光周期途径成花关键基因CONSTANS的进化机制

Evolution of the flowering time gene CONSTANS in a photoperiod pathway

CONSTANS(CO)是植物响应光周期调节的重要基因和监测日照长度的重要元件,可将光信号和生物钟信号转变为开花信号,激活下游基因(FT)的表达,从而诱导植物开花。选取14个已被测序的物种,采用生物信息学手段,从外显子-内含子结构、基因重复、基因差异表达等方面开展CO基因家族研究。结果表明:14个物种共鉴定到159个CO家族成员, CO基因常以多拷贝的形式存在,多数含2～4个外显子,在进化过程中表现出多样性。CO家族重复基因的扩张与基因组重复相关。CO在水稻Oryza sativa根、旗叶、花和种子中均有表达,花芽到花的转变过程中OsCO3的表达量上升,而OsCO7下降,说明水稻CO家族成员之间存在功能差异。

CONSTANS(CO),an essential element for monitoring the duration of a day and an important gene responding to photoperiod regulation,can transform light and biological clock signals into flowering signals,as well as activate the expression of downstream genes(FT),which induces plant flowering.However,their evolutionary history and patterns have not been examined systematically.In this study,a total of 14 species,whose whole-genomes have been sequenced,were selected.Then,via the analyses of bioinformatics,the CO family was studied in regards to exon-intron structure,gene duplication,and differential expression.Results showed 159 members in the CO family.For each plant species,the CO family existed in the form of multiple copies.Almost every copy contained 2 to 4 exons indicating diversity in the evolution process.The synteny analysis showed that expansion of duplicate genes in the CO family was related to genome duplication.In addition,the gene differential expression analysis showed that CO members were expressed in roots,flag leaves,flowers,and seeds of rice(Oryza sativa).Especially,OsCO3 was up-regulated in the process of floral development;whereas,the expression of OsCO7 was down-regulated.This suggested that members of the CO gene family played different roles in rice.