小麦甘油-3-磷酸酰基转移酶基因在植物耐碱中的作用机制研究

Soil saline-alkalinity shows significant constraints to crop productivity. The plant response to salinity stress has been exhaustively researched, but much less attention has been paid to analyze the mechanism of soil alkalinity on plant growth and development, especially the research on molecular basis of alkalinity tolerance in wheat has rarely been reported. Studies have shown that sn-glycerol-3-phosphate acyltransferases influence the development of plant and the tolerance to low temperature and salt, but no studies have shown whether they influence the response of plant to alkalinity. We have isolated a sn-glycerol-3-phosphate acyltransferase gene TaGPAT6 from salt-alkali tolerant line Shanrong No. 4 and proved that it decreased the tolerance of plant to alkaline stress and involved in ABA signaling pathway. In this study, we intend to systematically analyze the response of TaGPAT6 to different stresses, measure the enzyme activity in vivo and in vitro, analyze the regulatory mechanism of TaGPAT6 to PM H+-ATPase, isolate and character the regulators of TaGPAT6, screen and find the interacting proteins with TaGPAT6. This object mean to preliminary illuminate the regulatory mechanism of TaGPAT6 to alkalinity, which lay the foundation for further revealing the mechanism of wheat to alkali stress.

土壤盐碱化是制约农业生产的重要因素。目前关于植物耐盐机制已经开展了广泛深入的研究，然而植物耐碱机制的研究很少，有关小麦耐碱分子机制的研究鲜见报道。近年来有研究表明，甘油-3-磷酸酰基转移酶参与植物的生长发育及耐低温、耐盐响应，但它是否调控植物对碱胁迫的应答过程尚无报道。我们前期从小麦耐盐碱新品系山融4号中克隆到甘油-3-磷酸酰基转移酶基因TaGPAT6，初步鉴定了该基因导致的碱胁迫敏感表型及与ABA信号途径的相关性。本项目拟系统分析TaGPAT6的胁迫应答特征，测定其编码蛋白的体内和体外活性，分析TaGPAT6对质膜H+-ATP酶可能的调控作用，鉴定其功能，分离调控TaGPAT6表达的关键因子，筛选TaGPAT6的互作蛋白，初步阐明TaGPAT6在植物耐碱途径中的调控作用，为进一步揭示小麦耐碱应答机制奠定基础。

土壤盐碱化是制约农业生产的重要因素。有关植物耐盐机制已有广泛深入的研究，然而对植物耐碱机制的探讨不够深入，特别是小麦耐碱分子机制的研究鲜见报道。在前期研究中，我们从小麦耐盐碱新品系山融4号中获得甘油-3-磷酸酰基转移酶基因TaGPAT6，初步鉴定了该基因导致的碱胁迫敏感表型及与ABA信号途径的相关性。在前期研究基础上，我们克隆了TaGPAT6的启动子并构建GUS表达载体转化拟南芥，通过GUS染色明确了该基因的组织表达特异性；采用酵母表达系统和拟南芥脂质组分析，揭示了该基因编码的蛋白同时具有甘油-3-磷酸酰基转移酶活性和磷酸酶活性；利用茎尖生长点转化法构建小麦转基因株系，通过PCR检测筛选得到阳性植株，选取表达量较高的株系进行了碱胁迫表型的鉴定，结果显示，在对照条件下，转基因小麦与对照组无明显差异，但在碱胁迫条件下，过表达小麦植株呈现出敏感表型；筛选拟南芥突变体，分析了不同转基因株系在碱胁迫条件下及ABA胁迫条件下的表型，揭示了TaGPAT6在植物响应碱及ABA胁迫过程中的功能；过表达拟南芥植株中ABA信号途径、磷脂酸合成与代谢及ROS清除相关基因的表达量与野生型相比表现出差异；研究结果初步阐明了TaGPAT6调控植物响应碱胁迫的生理及分子作用机制，为进一步完善小麦耐碱机理奠定了良好基础，对于作物抗盐碱育种有重要的参考价值。