Genome-wide identification of WRKY45-regulated genes that mediate benzothiadiazole-induced defense responses in rice

BMC Plant Biology

Research Article

Shingo Goto¹  Muneo Yamazaki¹  Setsuko Fukushima¹  Chang-Jie Jiang¹  Haruhiko Inoue¹  Shoji Sugano¹  Aya Akagi²  Masaki Shimono³  Hiroshi Takatsuji⁴  Akane Matsushita⁵  Akira Nakayama⁶ 

[1] Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Bayer CropScience, 100-8262, Tokyo, Japan;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Department of Plant Pathology, Michigan State University, 48824, East Lansing, MI, USA;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 2-1-2, Kannondai, 305–8602, Tsukuba, Ibaraki, Japan;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Du Pont Kabushiki Kaisha, 2-11-1, Nagata-cho, 100-6111, Chiyoda-ku, Tokyo, Japan;Disease Resistant Crops Research Unit, National Institute of Agrobiological Sciences, 305-8602, Ibaraki, Japan;Maebashi Institute of Technology, 371-0816, Maebashi, Japan;

关键词: WRKY;    Salicylic acid;    Benzothiadiazole;    Magnaporthe oryzae;    OsNPR1;   

DOI  :  10.1186/1471-2229-13-150

 received in 2013-06-26, accepted in 2013-10-02,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe rice transcription factor WRKY45 plays a crucial role in salicylic acid (SA)/benzothiadiazole (BTH)-induced disease resistance. Its knockdown severely reduces BTH-induced resistance to the fungal pathogen Magnaporthe oryzae and the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). Conversely, overexpression of WRKY45 induces extremely strong resistance to both of these pathogens. To elucidate the molecular basis of WRKY45-dependent disease resistance, we analyzed WRKY45-regulated gene expression using rice transformants and a transient gene expression system.ResultsWe conducted a microarray analysis using WRKY45-knockdown (WRKY45-kd) rice plants, and identified WRKY45-dependent genes among the BTH-responsive genes. The BTH-responsiveness of 260 genes was dependent on WRKY45. Among these, 220 genes (85%), many of which encoded PR proteins and proteins associated with secondary metabolism, were upregulated by BTH. Only a small portion of these genes overlapped with those regulated by OsNPR1/NH1, supporting the idea that the rice SA pathway branches into WRKY45- regulated and OsNPR1/NH1-regulated subpathways. Dexamethazone-induced expression of myc-tagged WRKY45 in rice immediately upregulated transcription of endogenous WRKY45 and genes encoding the transcription factors WRKY62, OsNAC4, and HSF1, all of which have been reported to have defense-related functions. This was followed by upregulation of defense genes encoding PR proteins and secondary metabolic enzymes. Many of these genes were also induced after M. oryzae infection. Their temporal transcription patterns were consistent with those after dexamethazone-induced WRKY45 expression. In a transient expression system consisting of particle bombardment of rice coleoptiles, WRKY45 acted as an effector to trans-activate reporter genes in which the luciferase coding sequence was fused to upstream and intragenic sequences of WRKY62 and OsNAC4. Trans-activation of transcription occurred through a W-box-containing sequence upstream of OsNAC4 and mutations in the W-boxes abolished the trans-activation.ConclusionsThese data suggest a role of WRKY45 in BTH-induced disease resistance as a master regulator of the transcriptional cascade regulating defense responses in one of two branches in the rice SA pathway.

【 授权许可】

Unknown   
© Nakayama et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.