水稻转录因子OsHOX6过量表达及其对水稻根生长作用

Over Expression of Rice Transcription Factor OsHOX6 in Rice Effect on Rice Root Growth

同源异型域-亮氨酸拉链(Home domain-leucine-zipper)蛋白是植物发育进程和应答外界环境胁迫信号作用的一类转录因子,OsHOX6基因是HD-ZipⅠ转录因子家族的一个成员。本研究利用RT-PCR技术,从水稻中克隆OsHOX6基因,并构建了以Oslea为启动子的植物表达载体pCAMBIA2300-Oslea:OsHOX6,并以水稻未成熟胚作为材料,通过农杆菌介导法,获得OsHOX6基因过量表达的36株转基因植株。利用Southern杂交技术确定各个株系的拷贝数后,选出3个单拷贝株系与野生型植株,并对其进行干旱胁迫研究。结果表明,在干旱胁迫条件下,OsHOX6过量表达植株的根长度、深度、密度明显高于野生型,株高与野生型没有明显的差异。正常灌水条件下转基因植株的表型与野生型没有明显的差异。研究结果说明,Oslea启动子是干旱胁迫诱导性启动子,OsHOX6基因对水稻根生长起促进作用,但其调控水稻根生长发育中和提高植物抗旱、抗盐等抗逆性机理有待进一步研究。

Homeodomain-leucine zipper(HD-Zip)protein is a kind of transcription factor in plant development and response to environmental stress signals.OsHOX6 gene is a member of HD-ZipⅠtranscription factor family.In this study,we used RT-PCR techniques to clone OsHOX6 gene from rice and constructed pCAMBIA2300-Oslea:OsHOX6 plant expression vector,and the immature embryo was used as transformation material to obtain 36 OsHOX6 over expressed independent lines through the agrobacterium-mediated transformation method.After the copy numbers of these transgenic plants were confirmed with Southern blotting analysis,three independent single copy and one wild type lines were used for drought stress studying.The results showed that the OsHOX6 over expressed transgenic plants root length,root depth and root density is higher than that of wild type in drought stress condition,and there is no obvious difference between plant height and wild type.However,there is also no significant difference between the phenotype of transgenic plants and wild type under normal irrigation.Our research results indicated thatOslea promoter is drought induce able promoter.OsHOX6 gene plays a promoting role in root growth of rice.However,the mechanism of regulating rice root growth and improving plant drought resistance and salt resistance needs to be further studied.