Spoel, Steven H. Koornneef, Annemart Claessens, Susanne M. C. Korzelius, Jerôme P. Pelt, Johan A. van Mueller, Martin J. Buchala, Antony J. Métraux, Jean-Pierre Brown, Rebecca Kazan, Kemal Loon, L. C. van Dong, Xinnian Pieterse, Corné M. J. 2003-02-21 Plant defenses against pathogens and insects are regulated differentially by cross-communicating signal transduction pathways in which salicylic acid (SA) and jasmonic acid (JA) play key roles. In this study, we investigated the molecular mechanism of the antagonistic effect of SA on JA signaling. Arabidopsis plants unable to accumulate SA produced 25-fold higher levels of JA and showed enhanced expression of the JA-responsive genes <i>LOX2</i>, <i>PDF1.2</i>, and <i>VSP</i> in response to infection by <i>Pseudomonas syringae</i> pv <i>tomato</i> DC3000, indicating that in wild-type plants, pathogen-induced SA accumulation is associated with the suppression of JA signaling. Analysis of the Arabidopsis mutant <i>npr1</i>, which is impaired in SA signal transduction, revealed that the antagonistic effect of SA on JA signaling requires the regulatory protein NPR1. Nuclear localization of NPR1, which is essential for SA-mediated defense gene expression, is not required for the suppression of JA signaling, indicating that cross-talk between SA and JA is modulated through a novel function of NPR1 in the cytosol. application/pdf https://folia.unifr.ch/global/documents/300148 https://folia.unifr.ch/documents/300148/files/1_metraux_nmc.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1105/tpc.009159 info:eu-repo/semantics/openAccess License undefined The Plant Cell. - 2003, vol. 15, p. 760 info:eu-repo/classification/udc/57 NPR1 modulates cross-talk between salicylate- and jasmonate-dependent defense pathways through a novel function in the cytosol http://purl.org/coar/resource_type/c_6501