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Publikationen - Molekulare Signalverarbeitung

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Publikation

Wasternack, C.; Termination in Jasmonate Signaling by MYC2 and MTBs Trends Plant Sci. 24, 667-669, (2019) DOI: 10.1016/j.tplants.2019.06.001

Jasmonic acid (JA) signaling can be switched off by metabolism of JA. The master regulator MYC2, interacting with MED25, has been shown to be deactivated by the bHLH transcription factors MTB1, MTB2, and MTB3. An autoregulatory negative feedback loop has been proposed for this termination in JA signaling.
Publikation

Wasternack, C.; New Light on Local and Systemic Wound Signaling Trends Plant Sci. 24, 102-105, (2019) DOI: 10.1016/j.tplants.2018.11.009

Electric signaling and Ca2+ waves were discussed to occur in systemic wound responses. Two new overlapping scenarios were identified: (i) membrane depolarization in two special cell types followed by an increase in systemic cytoplasmic Ca2+ concentration ([Ca2+]cyt), and (ii) glutamate sensed by GLUTAMATE RECEPTOR LIKE proteins and followed by Ca2+-based defense in distal leaves.
Publikation

Wasternack, C.; Hause, B.; A Bypass in Jasmonate Biosynthesis – the OPR3-independent Formation Trends Plant Sci. 23, 276-279, (2018) DOI: 10.1016/j.tplants.2018.02.011

For the first time in 25 years, a new pathway for biosynthesis of jasmonic acid (JA) has been identified. JA production takes place via 12-oxo-phytodienoic acid (OPDA) including reduction by OPDA reductases (OPRs). A loss-of-function allele, opr3-3, revealed an OPR3-independent pathway converting OPDA to JA.
Publikation

Dinesh, D. C.; Calderón Villalobos, L. I. A.; Abel, S.; Structural Biology of Nuclear Auxin Action Trends Plant Sci. 21, 302-316, (2016) DOI: 10.1016/j.tplants.2015.10.019

Auxin coordinates plant development largely via hierarchical control of gene expression. During the past decades, the study of early auxin genes paired with the power of Arabidopsis genetics have unraveled key nuclear components and molecular interactions that perceive the hormone and activate primary response genes. Recent research in the realm of structural biology allowed unprecedented insight into: (i) the recognition of auxin-responsive DNA elements by auxin transcription factors; (ii) the inactivation of those auxin response factors by early auxin-inducible repressors; and (iii) the activation of target genes by auxin-triggered repressor degradation. The biophysical studies reviewed here provide an impetus for elucidating the molecular determinants of the intricate interactions between core components of the nuclear auxin response module.
Publikation

Wasternack, C.; Hause, B.; Blütenduft, Abwehr, Entwicklung: Jasmonsäure - ein universelles Pflanzenhormon Biologie in unserer Zeit 44, 164-171, (2014) DOI: 10.1002/biuz.201410535

Pflanzen müssen gegen vielfältige biotische und abiotische Umwelteinflusse eine Abwehr aufbauen. Aber gleichzeitig müssen sie wachsen und sich vermehren. Jasmonate sind neben anderen Hormonen ein zentrales Signal bei der Etablierung von Abwehrmechanismen, aber auch Signal von Entwicklungsprozessen wie Blüten‐ und Trichombildung, sowie der Hemmung von Wachstum. Biosynthese und essentielle Komponenten der Signaltransduktion von JA und seinem biologisch aktiven Konjugat JA‐Ile sind gut untersucht. Der Rezeptor ist ein Proteinkomplex, der “JA‐Ile‐Wahrnehmung” mit proteasomalem Abbau von Repressorproteinen verbindet. Dadurch können positiv agierende Transkriptionsfaktoren wirksam werden und vielfältige Genexpressionsänderungen auslösen. Dies betrifft die Bildung von Abwehrproteinen, Enzymen der JA‐Biosynthese und Sekundärstoffbildung, und Proteinen von Signalketten und Entwicklungsprozessen. Die Kenntnisse zur JA‐Ile‐Wirkung werden in Landwirtschaft und Biotechnologie genutzt.
Publikation

