山核桃水通道蛋白CcPIP同源基因克隆与表达分析

The analysis of Carya carthayensis plasma membrane intrinsic protein gene CcPIP clone and expression

利用RACE方法,在山核桃嫁接过程中扩增出山核桃水通道蛋白同源基因CcPIP。应用生物信息学软件进行分析,预测该序列编码294个氨基酸,具有6个跨膜区,有MIP家族信号序列和高等植物PIP高度保守序列。通过NCBI同源性比较分析表明,该基因与葡萄、菜豆等物种的水通道蛋白基因同源性达到99%。荧光定量RT-PCR分析表明,CcPIP基因在芽中的表达量最低,其次是雄花序,果实,幼叶和茎,而在根中表达量最高。在山核桃嫁接前后,CcPIP基因在接穗中表达趋势和在砧木中的表达一致。CcPIP基因的表达量在山核桃嫁接前砧木和接穗中都有强烈表达,但在嫁接后3 d急剧下降,分别在砧木和接穗中下降了5倍和2倍。在随后的11 d里,CcPIP基因的表达量在砧木和接穗中开始上升,至嫁接后14 d基因的转录水平比嫁接后3 d分别增加了7倍和4倍。该CcPIP基因参与山核桃嫁接成活的水分运输过程中起到基因表达调控的作用。

A cDNA fragment related to Carya carthayensis grafting was obtained by RACE techniques during grafting process. The cDNA named CcPIP encode 294 amino acids, has six transmembrane area and signal sequence of MIP family and high conserved sequence of PIP in higher plant. The CcPIP has 99% homology with grape and bean section of the plasma membrane intrinsic protein by NCB1 homology comparison analysis. Fluorescence real time RT-PCR analysis showed that the gene expressions were weakly induced in bud, then inflorescence, fruit, leaf and stem, strongerly in root. The expression trends in the scion are the same with that in the rootstock. The gene expressions were strongly induced both in rootstock and scion of C. carthayensis before grafting and declined sharply 3 days after grafting, which declined five times and two times. The expression in rootstock and scion were increased in the following days and reached to a high level 14 days after grafting, which was 7 times and 4 times stronger than that 3 days after grafting. CcPIP may be involved in the regulation of gene expression in water transportation of C. carthayensis grafting.