Hwang Seon-Hee, Kwon Soon Il, Jang Ji-Young, Fang Il Lan, Lee Heyoung, Choi Changhyun, Park Sangryeol, Ahn Ilpyung, Bae Shin-Chul, Hwang Duk-Ju
National Institute of Agricultural Science, Rural Development Administration, Jeonju, 560-500, Korea.
Convergence Research Center for Functional Plant Products, Advanced Institutes of Convergence Technology (AICT), Suwon, 443-270, Korea.
Plant Cell Rep. 2016 Sep;35(9):1975-85. doi: 10.1007/s00299-016-2012-0. Epub 2016 Jun 14.
OsWRKY51 functions as a positive transcriptional regulator in defense signaling against Xanthomonas oryzae pv. oryzae by direct DNA binding to the promoter of defense related gene, OsPR10a. OsWRKY51 in rice (Oryza sativa L.) is induced by exogenous salicylic acid (SA) and inoculation with Xanthomonas oryzae pv. oryzae (Xoo). To examine the role of OsWRKY51 in the defense response of rice, we generated OsWRKY51 overexpressing and underexpressing transgenic rice plants. OsWRKY51-overexpressing transgenic rice lines were more resistant to Xoo and showed greater expression of defense-related genes than wild-type (WT) plants, while OsWRKY51-underexpressing lines were more susceptible to Xoo and showed less expression of defense-associated genes than WT plants. Transgenic lines overexpressing OsWRKY51 showed growth retardation compared to WT plants. In contrast, transgenic lines underexpressing OsWRKY51 by RNA interference showed similar plant height with WT plants. Transient expression of OsWRKY51-green fluorescent protein fusion protein in rice protoplasts revealed that OsWRKY51 was localized in the nucleus. OsWRKY51 bound to the W-box and WLE1 elements of the OsPR10a promoter. Based on these results, we suggest that OsWRKY51 is a positive transcriptional regulator of defense signaling and has direct DNA binding ability to the promoter of OsPR10a, although it is reported to be a negative regulator in GA signaling.
OsWRKY51作为一种正向转录调节因子，通过直接与防御相关基因OsPR10a的启动子结合，参与水稻对水稻白叶枯病菌的防御信号传导。水稻（Oryza sativa L.）中的OsWRKY51受外源水杨酸（SA）和接种水稻白叶枯病菌（Xoo）诱导。为了研究OsWRKY51在水稻防御反应中的作用，我们构建了OsWRKY51过表达和低表达的转基因水稻植株。与野生型（WT）植株相比，过表达OsWRKY51的转基因水稻株系对白叶枯病菌更具抗性，防御相关基因的表达水平更高；而低表达OsWRKY51的株系对白叶枯病菌更敏感，防御相关基因的表达水平低于野生型植株。与野生型植株相比，过表达OsWRKY51的转基因株系生长迟缓。相反，通过RNA干扰低表达OsWRKY51的转基因株系与野生型植株株高相似。OsWRKY51-绿色荧光蛋白融合蛋白在水稻原生质体中的瞬时表达表明，OsWRKY51定位于细胞核。OsWRKY51与OsPR10a启动子的W-box和WLE1元件结合。基于这些结果，我们认为OsWRKY51是防御信号的正向转录调节因子，对OsPR10a启动子具有直接的DNA结合能力，尽管据报道它在赤霉素信号传导中是负调节因子。
