低温胁迫下百合甘油-3-磷酸酰基转移酶基因的作用及其表达调控机制

Glycerol-3-phosphate acyltransferase (GPAT) plays a very important role in regulating plants against low temperature stress. The present studies only focus on in vitro experimental analysis, and it is still not clear that the low-temperature resistance is determined by the structure of GPAT amino acid sequence or by expression level of protein. Until now, there is no report about functional and physiology analysis from the whole plant level. Based on our preliminary studies, GPAT genes will be isolated from four kinds of lilies with different low-temperature resistance, and the differences of their protein structures and promoters will be compared. In addition, the changes in temperature and contents of fatty acids during different stages of growth and development under cold stress will be analyzed to reveal the main stages and positions which are crucial for GPAT function. In addition, GPAT genes will be performed over-expression, non-expression and re-expression to analyze its effects on plant phenotype, growth, photosynthesis, and other physiological and biochemical characteristics. As a result, the physiological functions could be analyzed on the whole plant level. Additionally, promoter deletion analysis will be performed to identify the elements responding to adversity. Then the effects of low temperature, high temperature, Ca2+, ABA on the expression of GPAT will be analyzed, to provide new idea and theory evidence for GPAT function, and lay a foundation for exploring low-temperature resistant genes and improving low-temperature resistance of lilies.

GPAT基因在植物抵御低温胁迫过程中起非常重要的调控作用，目前研究只局限在体外实验分析，低温抗性是由GPAT基因结构还是由其表达水平决定的尚不清楚，没有从整株水平活体角度揭示其参与低温胁迫的分子机制的报道。项目组在前期基础上，从抗寒性差异明显4种百合中分离到GPATs，比较各GPAT基因及启动子的结构差异；全面调查百合生长发育过程中温度变化对脂肪酸组成和含量动态变化，寻找百合低温抗性与脂肪酸变化关系的证据，揭示GPAT发挥生理作用的主要时期和关键部位；综合分析低温胁迫下GPAT基因过表达、缺失和回复表达后对植物表型、生长发育、光合作用及生理生化特性的影响, 全面多角度解析其体内生理功能；采用启动子缺失技术鉴定逆境响应元件，通过分析低温、高温、钙、 ABA等对 GPAT基因表达的影响，为阐明GPAT作用及调节机制提供新思路和理论依据，并为抗寒基因的发掘及利用转基因技术提高百合抗寒力奠定基础。

GPAT基因在植物抵御低温胁迫过程中起非常重要的调控作用。目前研究只局限在体外实验分析，低温抗性是由GPAT基因结构还是由其表达水平决定的尚不清楚，没有从整株水平活体角度揭示其参与低温胁迫的分子机制的报道。本研究从整株水平活体角度验证了脂肪酸组成和含量动态变化与植物适应低温胁迫的相关性，寻找到了百合低温抗性与脂肪酸变化关系的证据，揭示了GPAT发挥生理作用的主要时期和关键部位；并以抗寒性不同的毛百合、岷江百合、亚洲百合“精粹”和新铁炮百合为试材，克隆了得到4个甘油-3-磷酸酰基转移酶（GPAT）基因，比较不同百合GPAT基因的结构差异，在此基础上，将采用异源酵母表达分析各GPAT蛋白的抗冻能力；并通过稳定遗传转化揭示了它们的功能，通过分析GPAT基因的表达模式揭示了其发挥生理作用的主要时期，采用启动子缺失技术鉴定逆境响应元件，通过分析低温、高温、多种激素等对 GPAT基因表达的影响，揭示了了GPAT基因的调控机制。项目结果表明百合低温抗性是由GPAT基因结构和其表达水平共同决定，GAPT基因的表达受低温和多种激素调控。本项目的研究结果为阐明GPAT作用及调节机制提供了理论依据，并为抗寒基因的发掘及利用转基因技术提高百合抗寒力奠定了基础。项目组完成了研究目标，培养硕士研究生9名，培养中青年教师2人，发表文章8篇其中SCI收录论文6篇，获授权发明专利和实用新型专利12项，研究成果获得科研奖励3项。