, whereas they were more tolerant in the mutants of type II. The mutants of type II displayed a hypertrophic development of vasculature, manifest in form of supernumerary leaf veins and extended xylem layers in stems and petioles. Whereas mutants of type I were characterized by a normal, but aluminum-tolerant polar auxin-transport, auxin-transport was strongly promoted in the mutants of type II. The phenotype of these mutants is discussed in terms of reduced endocytosis leading, concomitantly with aluminum tolerance, to changes in polar auxin transport.

  • 8. Ahlfors, Reetta
    et al.
    Lång, Saara
    Overmyer, Kirk
    Jaspers, Pinja
    Brosché, Mikael
    Tauriainen, Airi
    Kollist, Hannes
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Belles-Boix, Enric
    Piippo, Mirva
    Inzé, Dirk
    Palva, E Tapio
    Kangasjärvi, Jaakko
    Arabidopsis RADICAL-INDUCED CELL DEATH1 belongs to the WWE protein-protein interaction domain protein family and modulates abscisic acid, ethylene, and methyl jasmonate responses.2004In: The Plant Cell, ISSN 1040-4651, Vol. 16, no 7, 1925-37 p.Article in journal (Refereed)
    Abstract [en]

    Experiments with several Arabidopsis thaliana mutants have revealed a web of interactions between hormonal signaling. Here, we show that the Arabidopsis mutant radical-induced cell death1 (rcd1), although hypersensitive to apoplastic superoxide and ozone, is more resistant to chloroplastic superoxide formation, exhibits reduced sensitivity to abscisic acid, ethylene, and methyl jasmonate, and has altered expression of several hormonally regulated genes. Furthermore, rcd1 has higher stomatal conductance than the wild type. The rcd1-1 mutation was mapped to the gene At1g32230 where it disrupts an intron splice site resulting in a truncated protein. RCD1 belongs to the (ADP-ribosyl)transferase domain–containing subfamily of the WWE protein–protein interaction domain protein family. The results suggest that RCD1 could act as an integrative node in hormonal signaling and in the regulation of several stress-responsive genes.

  • 9. Aksmann, Anna
    et al.
    Shutova, Tatiana
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tukaj, Zbigniew
    The mechanism of anthracene interaction with photosynthetic apparatus: A study using intact cells, thylakoid membranes and PS II complexes isolated from Chlamydomonas reinhardtii2011In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 104, no 3-4, 205-210 p.Article in journal (Refereed)
    Abstract [en]

    Intact cells of Chlamydomonas reinhardtii as well as isolated thylakoid membranes and photosystem II complexes were used to examine a possible mechanism of anthracene (ANT) interaction with the photosynthetic apparatus. Since ANT concentrations above 1 mM were required to significantly inhibit the rate of oxygen evolution in PS II membrane fragments it may indicate that the toxicant did not directly interact with this photosystem. On the other hand, stimulation of oxygen uptake by ANT-treated thylakoids suggested that ANT could either act as an artificial electron acceptor in the photosynthetic electron transport chain or function as an uncoupler. Electron transfer from excited chlorophyll to ANT is impossible due to the very low reduction potential of ANT and therefore we propose that toxic concentrations of ANT increase the thylakoid membrane permeability and thereby function as an uncoupler, enhancing electron transport in vitro. Hence, its unspecific interference with photosynthetic membranes in vitro suggests that the inhibitory effect observed on intact cell photosynthesis is caused by uncoupling of phosphorylation. 

  • 10.
    Albrectsen, Benedicte
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gutierrez, Laura
    Fritz, Robert S
    Fritz, Robert D
    Orians, Colin M
    Does the differential seedling mortality caused by slugs alter the foliar traits and subsequent susceptibility of hybrid willows to a generalist herbivore?2007In: Ecological Entomology, Vol. 32, 211-220 p.Article in journal (Refereed)
    Abstract [en]

    Abstract. 1. Many Salicaceae species naturally form hybrid swarms with parental and hybrid taxa that differ in secondary chemical profile and in resistance to herbivores. Theoretically, the differential mortality in the seedling stage can lead to changes in trait expression and alter subsequent interactions between plants and herbivores. This study examines whether herbivory by the generalist slug Arion subfuscus, which causes extensive mortality in young willow seedlings, causes shifts in (a) the foliar chemistry of F2 willow hybrids (Salix sericea and Salix eriocephala), and (b) the subsequent susceptibility to Japanese Beetles, Popillia japonica.

    2. In 2001, two populations of F2 seedlings were generated: those that survived slug herbivory (80–90% of seedlings placed in the field were killed by the slugs) were designated as S-plants, whereas C-plants (controls) experienced no mortality.

    3. Common garden experiments with cuttings from these populations, in 2001 and 2002, revealed extensive variation in the phenolic chemistry of F2 hybrids, but revealed no significant difference between S- and C-plants, although the levels of foliar nutrients, proteins and nitrogen tended to be higher in S-plants.

    4. Concentrations of salicortin and 2'-cinnamoylsalicortin explained 55 and 38% of the the variation in leaf damage caused by Japanese beetles, and secondary chemistry was highly correlated within replicate clones (salicortin R2 = 0.85, 2-cinnamoylsalicortin R2 = 0.77, condensed tannins R2 = 0.68).

    5. Interestingly, Japanese beetle damage and condensed tannins were positively correlated within the S-plants, but not in the C-plants, suggesting that slugs had selected for plants with a positive relationship between tannins and P. japonica damage. This is unlikely to be a consequence of a preference for tannins, but is suggested to be related to the elevated nutrient levels in the S-plants, perhaps in combination with the complex-binding properties of tannins.

    6. The damage was highly correlated within replicate clones and a model choice analysis suggested that Japanese beetle damage may be explained by four factors: concentrations of salicortin, condensed tannins, and nitrogen, as well as the specific leaf area (thick leaves were damaged less).

  • 11.
    Albrectsen, Benedicte
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    From micro towards the macro scale2006In: New Phytologist, Vol. 172, 7-10 p.Article in journal (Refereed)
  • 12.
    Albrectsen, Benedicte R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Björkén, Lars
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Varad, Akkamahadevi
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hagner, Åsa
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Wedin, Mats
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Endophytic fungi in European aspen (Populus tremula) leaves - diversity, detection, and a suggested correlation with herbivory resistance2010In: Fungal diversity, ISSN 1560-2745, Vol. 41, no 1, 17-28 p.Article in journal (Refereed)
    Abstract [en]

    According to the geographic mosaic theory of coevolution (GMTC), clines of traits reflecting local co-adaptation (including resistance genes) should be common between a host and its parasite and should persist across time. To test the GMTC-assumption of persistent clinal patterns we compared the natural prevalence of two parasites on aspen Populus tremula trees: mining moths of the genus Phyllocnistis and leaf rust Melampsora spp. Damage data were collated from the Swedish National Forest Damage Inventory (2004–2006). In addition, occurrence of the parasites was scored in field conditions in two common gardens in the north and south of Sweden over five growing seasons (2004–2008), then related to biomass (stem height and diameter) and to concentrations of eleven leaf phenolics. Phyllocnistis mainly occurred in the northern garden, a distribution range which was confirmed by the countrywide inventory, although Phyllocnistis was more abundant on southern clones, providing evidence for possible local maladaptation. Melampsora occurred all over the country and in both gardens, but built up more quickly on northern clones, which suggests a centre of local clone maladaptation in the north. Stem growth also followed a clinal pattern as did the concentration of three phenolic compounds: benzoic acid, catechin and cinnamic acid. However, only benzoic acid was related to parasite presence: negatively to Phyllocnistis and positively to Melampsora and it could thus be a potential trait under selection.

    In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots.

