Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
To maintain homeostasis in the face of intrinsic and extrinsic insults, cells have evolved elaborate quality control networks to resolve damage at multiple levels. Interorganellar communication is a key requirement for this maintenance, however the underlying mechanisms of this communication have remained an enigma. Here we integrate the outcome of transcriptomic, proteomic, and metabolomics analyses of genotypes including ceh1, a mutant with constitutively elevated levels of both the stress‐specific plastidial retrograde signaling metabolite methyl‐erythritol cyclodiphosphate (MEcPP) and the defense hormone salicylic acid (SA), as well as the high MEcPP but SA deficient genotype ceh1/eds16, along with corresponding controls. Integration of multi‐omic analyses enabled us to delineate the function of MEcPP from SA, and expose the compartmentalized role of this retrograde signaling metabolite in induction of distinct but interdependent signaling cascades instrumental in adaptive responses. Specifically, here we identify strata of MEcPP‐sensitive stress‐response cascades, among which we focus on selected pathways including organelle‐specific regulation of jasmonate biosynthesis; simultaneous induction of synthesis and breakdown of SA; and MEcPP‐mediated alteration of cellular redox status in particular glutathione redox balance. Collectively, these integrated multi‐omic analyses provided a vehicle to gain an in‐depth knowledge of genome‐metabolism interactions, and to further probe the extent of these interactions and delineate their functional contributions. Through this approach we were able to pinpoint stress‐mediated transcriptional and metabolic signatures and identify the downstream processes modulated by the independent or overlapping functions of MEcPP and SA in adaptive responses.
Publikation
Voiniciuc, C.;Whole-seed Immunolabeling of Arabidopsis Mucilage PolysaccharidesBio Protoc.7e2323(2017)DOI: 10.21769/BioProtoc.2323
In addition to synthesizing and secreting copious amounts of pectic polymers (Young et al., 2008), Arabidopsis thaliana seed coat epidermal cells produce small amounts of cellulose and hemicelluloses typical of secondary cell walls (Voiniciuc et al., 2015c). These components are intricately linked and are released as a large mucilage capsule upon hydration of mature seeds. Alterations in the structure of minor mucilage components can have dramatic effects on the architecture of this gelatinous cell wall. The immunolabeling protocol described here makes it possible to visualize the distribution of specific polysaccharides in the seed mucilage capsule.
Publikation
Schönberg, A.; Rödiger, A.; Mehwald, W.; Galonska, J.; Christ, G.; Helm, S.; Thieme, D.; Majovsky, P.; Hoehenwarter, W.; Baginsky, S.;Identification of STN7/STN8 kinase targets reveals connections between electron transport, metabolism and gene expressionPlant J.901176-1186(2017)DOI: 10.1111/tpj.13536
The thylakoid‐associated kinases STN7 and STN8 are involved in short‐ and long‐term acclimation of photosynthetic electron transport to changing light conditions. Here we report the identification of STN7/STN8 in vivo targets that connect photosynthetic electron transport with metabolism and gene expression. Comparative phosphoproteomics with the stn7 and stn8 single and double mutants identified two proteases, one RNA‐binding protein, a ribosomal protein, the large subunit of Rubisco and a ferredoxin‐NADP reductase as targets for the thylakoid‐associated kinases. Phosphorylation of three of the above proteins can be partially complemented by STN8 in the stn7 single mutant, albeit at lower efficiency, while phosphorylation of the remaining three proteins strictly depends on STN7. The properties of the STN7‐dependent phosphorylation site are similar to those of phosphorylated light‐harvesting complex proteins entailing glycine or another small hydrophobic amino acid in the −1 position. Our analysis uncovers the STN7/STN8 kinases as mediators between photosynthetic electron transport, its immediate downstream sinks and long‐term adaptation processes affecting metabolite accumulation and gene expression.
Publikation
Nakano, R. T.; Piślewska-Bednarek, M.; Yamada, K.; Edger, P. P.; Miyahara, M.; Kondo, M.; Böttcher, C.; Mori, M.; Nishimura, M.; Schulze-Lefert, P.; Hara-Nishimura, I.; Bednarek, P.;PYK10 myrosinase reveals a functional coordination between endoplasmic reticulum bodies and glucosinolates in Arabidopsis thalianaPlant J.89204-220(2017)DOI: 10.1111/tpj.13377
The endoplasmic reticulum body (ER body) is an organelle derived from the ER that occurs in only three families of the order Brassicales and is suggested to be involved in plant defense. ER bodies in Arabidopsis thaliana contain large amounts of β‐glucosidases, but the physiological functions of ER bodies and these enzymes remain largely unclear. Here we show that PYK10, the most abundant β‐glucosidase in A. thaliana root ER bodies, hydrolyzes indole glucosinolates (IGs) in addition to the previously reported in vitro substrate scopolin. We found a striking co‐expression between ER body‐related genes (including PYK10), glucosinolate biosynthetic genes and the genes for so‐called specifier proteins affecting the terminal products of myrosinase‐mediated glucosinolate metabolism, indicating that these systems have been integrated into a common transcriptional network. Consistent with this, comparative metabolite profiling utilizing a number of A. thaliana relatives within Brassicaceae identified a clear phylogenetic co‐occurrence between ER bodies and IGs, but not between ER bodies and scopolin. Collectively, our findings suggest a functional link between ER bodies and glucosinolate metabolism in planta. In addition, in silico three‐dimensional modeling, combined with phylogenomic analysis, suggests that PYK10 represents a clade of 16 myrosinases that arose independently from the other well‐documented class of six thioglucoside glucohydrolases. These findings provide deeper insights into how glucosinolates are metabolized in cruciferous plants and reveal variation of the myrosinase–glucosinolate system within individual plants.