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  • 1. 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, p. E8106-E8113Article 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.

  • 2.
    Bylesjö, Max
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Segura, Vincent
    Soolanayakanahally, Raju Y
    Rae, Anne M
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gustafsson, Petter
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    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).
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    LAMINA: a tool for rapid quantification of leaf size and shape parameters2008In: BMC Plant Biology, ISSN 1471-2229, Vol. 8, no 82, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Background

    An increased understanding of leaf area development is important in a number of fields: in food and non-food crops, for example short rotation forestry as a biofuels feedstock, leaf area is intricately linked to biomass productivity; in paleontology leaf shape characteristics are used to reconstruct paleoclimate history. Such fields require measurement of large collections of leaves, with resulting conclusions being highly influenced by the accuracy of the phenotypic measurement process.

    Results

    We have developed LAMINA (Leaf shApe deterMINAtion), a new tool for the automated analysis of images of leaves. LAMINA has been designed to provide classical indicators of leaf shape (blade dimensions) and size (area), which are typically required for correlation analysis to biomass productivity, as well as measures that indicate asymmetry in leaf shape, leaf serration traits, and measures of herbivory damage (missing leaf area). In order to allow Principal Component Analysis (PCA) to be performed, the location of a chosen number of equally spaced boundary coordinates can optionally be returned.

    Conclusion

    We demonstrate the use of the software on a set of 500 scanned images, each containing multiple leaves, collected from a common garden experiment containing 116 clones of Populus tremula (European trembling aspen) that are being used for association mapping, as well as examples of leaves from other species. We show that the software provides an efficient and accurate means of analysing leaf area in large datasets in an automated or semi-automated work flow.

  • 3.
    de La Torre, Amanda R
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Birol, Inanc
    Bousquet, Jean
    Ingvarsson, Pär K
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Jones, Steven J. M
    Keeling, Christopher I
    MacKay, John
    Nilsson, Ove
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ritland, Kermit
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Yanchuk, Alvin
    Zerbe, Philipp
    Bohlmann, Jörg
    Insights into conifer giga-genomes2014In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 166, no 4, p. 1724-1732Article in journal (Refereed)
    Abstract [en]

    Insights from sequenced genomes of major land plant lineages have advanced research in almost every aspect of plant biology. Until recently, however, assembled genome sequences of gymnosperms have been missing from this picture. Conifers of the pine family (Pinaceae) are a group of gymnosperms that dominate large parts of the world's forests. Despite their ecological and economic importance, conifers seemed long out of reach for complete genome sequencing, due in part to their enormous genome size (20-30 Gb) and the highly repetitive nature of their genomes. Technological advances in genome sequencing and assembly enabled the recent publication of three conifer genomes: white spruce (Picea glauca), Norway spruce (Picea abies), and loblolly pine (Pinus taeda). These genome sequences revealed distinctive features compared with other plant genomes and may represent a window into the past of seed plant genomes. This Update highlights recent advances, remaining challenges, and opportunities in light of the publication of the first conifer and gymnosperm genomes.

  • 4.
    Delhomme, Nicolas
    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).
    Sundström, Görel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Uppsala Univ, Dept Med Biochem & Microbiol, Sci Life Lab, Uppsala, Sweden.
    Zamani, Neda
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Uppsala Univ, Dept Med Biochem & Microbiol, Sci Life Lab, Uppsala, Sweden.
    Lantz, Henrik
    Lin, Yao-Cheng
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Norwegian Univ Life Sci, Dept Chem Biotechnol & Food Sci, As, Norway.
    Hoppner, Marc P.
    Jern, Patric
    Van de Peer, Yves
    Lundeberg, Joakim
    Grabherr, Manfred G.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Serendipitous Meta-Transcriptomics: The Fungal Community of Norway Spruce (Picea abies)2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 9, article id e0139080Article in journal (Refereed)
    Abstract [en]

    After performing de novo transcript assembly of >1 billion RNA-Sequencing reads obtained from 22 samples of different Norway spruce (Picea abies) tissues that were not surface sterilized, we found that assembled sequences captured a mix of plant, lichen, and fungal transcripts. The latter were likely expressed by endophytic and epiphytic symbionts, indicating that these organisms were present, alive, and metabolically active. Here, we show that these serendipitously sequenced transcripts need not be considered merely as contamination, as is common, but that they provide insight into the plant's phyllosphere. Notably, we could classify these transcripts as originating predominantly from Dothideomycetes and Leotiomycetes species, with functional annotation of gene families indicating active growth and metabolism, with particular regards to glucose intake and processing, as well as gene regulation.

  • 5. Giacomello, Stefania
    et al.
    Salmen, Fredrik
    Terebieniec, Barbara K.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Vickovic, Sanja
    Navarro, Jose Fernandez
    Alexeyenko, Andrey
    Reimegard, Johan
    McKee, Lauren S.
    Mannapperuma, Chanaka
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bulone, Vincent
    Stahl, Patrik L.
    Sundstrom, Jens F.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Lundeberg, Joakim
    Spatially resolved transcriptome profiling in model plant species2017In: Nature Plants, ISSN 2055-026X, Vol. 3, no 6, article id 17061Article in journal (Refereed)
    Abstract [en]

    Understanding complex biological systems requires functional characterization of specialized tissue domains. However, existing strategies for generating and analysing high-throughput spatial expression profiles were developed for a limited range of organisms, primarily mammals. Here we present the first available approach to generate and study highresolution, spatially resolved functional profiles in a broad range of model plant systems. Our process includes highthroughput spatial transcriptome profiling followed by spatial gene and pathway analyses. We first demonstrate the feasibility of the technique by generating spatial transcriptome profiles from model angiosperms and gymnosperms microsections. In Arabidopsis thaliana we use the spatial data to identify differences in expression levels of 141 genes and 189 pathways in eight inflorescence tissue domains. Our combined approach of spatial transcriptomics and functional profiling offers a powerful new strategy that can be applied to a broad range of plant species, and is an approach that will be pivotal to answering fundamental questions in developmental and evolutionary biology.

  • 6.
    Ingvarsson, Pär K.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1432,As, Norway.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Towards integration of population and comparative genomics in forest trees2016In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 212, no 2, p. 338-344Article, review/survey (Refereed)
    Abstract [en]

    The past decade saw the initiation of an ongoing revolution in sequencing technologies that is transforming all fields of biology. This has been driven by the advent and widespread availability of high-throughput, massively parallel short-read sequencing (MPS) platforms. These technologies have enabled previously unimaginable studies, including draft assemblies of the massive genomes of coniferous species and population-scale resequencing. Transcriptomics studies have likewise been transformed, with RNA-sequencing enabling studies in nonmodel organisms, the discovery of previously unannotated genes (novel transcripts), entirely new classes of RNAs and previously unknown regulatory mechanisms. Here we touch upon current developments in the areas of genome assembly, comparative regulomics and population genetics as they relate to studies of forest tree species.

