一条全新的蛋白激酶与转录因子信号通路调控ABA与干旱应答的分子机制研究

项目名称： 一条全新的蛋白激酶与转录因子信号通路调控ABA与干旱应答的分子机制研究

项目编号： No.31471153

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 江元清

作者单位： 西北农林科技大学

项目金额： 86万元

中文摘要： 钙离子是参与干旱与盐害等逆境应答的重要第二信使，脱落酸(ABA)是调控逆境信号转导的重要激素。发掘钙离子相关蛋白激酶基因，并解析它们在干旱与ABA应答中的功能，将为提高作物耐逆性奠定基础。我们在前期研究中发现一个新颖的钙相关蛋白激酶基因，受干旱与ABA处理诱导，并且突变体对ABA与干旱处理均高度敏感，命名为ksa1。进一步通过酵母双杂交筛选发现它分别能与调控ABA应答的核心转录因子ABF2、ABF4互作，又通过BiFC验证了互作的真实性，暗示激酶磷酸化转录因子调控下游靶基因的转录与抗逆性。本立项拟利用植物生理学、生物化学与分子遗传学方法，围绕这个蛋白激酶-转录因子信号通路，从启动子分析、蛋白表达与磷酸化修饰后的活性分析、过表达以及抗逆性鉴定等层面，着重解析它们调控干旱与ABA的信号转导分子机制。预计将阐明一条全新的调控干旱与ABA应答的信号通路及作用机制，为抗旱育种提供候选基因并奠定基础。

中文关键词： 蛋白激酶；转录因子；干旱；脱落酸；拟南芥

英文摘要： Calcium ions (Ca2+) are one type of imporant sencond messengers mediating abiotic stress responses including dought and salinity. Abscisic acid(ABA) is a famous phytohormone regulating signal transduction of abiotic stresses. Mining calcium-associated protein kinase genes and understanding their roles in drought and ABA signaling, is expected to be helpful to improve the tolerance or resistance of crop plants to abiotic stresses. In our previous work, we identified a drought and ABA-induced calcium-associated protein kinase gene from both Canola (Brassica napus L.) and Arabidopsis, with the T-DNA insertion mutant sensitive to both ABA and drougth treatments. Therefore, this mutant was named as ksa1(kinase sensitive to ABA 1). Moreover,yeast two-hybrid (Y2H) screeing of cDNA library using KSA1 as a bait demonstrated that it interacted with two core transcription factors (TFs), ABF2 and ABF4(ABA responsive element binding factor 2 and 4), which are two known TFs mediating ABA resoponse during seed germination, drought response, and post-germination seedling growth. Besides, bimolecular fluorescence complementation (BiFC) assay in Nicotiana benthamiana leaf cells indicated that KSA1 indeed formed a complex with both ABF2 and ABF4 in nuclei, suggesting that a novel pathway of protein kinase mediated phosphorylation of ABF TFs possibly modulates ABA and drought responses. In this proposal, we plan to analyze the phenotypes of relevant single, double and triple mutants, promoter activity and related cis-elements, test the phenotype of KSA1-overexpressing plants, as well as phosphorylation assy and target gene identification, using a combination of techniques involving plant physiology, biochemistry and molecular genetics. Through this proposal, we aim to dissect the molecular mechanism of signal transduction of a novel KSA1-ABF pathway modulating plant responses to ABA and drought and, provide candidate gene and lay theoretic foundation for molecular breeding and genetic improvement of crop plants.

英文关键词： protein kinase;transcription factor;drought;ABA;Arabidopsis