水稻Rho GDP解离抑制因子OsRhoGDI1基因的特征分析

Characterization of a Rho GDP dissociation inhibitor gene OsRhoGDI1 from rice

摘要:

水稻Rho GDP解离抑制因子1(Rho GDP dissociation inhibitor 1,RhoGDI1)是本课题组前期通过酵母双杂交筛选从幼穗中分离的一个与小G蛋白Rho/Rop家族成员OsRac5相互作用蛋白的编码基因，对该基因特征及其功能的研究报道较少。本研究在对OsRhoGDI1开展生物信息学分析的基础上，利用表达谱芯片挖掘和实时荧光定量聚合酶链式反应(quantitative real time polymerase chain reaction,RT-qPCR)对OsRhoGDI1基因的表达模式进行分析，发现该基因在水稻多种组织中广泛表达，尤其在幼穗发育过程中高表达，且该基因的表达受脱落酸(abscisic acid,ABA)、油菜素内酯(brassinolide,BL)、水杨酸(salicylic acid,SA)、吲哚-3-乙酸(indole-3-acetic acid,IAA)、赤霉素(gibberellin,GA)及盐胁迫的调控。亚细胞定位鉴定显示，OsRhoGDI1分布在细胞膜、细胞质以及细胞核中。双分子荧光互补(bimolecular fluorescence complementation,BiFC)技术检测发现OsRhoGDI1与OsRac5在细胞膜、细胞质和细胞核均能发生互作，OsRhoGDI1还可与OsRac1在细胞膜上相互作用。本研究表明，OsRhoGDI1与水稻穗发育等过程密切相关，并且OsRhoGDI1可能通过与不同Rho/Rop蛋白结合并调节其活性，参与调控水稻生长发育、激素应答以及非生物胁迫等多种生物学过程。

Abstract:

The Rho GDP dissociation inhibitor gene OsRhoGDI1 was isolated as the putative partner of OsRac5 from rice young panicles by the yeast two-hybrid screening, but the characterization and functions of the gene remains unknown. In this study, on the basis of the bioinformatics analysis, expression profile chip mining and RT-qPCR were employed to analyze the expression pattern of OsRhoGDI1, and it was found that the gene was widely expressed in various tissues of rice, especially with high abundance during the development of young panicles, and its expression was regulated by abscisic acid (ABA), brassinolide (BL), salicylic acid (SA), indole-3-acetic acid (IAA), gibberellin (GA) and high salinity. Subcellular localization identification showed that OsRhoGDI1 was distributed in the cytomembrane, cytoplasm, and nucleus. Bimolecular fluorescence completion (BiFC) was further performed to identify the in vivo interaction between OsRhoGDI1 and OsRac5, the results suggested that the interaction occurred in the nucleus, cytomembrane, and cytoplasm. In addition, OsRhoGDI1 interacted with OsRac1 in the cytomembrane. Our results indicated that OsRhoGDI1 may be involved in rice panicle development, and participate in regulating various biological processes such as rice growth and development, hormone response, and abiotic stress by regulating the activities of different Rho/Rop proteins via interactions.