  • 7.
    Ingvarsson, Pär K
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Association genetics of complex traits in plants2011In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 189, no 4, p. 909-922Article in journal (Refereed)
    Abstract [en]

    Association mapping is rapidly becoming the main method for dissecting the genetic architecture of complex traits in plants. Currently most association mapping studies in plants are preformed using sets of genes selected to be putative candidates for the trait of interest, but rapid developments in genomics will allow for genome-wide mapping in virtually any plant species in the near future. As the costs for genotyping are decreasing, the focus has shifted towards phenotyping. In plants, clonal replication and/or inbred lines allows for replicated phenotyping under many different environmental conditions. Reduced sequencing costs will increase the number of studies that use RNA sequencing data to perform expression quantitative trait locus (eQTL) mapping, which will increase our knowledge of how gene expression variation contributes to phenotypic variation. Current population sizes used in association mapping studies are modest in size and need to be greatly increased if mutations explaining less than a few per cent of the phenotypic variation are to be detected. Association mapping has started to yield insights into the genetic architecture of complex traits in plants, and future studies with greater genome coverage will help to elucidate how plants have managed to adapt to a wide variety of environmental conditions.

  • 8.
    Jokipii-Lukkari, Soile
    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). Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Sveriges Lantbruksuniversitet, SE-901 83 Umeå, Sweden.
    Delhomme, Nicolas
    Schiffthaler, Bastian
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Mannapperuma, Chanaka
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Prestele, Jakob
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Nilsson, Ove
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Transcriptional Roadmap to Seasonal Variation in Wood Formation of Norway Spruce2018In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 176, no 4, p. 2851-2870Article in journal (Refereed)
    Abstract [en]

    Seasonal cues influence several aspects of the secondary growth of tree stems, including cambial activity, wood chemistry, and transition to latewood formation. We investigated seasonal changes in cambial activity, secondary cell wall formation, and tracheid cell death in woody tissues of Norway spruce (Picea abies) throughout one seasonal cycle. RNA sequencing was performed simultaneously in both the xylem and cambium/phloem tissues of the stem. Principal component analysis revealed gradual shifts in the transcriptomes that followed a chronological order throughout the season. A notable remodeling of the transcriptome was observed in the winter, with many genes having maximal expression during the coldest months of the year. A highly coexpressed set of monolignol biosynthesis genes showed high expression during the period of secondary cell wall formation as well as a second peak in midwinter. This midwinter peak in expression did not trigger lignin deposition, as determined by pyrolysis-gas chromatography/mass spectrometry. Coexpression consensus network analyses suggested the involvement of transcription factors belonging to the ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES and MYELOBLASTOSIS-HOMEOBOX families in the seasonal control of secondary cell wall formation of tracheids. Interestingly, the lifetime of the latewood tracheids stretched beyond the winter dormancy period, correlating with a lack of cell death-related gene expression. Our transcriptomic analyses combined with phylogenetic and microscopic analyses also identified the cellulose and lignin biosynthetic genes and putative regulators for latewood formation and tracheid cell death in Norway spruce, providing a toolbox for further physiological and functional assays of these important phase transitions.

  • 9.
    Jokipii-Lukkari, Soile
    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. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology,Swedish University of Agricultural Sciences, SE-901 84 Umeå, Sweden.
    Sundell, David
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Nilsson, Ove
    Hvidsten, Torgeir R.
    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 Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Ås, Norway.
    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.
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    NorWood: a gene expression resource for evo-devo studies of conifer wood development2017In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 216, no 2, p. 482-494Article in journal (Refereed)
    Abstract [en]

    The secondary xylem of conifers is composed mainly of tracheids that differ anatomically and chemically from angiosperm xylem cells. There is currently no high-spatial-resolution data available profiling gene expression during wood formation for any coniferous species, which limits insight into tracheid development.

    RNA-sequencing data from replicated, high-spatial-resolution section series throughout the cambial and woody tissues of Picea abies were used to generate the NorWood.conGenIE.org web resource, which facilitates exploration of the associated gene expression profiles and co-expression networks.

    Integration within PlantGenIE.org enabled a comparative regulomics analysis, revealing divergent co-expression networks between P. abies and the two angiosperm species Arabidopsis thaliana and Populus tremula for the secondary cell wall (SCW) master regulator NAC Class IIB transcription factors. The SCW cellulose synthase genes (CesAs) were located in the neighbourhoods of the NAC factors in Athaliana and P. tremula, but not in Pabies. The NorWood co-expression network enabled identification of potential SCW CesA regulators in P. abies.

    The NorWood web resource represents a powerful community tool for generating evo-devo insights into the divergence of wood formation between angiosperms and gymnosperms and for advancing understanding of the regulation of wood development in P. abies.

  • 10.
    Klevebring, Daniel
    et al.
    School of Biotechnology, Division of Gene Technology, AlbaNova University Center, Royal Institute of Technology, 106 91 Stockholm, Sweden.
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Fahlgren, Noah
    Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA.
    Kasschau, Kristin D
    Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA.
    Carrington, James C
    Center for Genome Research and Biocomputing, Oregon State University, Corvallis, Oregon 97331, USA.
    Lundeberg, Joakim
    School of Biotechnology, Division of Gene Technology, AlbaNova University Center, Royal Institute of Technology, 106 91 Stockholm, Sweden.
    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).
    Genome-wide profiling of populus small RNAs2009In: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 10, p. 620-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Short RNAs, and in particular microRNAs, are important regulators of gene expression both within defined regulatory pathways and at the epigenetic scale. We investigated the short RNA (sRNA) population (18-24 nt) of the transcriptome of green leaves from the sequenced Populus trichocarpa using a concatenation strategy in combination with 454 sequencing. RESULTS: The most abundant size class of sRNAs were 24 nt. Long Terminal Repeats were particularly associated with 24 nt sRNAs. Additionally, some repetitive elements were associated with 22 nt sRNAs. We identified an sRNA hot-spot on chromosome 19, overlapping a region containing both the proposed sex-determining locus and a major cluster of NBS-LRR genes. A number of phased siRNA loci were identified, a subset of which are predicted to target PPR and NBS-LRR disease resistance genes, classes of genes that have been significantly expanded in Populus. Additional loci enriched for sRNA production were identified and characterised. We identified 15 novel predicted microRNAs (miRNAs), including miRNA*sequences, and identified a novel locus that may encode a dual miRNA or a miRNA and short interfering RNAs (siRNAs). CONCLUSIONS: The short RNA population of P. trichocarpa is at least as complex as that of Arabidopsis thaliana. We provide a first genome-wide view of short RNA production for P. trichocarpa and identify new, non-conserved miRNAs.

