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Salicylic Acid Inhibits Pathogen Growth in Plants through Repression of the Auxin Signaling Pathway

2007; Elsevier BV; Volume: 17; Issue: 20 Linguagem: Inglês

10.1016/j.cub.2007.09.025

1879-0445

Dong Wang, Karolina M. Pajerowska‐Mukhtar, Angela Hendrickson Culler, Xinnian Dong,

Plant Parasitism and Resistance

The phytohormone auxin regulates almost every aspect of plant development. At the molecular level, auxin induces gene expression through direct physical interaction with the TIR1-like F box proteins, which in turn remove the Aux/IAA family of transcriptional repressors [1Dharmasiri N. Dharmasiri S. Estelle M. The F-box protein TIR1 is an auxin receptor.Nature. 2005; 435: 441-445Crossref PubMed Scopus (1438) Google Scholar, 2Kepinski S. Leyser O. The Arabidopsis F-box protein TIR1 is an auxin receptor.Nature. 2005; 435: 446-451Crossref PubMed Scopus (1215) Google Scholar, 3Dharmasiri N. Dharmasiri S. Weijers D. Lechner E. Yamada M. Hobbie L. Ehrismann J.S. Jurgens G. Estelle M. Plant development is regulated by a family of auxin receptor F box proteins.Dev. Cell. 2005; 9: 109-119Abstract Full Text Full Text PDF PubMed Scopus (712) Google Scholar, 4Gray W.M. Kepinski S. Rouse D. Leyser O. Estelle M. Auxin regulates SCF(TIR1)-dependent degradation of AUX/IAA proteins.Nature. 2001; 414: 271-276Crossref PubMed Scopus (969) Google Scholar]. A growing body of evidence indicates that many plant pathogens can either produce auxin themselves or manipulate host auxin biosynthesis to interfere with the host's normal developmental processes [5Manulis S. Haviv-Chesner A. Brandl M.T. Lindow S.E. Barash I. Differential involvement of indole-3-acetic acid biosynthetic pathways in pathogenicity and epiphytic fitness of Erwinia herbicola pv. gypsophilae.Mol. Plant Microbe Interact. 1998; 11: 634-642Crossref PubMed Scopus (125) Google Scholar, 6Manulis S. Shafrir H. Epstein E. Lichter A. Barash I. Biosynthesis of indole-3-acetic acid via the indole-3-acetamide pathway in Streptomyces spp.Microbiology. 1994; 140: 1045-1050Crossref PubMed Scopus (88) Google Scholar, 7Glickmann E. Gardan L. Jacquet S. Hussain S. Elasri M. Petit A. Dessaux Y. Auxin production is a common feature of most pathovars of Pseudomonas syringae.Mol. Plant Microbe Interact. 1998; 11: 156-162Crossref PubMed Scopus (140) Google Scholar, 8Ansari M.M. Sridhar R. Some tryptophan pathways in the phytopathogen Xanthomonas oryzae pv. oryzae.Folia Microbiol. (Praha). 2000; 45: 531-537Crossref PubMed Scopus (5) Google Scholar, 9Chung K.R. Shilts T. Erturk U. Timmer L.W. Ueng P.P. Indole derivatives produced by the fungus Colletotrichum acutatum causing lime anthracnose and postbloom fruit drop of citrus.FEMS Microbiol. Lett. 2003; 226: 23-30Crossref PubMed Scopus (79) Google Scholar, 10Maor R. Haskin S. Levi-Kedmi H. Sharon A. In planta production of indole-3-acetic acid by Colletotrichum gloeosporioides f. sp. aeschynomene.Appl. Environ. Microbiol. 2004; 70: 1852-1854Crossref PubMed Scopus (88) Google Scholar, 11Vandeputte O. Oden S. Mol A. Vereecke D. Goethals K. El Jaziri M. Prinsen E. Biosynthesis of auxin by the gram-positive phytopathogen Rhodococcus fascians is controlled by compounds specific to infected plant tissues.Appl. Environ. Microbiol. 2005; 71: 1169-1177Crossref PubMed Scopus (94) Google Scholar]. In response, plants probably evolved mechanisms to repress auxin signaling during infection as a defense strategy. Plants overaccumulating the defense signal molecule salicylic acid (SA) frequently display morphological phenotypes that are reminiscent of auxin-deficient or auxin-insensitive mutants, indicating that SA might interfere with auxin responses. By using the Affymetrix ATH1 GeneChip for Arabidopsis thaliana, we performed a comprehensive study of the effects of SA on auxin signaling [12Wang D. Amornsiripanitch N. Dong X. A genomic approach to identify regulatory nodes in the transcriptional network of systemic acquired resistance in plants.PLoS Pathog. 2006; 2: e123Crossref PubMed Scopus (470) Google Scholar]. We found that SA causes global repression of auxin-related genes, including the TIR1 receptor gene, resulting in stabilization of the Aux/IAA repressor proteins and inhibition of auxin responses. We demonstrate that this inhibitory effect on auxin signaling is a part of the SA-mediated disease-resistance mechanism.