  • 13.
    Albrectsen, Benedicte R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lundberg, Per
    Nutrient addition extends flowering display, which gets tracked by seed predators, but not by their parasitoids2008In: Oikos, Vol. 117, 473-480 p.Article in journal (Refereed)
    Abstract [en]

    Although phenological matching between two and three trophic interactions has received some attention, it has largely been disregarded in explaining the lack of strong cascade dynamics in terrestrial systems. We studied the response of the specialist seed predator, Paroxyna plantaginis (Tephritidae) and associated generalist parasitoids (Chalcidoidea) to controlled fertilisation of individuals of naturally growing Tripolium vulgare (Asteraceae) on four island populations (Skeppsvik Archipelago, Sweden). We consistently found evidence of nutrient limitation: fertilised plants increased their biomass, produced more capitula (the oviposition units for tephritid flies), were more at risk of attack by the tephritids, and puparia were heavier in fertilised plants. During some parts of the season tephritids became more heavily parasitized, supporting the presence of cascade dynamics, however net parasitism over season decreased in response to nutrient addition. We found no evidence that capitulum size complicated parasitoid access to the tephritids, however the extended bud production prolonged the flowering season. Thus, tephritids utilized the surplus production of capitula throughout the entire season, while parasitoids did not expand their oviposition time window accordingly. Implications for top down regulation and cascade dynamics in the system are discussed.

  • 14.
    Albrectsen, Benedicte R
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Witzell, Johanna
    Robinson, Kathryn M
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Wulff, Sören
    Luquez, Virginia MC
    Ågren, Rickard
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Large scale geographic clines of parasite damage to Populus tremula L2010In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 33, no 3, 483-493 p.Article in journal (Refereed)
    Abstract [en]

    In conclusion, clines of Phyllocnistis were stronger and more persistent compared to Melampsora, which showed contrasting clines of varying strength. Our data thus support the assumption of the GMTC model that clines exist in the border between hot and cold spots and that they may be less persistent for parasites with an elevated gene flow, and/or for parasites which cover relatively larger hot spots surrounded by fewer cold spots.

  • 15. Ali, Qasim
    et al.
    Haider, Muhammad Zulqurnain
    Iftikhar, Wasif
    Jamil, Sidra
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Department of Botany, Faculty of Science and Technology, Government College University, Faisalabad, Pakistan.
    Javed, M. Tariq
    Noman, Ali
    Iqbal, Muhammad
    Perveen, Rashida
    Drought tolerance potential of Vigna mungo L. lines as deciphered by modulated growth, antioxidant defense, and nutrient acquisition patterns2016In: Revista Brasileira de Botânica, ISSN 0100-8404, E-ISSN 1806-9959, Vol. 39, no 3, 801-812 p.Article in journal (Refereed)
    Abstract [en]

    Water shortage is one of the major environmental constraints that hamper the crop productivity worldwide. The present study was aimed to examine the drought tolerance potential of seven cultivars/lines of Vigna mungo L. depending upon their germination behavior, seedling growth, antioxidative defense mechanism, and nutrient acquisition. An experiment was conducted in the growth chamber using petri-plates and laid out in a completely randomized design (CRD). Hoagland's nutrient solution supplemented with 12 % PEG-8000 (drought treatment) or without PEG-800 (control) was used. Drought stress significantly altered the germination attributes as well as biomass production of all the studied cultivars/lines. Least adversative effects of drought stress were recorded in lines M-01001-1 and M-6036-21, respectively. The studied cultivars/lines exhibited differential response for various biochemical attributes under drought stress. The maximum increase in MDA and SOD activities and protein content was recorded in line M-603621, while the maximum AsA was recorded in line M-01001-1. Drought stress resulted in a significant reduction of plant N, P, K, Ca, and Mg contents, while the plant iron (Fe) contents remained unaffected. Results revealed that cultivars/lines M-01001-1 and M-6036-21 exhibited enhanced performance in terms of nutrient acquisition when stressed by drought. Based upon seed germination behavior, plant biomass production, biochemical attributes and mineral elements, the cultivars/lines M-01001-1 and M-6036-21 were identified as drought tolerant, while M-97 and Arroj-II were identified as drought sensitive.

  • 16. ANDERSSON, A
    et al.
    FALK, S
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    HAGSTROM, A
    NUTRITIONAL CHARACTERISTICS OF A MIXOTROPHIC NANOFLAGELLATE, OCHROMONAS SP1989In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 17, no 3, 251-262 p.Article in journal (Refereed)
  • 17. Andersson, A
    et al.
    Wallberg, P
    Nordback, J
    Bergqvist, P A
    Selstam, Eva
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Effect of nutrient enrichment on the distribution and sedimentation of polychlorinated biphenyls (PCBs) in seawater1998In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 377, 45-56 p.Article in journal (Refereed)
    Abstract [en]

    The effect of nutrient enrichment on the distribution of polychlorinated biphenyl's (PCBs) in the microbial food web and the residence time of PCBs in seawater was studied in an experimental mesocosm system. Two 5 m high temperature and light controlled mesocosm tubes (empty set = 0.5 m) were filled with seawater from the northern Baltic Sea. Inorganic phosphorus and nitrogen were added daily to one mesocosm, while the other served as a control. Experiments were conducted at 5, 10 and 20 degrees C. Three C-14-labelled PCBs of different degree of chlorination were added to subsamples of the mesocosms: 4-chlorobiphenyl (MCB), IUPAC # 3, 2,2',5,5'-tetrachlorobiphenyl (TCB), IUPAC # 52 and 2,2',4,4',5,5'-hexachlorobiphenyl (HCB) IUPAC # 153. The biomasses and growth rates of the microorganisms as well as the sedimentation rate of particulate organic material increased with nutrient enrichment. The size distribution of the microorganisms changed with nutrient status, from dominance of picoplankton (< 2 mu m) in the control towards increased importance of micro (> 10 mu m) and nanoplankton (2-10 mu m) in nutrient enrichment. The specific growth rate of the bacterial community was found to be more temperature dependent than that of the phytoplankton community. The relative proportion of PCBs in the > 2 mu m fraction was observed to be in the order MCB < TCB < HCB, while the opposite distribution prevailed in the < 2 mu m fraction. We hypothesize that this is due to the combined effect of the different K-ow values of the PCBs and a different composition of the particulate organic carbon in the > 2 mu m and < 2 mu m fractions (e.g. different lipid composition). The residence time of the PCBs in the mesocosm generally decreased with nutrient enrichment, but was dependent on the degree of chlorination of the PCB. Our results indicate that the transport of organic pollutants up through the food web is more important in nutrient poor than in nutrient rich waters and that the importance of sedimentation is higher in eutrophic ecosystems.

  • 18.
    Andersson, Agneta
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Marine Sciences Centre (UMF). Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Selstam, Eva
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hagström, Åke
    Vertical transport of lipid in seawater1993In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 98, no 1-2, 149-155 p.Article in journal (Refereed)
    Abstract [en]

    Lipids in seawater act as solvents and transporters of lipophilic organic pollutants. To investigate a possible transport route of lipophilic pollutants, the vertical flux of lipid was quantified during an annual cycle in the northern Baltic Sea. The lipid content in both sedimenting material and different size fractions of seawater was analyzed. During the year, 8 g lipid m-2 sedimented out from the photic zone to the benthic system. The sedimentation of lipid accounted for 300 to 400 % of the average standing stock of pelagic lipid and was concentrated in the spring bloom period (April-June) when 70 % of the total lipid sedimentation occurred. About 30 % of the produced pelagic lipid settled out from the system. In seawater the lipid maximum occurred at the end of the spring bloom, shortly after nutrient depletion, indicating a stress response in the algae. Since lipid sedimentation is concentrated in the spring bloom, removal of lipophilic organic pollutants may be important during this period.

  • 19. Andersson, Anders
    et al.
    Keskitalo, Johanna
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Sjödin, Andreas
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Bhalerao, Rupali
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Sterky, Fredrik
    Wissel, Kirsten
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tandre, Karolina
    Aspeborg, Henrik
    Moyle, Richard
    Ohmiya, Yasunori
    Bhalerao, Rishikesh
    Brunner, Amy
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Karlsson, Jan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Lundeberg, Joakim
    Nilsson, Ove
    Sandberg, Göran
    Strauss, Steven
    Sundberg, Björn
    Uhlen, Mathias
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Peter
    A transcriptional timetable of autumn senescence2004In: Genome Biology, ISSN 1465-6906, E-ISSN 1474-760X, Vol. 5, no 4, R24- p.Article in journal (Refereed)
    Abstract [en]

    Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.

