SiWRKY89介导谷子抗旱性的调控机制

Foxtail millet (Setaria italica) has many advantages such as drought resistant, water use efficiency, low coefficient of transpiration, which is an excellent germplasm to investigate drought-resistant genes. WRKY is a plant specific transcription factor family which is involved in regulation of plant growth and development. We previously identified 94 SiWRKY transcription factors from Setaria italica and phylogenetic analysis and expression profiling against drought stress was performed. The expression of SiWRKY89 was induced greatly under drought stress and overexpression of SiWRKY89 simultaneously improved drought resistance in Arabidopsis. The present project is to analyze the function of SiWRKY89 and its regulation mechanism responsible for drought resistance in foxtail millet. Firstly, SiWRKY89 overexpression and RNAi expression vectors will be constructed and transformed to foxtail millet by Agrobacterium. Secondly, Pull-down method will be used to isolate its target genes and analyze their roles in the drought response pathways. Finally, to investigate the interaction with SA and MeJA regulation pathway, further analysis need to be carried out. Our work could provide new knowledge for analyzing the molecular mechanism of millet drought resistance and new genes for transgenic approaches.

谷子具有耐旱性强、水分利用率高、蒸腾系数低等生物学特性, 是发掘抗旱基因的优异种质。WRKY是植物特有的一个转录因子超家族，参与植物生长发育等多种生命活动的调控。前期我们已经从谷子中筛选和鉴定出94个SiWRKY转录因子，并对其分类和表达谱进行了系统研究。研究发现SiWRKY89受干旱胁迫诱导表达明显提高，超量表达SiWRKY89的拟南芥植株表现出较强的抗干旱胁迫的能力。本项目拟深入研究SiWRKY89介导谷子抗旱性调控机制。构建谷子SiWRKY89超表达和沉默表达载体，转化谷子，获得突变体并进行表型分析；采用Pull-down技术鉴定SiWRKY89调控的下游靶基因及其参与谷子抗旱性的生理功能分析；探讨SiWRKY89上游调控因子以及与SA 、MeJA等信号通道的互作。研究结果将为全面解析谷子抗旱的分子机制提供新信息，为高抗旱型谷子转基因育种奠定理论基础。

干旱是影响粮食作物产量的主要逆境因素之一。WRKY类转录因子在植物防御抵抗非生物胁迫等方面发挥重要作用。本项目以解析SiWRKY89介导谷子抗旱性的调控机制为目的，通过开展SiWRKY89的克隆、时空表达情况及靶基因的鉴定等工作，为全面解析谷子抗旱的分子机制提供新信息，为高抗旱型谷子转基因育种奠定理论基础。时空表达分析结果表明：SiWRKY89主要在老叶中表达，在根尖、侧根和花中也有表达，且在干旱胁迫处理后，表达量明显增加。表型分析结果表明：转基因拟南芥的种子在含有NaCl的MS培养上发芽率和根长明显高于野生型。正常培养20天，干旱处理2周后，转基因植物生长较好，而野生型植株干枯死亡，复水后转基因植株的存活率为80%，明确SiWRKY89的耐旱功能。以干旱处理2周的转基因拟南芥和野生型植株为材料，利用Illumina高通量测序，在转录水平上分析了干旱胁迫和正常培养植株之间差异表达基因的数目和类型，选出30个与抗旱相关的基因，其中13个含有W-box原件。本项目共发表了SCI论文2篇，中文核心5篇，培养研究生2名。