  • 11. Lafon-Placette, Clément
    et al.
    Faivre-Rampant, Patricia
    Delaunay, Alain
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Brignolas, Franck
    Maury, Stéphane
    Methylome of DNase I sensitive chromatin in Populus trichocarpa shoot apical meristematic cells: a simplified approach revealing characteristics of gene-body DNA methylation in open chromatin state2013In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 197, no 2, p. 416-430Article in journal (Refereed)
    Abstract [en]

    DNA methylation is involved in the control of plant development and adaptation to the environment through modifications of chromatin compaction and gene expression. In poplar (Populus trichocarpa), a perennial plant, variations in DNA methylation have been reported between genotypes and tissues or in response to drought. Nevertheless, the relationships between gene-body DNA methylation, gene expression and chromatin compaction still need clarification.

    Here, DNA methylation was mapped in the noncondensed chromatin fraction from P. trichocarpa shoot apical meristematic cells, the center of plant morphogenesis, where DNA methylation variations could influence the developmental trajectory. DNase I was used to isolate the noncondensed chromatin fraction. Methylated sequences were immunoprecipitated, sequenced using Illumina/Solexa technology and mapped on the v2.0 poplar genome. Bisulfite sequencing of candidate sequences was used to confirm mapping data and to assess cytosine contexts and methylation levels.

    While the methylated DNase I hypersensitive site fraction covered 1.9% of the poplar genome, it contained sequences corresponding to 74% of poplar gene models, mostly exons. The level and cytosine context of gene-body DNA methylation varied with the structural characteristics of the genes.

    Taken together, our data show that DNA methylation is widespread and variable among genes in open chromatin of meristematic cells, in agreement with a role in their developmental trajectory.

  • 12.
    Liu, Lijun
    et al.
    Davis, CA, USA.
    Ramsay, Trevor
    Davis, CA, USA.
    Zinkgraf, Matthew
    Davis, CA, USA.
    Sundell, David
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Street, Nathaniel Robert
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Filkov, Vladimir
    Davis, CA, USA.
    Groover, Andrew
    Davis, CA, USA.
    A resource for characterizing genome-wide binding and putative target genes of transcription factors expressed during secondary growth and wood formation in Populus2015In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 82, no 5, p. 887-898Article in journal (Refereed)
    Abstract [en]

    Identifying transcription factor target genes is essential for modeling the transcriptional networks underlying developmental processes. Here we report a chromatin immunoprecipitation sequencing (ChIP-seq) resource consisting of genome-wide binding regions and associated putative target genes for four Populus homeodomain transcription factors expressed during secondary growth and wood formation. Software code (programs and scripts) for processing the Populus ChIP-seq data are provided within a publically available iPlant image, including tools for ChIP-seq data quality control and evaluation adapted from the human Encyclopedia of DNA Elements (ENCODE) project. Basic information for each transcription factor (including members of Class I KNOX, Class III HD ZIP, BEL1-like families) binding are summarized, including the number and location of binding regions, distribution of binding regions relative to gene features, associated putative target genes, and enriched functional categories of putative target genes. These ChIP-seq data have been integrated within the Populus Genome Integrative Explorer (PopGenIE) where they can be analyzed using a variety of web-based tools. We present an example analysis that shows preferential binding of transcription factor ARBORKNOX1 to the nearest neighbor genes in a pre-calculated co-expression network module, and enrichment for meristem-related genes within this module including multiple orthologs of Arabidopsis KNOTTED-like Arabidopsis 2/6.

  • 13.
    Mähler, Niklas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Norwegian Univ Life Sci, Dept Chem Biotechnol & Food Sci, Norway.
    Wang, Jing
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Centre for Integrative Genetics, Faculty of Biosciences, Norwegian University of Life Sciences, Norway.
    Terebieniec, Barbara K.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Swedish Univ Agr Sci, Dept Plant Biol, Uppsala, Sweden.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Norwegian Univ Life Sci, Dept Chem Biotechnol & Food Sci, As, Norway.
    Gene co-expression network connectivity is an important determinant of selective constraint2017In: PLoS Genetics, ISSN 1553-7390, E-ISSN 1553-7404, Vol. 13, no 4, article id e1006402Article in journal (Refereed)
    Abstract [en]

    While several studies have investigated general properties of the genetic architecture of natural variation in gene expression, few of these have considered natural, outbreeding populations. In parallel, systems biology has established that a general feature of biological networks is that they are scale-free, rendering them buffered against random mutations. To date, few studies have attempted to examine the relationship between the selective processes acting to maintain natural variation of gene expression and the associated co-expression network structure. Here we utilised RNA-Sequencing to assay gene expression in winter buds undergoing bud flush in a natural population of Populus tremula, an outbreeding forest tree species. We performed expression Quantitative Trait Locus (eQTL) mapping and identified 164,290 significant eQTLs associating 6,241 unique genes (eGenes) with 147,419 unique SNPs (eSNPs). We found approximately four times as many local as distant eQTLs, with local eQTLs having significantly higher effect sizes. eQTLs were primarily located in regulatory regions of genes (UTRs or flanking regions), regardless of whether they were local or distant. We used the gene expression data to infer a co-expression network and investigated the relationship between network topology, the genetic architecture of gene expression and signatures of selection. Within the co-expression network, eGenes were underrepresented in network module cores (hubs) and overrepresented in the periphery of the network, with a negative correlation between eQTL effect size and network connectivity. We additionally found that module core genes have experienced stronger selective constraint on coding and non-coding sequence, with connectivity associated with signatures of selection. Our integrated genetics and genomics results suggest that purifying selection is the primary mechanism underlying the genetic architecture of natural variation in gene expression assayed in flushing leaf buds of P. tremula and that connectivity within the co-expression network is linked to the strength of purifying selection.

  • 14.
    Netotea, Sergiu
    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).
    Sundell, David
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    ComPlEx: conservation and divergence of co-expression networks in A. thaliana, Populus and O. sativa2014In: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 15, p. 106-Article in journal (Refereed)
    Abstract [en]

    Background: Divergence in gene regulation has emerged as a key mechanism underlying species differentiation. Comparative analysis of co-expression networks across species can reveal conservation and divergence in the regulation of genes. Results: We inferred co-expression networks of A. thaliana, Populus spp. and O. sativa using state-of-the-art methods based on mutual information and context likelihood of relatedness, and conducted a comprehensive comparison of these networks across a range of co-expression thresholds. In addition to quantifying gene-gene link and network neighbourhood conservation, we also applied recent advancements in network analysis to do cross-species comparisons of network properties such as scale free characteristics and gene centrality as well as network motifs. We found that in all species the networks emerged as scale free only above a certain co-expression threshold, and that the high-centrality genes upholding this organization tended to be conserved. Network motifs, in particular the feed-forward loop, were found to be significantly enriched in specific functional subnetworks but where much less conserved across species than gene centrality. Although individual gene-gene co-expression had massively diverged, up to similar to 80% of the genes still had a significantly conserved network neighbourhood. For genes with multiple predicted orthologs, about half had one ortholog with conserved regulation and another ortholog with diverged or non-conserved regulation. Furthermore, the most sequence similar ortholog was not the one with the most conserved gene regulation in over half of the cases. Conclusions: We have provided a comprehensive analysis of gene regulation evolution in plants and built a web tool for Comparative analysis of Plant co-Expression networks (ComPlEx, http:// complex. plantgenie. org/). The tool can be particularly useful for identifying the ortholog with the most conserved regulation among several sequence-similar alternatives and can thus be of practical importance in e. g. finding candidate genes for perturbation experiments.

