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First published online September 1, 2006; 10.1104/pp.106.082107 Plant Physiology 142:1169-1179 (2006) © 2006 American Society of Plant Biologists Characterization of a Mitogen-Activated Protein Kinase Gene from Cucumber Required for Trichoderma-Conferred Plant Resistance1Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (M.S., I.C.); and Department of Virology, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel (A.G.-O., D.L.)
The fungal biocontrol agent Trichoderma asperellum has been recently shown to induce systemic resistance in plants through a mechanism that employs jasmonic acid and ethylene signal transduction pathways. Mitogen-activated protein kinase (MAPK) proteins have been implicated in the signal transduction of a wide variety of plant stress responses. Here we report the identification and characterization of a Trichoderma-induced MAPK (TIPK) gene function in cucumber (Cucumis sativus). Similar to its homologs, wound-induced protein kinase, MPK3, and MPK3a, TIPK is also induced by wounding. Normally, preinoculation of roots with Trichoderma activates plant defense mechanisms, which result in resistance to the leaf pathogen Pseudomonas syringae pv lachrymans. We used a unique attenuated virus vector, Zucchini yellow mosaic virus (ZYMV-AGII), to overexpress TIPK protein and antisense (AS) RNA. Plants overexpressing TIPK were more resistant to pathogenic bacterial attack than control plants, even in the absence of Trichoderma preinoculation. On the other hand, plants expressing TIPK-AS revealed increased sensitivity to pathogen attack. Moreover, Trichoderma preinoculation could not protect these AS plants against subsequent pathogen attack. We therefore demonstrate that Trichoderma exerts its protective effect on plants through activation of the TIPK gene, a MAPK that is involved in signal transduction pathways of defense responses.
1 This work was supported by the U.S.-Israel Binational Agricultural Research and Development Fund (grant no. 350704), by the Dr. Alexander and Myrna Strelinger Endowment Fund, and by the Fienberg Graduate School of the Weizmann Institute of Science (postdoctoral fellowship to M.S.). 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: Michal Shoresh (ms534{at}cornell.edu). www.plantphysiol.org/cgi/doi/10.1104/pp.106.082107 * Corresponding author; e-mail ms534{at}cornell.edu; fax 3157872320. Received April 13, 2006; accepted August 15, 2006; published September 1, 2006. This article has been cited by other articles:
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