水稻延伸蛋白基因OsEXPB7干涉载体的构建、遗传转化与基因功能分析

Construction and Genetic Transformation of the RNA Interference Vector and Functional Analysis of Rice Expansin Gene OsEXPB7

延伸蛋白(Expansin)是植物细胞壁的重要组成成分,参与植物各种生理活动.利用RNA干涉技术构建水稻OsEXPB7基因RNAi干涉载体,通过农杆菌介导遗传转化将其导入粳稻品种日本晴.对转基因植株的定量PCR分析表明,转基因植株中OsEXPB7的表达量明显降低.与野生型日本晴相比,OsEXPB7下调T0代转基因植株株高变矮,秕谷率增高,谷粒变小.T1代转基因幼苗实验显示,与野生型相比,转基因植株生长缓慢,叶片披垂.在赤霉素诱导下转基因幼苗的生长抑制得到部分补偿,水淹条件下转基因植株的苗长伸长速度也慢于野生型,提示OsEXPB7基因可能通过调节细胞壁的延展而影响水稻生长发育,并受赤霉素的调控.

Expansin, a vital component of plant cell wall, involves in various physiological activities of plants. In the present study, RNA interference （RNAi） vector of rice expansin gene OsEXPB7 was constructed and introduced into rice cultivar Nipponbare by Agrobacterium-mediated transformation. The quantitative PCR analysis revealed the suppression of OsEXPB7 in transgenic lines. Compared with wild-type, the OsEXPB7 down-regulation primary generation （T0） transgenic plants exhibited a shorter plant height and smaller size in grains. T1 transgenic seedlings showed retardant growth and drooping leaf phenotype. The growth defect could be partially compensated with gibberellin （GA） treatment. Under flooded conditions, the transgenic seedlings showed slower stem elongations than that of wild type plants. It suggested that OsEXPB7, probably regulated by GA, might play an role in influencing rice development through adjusting the extension of cell wall. Fig 9, Tab 3, Ref 30