  • 15.
    Norman, Anita J.
    et al.
    Sveriges lantbruksuniversitet.
    Street, Nathaniel Robert
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Spong, Goran
    Sveriges lantbruksuniversitet.
    De Novo SNP Discovery in the Scandinavian Brown Bear (Ursus arctos)2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 11, p. e81012-Article in journal (Refereed)
    Abstract [en]

    Information about relatedness between individuals in wild populations is advantageous when studying evolutionary, behavioural and ecological processes. Genomic data can be used to determine relatedness between individuals either when no prior knowledge exists or to confirm suspected relatedness. Here we present a set of 96 SNPs suitable for inferring relatedness for brown bears (Ursus arctos) within Scandinavia. We sequenced reduced representation libraries from nine individuals throughout the geographic range. With consensus reads containing putative SNPs, we applied strict filtering criteria with the aim of finding only high-quality, highly-informative SNPs. We tested 150 putative SNPs of which 96% were validated on a panel of 68 individuals. Ninety-six of the validated SNPs with the highest minor allele frequency were selected. The final SNP panel includes four mitochondrial markers, two monomorphic Y-chromosome sex-determination markers, three X-chromosome SNPs and 87 autosomal SNPs. From our validation sample panel, we identified two previously known parent-offspring dyads with reasonable accuracy. This panel of SNPs is a promising tool for inferring relatedness in the brown bear population in Scandinavia.

  • 16. Norman, Anita J.
    et al.
    Stronen, Astrid V.
    Fuglstad, Geir-Arne
    Ruiz-Gonzalez, Aritz
    Kindberg, Jonas
    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.
    Spong, Goran
    Landscape relatedness: detecting contemporary fine-scale spatial structure in wild populations2017In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 32, no 1, p. 181-194Article in journal (Refereed)
    Abstract [en]

    Methods for detecting contemporary, fine-scale population genetic structure in continuous populations are scarce. Yet such methods are vital for ecological and conservation studies, particularly under a changing landscape. Here we present a novel, spatially explicit method that we call landscape relatedness (LandRel). With this method, we aim to detect contemporary, fine-scale population structure that is sensitive to spatial and temporal changes in the landscape. We interpolate spatially determined relatedness values based on SNP genotypes across the landscape. Interpolations are calculated using the Bayesian inference approach integrated nested Laplace approximation. We empirically tested this method on a continuous population of brown bears (Ursus arctos) spanning two counties in Sweden. Two areas were identified as differentiated from the remaining population. Further analysis suggests that inbreeding has occurred in at least one of these areas. LandRel enabled us to identify previously unknown fine-scale structuring in the population. These results will help direct future research efforts, conservation action and aid in the management of the Scandinavian brown bear population. LandRel thus offers an approach for detecting subtle population structure with a focus on contemporary, fine-scale analysis of continuous populations.

  • 17. Nystedt, Bjorn
    et al.
    Street, Nathaniel Robert
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Wetterbom, Anna
    Zuccolo, Andrea
    Lin, Yao-Cheng
    Scofield, Douglas G.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Vezzi, Francesco
    Delhomme, Nicolas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Giacomello, Stefania
    Alexeyenko, Andrey
    Vicedomini, Riccardo
    Sahlin, Kristoffer
    Sherwood, Ellen
    Elfstrand, Malin
    Gramzow, Lydia
    Holmberg, Kristina
    Hallman, Jimmie
    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).
    Klasson, Lisa
    Koriabine, Maxim
    Kucukoglu, Melis
    Kaller, Max
    Luthman, Johannes
    Lysholm, Fredrik
    Niittyla, Totte
    Olson, Ake
    Rilakovic, Nemanja
    Ritland, Carol
    Rossello, Josep A.
    Sena, Juliana
    Svensson, Thomas
    Talavera-Lopez, Carlos
    Theissen, Guenter
    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).
    Vanneste, Kevin
    Wu, Zhi-Qiang
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Zhang, Bo
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Zerbe, Philipp
    Arvestad, Lars
    Bhalerao, Rishikesh
    Bohlmann, Joerg
    Bousquet, Jean
    Gil, Rosario Garcia
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    de Jong, Pieter
    MacKay, John
    Morgante, Michele
    Ritland, Kermit
    Sundberg, Bjorn
    Thompson, Stacey Lee
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Van de Peer, Yves
    Andersson, Bjorn
    Nilsson, Ove
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Lundeberg, Joakim
    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).
    The Norway spruce genome sequence and conifer genome evolution2013In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 497, no 7451, p. 579-584Article in journal (Refereed)
    Abstract [en]

    Conifers have dominated forests for more than 200 million years and are of huge ecological and economic importance. Here we present the draft assembly of the 20-gigabase genome of Norway spruce (Picea abies), the first available for any gymnosperm. The number of well-supported genes (28,354) is similar to the >100 times smaller genome of Arabidopsis thaliana, and there is no evidence of a recent whole-genome duplication in the gymnosperm lineage. Instead, the large genome size seems to result from the slow and steady accumulation of a diverse set of long-terminal repeat transposable elements, possibly owing to the lack of an efficient elimination mechanism. Comparative sequencing of Pinus sylvestris, Abies sibirica, Juniperus communis, Taxus baccata and Gnetum gnemon reveals that the transposable element diversity is shared among extant conifers. Expression of 24-nucleotide small RNAs, previously implicated in transposable element silencing, is tissue-specific and much lower than in other plants. We further identify numerous long (>10,000 base pairs) introns, gene-like fragments, uncharacterized long non-coding RNAs and short RNAs. This opens up new genomic avenues for conifer forestry and breeding.

