IQM1基因过量表达对拟南芥气孔运动及根系生长的影响

摘要

拟南芥钙调素结合蛋白IQM家族共有6个成员,已证实IQM1是一个不依赖Ca2+的钙调素结合蛋白,其功能缺失突变体iqm1表现气孔开度小和根短的表型,而且突变体气孔开度并不因光、暗、脱落酸等诱导而变大或变小.该实验构建了IQM1基因双元表达载体并转化拟南芥,通过分子筛选及IQM1表达量分析,获得了IQM1基因过量表达植株.表型分析发现,IQM1过量表达植株在光诱导气孔开放处理后气孔开放度明显比野生型和iqm1-1增大,在暗诱导气孔关闭处理后气孔开度则显著变小；IQM1过量表达植株的主根比野生型和iqm1-1长,侧根数量比野生型和iqm1-1多,但IQM1过量表达对植株的生长形态、抽薹期、开花期及座果等方面却没有明显影响.研究表明,IQM1基因在植物气孔运动及根系生长中起着重要作用.%In Arabidopsis,IQM family has six members and IQM1 is a Ca2+-independent calmodulin-binding protein.We previously found that the loss-of-function mutant iqm1 displayed a smaller stomatal aperture and a shorter primary root,and did not obviously change its stomatal aperture when treated with light,darkness or ABA.Here,we constructed a binary expression vector harboring the IQM1 gene,and introduced it into wild-type Arabidopsis,and obtained 10 IQM1 overexpression lines through PCR identification and semiquantitative RT-PCR assay.The IQM1 overexpression lines exhibited significantly bigger and smaller stomatal aperture than wild-type and iqm1-1 when treated with light and darkness,respectively.These lines also showed longer primary root and more lateral root than wild-type and iqm1-1.Besides these IQM1 overexpression lines did not display phenotype in plant growth,bolting,flowering and fruiting.These results further suggest that IQM1 plays an important role in stomatal movement and root growth.