  • 20.
    Andersson, Jenny
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Walters, Robin G
    Horton, Peter
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Antisense inhibition of the photosynthetic antenna proteins CP29 and CP26: implications for the mechanism of protective energy dissipation2001In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 13, no 5, 1193-1204 p.Article in journal (Refereed)
    Abstract [en]

    The specific roles of the chlorophyll a/b binding proteins CP29 and CP26 in light harvesting and energy dissipation within the photosynthetic apparatus have been investigated. Arabidopsis was transformed with antisense constructs against the genes encoding the CP29 or CP26 apoprotein, which gave rise to several transgenic lines with remarkably low amounts of the antisense target proteins. The decrease in the level of CP24 protein in the CP29 antisense lines indicates a physical interaction between these complexes. Analysis of chlorophyll fluorescence showed that removal of the proteins affected photosystem II function, probably as a result of changes in the organization of the light-harvesting antenna. However, whole plant measurements showed that overall photosynthetic rates were similar to those in the wild type. Both antisense lines were capable of the qE type of nonphotochemical fluorescence quenching, although there were minor changes in the capacity for quenching and in its induction kinetics. High-light-induced violaxanthin deepoxidation to zeaxanthin was not affected, although the pool size of these pigments was decreased slightly. We conclude that CP29 and CP26 are unlikely to be sites for nonphotochemical quenching.

  • 21.
    Andersson, Jenny
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Wentworth, Mark
    Walters, Robin G
    Howard, Caroline A
    Ruban, Alexander V
    Horton, Peter
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Absence of the Lhcb1 and Lhcb2 proteins of the light-harvesting complex of photosystem II - effects on photosynthesis, grana stacking and fitness2003In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 35, no 3, 350-361 p.Article in journal (Refereed)
    Abstract [en]

    We have constructed Arabidopsis thaliana plants that are virtually devoid of the major light-harvesting complex, LHC II. This was accomplished by introducing the Lhcb2.1 coding region in the antisense orientation into the genome by Agrobacterium-mediated transformation. Lhcb1 and Lhcb2 were absent, while Lhcb3, a protein present in LHC II associated with photosystem (PS) II, was retained. Plants had a pale green appearance and showed reduced chlorophyll content and an elevated chlorophyll a/b ratio. The content of PS II reaction centres was unchanged on a leaf area basis, but there was evidence for increases in the relative levels of other light harvesting proteins, notably CP26, associated with PS II, and Lhca4, associated with PS I. Electron microscopy showed the presence of grana. Photosynthetic rates at saturating irradiance were the same in wild-type and antisense plants, but there was a 10-15% reduction in quantum yield that reflected the decrease in light absorption by the leaf. The antisense plants were not able to perform state transitions, and their capacity for non-photochemical quenching was reduced. There was no difference in growth between wild-type and antisense plants under controlled climate conditions, but the antisense plants performed worse compared to the wild type in the field, with decreases in seed production of up to 70%.

  • 22. Andersson-Gunnerås, Sara
    et al.
    Mellerowicz, Ewa J
    Love, Jonathan
    Segerman, Bo
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ohmiya, Yasunori
    Coutinho, Pedro M
    Nilsson, Peter
    Henrissat, Bernard
    Moritz, Thomas
    Sundberg, Björn
    Biosynthesis of cellulose-enriched tension wood in Populus: global analysis of transcripts and metabolites identifies biochemical and developmental regulators in secondary wall biosynthesis2006In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 45, no 2, 144-165 p.Article in journal (Refereed)
    Abstract [en]

    Stems and branches of angiosperm trees form tension wood (TW) when exposed to a gravitational stimulus. One of the main characteristics of TW, which distinguishes it from normal wood, is the formation of fibers with a thick inner gelatinous cell wall layer mainly composed of crystalline cellulose. Hence TW is enriched in cellulose, and deficient in lignin and hemicelluloses. An expressed sequence tag library made from TW-forming tissues in Populus tremula (L.) x tremuloides (Michx.) and data from transcript profiling using microarray and metabolite analysis were obtained during TW formation in Populus tremula (L.) in two growing seasons. The data were examined with the aim of identifying the genes responsible for the change in carbon (C) flow into various cell wall components, and the mechanisms important for the formation of the gelatinous cell wall layer (G-layer). A specific effort was made to identify carbohydrate-active enzymes with a putative function in cell wall biosynthesis. An increased C flux to cellulose was suggested by a higher abundance of sucrose synthase transcripts. However, genes related to the cellulose biosynthetic machinery were not generally affected, although the expression of secondary wall-specific CesA genes was modified in both directions. Other pathways for which the data suggested increased activity included lipid and glucosamine biosynthesis and the pectin degradation machinery. In addition, transcripts encoding fasciclin-like arabinogalactan proteins were particularly increased and found to lack true Arabidopsis orthologs. Major pathways for which the transcriptome and metabolome analysis suggested decreased activity were the pathway for C flux through guanosine 5'-diphosphate (GDP) sugars to mannans, the pentose phosphate pathway, lignin biosynthesis, and biosynthesis of cell wall matrix carbohydrates. Several differentially expressed auxin- and ethylene-related genes and transcription factors were also identified.

  • 23. Andreazza, N
    et al.
    Abreu, Ilka Nacif
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sawaya, A
    Eberlin, M
    Mazzafera, P
    Production of imidazole alkaloids in cell cultures of jaborandi as affected by the medium pH2009In: Biotechnology letters, ISSN 0141-5492, E-ISSN 1573-6776, Vol. 31, no 4, 607-614 p.Article in journal (Refereed)
    Abstract [en]

    The effect of pH (from 4.8 to 9.8) on the production of pilosine and pilocarpine and on their partition between cell and medium was studied in two lineages (P and PP) of Pilocarpus microphyllus cell suspension cultures. Highest mass accumulation was observed at high pHs and both lineages produced pilocarpine while only lineage PP produced pilosine. Both alkaloids were released in the medium but higher accumulation occurred in the cells. The highest production of pilocarpine was at pH 8.8-9.8 in both cell lineages. Other imidazole alkaloids were also identified in both lineages. At all pHs tested, the pH in the media cultures tended to stabilize around 6 after 10-15 days of cultivation. NO(3) (-) and NH(4) (+) variation in the media might partially explain the pH stabilization.

  • 24.
    André, Domenique
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    The role of the Populus FT genes in the regulation of tree growth.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In annual plants, flowering related genes were initially thought to have the only function to coordinate and execute reproductive development. In perennial species like poplar, however, it became clear that these genes seem to have acquired additional functions in the regulation of the yearly growth cycle. The two poplar orthologs of the Arabidopsis “florigen” FLOWERING LOCUS T (FT), PtFT1 and PtFT2, are associated with flowering as well as other aspects of phenology. After duplication they have diverged in expression pattern, and maybe also in function and their gene regulatory networks. In this study I have characterized the role of PtFT1 and PtFT2 during the yearly growth cyle, as well as the interaction between, FT-like genes, poplar homologs of the Arabidopsis flowering time repressor TFL1 and PHYTOCHROME A in the regulation of tree flowering. The preliminary data show new unexpected functional relations between these genes and new previously undescribed effects on plant growth and development.

  • 25.
    Angelcheva, Liudmila
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mishra, Yogesh
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Antti, Henrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kjellsen, Trygve D.
    Department of Biology, Norwegian University of Science and Technology.
    Funk, Christiane
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Strimbeck, Richard G.
    Department of Biology, Norwegian University of Science and Technology.
    Schröder, Wolfgang P.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Metabolomic analysis of extreme freezing tolerance in Siberian spruce (Picea obovata)2014In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 204, no 3, 545-555 p.Article in journal (Refereed)
    Abstract [en]

    Siberian spruce (Picea obovata) is one of several boreal conifer species that can survive at extremely low temperatures (ELTs). When fully acclimated, its tissues can survive immersion in liquid nitrogen. Relatively little is known about the biochemical and biophysical strategies of ELT survival. We profiled needle metabolites using gas chromatography coupled with mass spectrometry (GC-MS) to explore the metabolic changes that occur during cold acclimation caused by natural temperature fluctuations. In total, 223 metabolites accumulated and 52 were depleted in fully acclimated needles compared with pre-acclimation needles. The metabolite profiles were found to develop in four distinct phases, which are referred to as pre-acclimation, early acclimation, late acclimation and fully acclimated. Metabolite changes associated with carbohydrate and lipid metabolism were observed, including changes associated with increased raffinose family oligosaccharide synthesis and accumulation, accumulation of sugar acids and sugar alcohols, desaturation of fatty acids, and accumulation of digalactosylglycerol. We also observed the accumulation of protein and nonprotein amino acids and polyamines that may act as compatible solutes or cryoprotectants. These results provide new insight into the mechanisms of freezing tolerance development at the metabolite level and highlight their importance in rapid acclimation to ELT in P.obovata.