  • 18.
    Pacurar, Daniel Ioan
    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).
    Pacurar, Monica Lacramioara
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bussell, John Desmond
    Pop, Tiberia Ioana
    Gutierrez, Laurent
    Bellini, Catherine
    A collection of INDEL markers for map-based cloning in seven Arabidopsis accessions2012In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 63, no 7, p. 2491-2501Article in journal (Refereed)
    Abstract [en]

    The availability of a comprehensive set of resources including an entire annotated reference genome, sequenced alternative accessions, and a multitude of marker systems makes Arabidopsis thaliana an ideal platform for genetic mapping. PCR markers based on INsertions/DELetions (INDELs) are currently the most frequently used polymorphisms. For the most commonly used mapping combination, ColumbiaxLandsberg erecta (Col-0xLer-0), the Cereon polymorphism database is a valuable resource for the generation of polymorphic markers. However, because the number of markers available in public databases for accessions other than Col-0 and Ler-0 is extremely low, mapping using other accessions is far from straightforward. This issue arose while cloning mutations in the Wassilewskija (Ws-4) background. In this work, approaches are described for marker generation in Ws-4 x Col-0. Complementary strategies were employed to generate 229 INDEL markers. Firstly, existing Col-0/Ler-0 Cereon predicted polymorphisms were mined for transferability to Ws-4. Secondly, Ws-0 ecotype Illumina sequence data were analyzed to identify INDELs that could be used for the development of PCR-based markers for Col-0 and Ws-4. Finally, shotgun sequencing allowed the identification of INDELs directly between Col-0 and Ws-4. The polymorphism of the 229 markers was assessed in seven widely used Arabidopsis accessions, and PCR markers that allow a clear distinction between the diverged Ws-0 and Ws-4 accessions are detailed. The utility of the markers was demonstrated by mapping more than 35 mutations in a Col-0xWs-4 combination, an example of which is presented here. The potential contribution of next generation sequencing technologies to more traditional map-based cloning is discussed.

  • 19. Reza, Salim H.
    et al.
    Delhomme, Nicolas
    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.
    Ramachandran, Prashanth
    Dalman, Kerstin
    Nilsson, Ove
    Minina, Elena A.
    Bozhkov, Peter V.
    Transcriptome analysis of embryonic domains in Norway spruce reveals potential regulators of suspensor cell death2018In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 3, article id e0192945Article in journal (Refereed)
    Abstract [en]

    The terminal differentiation and elimination of the embryo-suspensor is the earliest manifestation of programmed cell death (PCD) during plant ontogenesis. Molecular regulation of suspensor PCD remains poorly understood. Norway spruce (Picea abies) embryos provide a powerful model for studying embryo development because of their large size, sequenced genome, and the possibility to obtain a large number of embryos at a specific developmental stage through somatic embryogenesis. Here, we have carried out global gene expression analysis of the Norway spruce embryo-suspensor versus embryonal mass (a gymnosperm analogue of embryo proper) using RNA sequencing. We have identified that suspensors have enhanced expression of the NAC domain-containing transcription factors, XND1 and ANAC075, previously shown to be involved in the initiation of developmental PCD in Arabidiopsis. The analysis has also revealed enhanced expression of Norway spruce homologues of the known executioners of both developmental and stress-induced cell deaths, such as metacaspase 9 (MC9), cysteine endopeptidase-1 (CEP1) and ribonuclease 3 (RNS3). Interestingly, a spruce homologue of bax inhibitor-1 (PaBI-1, for Picea abies BI-1), an evolutionarily conserved cell death suppressor, was likewise up-regulated in the embryosuspensor. Since Arabidopsis BI-1 so far has been implicated only in the endoplasmic reticulum (ER)-stress induced cell death, we investigated its role in embryogenesis and suspensor PCD using RNA interference (RNAi). We have found that PaBI-1-deficient lines formed a large number of abnormal embryos with suppressed suspensor elongation and disturbed polarity. Cytochemical staining of suspensor cells has revealed that PaBI-1 deficiency suppresses vacuolar cell death and induces necrotic type of cell death previously shown to compromise embryo development. This study demonstrates that a large number of cell-death components are conserved between angiosperms and gymnosperms and establishes a new role for BI-1 in the progression of vacuolar cell death.

  • 20.
    Robinson, Kathryn
    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).
    Delhomme, Nicolas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Mahler, Niklas
    Schiffthaler, Bastian
    Önskog, Jenny
    Albrectsen, Benedicte
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ingvarsson, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    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).
    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).
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Populus tremula (European aspen) shows no evidence of sexual dimorphism2014In: BMC Plant Biology, ISSN 1471-2229, E-ISSN 1471-2229, Vol. 14, p. 276-Article in journal (Refereed)
    Abstract [en]

    Background:

    Evolutionary theory suggests that males and females may evolve sexually dimorphic phenotypic and biochemical traits concordant with each sex having different optimal strategies of resource investment to maximise reproductive success and fitness. Such sexual dimorphism would result in sex biased gene expression patterns in non-floral organs for autosomal genes associated with the control and development of such phenotypic traits.

    Results:

    We examined morphological, biochemical and herbivory traits to test for sexually dimorphic resource allocation strategies within collections of sexually mature and immature Populus tremula (European aspen) trees. In addition we profiled gene expression in mature leaves of sexually mature wild trees using whole-genome oligonucleotide microarrays and RNA-Sequencing.

    Conclusions:

    We found no evidence of sexual dimorphism or differential resource investment strategies between males and females in either sexually immature or mature trees. Similarly, single-gene differential expression and machine learning approaches revealed no evidence of large-scale sex biased gene expression. However, two significantly differentially expressed genes were identified from the RNA-Seq data, one of which is a robust diagnostic marker of sex in P. tremula.

  • 21. Sahlin, Kristoffer
    et al.
    Street, Nathaniel
    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
    Arvestad, Lars
    Improved gap size estimation for scaffolding algorithms2012In: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 28, no 17, p. 2215-2222Article in journal (Refereed)
    Abstract [en]

    Motivation: One of the important steps of genome assembly is scaffolding, in which contigs are linked using information from read-pairs. Scaffolding provides estimates about the order, relative orientation and distance between contigs. We have found that contig distance estimates are generally strongly biased and based on false assumptions. Since erroneous distance estimates can mislead in subsequent analysis, it is important to provide unbiased estimation of contig distance.

    Results: In this article, we show that state-of-the-art programs for scaffolding are using an incorrect model of gap size estimation. We discuss why current maximum likelihood estimators are biased and describe what different cases of bias we are facing. Furthermore, we provide a model for the distribution of reads that span a gap and derive the maximum likelihood equation for the gap length. We motivate why this estimate is sound and show empirically that it outperforms gap estimators in popular scaffolding programs. Our results have consequences both for scaffolding software, structural variation detection and for library insert-size estimation as is commonly performed by read aligners.

  • 22.
    Schiffthaler, Bastian
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Bernhardsson, Carolina
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ingvarsson, Par K.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    BatchMap: A parallel implementation of the OneMap R package for fast computation of F-1 linkage maps in outcrossing species2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 12, article id e0189256Article in journal (Refereed)
    Abstract [en]

    With the rapid advancement of high throughput sequencing, large numbers of genetic markers can be readily and cheaply acquired, but most current software packages for genetic map construction cannot handle such dense input. Modern computer architectures and server farms represent untapped resources that can be used to enable higher marker densities to be processed in tractable time. Here we present a pipeline using a modified version of OneMap that parallelizes over bottleneck functions and achieves substantial speedups for producing a high density linkage map (N = 20,000). Using simulated data we show that the outcome is as accurate as the traditional pipeline. We further demonstrate that there is a direct relationship between the number of markers used and the level of deviation between true and estimated order, which in turn impacts the final size of a genetic map.

