玉米ZmPHO2基因家族克隆及其低磷胁迫下的表达  

Cloning and Expression of ZmPHO2 Gene Family Members under Low Phosphate Stress in Maize

作　　者：田跃辉[1] 吴玲[1] 刘丹[1] 张素芝[1] 聂治[1] 张啸[1] 苏顺宗[1] 罗博文[1] 高世斌[1] 

机构地区：[1]四川农业大学玉米研究所,成都611130

出　　处：《西北植物学报》2014年第8期1514-1521,共8页Acta Botanica Boreali-Occidentalia Sinica

基　　金：国家自然科学基金(31361140364;31171566);948计划(2011-G15-2;2013-Z38)

摘　　要：PHO2(编码一个泛素结合酶E2)作为磷高亲和转运体PHT1的负调控子,在维持植物体内磷的动态平衡中发挥重要作用。该研究以拟南芥和水稻中的PHO2为基础,从玉米自交系B73基因组中鉴定出9个ZmPHO2基因家族成员,在系统进化关系上将其分为3类。在玉米自交系178中克隆了上述9个基因的CDS全长序列,保守结构域分析发现,ZmPHO2蛋白质序列中均有1个由约130个氨基酸组成的泛素结合酶E2催化结构域(UBCc),其中包含1个重要的保守氨基酸(半胱氨酸)。实时荧光定量结果表明,低磷胁迫处理后,所有ZmPHO2基因均有表达,并呈现不同的表达模式,主要表现为叶与根之间的组织差异和玉米自交系178与9782之间的基因型差异,而在同一组织多数基因间的表达差异不明显。其中,ZmPHO2;H2在自交系9782的根中持续下调表达,但在叶中持续上调表达,表明ZmPHO2;H2可能参与调控磷素在叶与根之间的运输,以维持地上部分和地下部分磷的平衡。PHO2（encoding a ubiquitin-conjugating E2enzyme）,a negative regulator of phosphate transporter PHT1,is known to play a key role in the maintenance of phosphate homeostasis.In this study,nine members of ZmPHO2 gene family were identified from whole genome sequence of maize inbred line B73 based on PHO2 orthologs in Arabidopsis thaliana and Oryza sativa,which can be subdivided into at least three clusters based on phylogenetic relationship among several plants.The complete CDSs of all PHO2 homologs have been cloned from maize inbred line 178,and the conserved domain analysis revealed that all proteins have the same topology and harbor an ubiquitin-conjugating E2 enzyme catalytic domain（UBCc）which is fabricated of about 130 amino acids residues including a conserved cysteine.Based on quantitative real-time PCR,the transcripts of all ZmPHO2 genes were detected and exhibited different expression profiles in different organs and genotypes under low phosphate stress,but there are no distinct expression profiles among most of genes in the same tissue.Among them,ZmPHO2;H2 showed decreased expressionlevels in roots and increased expression levels in leaves at all sampled time points in maize inbred line 9782,indicating that ZmPHO2;H2 in maize may be involved in the regulation of phosphate transport from leaves to roots in order to maintain phosphorus homeostasis between the shoot and the root.

关 键 词：玉米 ZmPHO2基因家族 低磷胁迫 定量分析 

分 类 号：Q789[生物学—分子生物学]