  • 26. Ankele, Elisabeth
    et al.
    Kindgren, Peter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Pesquet, Edouard
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Strand, Åsa
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    In vivo visualization of Mg-ProtoporphyrinIX, a coordinator of photosynthetic gene expression in the nucleus and the chloroplast2007In: Plant Cell, ISSN 1040-4651, Vol. 19, no 6, 1964-1979 p.Article in journal (Refereed)
    Abstract [en]

    The photosynthetic apparatus is composed of proteins encoded by genes from both the nucleus and the chloroplast. To ensure that the photosynthetic complexes are assembled stoichiometrically and to enable their rapid reorganization in response to a changing environment, the plastids emit signals that regulate nuclear gene expression to match the status of the plastids. One of the plastid signals, the chlorophyll intermediate Mg-ProtoporphyrinIX (Mg-ProtoIX) accumulates under stress conditions and acts as a negative regulator of photosynthetic gene expression. By taking advantage of the photoreactive property of tetrapyrroles, Mg-ProtoIX could be visualized in the cells using confocal laser scanning spectroscopy. Our results demonstrate that Mg-ProtoIX accumulated both in the chloroplast and in the cytosol during stress conditions. Thus, the signaling metabolite is exported from the chloroplast, transmitting the plastid signal to the cytosol. Our results from the Mg-ProtoIX over- and underaccumulating mutants copper response defect and genome uncoupled5, respectively, demonstrate that the expression of both nuclear- and plastid-encoded photosynthesis genes is regulated by the accumulation of Mg-ProtoIX. Thus, stress-induced accumulation of the signaling metabolite Mg-ProtoIX coordinates nuclear and plastidic photosynthetic gene expression.

  • 27.
    Ashelford, Kevin
    et al.
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Eriksson, Maria E
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Allen, Christopher M
    Applied Biosystems, part of Life Technologies, Warrington, UK.
    D’Amore, Linda
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Johansson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gould, Peter
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Kay, Susanne
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Millar, Andrew J.
    Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
    Hall, Neil
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Hall, Anthony
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Full genome re-sequencing reveals a novel circadian clock mutationin Arabidopsis2011In: Genome Biology, ISSN 1465-6906, E-ISSN 1465-6914, Vol. 12, R28- p.Article in journal (Refereed)
    Abstract [en]

    Background: Map based cloning in Arabidopsis thaliana can be a difficult and time-consuming process,specifically if the phenotype is subtle and scoring labour intensive. An alternative to map basedcloning would be to directly sequence the whole genome of a mutant to uncover the mutationresponsible for the phenotype.

    Results: Here, we have re-sequenced the 120 Mb genome of a novel Arabidopsis clock mutant earlybird (ebi-1), using massively parallel sequencing by ligation. This process was further complicated by the fact that ebi-1 is in Wassilewskija (Ws-2), not the reference accession ofArabidopsis. The approach reveals evidence of DNA strand bias in the ethyl methanesulfonate(EMS) mutation process. We have demonstrated the utility of sequencing a backcrossed line andusing gene expression data to limit the number of SNP considered. Using new SNP informationwe have excluded a previously identified clock gene, PRR7. Finally, we have identified a SNPin the gene AtNFXL-2 as the likely cause of the ebi-1 phenotype and validated this bycharacterising a further allele.

    Conclusion: In Arabidopsis, as in other organisms, the (EMS) mutation load can be high. Here wedescribe how sequencing a backcrossed line, using functional genomics and analysing new SNPinformation can be used to reduce the number EMS mutations for consideration. Moreover, theapproach we describe here does not require out-crossing and scoring F2 mapping populations, anapproach which can be compromised by background effects. The strategy has broad utility andwill be an extremely useful tool to identify causative SNP in other organisms.

  • 28. Atkin, Owen K
    et al.
    Atkinson, Lindsey J
    Fischer, Rosie A
    Campbell, Catherine
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Zaragoza-Castells, Joana
    Pitchford, Jon W
    Woodward, F Ian
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Using temperature-dependent changes in leaf scaling relationships to quantitatively account forthermal acclimation of respiration in a coupled global climate-vegetation model2008In: Global Change Biology, Vol. 14, 2709-2726 p.Article in journal (Refereed)
    Abstract [sv]

    The response of plant respiration (R) to temperature is an important component of the biosphere's response to climate change. At present, most global models assume that R increases exponentially with temperature and does not thermally acclimate. Although we now know that acclimation does occur, quantitative incorporation of acclimation into models has been lacking. Using a dataset for 19 species grown at four temperatures (7, 14, 21, and 28 °C), we have assessed whether sustained differences in growth temperature systematically alter the slope and/or intercepts of the generalized log–log plots of leaf R vs. leaf mass per unit leaf area (LMA) and vs. leaf nitrogen (N) concentration. The extent to which variations in growth temperature account for the scatter observed in log–log R–LMA–N scaling relationships was also assessed. We show that thermal history accounts for up to 20% of the scatter in scaling relationships used to predict R, with the impact of thermal history on R–LMA–N generalized scaling relationships being highly predictable. This finding enabled us to quantitatively incorporate acclimation of R into a coupled global climate–vegetation model. We show that accounting for acclimation of R has negligible impact on predicted annual rates of global R, net primary productivity (NPP) or future atmospheric CO2 concentrations. However, our analysis suggests that accounting for acclimation is important when considering carbon fluxes among thermally contrasting biomes (e.g. accounting for acclimation decreases predicted rates of R by up to 20% in high-temperature biomes). We conclude that acclimation of R needs to be accounted for when predicting potential responses of terrestrial carbon exchange to climatic change at a regional level.

  • 29. Atkin, Owen K
    et al.
    Bruhn, Dan
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Tjoelker, Mark G
    Evans Review No. 2: The hot and the cold: unravelling the variable response of plant respiration to temperature2005In: Functional Plant Biology, Vol. 32, 87-105 p.Article in journal (Refereed)
    Abstract [en]

    When predicting the effects of climate change, global carbon circulation models that include a positive feedback effect of climate warming on the carbon cycle often assume that (1) plant respiration increases exponentially with temperature (with a constant Q10) and (2) that there is no acclimation of respiration to long-term changes in temperature. In this review, we show that these two assumptions are incorrect. While Q10 does not respond systematically to elevated atmospheric CO2 concentrations, other factors such as temperature, light, and water availability all have the potential to influence the temperature sensitivity of respiratory CO2 efflux. Roots and leaves can also differ in their Q10 values, as can upper and lower canopy leaves. The consequences of such variable Q10 values need to be fully explored in carbon modelling. Here, we consider the extent of variability in the degree of thermal acclimation of respiration, and discuss in detail the biochemical mechanisms underpinning this variability; the response of respiration to long-term changes in temperature is highly dependent on the effect of temperature on plant development, and on interactive effects of temperature and other abiotic factors (e.g. irradiance, drought and nutrient availability). Rather than acclimating to the daily mean temperature, recent studies suggest that other components of the daily temperature regime can be important (e.g. daily minimum and / or night temperature). In some cases, acclimation may simply reflect a passive response to changes in respiratory substrate availability, whereas in others acclimation may be critical in helping plants grow and survive at contrasting temperatures. We also consider the impact of acclimation on the balance between respiration and photosynthesis; although environmental factors such as water availability can alter the balance between these two processes, the available data suggests that temperature-mediated differences in dark leaf respiration are closely linked to concomitant differences in leaf photosynthesis. We conclude by highlighting the need for a greater process-based understanding of thermal acclimation of respiration if we are to successfully predict future ecosystem CO2 fluxes and potential feedbacks on atmospheric CO2 concentrations.

