野生豆Pht1基因家族的全基因组鉴定和表达分析

Genome-wide Identification and Expression Analysis of the Pht1 Gene Family in Glycine soja

植物体内磷的吸收、转运和再利用过程主要是由位于质膜上的磷酸盐转运蛋白基因(phosphate transporter 1,Pht1)家族调控。目前野生豆Pht1家族基因的鉴定和系统分析尚未见报道,为了研究野生豆Pht1家族基因的进化和功能,本研究通过同源序列比对的方法鉴定并获得了野生豆Pht1家族的15个基因,分布在8条染色体上。多序列比对和系统发育分析显示这些基因分为四组,分别包含10,2,2,1个基因。基因共线性分析显示Gs Pht1家族存在6对复制基因,分别是GsPht1;1/1;5,GsPht1;2/1;7,GsPht1;3/1;14,GsPht1;6/1;10,GsPht1;8/1;9和GsPht1;12/1;13。Ka/Ks分析显示野生豆Pht1家族基因的进化经受纯化选择,Tajima相对速率测验表明基因复制事件后复制基因增加了进化速率。Gs Pht1家族基因在不同组织的表达模式显示复制基因对具有组织表达特异性,低磷胁迫条件下该家族大部分基因在不同组织中被诱导表达。本研究结果为野生豆耐低磷分子机制的研究提供了依据。

Phosphate(Pi) acquisition,translocation and remobilization are primarily mediated by plasma membrane-localized Pi transporters,which generally belong to the phosphate transporter 1(Pht1) family.Currently,there is no comprehensive report on identification and systematic analysis of Pht1 members in wild soybean(Glycine soja).To explore the evolution and function of the Pht1 family in wild soybean,15 GsPht1 genes were identified from wild soybean genome by homologous sequence alignment,and distributed on 8 chromosomes.According to phylogenetic analysis and multiple sequence alignment,these putative genes were divided into four Groups,Groups I~IV,which includes 10,2,2 and 1 members,respectively.Gene syntenic analysis showed that there were six pairs of duplication genes in wild soybean:GsPht1;1/1;5,GsPht1;2/1;7,GsPht1;3/1;14,GsPht1;6/1;10,GsPht1;8/1;9 and GsPht1;12/1;13.Ka(non-synonymous substitution rate)/Ks(synonymous substitution rate)ratios suggested that the duplication of GsPht1 mainly underwent purifyin g selection,Tajima analysis indicated that evolution of six duplication genes pairs were accelerated after the duplication event.According to the expression profile of GsPht1 in leaves,stems and roots under normal and low-Pi conditions,we found that paralog gene pairs had gene-biased expressions;most Gs Pht1 genes had increased expression levels in roots,stems or leaves under low-phosphorus condition.These results provide a foundation for the molecular mechanism of low-phosphorus tolerance in wild soybean.