Robson, F.; Okamoto, H.; Patrick, E.; Harris, S.-R.; Wasternack, C.; Brearley, C.; Turner, J. G.; Jasmonate and Phytochrome A Signaling in Arabidopsis Wound and Shade Responses Are Integrated through JAZ1 Stability Plant Cell 22, 1143-1160, (2010) DOI: 10.1105/tpc.109.067728

Jasmonate (JA) activates plant defense, promotes pollen maturation, and suppresses plant growth. An emerging theme in JA biology is its involvement in light responses; here, we examine the interdependence of the JA- and light-signaling pathways in Arabidopsis thaliana. We demonstrate that mutants deficient in JA biosynthesis and signaling are deficient in a subset of high irradiance responses in far-red (FR) light. These mutants display exaggerated shade responses to low, but not high, R/FR ratio light, suggesting a role for JA in phytochrome A (phyA) signaling. Additionally, we demonstrate that the FR light–induced expression of transcription factor genes is dependent on CORONATINE INSENSITIVE1 (COI1), a central component of JA signaling, and is suppressed by JA. phyA mutants had reduced JA-regulated growth inhibition and VSP expression and increased content of cis-(+)-12-oxophytodienoic acid, an intermediate in JA biosynthesis. Significantly, COI1-mediated degradation of JASMONATE ZIM DOMAIN1-β-glucuronidase (JAZ1-GUS) in response to mechanical wounding and JA treatment required phyA, and ectopic expression of JAZ1-GUS resulted in exaggerated shade responses. Together, these results indicate that JA and phyA signaling are integrated through degradation of the JAZ1 protein, and both are required for plant responses to light and stress.
Publikation

Mugford, S. G.; Yoshimoto, N.; Reichelt, M.; Wirtz, M.; Hill, L.; Mugford, S. T.; Nakazato, Y.; Noji, M.; Takahashi, H.; Kramell, R.; Gigolashvili, T.; Flügge, U.-I.; Wasternack, C.; Gershenzon, J.; Hell, R.; Saito, K.; Kopriva, S.; Disruption of Adenosine-5′-Phosphosulfate Kinase in Arabidopsis Reduces Levels of Sulfated Secondary Metabolites Plant Cell 21, 910-927, (2009) DOI: 10.1105/tpc.109.065581

Plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5′-phosphosulfate (APS). APS can be reduced to sulfide and incorporated into Cys in the primary sulfate assimilation pathway or phosphorylated by APS kinase to 3′-phosphoadenosine 5′-phosphosulfate, which is the activated sulfate form for sulfation reactions. To assess to what extent APS kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in Arabidopsis thaliana. Analysis of T-DNA insertion knockout lines for each of the four isoforms did not reveal any phenotypical alterations. However, when all six combinations of double mutants were compared, the apk1 apk2 plants were significantly smaller than wild-type plants. The levels of glucosinolates, a major class of sulfated secondary metabolites, and the sulfated 12-hydroxyjasmonate were reduced approximately fivefold in apk1 apk2 plants. Although auxin levels were increased in the apk1 apk2 mutants, as is the case for most plants with compromised glucosinolate synthesis, typical high auxin phenotypes were not observed. The reduction in glucosinolates resulted in increased transcript levels for genes involved in glucosinolate biosynthesis and accumulation of desulfated precursors. It also led to great alterations in sulfur metabolism: the levels of sulfate and thiols increased in the apk1 apk2 plants. The data indicate that the APK1 and APK2 isoforms of APS kinase play a major role in the synthesis of secondary sulfated metabolites and are required for normal growth rates.
Publikation

