玉米促分裂原激活蛋白激酶ZmMPK7基因的表达特性及功能分析

Expression characterization and function analysis of ZmMPK7 from Zea mays seedlings

以玉米(Zea mags L.)为材料,利用RT-PCR和RACE技术,从ABA处理的玉米叶片中克隆了1个新的A族促分裂原激活蛋白激酶(MAPK)基因,命名为ZmMPK7(GenBank登录号:EU616650)。生物信息学分析表明:该基因全长1 709 bp,编码397个氨基酸,推测相对分子质量为44.9×103,pI 5.31。ZmMPK7包含有MAP激酶11个相对保守结构域和1个TEY的磷酸化基序。对玉米不同组织中ZmMPK7基因的转录水平分析表明:ZmMPK7基因的转录没有组织专一性。非生物胁迫处理下ZmMPK7基因表达研究发现:ABA、H2O2、干旱、盐胁迫、低温及重金属处理均诱导ZmMPK7基因的转录水平显著上调。原生质瞬时表达载体定位试验表明:ZmMPK7定位于玉米原生质体的细胞质中。上述结果显示:ZmMPK7在植物对环境胁迫响应中具有重要的作用。

A novel group A MAPK（mitogen-activated protein kinase）gene designated ZmMPK7 was isolated and characterized by RT-PCR and RACE from ABA treated maize（Zea mays L.）.Bioinformatics analysis indicated that the full-length cDNA sequence was 1 709 bp and encodes a 397 amino acid protein with a predicted molecular mass of 44.9 ×103 and a pI of 5.31.ZmMPK7 contains all 11 of MAPK conserved subdomains and the phosphorylation motif TEY.Amino acid sequence alignment revealed that ZmMPK7 shared high identity with group A MAPK in plants.A time course（30-240 min）experiment using a variety of abiotic stresses revealed that the transcripts level of ZmMPK7 accumulated markedly and rapidly when maize seedlings were subjected to exogenous signaling molecules：ABA,H2O2,various abiotic stimuli such as drought,salinity,cold,heavy metal.Its transcription has no tissue-specificity.Finally,we have shown that the group A ZmMPK7 protein was localized in the cytoplasm.These results suggest that the ZmMPK7 may play an important role in response to environmental stresses and transcription of certain genes.