  • 30.
    Atkin, Owen K
    et al.
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Sherlock, David
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Fitter, Alastair H
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Jarvis, Susan
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Hughes, John K
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Campbell, Catherine
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hodge, Angela
    Department of Biology, The University of York, PO Box 373, York YO10 5YW, UK.
    Temperature dependence of respiration in roots colonized by arbuscular mycorrhizal fungi2009In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 182, no 1, 188-199 p.Article in journal (Refereed)
    Abstract [en]

    * The arbuscular mycorrhizal (AM) symbiosis is ubiquitous, and the fungus represents a major pathway for carbon movement in the soil-plant system. Here, we investigated the impacts of AM colonization of Plantago lanceolata and temperature on the regulation of root respiration (R). * Warm-grown AM plants exhibited higher rates of R than did nonAM plants, irrespective of root mass. AM plants exhibited higher maximal rates of R (R(max)-R measured in the presence of an uncoupler and exogenous substrate) and greater proportional use of R(max) as a result of increased energy demand and/or substrate supply. The higher R values exhibited by AM plants were not associated with higher maximal rates of cytochrome c oxidase (COX) or protein abundance of either the COX or the alternative oxidase. * Arbuscular mycorrhizal colonization had no effect on the short-term temperature dependence (Q(10)) of R. Cold-acclimated nonAM plants exhibited higher rates of R than their warm-grown nonAM counterparts. By contrast, chilling had a negligible effect on R of AM-plants. Thus, AM plants exhibited less cold acclimation than their nonAM counterparts. * Overall, these results highlight the way in which AM colonization alters the underlying components of respiratory metabolism and the response of root R to sustained changes in growth temperature.

  • 31.
    Augusti, Angela
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Betson, Tatiana R.
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schleucher, Jurgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Deriving correlated climate and physiological signals from deuterium isotopomers in tree rings2008In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 252, no 1-2, 1-8 p.Article in journal (Refereed)
    Abstract [en]

    he deuterium (D) abundance of tree-ring cellulose archives past climatic conditions, but previous attempts to access this archive have led to conflicting results. Based on an overview of D fractionation mechanisms in plants, we explain why past measurements of D abundance yield unreliable paleo signals. Our data show that variation in D abundance among the C–H groups (isotopomer variation) of tree-ring cellulose is generally greater than variation in D abundance due to climatic influences. A comparison of the D isotopomer abundances of soluble sugars of annual plants and of trees, and of tree-ring cellulose shows that an “isotopomer pattern” of the C3 photosynthetic pathway is transmitted from soluble sugars to tree-ring cellulose. Differences in this pattern between oaks and conifers appear to be related to differences in metabolism. Furthermore, the patterns are modified by hydrogen isotope exchange between C–H groups and source water during cellulose synthesis. Based on these results, we propose a strategy to simultaneously reconstruct climate signals and signals related to tree physiology from D isotopomers of tree rings. Combination of climate signals and physiological signals may allow the detection of century-time-scale adaptations of trees to past environmental change, and help to forecast future adaptations.

  • 32.
    Augusti, Angela
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Betson, Tatiana R
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Schleucher, Jürgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Hydrogen exchange during cellulose synthesis distinguishes climatic and biochemical isotope fractionations in tree rings.2006In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 172, no 3, 490-499 p.Article in journal (Refereed)
    Abstract [en]

    • The abundance of the hydrogen isotope deuterium (D) in tree rings is an attractive record of climate; however, use of this record has proved difficult so far, presumably because climatic and physiological influences on D abundance are difficult to distinguish.

    • Using D labelling, we created a D gradient in trees. Leaf soluble sugars of relatively low D abundance entered cellulose synthesis in stems containing strongly D-labelled water. We used nuclear magnetic resonance (NMR) spectroscopy to quantify D in the C-H groups of leaf glucose and of tree-ring cellulose.

    • Ratios of D abundances of individual C-H groups of leaf glucose depended only weakly on leaf D labelling, indicating that the D abundance pattern was determined by physiological influences. The D abundance pattern of tree-ring cellulose revealed C-H groups that exchanged strongly (C(2)-H) or weakly (C(6)-H2) with water during cellulose synthesis.

    • We propose that strongly exchanging C-H groups of tree-ring cellulose adopt a climate signal stemming from the D abundance of source water. C-H groups that exchange weakly retain their D abundance established in leaf glucose, which reflects physiological influences. Combining both types of groups may allow simultaneous reconstruction of climate and physiology from tree rings.

  • 33. Ausin, Israel
    et al.
    Feng, Suhua
    Yu, Chaowei
    Liu, Wanlu
    Kuo, Hsuan Yu
    Jacobsen, Elise L.
    Zhai, Jixian
    Gallego-Bartolome, Javier
    Wang, Lin
    Egertsdotter, Ulrika
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Jacobsen, Steven E.
    Wang, Haifeng
    DNA methylome of the 20-gigabase Norway spruce genome2016In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, no 50, E8106-E8113 p.Article in journal (Refereed)
    Abstract [en]

    DNA methylation plays important roles in many biological processes, such as silencing of transposable elements, imprinting, and regulating gene expression. Many studies of DNA methylation have shown its essential roles in angiosperms (flowering plants). However, few studies have examined the roles and patterns of DNA methylation in gymnosperms. Here, we present genome-wide high coverage single-base resolution methylation maps of Norway spruce (Picea abies) from both needles and somatic embryogenesis culture cells via whole genome bisulfite sequencing. On average, DNA methylation levels of CG and CHG of Norway spruce were higher than most other plants studied. CHH methylation was found at a relatively low level; however, at least one copy of most of the RNA-directed DNA methylation pathway genes was found in Norway spruce, and CHH methylation was correlated with levels of siRNAs. In comparison with needles, somatic embryogenesis culture cells that are used for clonally propagating spruce trees showed lower levels of CG and CHG methylation but higher level of CHH methylation, suggesting that like in other species, these culture cells show abnormal methylation patterns.

  • 34. Baba, Kyoko
    et al.
    Karlberg, Anna
    Schmidt, Julien
    Schrader, Jarmo
    Hvidsten, Torgeir
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bako, Laszlo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bhalerao, Rishikesh P
    Activity-dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen.2011In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, no 8, 3418-23 p.Article in journal (Refereed)
    Abstract [en]

    The molecular basis of short-day-induced growth cessation and dormancy in the meristems of perennial plants (e.g., forest trees growing in temperate and high-latitude regions) is poorly understood. Using global transcript profiling, we show distinct stage-specific alterations in auxin responsiveness of the transcriptome in the stem tissues during short-day-induced growth cessation and both the transition to and establishment of dormancy in the cambial meristem of hybrid aspen trees. This stage-specific modulation of auxin signaling appears to be controlled via distinct mechanisms. Whereas the induction of growth cessation in the cambium could involve induction of repressor auxin response factors (ARFs) and down-regulation of activator ARFs, dormancy is associated with perturbation of the activity of the SKP-Cullin-F-box(TIR) (SCF(TIR)) complex, leading to potential stabilization of repressor auxin (AUX)/indole-3-acetic acid (IAA) proteins. Although the role of hormones, such as abscisic acid (ABA) and gibberellic acid (GA), in growth cessation and dormancy is well established, our data now implicate auxin in this process. Importantly, in contrast to most developmental processes in which regulation by auxin involves changes in cellular auxin contents, day-length-regulated induction of cambial growth cessation and dormancy involves changes in auxin responses rather than auxin content.

