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Publikationen - Molekulare Signalverarbeitung

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Publikation

Nishiyama, T.; Sakayama, H.; de Vries, J.; Buschmann, H.; Saint-Marcoux, D.; Ullrich, K. K.; Haas, F. B.; Vanderstraeten, L.; Becker, D.; Lang, D.; Vosolsobě, S.; Rombauts, S.; Wilhelmsson, P. K.; Janitza, P.; Kern, R.; Heyl, A.; Rümpler, F.; Calderón Villalobos, L. I. A.; Clay, J. M.; Skokan, R.; Toyoda, A.; Suzuki, Y.; Kagoshima, H.; Schijlen, E.; Tajeshwar, N.; Catarino, B.; Hetherington, A. J.; Saltykova, A.; Bonnot, C.; Breuninger, H.; Symeonidi, A.; Radhakrishnan, G. V.; Van Nieuwerburgh, F.; Deforce, D.; Chang, C.; Karol, K. G.; Hedrich, R.; Ulvskov, P.; Glöckner, G.; Delwiche, C. F.; Petrášek, J.; Van de Peer, Y.; Friml, J.; Beilby, M.; Dolan, L.; Kohara, Y.; Sugano, S.; Fujiyama, A.; Delaux, P.-M.; Quint, M.; Theißen, G.; Hagemann, M.; Harholt, J.; Dunand, C.; Zachgo, S.; Langdale, J.; Maumus, F.; Van Der Straeten, D.; Gould, S. B.; Rensing, S. A.; The Chara Genome: Secondary Complexity and Implications for Plant Terrestrialization Cell 174, 448-464.e24, (2018) DOI: 10.1016/j.cell.2018.06.033

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C. braunii employs unique xylan synthases for cell wall biosynthesis, a phragmoplast (cell separation) mechanism similar to that of land plants, and many phytohormones. C. braunii plastids are controlled via land-plant-like retrograde signaling, and transcriptional regulation is more elaborate than in other algae. The morphological complexity of this organism may result from expanded gene families, with three cases of particular note: genes effecting tolerance to reactive oxygen species (ROS), LysM receptor-like kinases, and transcription factors (TFs). Transcriptomic analysis of sexual reproductive structures reveals intricate control by TFs, activity of the ROS gene network, and the ancestral use of plant-like storage and stress protection proteins in the zygote.
Publikation

Ibañez, C.; Poeschl, Y.; Peterson, T.; Bellstädt, J.; Denk, K.; Gogol-Döring, A.; Quint, M.; Delker, C.; Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana BMC Plant Biol. 17, 114, (2017) DOI: 10.1186/s12870-017-1068-5

BackgroundGlobal increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best.ResultsHere, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions.ConclusionGenotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.
Publikation

Hoehenwarter, W.; Mönchgesang, S.; Neumann, S.; Majovsky, P.; Abel, S.; Müller, J.; Comparative expression profiling reveals a role of the root apoplast in local phosphate response BMC Plant Biol. 16, 106, (2016) DOI: 10.1186/s12870-016-0790-8

BackgroundPlant adaptation to limited phosphate availability comprises a wide range of responses to conserve and remobilize internal phosphate sources and to enhance phosphate acquisition. Vigorous restructuring of root system architecture provides a developmental strategy for topsoil exploration and phosphate scavenging. Changes in external phosphate availability are locally sensed at root tips and adjust root growth by modulating cell expansion and cell division. The functionally interacting Arabidopsis genes, LOW PHOSPHATE RESPONSE 1 and 2 (LPR1/LPR2) and PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2), are key components of root phosphate sensing. We recently demonstrated that the LOW PHOSPHATE RESPONSE 1 - PHOSPHATE DEFICIENCY RESPONSE 2 (LPR1-PDR2) module mediates apoplastic deposition of ferric iron (Fe3+) in the growing root tip during phosphate limitation. Iron deposition coincides with sites of reactive oxygen species generation and triggers cell wall thickening and callose accumulation, which interfere with cell-to-cell communication and inhibit root growth.ResultsWe took advantage of the opposite phosphate-conditional root phenotype of the phosphate deficiency response 2 mutant (hypersensitive) and low phosphate response 1 and 2 double mutant (insensitive) to investigate the phosphate dependent regulation of gene and protein expression in roots using genome-wide transcriptome and proteome analysis. We observed an overrepresentation of genes and proteins that are involved in the regulation of iron homeostasis, cell wall remodeling and reactive oxygen species formation, and we highlight a number of candidate genes with a potential function in root adaptation to limited phosphate availability. Our experiments reveal that FERRIC REDUCTASE DEFECTIVE 3 mediated, apoplastic iron redistribution, but not intracellular iron uptake and iron storage, triggers phosphate-dependent root growth modulation. We further highlight expressional changes of several cell wall-modifying enzymes and provide evidence for adjustment of the pectin network at sites of iron accumulation in the root.ConclusionOur study reveals new aspects of the elaborate interplay between phosphate starvation responses and changes in iron homeostasis. The results emphasize the importance of apoplastic iron redistribution to mediate phosphate-dependent root growth adjustment and suggest an important role for citrate in phosphate-dependent apoplastic iron transport. We further demonstrate that root growth modulation correlates with an altered expression of cell wall modifying enzymes and changes in the pectin network of the phosphate-deprived root tip, supporting the hypothesis that pectins are involved in iron binding and/or phosphate mobilization.
Publikation