  • 23.
    Sjödin, Andreas
    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.
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Sandberg, Göran
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    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).
    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).
    The populus genome integrative explorer (PopGenIE): a new resource for exploring the populus genome2009In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 182, no 4, p. 1013-1025Article in journal (Refereed)
    Abstract [en]

    * Populus has become an important model plant system. However, utilization of the increasingly extensive collection of genetics and genomics data created by the community is currently hindered by the lack of a central resource, such as a model organism database (MOD). Such MODs offer a single entry point to the collection of resources available within a model system, typically including tools for exploring and querying those resources. * As a starting point to overcoming the lack of such an MOD for Populus, we present the Populus Genome Integrative Explorer (PopGenIE), an integrated set of tools for exploring the Populus genome and transcriptome. The resource includes genome, synteny and quantitative trait locus (QTL) browsers for exploring genetic data. * Expression tools include an electronic fluorescent pictograph (eFP) browser, expression profile plots, co-regulation within collated transcriptomics data sets, and identification of over-represented functional categories and genomic hotspot locations. A number of collated transcriptomics data sets are made available in the eFP browser to facilitate functional exploration of gene function. Additional homology and data extraction tools are provided. * PopGenIE significantly increases accessibility to Populus genomics resources and allows exploration of transcriptomics data without the need to learn or understand complex statistical analysis methods. PopGenIE is available at http://www.popgenie.org or via http://www.populusgenome.info.

  • 24. Soolanayakanahally, Raju Y
    et al.
    Guy, Robert D
    Street, Nathaniel R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    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).
    Silim, Salim N.
    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).
    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).
    Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens2015In: Frontiers in Plant Science, ISSN 1664-462X, E-ISSN 1664-462X, Vol. 6, article id 528Article in journal (Refereed)
    Abstract [en]

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g(S)) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (delta C-13) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects.

  • 25.
    Stachula, Paulina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Vergara, Alexander
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences.
    Delhomme, Nicolas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Essential processes determining life in cold in Arabidopsis thalianaManuscript (preprint) (Other academic)
  • 26.
    Street, Nathaniel Robert
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Populus Short RNAs2011In: Non Coding RNAs in Plants / [ed] Volker A. Erdmann, Jan Barciszewski, Berlin: Springer Berlin/Heidelberg, 2011, p. 375-384Chapter in book (Other academic)
    Abstract [en]

    As a model species, Populus offers opportunities to study processes unique to woody, perennial species, such as seasonal senescence, dormancy and wood production. As a long-lived species, it is also possible that different adaptive survival strategies have been selected for in comparison to annual species. To date, a number of miRNAs have been shown to be differentially expressed or induced in response to abiotic stress and to be involved in processes such as wood development. Although Populus has not yet been extensively profiled for short RNAs, the available data has been used to identify a number of phased loci and to characterise association of short RNA and repetitive elements in the genome. There appears to be a hotspot of sRNA production on chromosome 19, which contains the proposed sex-determining locus.

  • 27.
    Street, Nathaniel Robert
    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).
    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).
    A systems biology model of the regulatory network in Populus leaves reveals interacting regulators and conserved regulation2011In: BMC Plant Biology, ISSN 1471-2229, E-ISSN 1471-2229, Vol. 11, p. 13-Article in journal (Refereed)
    Abstract [en]

    We outline a computationally inferred model of the regulatory network of Populus leaves, and show how treating genes as interacting, rather than individual, entities identifies new regulators compared to traditional genomics analysis. Although systems biology models should be used with care considering the complexity of regulatory programs and the limitations of current genomics data, methods describing interactions can provide hypotheses about the underlying cause of emergent properties and are needed if we are to identify target genes other than those constituting the "low hanging fruit" of genomic analysis.

  • 28.
    Street, Nathaniel Robert
    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).
    Sjödin, Andreas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Bylesjö, Max
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    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).
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    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).
    A cross-species transcriptomics approach to identify genes involved in leaf development2008In: BMC Genomics, ISSN 1471-2164, E-ISSN 1471-2164, Vol. 9, no 1, p. 539-Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Background

    We have made use of publicly available gene expression data to identify transcription factors and transcriptional modules (regulons) associated with leaf development in Populus. Different tissue types were compared to identify genes informative in the discrimination of leaf and non-leaf tissues. Transcriptional modules within this set of genes were identified in a much wider set of microarray data collected from leaves in a number of developmental, biotic, abiotic and transgenic experiments.

    Results

    Transcription factors that were over represented in leaf EST libraries and that were useful for discriminating leaves from other tissues were identified, revealing that the C2C2-YABBY, CCAAT-HAP3 and 5, MYB, and ZF-HD families are particularly important in leaves. The expression of transcriptional modules and transcription factors was examined across a number of experiments to select those that were particularly active during the early stages of leaf development. Two transcription factors were found to collocate to previously published Quantitative Trait Loci (QTL) for leaf length. We also found that miRNA family 396 may be important in the control of leaf development, with three members of the family collocating with clusters of leaf development QTL.

    Conclusion

    This work provides a set of candidate genes involved in the control and processes of leaf development. This resource can be used for a wide variety of purposes such as informing the selection of candidate genes for association mapping or for the selection of targets for reverse genetics studies to further understanding of the genetic control of leaf size and shape.

  • 29.
    Street, Nathaniel Robert
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tsai, Chung-Jui
    Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA.
    Populus Resources and Bioinformatics2010In: Genetics and Genomics of Populus / [ed] Stefan Jansson, Rishikesh Bhalerao, Andrew Groover, New York: Springer-Verlag New York, 2010, Vol. 8, p. 135-152Chapter in book (Other academic)
    Abstract [en]

    As a model system, Populus offers the opportunity to study biological questions pertinent to perennial growth habits such as lignocellulosic cell wall biogenesis and dormancy cycles. In the past years, much has been learnt about the transcriptional control of such processes and there is an ever-growing resource of publicly available transcriptomics data and EST sequences available. More recently greater emphasis has been placed on the study of metabolomic data and particularly in linking metabolic changes to both development and ecosystem functioning. Populus represents an ideal model system in which genetic and genomic studies can be conducted in a ecological key-stone species as well in a commercially important forest tree crop. To facilitate biological understanding a number of bioinformatics resources have become available for Populus alongside greater integration of the species in centralized sequence data sources such as NCBI and Interpro. These developments are rapidly advancing the ability to use Populus as a model system for the study of developmental, ecological and comparative genomics questions. Here we overview the current state of bioinformatics resources available for studies involving Populus as well as detailing the genetic material available to conduct studies on. Since the emergence of Populus as the model tree species, there has been a steady and rapid development of resources enabling the use of new technologies and approaches for answering biological questions. The Populus genomics resources have been, and will continue to be, instrumental in addressing biological questions pertinent to perennial growth habits (e.g., lignocellulosic cell wall biogenesis and dormancy cycles). Increasingly, genomics tools are also being incorporated into ecological investigations

