OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 145/2/450    most recent pp.107.106021v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Zhang, Z. Articles by He, Z. Search for Related Content PubMed PubMed Citation Articles by Zhang, Z. Articles by He, Z. Agricola Articles by Zhang, Z. Articles by He, Z.

PLANTS INTERACTING WITH OTHER ORGANISMS

Dual Regulation Role of GH3.5 in Salicylic Acid and Auxin Signaling during Arabidopsis-Pseudomonas syringae Interaction^1,[W],[OA]

National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China (Z.Z., Q.L., M.W., Y.Z., Z.H.); Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (Z.L.); and Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583 (P.E.S.)

Salicylic acid (SA) plays a central role in plant disease resistance, and emerging evidence indicates that auxin, an essential plant hormone in regulating plant growth and development, is involved in plant disease susceptibility. GH3.5, a member of the GH3 family of early auxin-responsive genes in Arabidopsis (Arabidopsis thaliana), encodes a protein possessing in vitro adenylation activity on both indole-3-acetic acid (IAA) and SA. Here, we show that GH3.5 acts as a bifunctional modulator in both SA and auxin signaling during pathogen infection. Overexpression of the GH3.5 gene in an activation-tagged mutant gh3.5-1D led to elevated accumulation of SA and increased expression of PR-1 in local and systemic tissues in response to avirulent pathogens. In contrast, two T-DNA insertional mutations of GH3.5 partially compromised the systemic acquired resistance associated with diminished PR-1 expression in systemic tissues. The gh3.5-1D mutant also accumulated high levels of free IAA after pathogen infection and impaired different resistance-gene-mediated resistance, which was also observed in the GH3.6 activation-tagged mutant dfl1-D that impacted the auxin pathway, indicating an important role of GH3.5/GH3.6 in disease susceptibility. Furthermore, microarray analysis showed that the SA and auxin pathways were simultaneously augmented in gh3.5-1D after infection with an avirulent pathogen. The SA pathway was amplified by GH3.5 through inducing SA-responsive genes and basal defense components, whereas the auxin pathway was derepressed through up-regulating IAA biosynthesis and down-regulating auxin repressor genes. Taken together, our data reveal novel regulatory functions of GH3.5 in the plant-pathogen interaction.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Zuhua He (zhhe{at}sibs.ac.cn).

^[W] The online version of this article contains Web-only data.

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.107.106021

^* Corresponding author; e-mail zhhe{at}sibs.ac.cn.

Received July 23, 2007; accepted August 9, 2007; published August 17, 2007.

This article has been cited by other articles:

				D.-L. Yang, Q. Li, Y.-W. Deng, Y.-G. Lou, M.-Y. Wang, G.-X. Zhou, Y.-Y. Zhang, and Z.-H. He Altered Disease Development in the eui Mutants and Eui Overexpressors Indicates that Gibberellins Negatively Regulate Rice Basal Disease Resistance Mol Plant, May 13, 2008; (2008) ssn021v2. [Abstract] [Full Text] [PDF]

				X. Ding, Y. Cao, L. Huang, J. Zhao, C. Xu, X. Li, and S. Wang Activation of the Indole-3-Acetic Acid-Amido Synthetase GH3-8 Suppresses Expansin Expression and Promotes Salicylate- and Jasmonate-Independent Basal Immunity in Rice PLANT CELL, January 1, 2008; 20(1): 228 - 240. [Abstract] [Full Text] [PDF]