苹果蛋白磷酸酶基因MdPP2C-Like的克隆及其对ABA的响应分析

以‘嘎拉’苹果(Malus×domestica Borkh.)为试材,克隆了ABA信号转导过程中的响应基因蛋白磷酸酶基因MdPP2C-Like(基因序列号MDP0000126636)。基因结构分析显示,MdPP2C-Like定位于苹果8号染色体上,含有5个外显子与4个内含子;该基因全长1 035 bp,编码344个氨基酸,预测其蛋白质分子量为37.84 k D,等电点(p I)为5.72。蛋白质结构分析发现,其存在1个蛋白磷酸酶2C(PP2C)保守结构域,并与拟南芥中的A类PP2C保守结构域高度同源。构建的系统进化树表明MdPP2C-Like与At4G32950位于同一进化支,同源性较高。亚细胞定位结果表明,MdPP2C-Like主要定位于细胞核,少数分布在细胞质。定量分析显示,MdPP2C-Like在苹果不同组织中表达量不同,根中表达量较高。对获得的转基因拟南芥株系和苹果愈伤组织进行ABA响应分析,结果表明该基因的过量表达降低了植株和愈伤组织对ABA的敏感性。以上结果表明,克隆得到的MdPP2C-Like在响应ABA信号过程中起着重要作用。

Molecular Cloning of Protein Phosphatase Gene MdPP2C-Like in Apple and the Response Analysis of ABA

Protein phosphatase gene MdPP2C-Like（MDP0000126636），an important factor that was involved in ABA signal pathway，was cloned from apple（Malus × domestica Borkh.）. Gene structure analysis showed that MdPP2C-Like gene contained 5 exons and 4 introns，and it was located on the eighth chromosome of apple genome. After amplification，a 1 035 bp open reading frame（ORF）was obtained. MdPP2C-Like gene encoded a protein of 344 amino acids with a calculated mass of 37.84 kD and an isoelectric point（pI）of 5.72. MdPP2C-Like protein sequence comprised a conserved phosphatase 2C （PP2C）domain，just as group A AtPP2Cs. The phylogenetic tree of the construction indicated that MdPP2C-Like and At4G32950 were located in the same evolutionary branch and had high homology. MdPP2C-Like gene mainly localized in the nucleus，with a few in cytoplasm. The expression level of MdPP2C-Like was different in all apple tissues，with the highest level in roots. Moreover，overexpression of MdPP2C-Like gene in apple callus and Arabidopsis plants reduced the sensitivity to ABA. Taken together，these findings showed that MdPP2C-Like played an important role in response to ABA signaling.