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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 (GPXs) is an important peroxidase that exists widely in the body. It is one of the main enzymes that scavenge reactive oxygen species in plants and is closely related to plant stress resistance. In this study, a cDNA encoding glutathione peroxidase was cloned from banana root and named MaGPX (GenBank accession number: JX094345). Sequence analysis showed that the gene was 989bp in length and contained a complete open reading frame (504 bp) encoding 168 amino acids. Amino acid sequence analysis showed that it has a typical conserved domain of GPX family. Compared with glutathione peroxidase genes of other plants, it has higher similarity. The homologies with the amino acid sequences encoded by rice, millet, barley, corn and sweet orange were 85.12%, 84.82%, 83.93%, 83.33%, 82.14% and 80.36%, respectively. The expression of this gene in different organs of banana was analyzed by fluorescence quantitative PCR. The results showed that MaGPX was expressed in banana root, bulb, leaf, flower and fruit, among which The expression level was higher in flowers and roots, but the lowest in leaves. The increased expression of MaGPX under salt, waterlogging, drought and Fusarium wilt stress indicated that the gene expression was organically differentiated and induced by stress. This study laid the foundation for further study on the biological function of MaGPX and its application.