  • 35. Baba, Kyoko
    et al.
    Schmidt, Julien
    Espinosa-Ruiz, Ana
    Villarejo, Arsenio
    Shiina, Takashi
    Gardeström, Per
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sane, Aniruddha P
    Bhalerao, Rishikesh P
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Organellar gene transcription and early seedling development are affected in the rpoT;2 mutant of Arabidopsis.2004In: Plant J, ISSN 0960-7412, Vol. 38, no 1, 38-48 p.Article in journal (Refereed)
    Abstract [en]

    An Arabidopsis mutant that exhibited reduced root length was isolated from a population of activation-tagged T-DNA insertion lines in a screen for aberrant root growth. This mutant also exhibited reduced hypocotyl length as well as a delay in greening and altered leaf shape. Molecular genetic analysis of the mutant indicated a single T-DNA insertion in the gene RpoT;2 encoding a homolog of the phage-type RNA polymerase (RNAP), that is targeted to both mitochondria and plastids. A second T-DNA-tagged allele also showed a similar phenotype. The mutation in RpoT;2 affected the light-induced accumulation of several plastid mRNAs and proteins and resulted in a lower photosynthetic efficiency. In contrast to the alterations in the plastid gene expression, no major effect of the rpoT;2 mutation on the accumulation of examined mitochondrial gene transcripts and proteins was observed. The rpoT;2 mutant exhibited tissue-specific alterations in the transcript levels of two other organelle-directed nuclear-encoded RNAPs, RpoT;1 and RpoT;3. This suggests the existence of cross-talk between the regulatory pathways of the three RNAPs through organelle to nucleus communication. These data provide an important information on a role of RpoT;2 in plastid gene expression and early plant development.

  • 36.
    Babst, Benjamin A
    et al.
    Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA 30602, USA.
    Sjödin, Andreas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Orians, Colin M
    Department of Biology, Tufts University, Medford, MA 02155, USA.
    Local and systemic transcriptome responses to herbivory and jasmonic acid in Populus2009In: The Genetics & Genomes, Vol. 5, no 3, 459-474 p.Article in journal (Refereed)
    Abstract [en]

    We used DNA microarrays to examine local and systemic transcriptional responses to herbivory by gypsy moth larvae (GM) and exogenous jasmonic acid (JAtrt) in leaves of Populus nigra L. to identify candidate signaling and defense genes and also to examine primary metabolism, as might relate to tolerance of damage. GM and JAtrt altered expression of over 800 genes, most of which have putative roles in defense signaling, secondary metabolism, and primary metabolism. Additionally, numerous uncharacterized genes responded to herbivory, providing a rich resource for future studies. There was limited overlap (14%) between the responses to GM and JAtrt. GM did, however, result in strong upregulation of genes involved not only in JA biosynthesis but also abscisic acid biosynthesis and other signaling pathways. GM induced known resistance transcripts, including polyphenolic biosynthetic genes, proteinase inhibitors, and amino acid deaminases. According to GOStats pathway level analysis, GM altered primary metabolism, including aromatic amino acid biosynthesis, fatty acid β-oxidation, and carbohydrate and organic acid metabolism. These alterations may be related to increased demands for substrate for secondary metabolites or may serve a tolerance-related role. Responses were more intense locally in treated leaves than in untreated (systemic) leaves and systemic responses were mostly a subset of the genes induced locally. A stronger local response might be needed to cope with localized stresses and wound healing. Since Populus in general and this clone in particular are known for their systemic induced resistance, genes induced both locally and systemically may be the highest quality candidates for resistance.

  • 37. BADER, P
    et al.
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    JONSSON, BG
    WOOD-INHABITING FUNGI AND SUBSTRATUM DECLINE IN SELECTIVELY LOGGED BOREAL SPRUCE FORESTS1995In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 72, no 3, 355-362 p.Article in journal (Refereed)
    Abstract [en]

    Eleven Norway spruce Picea abies (L.) Karst. forests in the boreal zone of Sweden were studied to investigate the effects of selective cuttings on wood-inhabiting fungi from the families Polyporaceae, Hymenochaetaceae and Corticiaceae (Basidiomycota). The II sites constitute a gradient from extensively logged to semi-natural forests. Old selective leggings that occurred about 100 years ago have significantly decreased the availability of large and highly decayed logs. Based on fruit bodies, both the total species number as well as the number of threatened species decreased with increasing degree of cutting. Some of the occurring wood-inhabiting fungi are commonly accepted as indicator species of forests with old-growth conditions. These species showed pronounced preferences for well decayed and large logs. They were also more frequent in the less affected sites and became rarer with increasing degree of cutting; they therefore seem to be good indicators of forests less affected by logging.

  • 38. Bailey, S
    et al.
    Walters, R G
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Horton, P
    Acclimation of Arabidopsis thaliana to the light environment: the existence of separate low light and high light responses2001In: Planta, ISSN 0032-0935, E-ISSN 1432-2048, Vol. 213, no 5, 794-801 p.Article in journal (Refereed)
    Abstract [en]

    The capacity for photosynthetic acclimation in Arabidopsis thaliana (L.) Heynh. cv. Landsberg erecta was assessed during growth over a broad range of irradiance. Discontinuities in the response to growth irradiance were revealed for the light- and CO2-saturated rate of photosynthesis (P-max) and the ratio of chlorophyll a to chlorophyll b (Chl a/b). Three separate phases in the response of P-max and Chl a/b to growth light were evident, with increases at low and high irradiance ranges and a plateau at intermediate irradiance. By measuring all chlorophyll-containing components of the thylakoid membrane that contribute to Chl alb we reveal that distinct strategies for growth at low and high irradiance underlie the discontinuous response. These strategies include, in addition to changes in the major light-harvesting complexes of photosystem II (LHCII) , large shifts in the amounts of both reaction centres as well as significant changes in the levels of minor LHCII and LHCI components.

  • 39.
    Bajhaiya, Amit K.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Univ Manchester, Fac Life Sci, Manchester, Lancs, England.
    Dean, Andrew P.
    Zeef, Leo A. H.
    Webster, Rachel E.
    Pittman, Jon K.
    PSR1 Is a Global Transcriptional Regulator of Phosphorus Deficiency Responses and Carbon Storage Metabolism in Chlamydomonas reinhardtii2016In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 170, no 3, 1216-1234 p.Article in journal (Refereed)
    Abstract [en]

    Many eukaryotic microalgae modify their metabolism in response to nutrient stresses such as phosphorus (P) starvation, which substantially induces storage metabolite biosynthesis, but the genetic mechanisms regulating this response are poorly understood. Here, we show that P starvation-induced lipid and starch accumulation is inhibited in a Chlamydomonas reinhardtii mutant lacking the transcription factor Pi Starvation Response1 (PSR1). Transcriptomic analysis identified specific metabolism transcripts that are induced by P starvation but misregulated in the psr1 mutant. These include transcripts for starch and triacylglycerol synthesis but also transcripts for photosynthesis-, redox-, and stress signaling-related proteins. To further examine the role of PSR1 in regulating lipid and starch metabolism, PSR1 complementation lines in the psr1 strain and PSR1 overexpression lines in a cell wall-deficient strain were generated. PSR1 expression in the psr1 lines was shown to be functional due to rescue of the psr1 phenotype. PSR1 overexpression lines exhibited increased starch content and number of starch granules per cell, which correlated with a higher expression of specific starch metabolism genes but reduced neutral lipid content. Furthermore, this phenotype was consistent in the presence and absence of acetate. Together, these results identify a key transcriptional regulator in global metabolism and demonstrate transcriptional engineering in microalgae to modulate starch biosynthesis.

  • 40.
    Bajhaiya, Amit K.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Univ Manchester, Fac Life Sci, Michael Smith Bldg,Oxford Rd, Manchester M13 9PT, Lancs, England.
    Moreira, Javiera Ziehe
    Pittman, Jon K.
    Transcriptional Engineering of Microalgae: Prospects for High-Value Chemicals2017In: Trends in Biotechnology, ISSN 0167-7799, E-ISSN 1879-3096, Vol. 35, no 2, 95-99 p.Article in journal (Refereed)
    Abstract [en]

    Microalgae are diverse microorganisms that are of interest as novel sources of metabolites for various industrial, nutritional, and pharmaceutical applications. Recent studies have demonstrated transcriptional engineering of some metabolic pathways. We propose here that transcriptional engineering could be a viable means to manipulate the biosynthesis of specific high-value metabolic products.

