玉米亚硫酸氧化酶基因的克隆及其结构与表达分析

摘要

To clarify structural characteristics of the gene encoding sulfite oxidase (SO) and its expression property in the development of various organs in maize,we cloned the full-length cDNA of SO by RACE. Sequence analysis has shown that the cDNA of ZmSO is 1 492 bp, which contains the 160 bp of 5'-UTR, 138 bp of 3'-UTR,and a 1 194 bp open reading frame (ORF). The structure prediction indicated that ZmSO contains one Moco-binding domain,one dimerization domain and one peroxisome targeting signal. Phyloge-netic tree of SO based on different species has demonstrated that ZmSO has quite high similarity with SO from other plant species. Quantitative real-time PCR has revealed that the ZmSO transcript levels were higher in aerial organs of maize including stems,leaves,silks and immature ears,especially in leaves and immature ears,but the lowest in roots. Moreover, the distribution status of SO activity in the six organs is similar to that of their mRNA abundance.%为明确亚硫酸氧化酶(sulfite oxidase,SO)基因的结构特征和进化关系及其在玉米不同组织器官发育过程中的表达和分布特性,采用RACE技术克隆了玉米SO基因(ZmSO)的全长cDNA.序列分析表明,获得的ZmSO全长1492 bp,其中5′-UTR 160 bp,3′-UTR 138 bp,开放阅读框为1194 bp,编码397个氨基酸组成的蛋白质.对该基因编码氨基酸保守结构域的分析发现,ZmSO包含1个钼辅因子结合域、1个自身二聚化域和1个过氧化物体靶信号序列.系统进化分析显示,SO在进化上较为保守,玉米与其它植物的SO相似性较高.荧光定量RT-PCR分析表明,在玉米成株期,根、茎、叶、雄花和幼穗中,ZmSO在根部表达丰度最低,在叶片和幼穗中表达量较高.酶活性测定结果显示,不同器官中SO活性与其mRNA转录水平上的表达趋势相似.