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Liebsch, Daniela
Publications (3 of 3) Show all publications
Blanco, N. E., Liebsch, D., Guinea Diaz, M., Strand, Å. & Whelan, J. (2019). Dual and dynamic intracellular localization of Arabidopsis thaliana SnRK1.1. Journal of Experimental Botany, 70(8), 2325-2338
Open this publication in new window or tab >>Dual and dynamic intracellular localization of Arabidopsis thaliana SnRK1.1
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2019 (English)In: Journal of Experimental Botany, ISSN 0022-0957, E-ISSN 1460-2431, Vol. 70, no 8, p. 2325-2338Article in journal (Refereed) Published
Abstract [en]

Sucrose non-fermenting 1 (SNF1)-related protein kinase 1.1 (SnRK1.1; also known as KIN10 or SnRK1 alpha) has been identified as the catalytic subunit of the complex SnRK1, the Arabidopsis thaliana homologue of a central integrator of energy and stress signalling in eukaryotes dubbed AMPK/Snf1/SnRK1. A nuclear localization of SnRK1.1 has been previously described and is in line with its function as an integrator of energy and stress signals. Here, using two biological models (Nicotiana benthamiana and Arabidopsis thaliana), native regulatory sequences, different microscopy techniques, and manipulations of cellular energy status, it was found that SnRK1.1 is localized dynamically between the nucleus and endoplasmic reticulum (ER). This distribution was confirmed at a spatial and temporal level by co-localization studies with two different fluorescent ER markers, one of them being the SnRK1.1 phosphorylation target HMGR. The ER and nuclear localization displayed a dynamic behaviour in response to perturbations of the plastidic electron transport chain. These results suggest that an ER-associated SnRK1.1 fraction might be sensing the cellular energy status, being a point of crosstalk with other ER stress regulatory pathways.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Keywords
Arabidopsis, chloroplast, dual localization, endoplasmic reticulum (ER), ER localization, energy atus, Nicotiana benthamiana, nuclear localization, retrograde signalling, SnRK1.1
National Category
Cell Biology
Identifiers
urn:nbn:se:umu:diva-163707 (URN)10.1093/jxb/erz023 (DOI)000483170800010 ()30753728 (PubMedID)
Available from: 2019-10-16 Created: 2019-10-16 Last updated: 2019-10-16Bibliographically approved
Liebsch, D. & Keech, O. (2016). Dark-induced leaf senescence: new insights into a complex light-dependent regulatory pathway. New Phytologist, 212(3), 563-570
Open this publication in new window or tab >>Dark-induced leaf senescence: new insights into a complex light-dependent regulatory pathway
2016 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 212, no 3, p. 563-570Article, review/survey (Refereed) Published
Abstract [en]

Leaf senescence - the coordinated, active process leading to the organized dismantling of cellular components to remobilize resources - is a fundamental aspect of plant life. Its tight regulation is essential for plant fitness and has crucial implications for the optimization of plant productivity and storage properties. Various investigations have shown light deprivation and light perception via phytochromes as key elements modulating senescence. However, the signalling pathways linking light deprivation and actual senescence processes have long remained obscure. Recent analyses have demonstrated that PHYTOCHROME-INTERACTING FACTORS (PIFs) are major transcription factors orchestrating dark-induced senescence (DIS) by targeting chloroplast maintenance, chlorophyll metabolism, hormone signalling and production, and the expression of senescence master regulators, uncovering potential molecular links to the energy deprivation signalling pathway. PIF-dependent feed-forward regulatory modules might be of critical importance for the highly complex and initially light-reversible DIS induction.

Keywords
carbon starvation, dark, phytochrome, PHYTOCHROME-INTERACTING FACTOR (PIF), senescence, shade, signalling
National Category
Plant Biotechnology Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-127593 (URN)10.1111/nph.14217 (DOI)000385797800006 ()27716940 (PubMedID)
Available from: 2016-12-09 Created: 2016-11-16 Last updated: 2018-06-09Bibliographically approved
Chrobok, D., Law, S. R., Brouwer, B., Linden, P., Ziolkowska, A., Liebsch, D., . . . Keech, O. (2016). Dissecting the Metabolic Role of Mitochondria during Developmental Leaf Senescence. Plant Physiology, 172(4), 2132-2153
Open this publication in new window or tab >>Dissecting the Metabolic Role of Mitochondria during Developmental Leaf Senescence
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2016 (English)In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 172, no 4, p. 2132-2153Article in journal (Refereed) Published
Abstract [en]

The functions of mitochondria during leaf senescence, a type of programmed cell death aimed at the massive retrieval of nutrients from the senescing organ to the rest of the plant, remain elusive. Here, combining experimental and analytical approaches, we showed that mitochondrial integrity in Arabidopsis (Arabidopsis thaliana) is conserved until the latest stages of leaf senescence, while their number drops by 30%. Adenylate phosphorylation state assays and mitochondrial respiratory measurements indicated that the leaf energy status also is maintained during this time period. Furthermore, after establishing a curated list of genes coding for products targeted to mitochondria, we analyzed in isolation their transcript profiles, focusing on several key mitochondrial functions, such as the tricarboxylic acid cycle, mitochondrial electron transfer chain, iron-sulfur cluster biosynthesis, transporters, as well as catabolic pathways. In tandem with a metabolomic approach, our data indicated that mitochondrial metabolism was reorganized to support the selective catabolism of both amino acids and fatty acids. Such adjustments would ensure the replenishment of alpha-ketoglutarate and glutamate, which provide the carbon backbones for nitrogen remobilization. Glutamate, being the substrate of the strongly up-regulated cytosolic glutamine synthase, is likely to become a metabolically limiting factor in the latest stages of developmental leaf senescence. Finally, an evolutionary age analysis revealed that, while branched-chain amino acid and proline catabolism are very old mitochondrial functions particularly enriched at the latest stages of leaf senescence, auxin metabolism appears to be rather newly acquired. In summation, our work shows that, during developmental leaf senescence, mitochondria orchestrate catabolic processes by becoming increasingly central energy and metabolic hubs.

National Category
Botany
Identifiers
urn:nbn:se:umu:diva-131100 (URN)10.1104/pp.16.01463 (DOI)000391173400006 ()27744300 (PubMedID)
Available from: 2017-02-13 Created: 2017-02-13 Last updated: 2018-06-09Bibliographically approved
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