  • 41.
    Bandau, Franziska
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Importance of tannins for responses of aspen to anthropogenic nitrogen enrichment2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Boreal forests are often strongly nitrogen (N) limited. However, human activities are leading to increased N inputs into these ecosystems, through atmospheric N deposition and forest fertilization. N input into boreal forests can promote net primary productivity, increase herbivore and pathogen damage, and shift plant species composition and community structure. Genetic diversity has been suggested as a key mechanism to promote a plant species’ stability within communities in response to environmental change. Within any plant population, specific traits (e.g. growth and defense traits) can vary substantially among individuals, and a greater variation in traits may increase chances for the persistence of at least some individuals of a population, when environmental conditions change. One aspect of plant chemistry that can greatly vary among different genotypes (GTs) are condensed tannin (CTs). These secondary metabolites have been suggested to affect plant performance in many ways, e.g. through influencing plant growth, the interactions of plants with herbivores and pathogens, and through affecting litter decomposition, and hence the return of nutrients to plants. To investigate how genotypic variation in foliar CT production may mediate the effects that anthropogenic N enrichment can have on plant performance and litter decomposition, I performed a series of experiments. For these experiments, aspen (Populus tremula) GTs with contrasting abilities to produce foliar CTs (i.e. low- vs. high-tannin producers) were grown under 3 N conditions, representing ambient N (+0 kg ha-1), upper level atmospheric N deposition (+15 kg ha-1), and forest fertilization rates (+150 kg ha-1). This general experimental set-up was once established in a field-like environment, from which natural enemies were excluded, and once in a field, in which enemies were present. In my first two studies, I investigated tissue chemistry and plant performance in both environments. I observed that foliar CT levels decreased in response to N in the enemy‑free environment (study I), but increased with added N when enemies were present (study II). These opposing responses to N may be explained by differences in soil N availability in the two environments, or by induction of CTs after enemy attack. Enemy damage generally increased in response to N, and was higher in low-tannin than in high-tannin plants across all N levels. Plant growth of high‑tannin plants was restricted under ambient and low N conditions, probably due to a trade-off between growth and defense. This growth constraint for high‑tannin plants was weakened, when high amounts of N were added (study I and II), and when enemy levels were sufficiently high, so that benefits gained through defense could outweigh the costs of defense production (study II). Despite those general responses of low- and high‑tannin producers to added N, I also observed a number of individual responses of GTs to N addition, which in some case were not connected to the intrinsic ability of the GTs to produce foliar CTs. In study III, gene expression levels in young leaves and phenolic pools of the plants that were grown in the enemy‑free environment were studied. This study revealed that gene control over the regulation of the phenylpropanoid pathway (PPP) was distributed across the entire pathway. Moreover, PPP gene expression was higher in high-tannin GTs than in low‑tannin GTs, particularly under ambient N. At the low N level, gene expressions declined for both low- and high-tannin producers, whereas at the high N level expression at the beginning and the end of the PPP was upregulated and difference between tannin groups disappeared. Furthermore, this study showed that phenolic pools were frequently uncorrelated, and that phenolic pools were only to some extent related to tannin production and gene expression. In study IV, I investigated the decomposability of litter from the field plants. I found that N enrichment generally decreased mass loss, but there was substantial genetic variation in decomposition rates, and GTs were differentially responsive to added N. Study IV further showed that CTs only had a weak effect on decomposition, and other traits, such as specific leaf area and the lignin:N ratio, could better explain genotypic difference in mass loss. Furthermore, N addition caused a shift in which traits most strongly influenced decomposition rates. Collectively, the result of these studies highlight the importance of genetic diversity to promote the stability of species in environments that experience anthropogenic change.

  • 42.
    Bandau, Franziska
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Decker, Vicki Huizu Guo
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Gundale, Michael J.
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE 90183 Umeå, Sweden.
    Albrectsen, Benedicte Riber
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK 1871 Frederiksberg C, Denmark.
    Genotypic tannin levels in Populus tremula impact the way nitrogen enrichment affects growth and allocation responses for some traits and not for others2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, e0140971Article in journal (Refereed)
    Abstract [en]

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root: shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a higher plasticity to nitrogen addition, and potentially an advantage when adapting to higher concentrations of soil nitrogen.

  • 43.
    Barajas-Lopez, Juan de Dios
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Kremnev, Dmitry
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Shaikhali, Jehad
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Pinas-Fernandez, Aurora
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Strand, Åsa
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    PAPP5 is involved in the tetrapyrrole mediated plastid signalling during chloroplast development2013In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 3, e60305Article in journal (Refereed)
    Abstract [en]

    The initiation of chloroplast development in the light is dependent on nuclear encoded components. The nuclear genes encoding key components in the photosynthetic machinery are regulated by signals originating in the plastids. These plastid signals play an essential role in the regulation of photosynthesis associated nuclear genes (PhANGs) when proplastids develop into chloroplasts. One of the plastid signals is linked to the tetrapyrrole biosynthesis and accumulation of the intermediates the Mg-ProtoIX and its methyl ester Mg-ProtoIX-ME. Phytochrome-Associated Protein Phosphatase 5 (PAPP5) was isolated in a previous study as a putative Mg-ProtoIX interacting protein. In order to elucidate if there is a biological link between PAPP5 and the tetrapyrrole mediated signal we generated double mutants between the Arabidopsis papp5 and the crd mutants. The crd mutant over-accumulates Mg-ProtoIX and Mg-ProtoIX-ME and the tetrapyrrole accumulation triggers retrograde signalling. The crd mutant exhibits repression of PhANG expression, altered chloroplast morphology and a pale phenotype. However, in the papp5crd double mutant, the crd phenotype is restored and papp5crd accumulated wild type levels of chlorophyll, developed proper chloroplasts and showed normal induction of PhANG expression in response to light. Tetrapyrrole feeding experiments showed that PAPP5 is required to respond correctly to accumulation of tetrapyrroles in the cell and that PAPP5 is most likely a component in the plastid signalling pathway down stream of the tetrapyrrole Mg-ProtoIX/Mg-ProtoIX-ME. Inhibition of phosphatase activity phenocopied the papp5crd phenotype in the crd single mutant demonstrating that PAPP5 phosphatase activity is essential to mediate the retrograde signal and to suppress PhANG expression in the crd mutant. Thus, our results suggest that PAPP5 receives an inbalance in the tetrapyrrole biosynthesis through the accumulation of Mg-ProtoIX and acts as a negative regulator of PhANG expression during chloroplast biogenesis and development.

  • 44. Barker-Åström, Kara
    et al.
    Schelin, Jenny
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Clarke, Adrian K
    Campbell, Douglas A
    Chlorosis during nitrogen starvation is altered by carbon dioxide and temperature status and is mediated by the ClpP1 protease in Synechococcus elongatus.2005In: Archives of Microbiology, ISSN 0302-8933, Vol. 183, no 1, 66-9 p.Article in journal (Refereed)
    Abstract [en]

    The interactive effects of inorganic carbon status, temperature and light on chlorosis induced by nitrogen deficiency, and the roles of Clp proteases in this process were investigated. In wild-type cultures grown in high or ambient CO2, following transfer to media lacking combined nitrogen, phycocyanin per cell dropped primarily through dilution of the pigment through cell division, and also suffered variable degrees of net degradation. When grown at high CO2 (5%), chlorophyll (Chl) suffered net degradation to a greater extent than phycocyanin. In marked contrast, growth at ambient CO2 resulted in Chl per cell dropping through dilution. Conditions that drove net Chl degradation in the wild-type resulted in little or no net Chl degradation in a clpPI inactivation mutant, with Chl content dropping largely through growth dilution in the mutant. The chlorotic response of a clpPII inactivation strain was nearly the same as that of wild-type, although phycocyanin degradation may have been slightly accelerated in the former.

  • 45.
    Barros, Jaime
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Serk, Henrik
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Granlund, Irene
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Pesquet, Edouard
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    The cell biology of lignification in higher plants2015In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 115, no 7, 1053-1074 p.Article, review/survey (Refereed)
    Abstract [en]

    Background Lignin is a polyphenolic polymer that strengthens and waterproofs the cell wall of specialized plant cell types. Lignification is part of the normal differentiation programme and functioning of specific cell types, but can also be triggered as a response to various biotic and abiotic stresses in cells that would not otherwise be lignifying.