Raschke, A.; Ibañez, C.; Ullrich, K. K.; Anwer, M. U.; Becker, S.; Glöckner, A.; Trenner, J.; Denk, K.; Saal, B.; Sun, X.; Ni, M.; Davis, S. J.; Delker, C.; Quint, M.; Natural variants of ELF3 affect thermomorphogenesis by transcriptionally modulating PIF4-dependent auxin response genes BMC Plant Biol. 15, 197, (2015) DOI: 10.1186/s12870-015-0566-6

BackgroundPerception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis.ResultsWe identified GIRAFFE2.1, a major QTL explaining ~18 % of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth.ConclusionsIn combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod information to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.
Publikation

Erickson, J. L.; Ziegler, J.; Guevara, D.; Abel, S.; Klösgen, R. B.; Mathur, J.; Rothstein, S. J.; Schattat, M. H.; Agrobacterium-derived cytokinin influences plastid morphology and starch accumulation in Nicotiana benthamiana during transient assays BMC Plant Biol. 14, 127, (2014) DOI: 10.1186/1471-2229-14-127

BackgroundAgrobacterium tumefaciens-based transient assays have become a common tool for answering questions related to protein localization and gene expression in a cellular context. The use of these assays assumes that the transiently transformed cells are observed under relatively authentic physiological conditions and maintain ‘normal’ sub-cellular behaviour. Although this premise is widely accepted, the question of whether cellular organization and organelle morphology is altered in Agrobacterium-infiltrated cells has not been examined in detail. The first indications of an altered sub-cellular environment came from our observation that a common laboratory strain, GV3101(pMP90), caused a drastic increase in stromule frequency. Stromules, or ‘stroma-filled-tubules’ emanate from the surface of plastids and are sensitive to a variety of biotic and abiotic stresses. Starting from this observation, the goal of our experiments was to further characterize the changes to the cell resulting from short-term bacterial infestation, and to identify the factor responsible for eliciting these changes.ResultsUsing a protocol typical of transient assays we evaluated the impact of GV3101(pMP90) infiltration on chloroplast behaviour and morphology in Nicotiana benthamiana. Our experiments confirmed that GV3101(pMP90) consistently induces stromules and alters plastid position relative to the nucleus. These effects were found to be the result of strain-dependant secretion of cytokinin and its accumulation in the plant tissue. Bacterial production of the hormone was found to be dependant on the presence of a trans-zeatin synthase gene (tzs) located on the Ti plasmid of GV3101(pMP90). Bacteria-derived cytokinins were also correlated with changes to both soluble sugar level and starch accumulation.ConclusionAlthough we have chosen to focus on how transient Agrobacterium infestation alters plastid based parameters, these changes to the morphology and position of a single organelle, combined with the measured increases in sugar and starch content, suggest global changes to cell physiology. This indicates that cells visualized during transient assays may not be as ‘normal’ as was previously assumed. Our results suggest that the impact of the bacteria can be minimized by choosing Agrobacterium strains devoid of the tzs gene, but that the alterations to sub-cellular organization and cell carbohydrate status cannot be completely avoided using this strategy.
Publikation

De Nardi, B.; Dreos, R.; Del Terra, L.; Martellossi, C.; Asquini, E.; Tornincasa, P.; Gasperini, D.; Pacchioni, B.; Rathinavelu, R.; Pallavicini, A.; Graziosi, G.; Differential responses of Coffea arabica L. leaves and roots to chemically induced systemic acquired resistance Genome 49, 1594-1605, (2006) DOI: 10.1139/g06-125

Coffea arabica is susceptible to several pests and diseases, some of which affect the leaves and roots. Systemic acquired resistance (SAR) is the main defence mechanism activated in plants in response to pathogen attack. Here, we report the effects of benzo(1,2,3)thiadiazole-7-carbothioic acid-s-methyl ester (BTH), a SAR chemical inducer, on the expression profile of C. arabica. Two cDNA libraries were constructed from the mRNA isolated from leaves and embryonic roots to create 1587 nonredundant expressed sequence tags (ESTs). We developed a cDNA microarray containing 1506 ESTs from the leaves and embryonic roots, and 48 NBS-LRR (nucleotide-binding site leucine-rich repeat) gene fragments derived from 2 specific genomic libraries. Competitive hybridization between untreated and BTH-treated leaves resulted in 55 genes that were significantly overexpressed and 16 genes that were significantly underexpressed. In the roots, 37 and 42 genes were over and underexpressed, respectively. A general shift in metabolism from housekeeping to defence occurred in the leaves and roots after BTH treatment. We observed a systemic increase in pathogenesis-related protein synthesis, in the oxidative burst, and in the cell wall strengthening processes. Moreover, responses in the roots and leaves varied significantly.
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