  • 30.
    Sullivan, Alexis R.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Schiffthaler, Bastian
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Thompson, Stacey Lee
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Biology, Dalhousie University, Halifax, NS, Canada.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Wang, Xiao-Ru
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Interspecific Plastome Recombination Reflects Ancient Reticulate Evolution in Picea (Pinaceae)2017In: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 34, no 7, p. 1689-1701Article in journal (Refereed)
    Abstract [en]

    Plastid sequences are a cornerstone in plant systematic studies and key aspects of their evolution, such as uniparental inheritance and absent recombination, are often treated as axioms. While exceptions to these assumptions can profoundly influence evolutionary inference, detecting them can require extensive sampling, abundant sequence data, and detailed testing. Using advancements in high-throughput sequencing, we analyzed the whole plastomes of 65 accessions of Picea, a genus of similar to 35 coniferous forest tree species, to test for deviations from canonical plastome evolution. Using complementary hypothesis and data-driven tests, we found evidence for chimeric plastomes generated by interspecific hybridization and recombination in the clade comprising Norway spruce (P. abies) and 10 other species. Support for interspecific recombination remained after controlling for sequence saturation, positive selection, and potential alignment artifacts. These results reconcile previous conflicting plastid-based phylogenies and strengthen the mounting evidence of reticulate evolution in Picea. Given the relatively high frequency of hybridization and biparental plastid inheritance in plants, we suggest interspecific plastome recombination may be more widespread than currently appreciated and could underlie reported cases of discordant plastid phylogenies.

  • 31.
    Sundell, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mannapperuma, Chanaka
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Netotea, Sergiu
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Delhomme, Nicolas
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Lin, Yao-Cheng
    Sjödin, Andreas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Van de Peer, Yves
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Hvidsten, Torgeir R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Department of Chemistry,Biotechnology and Food Science, Norwegi an University of Life Sciences, 1432As, Norw.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The Plant Genome Integrative Explorer Resource: PlantGenIE.org2015In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 208, no 4, p. 1149-1156Article in journal (Refereed)
    Abstract [en]

    Accessing and exploring large-scale genomics data sets remains a significant challenge to researchers without specialist bioinformatics training. We present the integrated PlantGenIE.org platform for exploration of Populus, conifer and Arabidopsis genomics data, which includes expression networks and associated visualization tools. Standard features of a model organism database are provided, including genome browsers, gene list annotation, BLAST homology searches and gene information pages. Community annotation updating is supported via integration of WebApollo. We have produced an RNA-sequencing (RNA-Seq) expression atlas for Populus tremula and have integrated these data within the expression tools. An updated version of the COMPLEX resource for performing comparative plant expression analyses of gene coexpression network conservation between species has also been integrated. The PlantGenIE.org platform provides intuitive access to large-scale and genome-wide genomics data from model forest tree species, facilitating both community contributions to annotation improvement and tools supporting use of the included data resources to inform biological insight.

  • 32.
    Sundell, David
    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.
    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.
    Kumar, Manoj
    Mellerowicz, Ewa J.
    Kucukoglu, Melis
    Johnsson, Christoffer
    Kumar, Vikash
    Mannapperuma, Chanaka
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Delhomme, Nicolas
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Nilsson, Ove
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    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. Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm, Sweden.
    Fischer, Urs
    Niittyla, Totte
    Sundberg, Bjorn
    Hvidsten, Torgeir R.
    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 Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, 1433 Ås, Norway.
    AspWood: High-Spatial-Resolution Transcriptome Profiles Reveal Uncharacterized Modularity of Wood Formation in Populus tremula2017In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 29, no 7, p. 1585-1604Article in journal (Refereed)
    Abstract [en]

    Trees represent the largest terrestrial carbon sink and a renewable source of ligno-cellulose. There is significant scope for yield and quality improvement in these largely undomesticated species, and efforts to engineer elite varieties will benefit from improved understanding of the transcriptional network underlying cambial growth and wood formation. We generated high-spatial-resolution RNA sequencing data spanning the secondary phloem, vascular cambium, and wood-forming tissues of Populus tremula. The transcriptome comprised 28,294 expressed, annotated genes, 78 novel protein-coding genes, and 567 putative long intergenic noncoding RNAs. Most paralogs originating from the Salicaceae whole-genome duplication had diverged expression, with the exception of those highly expressed during secondary cell wall deposition. Coexpression network analyses revealed that regulation of the transcriptome underlying cambial growth and wood formation comprises numerous modules forming a continuum of active processes across the tissues. A comparative analysis revealed that a majority of these modules are conserved in Picea abies. The high spatial resolution of our data enabled identification of novel roles for characterized genes involved in xylan and cellulose biosynthesis, regulators of xylem vessel and fiber differentiation and lignification. An associated web resource (AspWood, http://aspwood.popgenie.org) provides interactive tools for exploring the expression profiles and coexpression network.

  • 33.
    Sundell, David
    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.
    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.
    Kumar, Manoj
    Mellerowicz, Ewa J
    Kucukoglu, Melis
    Johnsson, Christoffer
    Kumar, Vikash
    Mannapperuma, Chanaka
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Nilsson, Ove
    Tuominen, Hannele
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    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. Department of Ecology, Environment and Plant Sciences, Stockholm University, Sweden.
    Fischer, Urs
    Niittyla, Totte
    Sundberg, Bjoern
    Hvidsten, Torgeir R
    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 Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, Ås, Norway.
    High-spatial-resolution transcriptome profiling reveals uncharacterized regulatory complexity underlying cambial growth and wood formation in Populus tremula2016Manuscript (preprint) (Other academic)
    Abstract [en]

    Trees represent the largest terrestrial carbon sink and a renewable source of ligno-cellulose. There is significant scope for yield and quality improvement in these largely undomesticated species, however, efforts to engineer new, elite varieties are constrained by the lack of a comprehensive understanding of the transcriptional network underlying cambial growth and wood formation. We generated RNA Sequencing transcriptome data for four mature, wild-growing aspens (Populus tremula) from high-spatial-resolution tangential cryosection series spanning the secondary phloem, vascular cambium, expanding and secondary cell wall forming xylem cells, cell death zone and the previous years annual ring. The transcriptome comprised 28,294 expressed, previously annotated protein-coding genes, 78 novel protein-coding genes and 567 long intergenic non-coding RNAs. Most paralogs originating from the Salicaceae whole genome duplication had diverged expression, with the notable exception of those with high expression during secondary cell wall deposition. We performed co-expression network analysis to identify central transcriptional modules and associated several of these with known biological processes. This revealed previously uncharacterized complexity underlying the regulation of cambial growth and wood formation, with modules forming a continuum of activated processes across the tissues. The high spatial resolution suggested novel roles for known genes involved in xylan and cellulose biosynthesis, regulators of xylem vessel and fiber differentiation and components of lignification. The associated web resource (AspWood, http://aspwood.popgenie.org) integrates the data within a set of interactive tools for exploring the co-expression network of cambial growth and wood formation.

