十字花科植物PEBP基因家族的分子进化

Analysis of the molecular evolution of the PEBP gene family in cruciferous plants

近年来植物基因组测序物种数量的指数增长,为我们对植物环境适应性状的遗传和变异的全面理解提供了保障。磷脂酰乙醇胺结合蛋白(phosphatidylethanolamine-binding protein,PEBP)在植物的开花转变和株型建立中起着重要作用,一直是植物生物学研究关注的热点领域之一。然而对该家族并没有利用新近测序的基因组数据进行比较基因组分析,制约了对其在分子水平上的进化研究。为了确定PEBP基因家族的分子进化机制,本研究利用生物信息学方法开展了7种十字花科植物拟南芥(Arabidopsis thaliana)、琴叶拟南芥(A.lyrata)、小鼠耳芥(A.pumila)、亚麻荠(Camelina sativa)、甘蓝(Brassica oleracea)、白菜(B.rapa)和油菜(B.napus)的PEBP基因家族成员的全基因组鉴定、结构特征和比较进化分析。从7个物种中共鉴定出91个PEBP基因,系统进化分析表明它们分属5个亚家族:MFT、FT/TSF、TFL1、CEN和BFT。基因结构分析发现甘蓝、白菜和油菜的CEN基因内含子明显比其余4个物种的内含子长。蛋白结构域分析表明MFT比其他4个亚家族成员少了一个motif 2,TFL1比其他亚家族多了motif 8。选择压力分析发现7个物种PEBP同源基因均受到较强的纯化选择,其中TFL1亚家族受到的纯化选择最弱。共线性分析表明十字花科植物PEBP基因家族随古代多倍体事件发生不同程度的扩张,TSF在甘蓝、白菜和油菜中丢失。非生物胁迫下,在拟南芥中过量表达小鼠耳芥的一个MFT基因,转基因拟南芥种子的萌发率明显低于野生型,暗示MFT基因在调控种子萌发上的功能保守。本研究为深入研究十字花科植物PEBP基因的进化特征和生物学功能奠定了基础。

Aims:In recent years,the exponential growth of genomic data across diverse plant species provides unprecedented comprehensive understanding of the inheritance and variation of plant environment adaptation traits.The phosphatidylethanolamine-binding protein(PEBP)plays crucial roles in flowering transition and architectural establishment of plants,a topic of extreme interest in plant biology research.However,comparative genome analysis of the PEBP gene family has not been performed using newly sequenced genome data,which restricts the study of its evolution at the molecular level.To explore its molecular evolution mechanism,we performed comparative genomics analysis of PEBP gene family in Cruciferae plants in this study.Methods:We utilized the methods of genome-wide identification,characterization,and evolution analysis of PEBP genes from seven Cruciferae plants:Arabidopsis thaliana,A.lyrata,A.pumila,Camelina sativa,Brassica oleracea,B.rapa,and B.napus.Results:Our results indicated that 91 PEBP genes were identified from seven plant species,and phylogenetic analysis suggested that they were categorized into five subfamilies:MFT,FT/TSF,TFL1,CEN,and BFT.Gene structure analysis indicated that the introns of CEN genes in B.oleracea,B.rapa and B.napus were significantly longer than those in the other four species.Protein domain analysis demonstrated that MFT lacks motif 2 and TFL1 has one more motif 8 than the other four subfamilies.Selection pressure analysis revealed that the PEBP genes form seven plant species were subject to strong purification selection,of which,the TFL1 subfamily was the weakest in purification selection.Collinearity analysis indicated that the PEBP genes in Cruciferous expanded in varying degrees with the ancient polyploid events,and all genes except CEN were partially lost after expansion.In addition,when overexpression of the A.pumila MFT gene in A.thaliana,the germination rates of transgenic seeds were significantly lower than that in wild type under abiotic stresses,suggesting that the functions of MFT were conserved in the regulation of seed germination.Conclusion:This study lays the foundation for the research of the evolutionary characterizations and biological functions of PEBP genes in cruciferous plants.