Publikation
Wasternack, C.; Hause, B.; BFP1: One of 700 Arabidopsis F-box proteins mediates degradation of JA oxidases to promote plant immunity Mol. Plant 17, 375-376, (2024) DOI: 10.1016/j.molp.2024.02.008
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Publikation
Bassal, M.; Abukhalaf, M.; Majovsky, P.; Thieme, D.; Herr, T.; Ayash, M.; Tabassum, N.; Al Shweiki, M. R.; Proksch, C.; Hmedat, A.; Ziegler, J.; Lee, J.; Neumann, S.; Hoehenwarter, W.; Reshaping of the Arabidopsis thaliana Proteome Landscape and Co-regulation of Proteins in Development and Immunity Mol. Plant 13, 1709-1732, (2020) DOI: 10.1016/j.molp.2020.09.024
Proteome remodeling is a fundamental adaptive response, and proteins in
complexes and functionally related proteins are often co-expressed.
Using a deep sampling strategy we define core proteomes of Arabidopsis thaliana
tissues with around 10 000 proteins per tissue, and absolutely quantify
(copy numbers per cell) nearly 16 000 proteins throughout the plant
lifecycle. A proteome-wide survey of global post-translational
modification revealed amino acid exchanges pointing to potential
conservation of translational infidelity in eukaryotes. Correlation
analysis of protein abundance uncovered potentially new tissue- and
age-specific roles of entire signaling modules regulating transcription
in photosynthesis, seed development, and senescence and abscission.
Among others, the data suggest a potential function of RD26 and other
NAC transcription factors in seed development related to desiccation
tolerance as well as a possible function of cysteine-rich receptor-like
kinases (CRKs) as ROS sensors in senescence. All of the components of
ribosome biogenesis factor (RBF) complexes were found to be co-expressed
in a tissue- and age-specific manner, indicating functional promiscuity
in the assembly of these less-studied protein complexes in Arabidopsis. Furthermore, we characterized detailed proteome remodeling in basal immunity by treating Arabidopsis
seeldings with flg22. Through simultaneously monitoring
phytohormone and transcript changes upon flg22 treatment, we obtained
strong evidence of suppression of jasmonate (JA) and JA-isoleucine
(JA-Ile) levels by deconjugation and hydroxylation by IAA-ALA RESISTANT3
(IAR3) and JASMONATE-INDUCED OXYGENASE 2 (JOX2), respectively, under
the control of JASMONATE INSENSITIVE 1 (MYC2), suggesting an
unrecognized role of a new JA regulatory switch in pattern-triggered
immunity. Taken together, the datasets generated in this study present
extensive coverage of the Arabidopsis proteome in various biological scenarios, providing a rich resource available to the whole plant science community.
Publikation
Schulze, A.; Zimmer, M.; Mielke, S.; Stellmach, H.; Melnyk, C. W.; Hause, B.; Gasperini, D.; Wound-Induced Shoot-to-Root Relocation of JA-Ile Precursors Coordinates Arabidopsis Growth Mol. Plant 12, 1383-1394, (2019) DOI: 10.1016/j.molp.2019.05.013
Multicellular organisms rely on the movement of signaling molecules across cells, tissues, and organs to communicate among distal sites. In plants, localized leaf damage activates jasmonic acid (JA)-dependent transcriptional reprogramming in both harmed and unharmed tissues. Although it has been indicated that JA species can translocate from damaged into distal sites, the identity of the mobile compound(s), the tissues through which they translocate, and the effect of their relocation remain unknown. Here, we found that following shoot wounding, the relocation of endogenous jasmonates through the phloem is essential to initiate JA signaling and stunt growth in unharmed roots of Arabidopsis thaliana. By employing grafting experiments and hormone profiling, we uncovered that the hormone precursor cis-12-oxo-phytodienoic acid (OPDA) and its derivatives, but not the bioactive JA-Ile conjugate, translocate from wounded shoots into undamaged roots. Upon root relocation, the mobile precursors cooperatively regulated JA responses through their conversion into JA-Ile and JA signaling activation. Collectively, our findings demonstrate the existence of long-distance translocation of endogenous OPDA and its derivatives, which serve as mobile molecules to coordinate shoot-to-root responses, and highlight the importance of a controlled redistribution of hormone precursors among organs during plant stress acclimation.
