玉米可溶性无机焦磷酸酶家族基因的克隆和表达分析

Cloning and Expression Analysis of Soluble Inorganic Pyrophosphatase Family Genes in Maize(Zea mays L.)

可溶性无机焦磷酸酶(Soluble inorganic pyrophosphatase)通过水解作用调节细胞质中无机焦磷酸盐(PPi,pyrophosphate)的含量使其维持在适当水平。本研究一共克隆了玉米(Zea mays L.)中7个可溶性无机焦磷酸酶基因Zm PPases,分别位于第2、4、5、6、8、10号染色体上。同源基因分子量介于22.8~25.6 kDa之间,等电点介于4.84~6.24之间。可溶性无机焦磷酸酶蛋白的二级结构主要由α螺旋和β折叠构成。系统进化分析表明可溶性无机焦磷酸酶基因在玉米、水稻(Oryza sativa L.)、高粱(Sorghum bicolor(L.)Moench)和拟南芥(Arabidopsis thaliana(L.)Heynh.)物种中可以分为3组。亚细胞定位进一步揭示了玉米可溶性无机焦磷酸酶在细胞膜和细胞核中表达。此外,在不同非生物胁迫(盐和干旱)下Zm PPases基因表现出不同的应激反应,除了Zm PPase2.1(Zm00001d051564)在盐胁迫下表达下调,其余Zm PPases在盐和干旱胁迫下均表达上调。本研究通过对Zm PPases家族成员序列及表达进行全面分析,为进一步探讨Zm PPases的基因功能提供理论基础。

Soluble inorganic pyrophosphatase regulates the homeostasis of inorganic pyrophosphate(PPi)in the cytoplasm through hydrolysis.In this study,seven genes encoded for soluble inorganic pyrophosphatase in maize(ZmPPases)were cloned and identified on chromosomes 2,4,5,6,8,10,respectively.The relative molecular mass of ZmPPases was varied from 22.8 kDa to 25.6 kDa with the isoelectric point of 4.84 to 6.24.Secondary structure analysis of ZmPPases revealed alpha helix and beta strand motifs.Phylogenetic analysis together with the homozygous proteins in maize,rice,Sorghum,and Arabidopsis suggested three phylogenetic branches of soluble inorganic pyrophosphatases.ZmPPases were localized in the cell membrane and nucleus by transient expression in Nicotiana benthamiana L..The ZmPPase genes were inducible under salt and drought stress treatments,whereas ZmPPase2.1(Zm00001 d051564)was down-regulated under salt stress treatment.Collectively,this study reported a comprehensive analysis of the sequence and expression of ZmPPases family members,which might provide a theoretical basis for further functional research.