香蕉谷胱甘肽过氧化物酶基因MaGPX的克隆和表达分析

Isolation and Expression Analysis of a cDNA Encoding Glutathione Peroxidase from Banana

谷胱甘肽过氧化物酶(glutathione peroxidase,GPXs)是机体内广泛存在的一种重要的过氧化物分解酶,是植物体清除活性氧的一种主要酶,与植物抗逆性密切相关。本研究中从香蕉根中克隆了一个编码谷胱甘肽过氧化物酶的cDNA,命名为MaGPX(GenBank登录号为:JX094345)。序列分析结果表明,该基因全长989bp,存在一个完整的开放阅读框504bp,编码168个氨基酸。氨基酸序列分析表明其具有GPX家族典型的保守结构域。与其他植物的谷胱甘肽过氧化物酶基因相比,具有较高的相似性。与水稻、谷子、小麦、大麦、玉米和甜橙编码的氨基酸序列的同源性分别为85.12%、84.82%、83.93%、83.33%、82.14%和80.36%。利用荧光定量PCR技术分析了该基因在香蕉不同器官中的表达特异性及不同胁迫条件下的表达特性,结果表明,MaGPX在香蕉的根、球茎、叶片、花和果实中均有所表达,其中在花和根中表达量较高,而在叶片中的表达量最低。在盐、涝害、干旱和枯萎病胁迫下MaGPX表达量升高,表明该基因表达具有器官差异性和受胁迫的诱导。本研究为进一步研究MaGPX的生物学功能及其应用奠定了基础。

Glutathione peroxidase （GPX） is an important peroxide decomposition enzyme eliminating reactive oxygen species in plants ceils, which is involved in plants response to stress resistance. In this study, a cDNA encoding GPX was isolated from banana root and designated as MaGPX （GenBank accession No. JX094345 ） respectively. Sequence analysis indicated that MaGPXwas 989 bp in length with an open reading frame of 504 bp predicted to encode 168 amino acids. Amino acid sequence ahgnment showed that MaGPX shared a typical conserved structure with GPXs from other plant species and showed high identity with Oryza sativa, Setaria italica, Triticum monococcum, Hordeum vulgare, Zea mays and Citrus sinensis as 85.12%, 84.82%, 83.93%, 83.33%, 82.14% and 80.36% respectively. The expression levels of MaGPXin different organs and in banana root under different stresses were analyzed by real-time qPCR. The results showed that MaGPX differentially expressed in different organs examined, with higher level in flowers and roots than that in rhizome, leaves and fruits. In addition, MaGPXexpression increased under stresses as salt, waterlogging, drought and in infected by Fusarium oxysporum f. sp. cubense. The results indicate that MaGPX is induced by both biotic and abiotic stress. Lay a foundation for the further research and application of biological function.