Publikation
Stenzel, I.; Ziethe, K.; Schurath, J.; Hertel, S. C.; Bosse, D.; Köck, M.; Differential expression of the LePS2 phosphatase gene family in response to phosphate availability, pathogen infection and during development Physiol. Plant. 118, 138-146, (2003) DOI: 10.1034/j.1399-3054.2003.00091.x
In this study, we report the cloning of the three‐member LePS2 gene family of acid phosphatases via subtractive screening of a cDNA library of Pi‐starved cultivated tomato cells (Lycopersicon esculentum Mill. cv. Lukullus). As members of the plant Pi‐starvation response, LePS2 genes were tightly regulated in cultivated cells and tomato seedlings by Pi availability. The LePS2 enzymes which are most likely expressed in the cytoplasma could be involved in processes that are accompanied by degradation of phosphorylated organic substrates. Independently from exogenous phosphate supply LePS2 expression was detected in tomato endosperm during germination. LePS2 genes were differentially induced after infection with the bacterial pathogen Pseudomonas syringae and in the early stages of flower development. Using RT–PCR it was found that the gene LePS2B was the most abundant transcript in phosphate‐depleted cells, but a reduced expression was determined in floral buds and it was not found during pathogen interaction. In this respect, it is interesting that the promoter sequences of the LePS2 genes are also divergent. LePS2 gene products may have functions in developmental processes which are restricted to distinct plant tissues or cell types.
Publikation
Phosphate (Pi) plays a central role as reactant and effector molecule in plant cell metabolism. However, Pi is the least accessible macronutrient in many ecosystems and its low availability often limits plant growth. Plants have evolved an array of molecular and morphological adaptations to cope with Pi limitation, which include dramatic changes in gene expression and root development to facilitate Pi acquisition and recycling. Although physiological responses to Pi starvation have been increasingly studied and understood, the initial molecular events that monitor and transmit information on external and internal Pi status remain to be elucidated in plants. This review summarizes molecular and developmental Pi starvation responses of higher plants and the evidence for coordinated regulation of gene expression, followed by a discussion of the potential involvement of plant hormones in Pi sensing and of molecular genetic approaches to elucidate plant signalling of low Pi availability. Complementary genetic strategies in Arabidopsis thaliana have been developed that are expected to identify components of plant signal transduction pathways involved in Pi sensing. Innovative screening methods utilize reporter gene constructs, conditional growth on organophosphates and the inhibitory properties of the Pi analogue phosphite, which hold the promise for significant advances in our understanding of the complex mechanisms by which plants regulate Pi‐starvation responses.
Publikation
Wasternack, C.; Atzorn, R.; Leopold, J.; Feussner, I.; Rademacher, W.; Parthier, B.; Synthesis of jasmonate-induced proteins in barley (Hordeum vulgare) is inhibited by the growth retardant tetcyclacis Physiol. Plant. 94, 335-341, (1995) DOI: 10.1111/j.1399-3054.1995.tb05320.x
BarJey leaf segments treated with jasmonate respond with the synthesis of specific proseins, referred to as jasmonate‐induced proteins (JIPs). Application of abscisic acid (ABAl also induced JIP synthesis (Weidhase et al. 1987). In this study the effects of inhibitors on sorbitol‐induced increases of endogenous jasmonates and ABA were investigated. The promotion of jasmonates by sorbitol was inhibited by the growth retardant tetcyclacis at concentrations as low as 1 ftM. In parallel with the decrease of jasmonates, JIP gene expression was reduced as reflected by a decline in the level of a 23‐kDa protein UIP‐23) and mRNAs of JIP‐6 and JIP‐23. 12‐Oxo‐phytodienoic acid, an inlermediale in the lipoxygenase (LOX) pathway leading to jasmonic acid was able to overcome the inhibition by tetcyclacis and increases both the endogenous jasmonate content and transcript accumulation. This suggests that tetcyclacis acts upstream of 12‐oxo‐phytodienoic acid and in keeping with this proposal, an increase in relative LOX activity was detected after tetcyclacis treatment. Although tetcyclacis was shown to inhibit the degradation of ABA to phaseic acid, its effect on jasmonate synthesis is much more pronounced.