小麦干旱响应转录因子TaZFP21的功能鉴定及调控机制解析

As important transcription factors, zinc finger proteins (ZFPs) play important roles in plant growth and abiotic stress responses. However, little is known about the role of ZFP transcription factors in abiotic stresses in the wheat (Triticum aestivum L.) which is one of the most important cereal crops. We cloned a ZFP transcription factor induced by drought and other abiotic stresses from wheat. The overexpression of the transgenic wheat had strong drought tolerance. The DNA binding target sequence and target genes of TaZFP21 will be determined by microarray technology, chromatin immunoprecitation and electrophoretic mobility shift assay in this study. We will use the GFP reporter system to analyze subcellular localization of TaZFP21 under drought stress. The transgenic overexpression and RNAi of TaZFP21 will be used as experimental materials to reveal the mechanism of TaZFP21 sensitivity to drought stress signals and the activation of related gene expressions. The implementation of this project has important scientific significance for revealing the new function of the TaZFP21 gene and clarifying the regulation mechanism of TaZFP21 in the drought resistance stress pathway of wheat. It also provides a basis for studying the ZFP transcription factors in improving the ability of drought stress tolerance and its regulatory network analysis of wheat. This research will lay an important theoretical and practical basis for designing new wheat varieties with high yield, good quality and strong resistance.

锌指蛋白(ZFP)是一类重要的转录因子，广泛参与植物的生长发育和非生物胁迫应答，而有关ZFP转录因子在重要粮食作物小麦中抵御非生物逆境胁迫过程中扮演的角色还知之甚少。我们已从小麦中克隆了一个受干旱等多种非生物胁迫诱导的ZFP转录因子，超表达转基因小麦具有很强的耐干旱特性。本项目将在此基础上通过芯片技术、染色质免疫沉淀技术及凝胶阻滞实验确定TaZFP21的DNA结合靶序列及其靶基因；通过观察GFP研究该基因在干旱胁迫条件下的定位。利用转基因超表达和RNAi小麦，揭示其感受干旱等信号、激活相关基因表达的机制。这一项目的实施对于揭示TaZFP21基因新功能，阐明TaZFP21在小麦耐干旱胁迫途径中的调控机制具有重要的科学意义。同时也为研究ZFP转录因子在提高小麦抗干旱胁迫能力及其调控网络的解析成为可能，为设计高产优质抗逆性强的小麦新品种奠定重要的理论和实践基础。

为研究干旱对小麦产量等农艺性状的影响，我们针对小麦转录因子TaZFP21开展了以下几方面的研究：①TaZFP21的DNA结合靶序列及其靶基因；②TaZFP21基因调控干旱胁迫响应的分子生理机制。取得以下主要研究结果：①获得小麦204个TaC2H2型锌指蛋白家族成员的特征；②TaZFP21过表达拟南芥植物提高了其对干旱、盐和外源ABA的敏感性；③小麦TaZFP21过表达导致小麦的耐旱性和产量下降；④TaZFP21通过抑制6个靶基因表达，负调控小麦干旱的耐受性。本研究阐明了小麦TaZFP21在调控干旱响应中的生理功能，为利用分子育种技术提高小麦抗旱性的遗传改良提供新的基因资源和选择靶点。