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Publikationen - Molekulare Signalverarbeitung

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Publikation

Gasperini, D., Chauvin, A., Acosta, I.F., Kurenda, A., Stolz, S., Chétalat, A., Wolfender J.-L. & Farmer, E.E. Axial and Radial Oxylipin Transport. Plant Physiol. 169, 2244-2254, (2015) DOI: 10.1104/pp.15.01104

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Publikation

Gasperini, D., Chételat, A., Acosta, I.F., Goossens, J., Pauwels, L., Goossens, A., Dreos, R., Alonso, E. & Farmer, E.E. Multilayered Organization of Jasmonate Signalling in the Regulation of Root Growth PLoS Genet. 11 (6), e1005300, (2015) DOI: 10.1371/journal.pgen.1005300

Physical damage can strongly affect plant growth, reducing the biomass of developing organs situated at a distance from wounds. These effects, previously studied in leaves, require the activation of jasmonate (JA) signalling. Using a novel assay involving repetitive cotyledon wounding in Arabidopsis seedlings, we uncovered a function of JA in suppressing cell division and elongation in roots. Regulatory JA signalling components were then manipulated to delineate their relative impacts on root growth. The new transcription factor mutant myc2-322B was isolated. In vitro transcription assays and whole-plant approaches revealed that myc2-322B is a dosage-dependent gain-of-function mutant that can amplify JA growth responses. Moreover, myc2-322B displayed extreme hypersensitivity to JA that totally suppressed root elongation. The mutation weakly reduced root growth in undamaged plants but, when the upstream negative regulator NINJA was genetically removed, myc2-322B powerfully repressed root growth through its effects on cell division and cell elongation. Furthermore, in a JA-deficient mutant background, ninja1 myc2-322B still repressed root elongation, indicating that it is possible to generate JA-responses in the absence of JA. We show that NINJA forms a broadly expressed regulatory layer that is required to inhibit JA signalling in the apex of roots grown under basal conditions. By contrast, MYC2, MYC3 and MYC4 displayed cell layer-specific localisations and MYC3 and MYC4 were expressed in mutually exclusive regions. In nature, growing roots are likely subjected to constant mechanical stress during soil penetration that could lead to JA production and subsequent detrimental effects on growth. Our data reveal how distinct negative regulatory layers, including both NINJA-dependent and -independent mechanisms, restrain JA responses to allow normal root growth. Mechanistic insights from this work underline the importance of mapping JA signalling components to specific cell types in order to understand and potentially engineer the growth reduction that follows physical damage.

Publikation

Farmer, E.E., Gasperini, D. & Acosta, I.F. The squeeze cell hypothesis for the activation of jasmonate synthesis in response to wounding New Phytol. 204, 282-288, (2014) DOI: 10.1111/nph.12897

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Publikation

Acosta, I.F., Gasperini, D., Chételat, A., Stolz, S., Santuari, L. & Farmer, E.E. Role of NINJA in root jasmonate signaling. In: PNAS 110 (38), 15473-15478, (2013) DOI: 10.1073/pnas.1307910110

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Publikation

Mur, L.A.J., Kenton, P., Atzorn, R., Miersch, O. & Wasternack, C. The outcomes of concentration specific interactions between salicylate and jasmonate signaling include synergy, antagonism and the activation of cell death Plant Physiol. 140, 249-262, (2006)

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Publikation

Kramell, R., Miersch, O., Atzorn, R., Parthier, B. & Wasternack, C. Octadecanoid-derived alteration of gene expression and the 'oxylipin signature' in stressed barley leaves - implications for different signalling pathways Plant Physiol. 123, 177-186, (2000)

Stress-induced gene expression in barley (Hordeum vulgare cv. Salome) leaves has been correlated with temporally changing levels of octadecanoids and jasmonates, quantified by means of gas chromatography/mass spectrometry-single ion monitoring. Application of sorbitol-induced stress led to a low and transient rise of jasmonic acid (JA), its precursor 12-oxophytodienoic acid (OPDA) and the methyl esters JAME and OPDAME, respectively, followed by a large increase in their levels. JA and JAME peaked between 12 and 16 h, about 4 hours before OPDA and OPDAME. However, OPDA accumulated up to a 2.5-fold higher level than the other compounds. Dihomo-jasmonic acid and 9,13-didehydro-12- oxophytoenoic acid were identified as minor components. Kinetic analyses revealed that a transient threshold of jasmonates or octadecanoids is necessary and sufficient to initiate JA responsive gene expression. Although OPDA and OPDAME applied exogenously were metabolized to JA in considerable amounts, both of them can induce gene expression per se as evidenced by those genes which do not respond to endogenously formed JA. Also, coronatine induces JA-responsive genes independently from endogenous JA. As evidenced by application of deuterated JA, endogenous synthesis of JA is not induced by JA treatment. The data are discussed in terms of distinct signalling pathways.
Publikation

Kenton, P., Mur, L.A.J., Atzorn, R., Wasternack, C. & Draper, J. ()-Jasmonic acid accumulation in tobacco hypersensitive response lesions Mol. Plant Microbiol. Interactions 12, 74-78, (1999) DOI: org/10.1094/MPMI.1999.12.1.74

Tobacco infected with Pseudomonas syringae pv. phaseolicola undergoes a hypersensitive response (HR). Jasmonic acid (JA) accumulated within the developing lesion 3 to 9 h after infection and this accumulation preceded protein loss, cell death, and malondialdehyde accumulation. Accumulating JA consisted largely of the (—)-JA stereoisomer and was essentially restricted to the HR lesion

Publikation

Peña-Cortés, H., Prat, S., Atzorn, R., Wasternack, C. & Willmitzer, L. Pin2 gene expression in potato and tomato detached leaves from ABA-deficient potato and tomato plants upon systemin treatment Planta 198, 447-451, (1996)

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Publikation

O'Donnell, P.J., Calvert, C., Atzorn, R., Wasternack, C., Leyser, H.M.O. & Bowles, D.J. Ethylene as a signal mediating the wound response of tomato plants Science 274, 1914-1917, (1996)

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Publikation

Herde, O., Atzorn, R., Fisahn, J., Wasternack, C., Willmitzer, L. & Peña-Cortés, H. Localized wounding by heat initiates the accumulation of proteinase inhibitor II in abscisic acid-deficient plants by triggering jasmonic acid biosynthesis Plant Physiol. 112, 853-860, (1996)

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