Lee, C.-W.; Efetova, M.; Engelmann, J. C.; Kramell, R.; Wasternack, C.; Ludwig-Müller, J.; Hedrich, R.; Deeken, R.; Agrobacterium tumefaciens Promotes Tumor Induction by Modulating Pathogen Defense in Arabidopsis thaliana Plant Cell 21, 2948-2962, (2009) DOI: 10.1105/tpc.108.064576

Agrobacterium tumefaciens causes crown gall disease by transferring and integrating bacterial DNA (T-DNA) into the plant genome. To examine the physiological changes and adaptations during Agrobacterium-induced tumor development, we compared the profiles of salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and auxin (indole-3-acetic acid [IAA]) with changes in the Arabidopsis thaliana transcriptome. Our data indicate that host responses were much stronger toward the oncogenic strain C58 than to the disarmed strain GV3101 and that auxin acts as a key modulator of the Arabidopsis–Agrobacterium interaction. At initiation of infection, elevated levels of IAA and ET were associated with the induction of host genes involved in IAA, but not ET signaling. After T-DNA integration, SA as well as IAA and ET accumulated, but JA did not. This did not correlate with SA-controlled pathogenesis-related gene expression in the host, although high SA levels in mutant plants prevented tumor development, while low levels promoted it. Our data are consistent with a scenario in which ET and later on SA control virulence of agrobacteria, whereas ET and auxin stimulate neovascularization during tumor formation. We suggest that crosstalk among IAA, ET, and SA balances pathogen defense launched by the host and tumor growth initiated by agrobacteria.
Publikation

Brüx, A.; Liu, T.-Y.; Krebs, M.; Stierhof, Y.-D.; Lohmann, J. U.; Miersch, O.; Wasternack, C.; Schumacher, K.; Reduced V-ATPase Activity in the trans-Golgi Network Causes Oxylipin-Dependent Hypocotyl Growth Inhibition in Arabidopsis Plant Cell 20, 1088-1100, (2008) DOI: 10.1105/tpc.108.058362

Regulated cell expansion allows plants to adapt their morphogenesis to prevailing environmental conditions. Cell expansion is driven by turgor pressure created by osmotic water uptake and is restricted by the extensibility of the cell wall, which in turn is regulated by the synthesis, incorporation, and cross-linking of new cell wall components. The vacuolar H+-ATPase (V-ATPase) could provide a way to coordinately regulate turgor pressure and cell wall synthesis, as it energizes the secondary active transport of solutes across the tonoplast and also has an important function in the trans-Golgi network (TGN), which affects synthesis and trafficking of cell wall components. We have previously shown that det3, a mutant with reduced V-ATPase activity, has a severe defect in cell expansion. However, it was not clear if this is caused by a defect in turgor pressure or in cell wall synthesis. Here, we show that inhibition of the tonoplast-localized V-ATPase subunit isoform VHA-a3 does not impair cell expansion. By contrast, inhibition of the TGN-localized isoform VHA-a1 is sufficient to restrict cell expansion. Furthermore, we provide evidence that the reduced hypocotyl cell expansion in det3 is conditional and due to active, hormone-mediated growth inhibition caused by a cell wall defect.
Publikation

Grubb, C. D.; Abel, S.; Glucosinolate metabolism and its control Trends Plant Sci. 11, 89-100, (2006) DOI: 10.1016/j.tplants.2005.12.006

Glucosinolates and their associated degradation products have long been recognized for their distinctive benefits to human nutrition and plant defense. Because most of the structural genes of glucosinolate metabolism have been identified and functionally characterized in Arabidopsis thaliana, current research increasingly focuses on questions related to the regulation of glucosinolate synthesis, distribution and degradation as well as to the feasibility of engineering customized glucosinolate profiles. Here, we highlight recent progress in glucosinolate research, with particular emphasis on the biosynthetic pathway and its metabolic relationships to auxin homeostasis. We further discuss emerging insight into the signaling networks and regulatory proteins that control glucosinolate accumulation during plant development and in response to environmental challenge.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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