  • 34. Tuskan, Gerald A.
    et al.
    DiFazio, Steve
    Faivre-Rampant, Patricia
    Gaudet, Muriel
    Harfouche, Antoine
    Jorge, Veronique
    Labbe, Jessy L.
    Ranjan, Priya
    Sabatti, Maurizio
    Slavov, Gancho
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tschaplinski, Timothy J.
    Yin, Tongming
    The obscure events contributing to the evolution of an incipient sex chromosome in Populus: a retrospective working hypothesis2012In: Tree Genetics & Genomes, ISSN 1614-2942, E-ISSN 1614-2950, Vol. 8, no 3, p. 559-571Article, review/survey (Refereed)
    Abstract [en]

    Genetic determination of gender is a fundamental developmental and evolutionary process in plants. Although it appears that dioecy in Populus is genetically controlled, the precise gender-determining systems remain unclear. The recently released second draft assembly and annotated gene set of the Populus genome provided an opportunity to revisit this topic. We hypothesized that over evolutionary time, selective pressure has reformed the genome structure and gene composition in the peritelomeric region of the chromosome XIX, which has resulted in a distinctive genome structure and cluster of genes contributing to gender determination in Populus trichocarpa. Multiple lines of evidence support this working hypothesis. First, the peritelomeric region of the chromosome XIX contains significantly fewer single nucleotide polymorphisms than the rest of Populus genome and has a distinct evolutionary history. Second, the peritelomeric end of chromosome XIX contains the largest cluster of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of disease resistance genes in the entire Populus genome. Third, there is a high occurrence of small microRNAs on chromosome XIX, which is coincident to the region containing the putative gender-determining locus and the major cluster of NBS-LRR genes. Further, by analyzing the metabolomic profiles of floral bud in male and female Populus trees using a gas chromatography-mass spectrometry, we found that there are gender-specific accumulations of phenolic glycosides. Taken together, these findings led to the hypothesis that resistance to and regulation of a floral pathogen and gender determination coevolved, and that these events triggered the emergence of a nascent sex chromosome. Further studies of chromosome XIX will provide new insights into the genetic control of gender determination in Populus.

  • 35.
    Wang, Jing
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Centre for Integrative Genetics, Department of Animal and Aquacultural Sciences, Faculty of Life Sciences, Norwegian University of Life Science.
    Ding, Jihua
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences.
    Tan, Biyue
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Stora Enso AB.
    Robinson, Kathryn M.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Michelson, Ingrid H.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Johansson, Anna
    Wallenberg Advanced Bioinformatics Infrastructure, Science for Life Laboratory, Uppsala University.
    Nystedt, Björn
    Wallenberg Advanced Bioinformatics Infrastructure, Science for Life Laboratory, Uppsala University.
    Scofield, Douglas G.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Ecology and Genetics, Evolutionary Biology, Uppsala University.
    Nilsson, Ove
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences.
    Jansson, Stefan
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Street, Nathaniel R.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences.
    A major locus controls local adaptation and adaptive life history variation in a perennial plantManuscript (preprint) (Other academic)
    Abstract [en]

    Background: The initiation of growth cessation and dormancy represent critical life-history trade-offs between survival and growth, and have important fitness effects in perennial plants. Such adaptive life history traits often show strong local adaptation along environmental gradients but despite their importance, the genetic architecture of these traits remains poorly understood.

    Results: We integrate whole genome re-sequencing with environmental and phenotypic data from common garden experiments to investigate the genomic basis of local adaptation across a latitudinal gradient in European aspen (Populus tremula). We discover a single genomic region containing the PtFT2 gene that mediates local adaptation in the timing of bud set and that explains 65% of the observed genetic variation in bud set. This locus is the likely target of a recent selective sweep that originated right before or during colonization of northern Scandinavia following the last glaciation. Field and greenhouse experiments confirm that variation in PtFT2 gene expression affect the phenotypic variation in bud set that we observe in wild natural populations.

    Conclusions: Our results reveal a major effect locus that determine the timing of bud set and that have facilitated rapid adaptation to shorter growing seasons and colder climates in European aspen. The discovery of a single locus explaining a substantial fraction of the variation in a key life history trait is remarkable given that such traits are generally considered to be highly polygenic. These findings provide a dramatic illustration of how loci of large-effect for adaptive traits can arise and be maintained over large geographical scales in natural populations.

  • 36.
    Wang, Jing
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Scofield, Douglas
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Ingvarsson, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Variant calling using NGS data in European aspen (Populus tremula)2015In: Advances in the Understanding of Biological Sciences Using Next Generation Sequencing (NGS) Approaches / [ed] Sablok, G., Kumar, S., Ueno, S., Kuo, J., Varotto, C. (Eds.), Springer, 2015, 1, p. 43-61Chapter in book (Refereed)
    Abstract [en]

    Analysis of next-generation sequencing (NGS) data is rapidly becoming an important source of information for genetics and genomics studies. The utility of such data does, however, rely crucially on the accuracy and quality of SNP and genotype calling. Identification of genetic variants (SNPs and short indels) from NGS data is an area of active research and many recent statistical methods have been developed to both improve and quantify the large uncertainty associated with genotype calling. The detection of genetic variants from NGS data is prone to errors, due to multiple factors such as base-calling, alignment errors and read coverage. Here we highlight some of the issues and review and exemplify some of the recent methods that have been developed for genotype calling. We also provide guidelines for their application to whole-genome re-sequencing data using a data set based on a number of European aspen (Populus tremula) individuals each sequenced to a depth of about 20x coverage per individual.

  • 37.
    Wang, Jing
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Street, Nathaniel
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Scofield, Douglas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Ecology and Genetics: Evolutionary Biology, Uppsala University, Uppsala; Uppsala Multidisciplinary Center for Advanced Computational Science, Uppsala University, Uppsala .
    Ingvarsson, Pär
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Natural Selection and Recombination Rate Variation Shape Nucleotide Polymorphism Across the Genomes of Three Related Populus Species2016In: Genetics, ISSN 0016-6731, E-ISSN 1943-2631, Vol. 202, no 3, p. 1185-1200Article in journal (Refereed)
    Abstract [en]