    Scope Cell wall lignification exhibits specific characteristics depending on the cell type being considered. These characteristics include the timing of lignification during cell differentiation, the palette of associated enzymes and substrates, the sub-cellular deposition sites, the monomeric composition and the cellular autonomy for lignin monomer production. This review provides an overview of the current understanding of lignin biosynthesis and polymerization at the cell biology level.

    Conclusions The lignification process ranges from full autonomy to complete co-operation depending on the cell type. The different roles of lignin for the function of each specific plant cell type are clearly illustrated by the multiple phenotypic defects exhibited by knock-out mutants in lignin synthesis, which may explain why no general mechanism for lignification has yet been defined. The range of phenotypic effects observed include altered xylem sap transport, loss of mechanical support, reduced seed protection and dispersion, and/or increased pest and disease susceptibility.

  • 46.
    Bashar Shafiul, Shamrat
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Characterization of cell wall in transgenic aspen with modified xylan acetylation2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    ABSTRACT

    Mature plant cells are enclosed by inflexible wall made up of cellulose microfibrils, pectins, hemicelluloses and in some cases lignin. This cell wall provides the structure and the defense for plant cells. In secondary cell walls of dicotyledons, major hemicellulose is xylan consisting of β-(1, 4)-linked xylose units. Xylan is synthesized in Golgi apparatus by several enzymes activities. REDUCED WALL ACETYLATION (RWA) genes are involved in xylan acetylation. These genes were downregulated in hybrid aspen in order to reduce xylan acetylation activity during its biosynthesis. In addition, acetyl xylan esterase (FC2) from the fungus Aspergillus niger was expressed in hybrid aspen to modify xylan acetylation post-synthetically. In this work, I have studied effects of these modifications on wood cell wall composition.

    The cell wall components were sequentially extracted by using the small scale method and the weight of extractives, lignin, hemicelluloses and celluloses per weight of dry wood were determined. In addition, the Updegraff cellulose, Klason lignin contents per weight of extractive free wood were determined and monosugar compositions of non-cellulosic components were analyzed by methanolysis and Trimethylsilyl derivatisation (TMS). 

    I have found that content of cellulose determined by sequential extraction method was significantly increased in all constructs as compared to the wild type. Reduction of lignin (as determined by sequential extraction) was found in DFC2 construct and RWA RNAi 35S-AB and CD constructs. Furthermore, RWA RNAi 35S-CD and RWA RNAi WP-ABCD constructs showed decreased hemicellulose as compared to the wild type. Moreover, DFC2 constructs exhibited decrease in non-cellulosic sugars hydrolyzed during TMS. FC2 expressing lines showed a reduction in xylose which is the main building block of xylan. In contrast, glucose and galactose contents were increased. Inhibition of expression of all RWA genes (WP-ABCD) caused similar changes.

    Considering all the data I conclude that, reduced acetylation of xylan can affect extractability, biosynthesis or modification of polysaccharides and lignin in cell wall.

    Keywords: Cellulose microfibrils; pectins; hemicellulose; lignin, xylan; secondary wall; aspen; xylan biosynthesis; biosynthesis of polysaccharides. 

  • 47.
    Bañares de Dios, Guillermo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Elucidating the role of CSK during early light response and chloroplast development2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Elucidating the role of CSK during early light response and chloroplast development

    Chloroplasts of higher plants have evolved from endosymbiotic, ancestor of modern prokaryotic cyanobacteria. During evolution most of the genes from the genome of the endosymbiont have moved to the nucleus of it host. As a consequence the components of the photosynthetic machinery are encoded both in the chloroplastic and in the nuclear genomes. Therefore, expression of both genomes must be tightly coordinated to ensure a simultaneous and stoichiometric biosynthesis of the chloroplast components at different developmental stages and under environmental or metabolic changes. This is achieved by a mechanism referred to as retrograde signalling. During retrograde signalling, signals are emitted from the chloroplast consisting on intracellular pathways emitted by the chloroplast communicating the status of the chloroplast and regulating the expression of nuclear genes encoding plastid components. The aim of this project was to elucidate the role of CSK (Chloroplast Sensor Kinase) in relation to previously described retrograde signalling components PRIN2 (Plastid Redox INsensitive 2) and GUN1 (Genomes UNcoupled 1). CSK is a plastid kinase involved in the long- term, acclimation response to balance the ratio between PSII and PSI by regulating the expression of psaA. The activity of CSK is regulated by the redox state of the plastoquinone pool. My work revealed that CSK is up- regulated upon light exposure. In addition, similarly to the prin2 and gun1 mutants, the csk mutant exhibited lower chlorophyll content, a striking yellow cotyledon tip phenotype, impaired chloroplast development and a down- regulation of PEP dependent genes psaA and psbA during a de- etiolation development and for the establishment of PEP activity in light. Furthermore, the similarity in the mutant phenotypes suggests that CSK is involved in the same signalling pathway as PRIN2 and GUN1.

  • 48.
    Bellini, Catherine
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Institut Jean-Pierre Bourgin, UMR 1318 INRA-AgroParisTech, Versailles, France.
    Pacurar, Daniel I
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Perrone, Irene
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Adventitious roots and lateral roots: similarities and differences2014In: Annual Review of Plant Biology, ISSN 1543-5008, E-ISSN 1545-2123, Vol. 65, 639-666 p.Article, book review (Refereed)
    Abstract [en]

    In addition to its role in water and nutrient uptake, the root system is fundamentally important because it anchors a plant to its substrate. Although a wide variety of root systems exist across different species, all plants have a primary root (derived from an embryonic radicle) and different types of lateral roots. Adventitious roots, by comparison, display the same functions as lateral roots but develop from aerial tissues. In addition, they not only develop as an adaptive response to various stresses, such as wounding or flooding, but also are a key limiting component of vegetative propagation. Lateral and adventitious roots share key elements of the genetic and hormonal regulatory networks but are subject to different regulatory mechanisms. In this review, we discuss the developmental processes that give rise to lateral and adventitious roots and highlight knowledge acquired over the past few years about the mechanisms that regulate adventitious root formation.

  • 49.
    Benedict, Catherine
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Geisler, Matt
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Huner, Norman
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Consensus by democracy. Using meta-analyses of microarray and genomic data to model the cold acclimation signaling pathway in Arabidopsis.2006In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 141, no 4, 1219-1232 p.Article in journal (Refereed)
    Abstract [en]

    The whole-genome response of Arabidopsis (Arabidopsis thaliana) exposed to different types and durations of abiotic stress has now been described by a wealth of publicly available microarray data. When combined with studies of how gene expression is affected in mutant and transgenic Arabidopsis with altered ability to transduce the low temperature signal, these data can be used to test the interactions between various low temperature-associated transcription factors and their regulons. We quantized a collection of Affymetrix microarray data so that each gene in a particular regulon could vote on whether a cis-element found in its promoter conferred induction (+1), repression (–1), or no transcriptional change (0) during cold stress. By statistically comparing these election results with the voting behavior of all genes on the same gene chip, we verified the bioactivity of novel cis-elements and defined whether they were inductive or repressive. Using in silico mutagenesis we identified functional binding consensus variants for the transcription factors studied. Our results suggest that the previously identified ICEr1 (induction of CBF expression region 1) consensus does not correlate with cold gene induction, while the ICEr3/ICEr4 consensuses identified using our algorithms are present in regulons of genes that were induced coordinate with observed ICE1 transcript accumulation and temporally preceding genes containing the dehydration response element. Statistical analysis of overlap and cis-element enrichment in the ICE1, CBF2, ZAT12, HOS9, and PHYA regulons enabled us to construct a regulatory network supported by multiple lines of evidence that can be used for future hypothesis testing.

  • 50.
    Benedict, Catherine
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Skinner, J. S.
    Meng, R.
    Chang, Y.
    Bhalerao, R.
    Finn, C.
    Chen, T. H. H.
    Umeå University, Faculty of Science and Technology.
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    The Role of the CBF-dependent Signalling Pathway in Woody Perennials2006In: Cold Hardiness in Plants: Molecular Genetics, Cell Biology and Physiology / [ed] T Chen, M Uemura, S Fujikawa, Wallingford: CABI Publishing, 2006, 167-180 p.Chapter in book (Other academic)
1234567 1 - 50 of 952
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