植物中3-磷酸甘油脱氢酶基因家族的物种特异性进化分析

Species-specific evolution of glycerol-3-phosphate dehydrogenase(GPDH) gene family in plant

3-磷酸甘油脱氢酶(GPDH)是一种在磷酸甘油酯的代谢过程中起重要调节作用的关键酶,研究植物中3-磷酸甘油脱氢酶基因家族的进化历史及其多样性对进一步探索其作用机制具有重要意义.以20个已报道的GPDH基因作为查询序列,与19种代表性的植物物种的基因组分别进行BLASTP和t BLASTN比对以及隐马尔科夫模型搜索,获得基因家族新成员,构建系统发育树,并对其进行基因结构、蛋白模体、功能差异性以及适应性进化分析.预测得到了75个新的GPDH基因家族成员,系统发育分析表明,植物中的GPDH基因属于3个单系类群(命名为族群I、族群II和族群III),并且在进化过程中主要分为两个进化枝,说明GPDH基因家族源自两个GPDH祖先基因;功能差异性分析表明,氨基酸特异性位点的选择性约束作用于不同族群的GPDH基因上,并且导致了不同族群多样化之后的特异性进化,同时,在族群I/III和族群II/III中也发现了Type-II功能差异性,表明氨基酸的理化性质也发生了本质的改变;适应性进化分析以及ka/ks比值分析表明,GPDH基因家族在物种特异性复制之后的进化过程中受到了纯化选择作用.因此,GPDH基因家族在其进化过程中受到不同的选择压力而出现了不同的进化方向,形成了多样化的族群.此外,对该基因家族进行的系统的分子进化探索为植物中GPDH基因家族的进一步生物化学和遗传方面的研究以及基因组分析提供了数据基础,在GPDH基因家族分析中的结果与发现也为研究其他基因家族提供了有力的帮助.

Glycerol-3-phosphate dehydrogenase（GPDH） is a kind of enzyme that plays an important role in phosphoric acid glyceride metabolism and regulates the process of glyceride metabolism by catalyzing the reversible redox conversion of dihydroxyacetone phosphate to SN-glycerol 3-phosphate.To better understand the evolutionary history and diversity of the GPDH gene family in plants,a series of genome-wide analysis was executed in our work.We acquired 20 known GPDH sequences through previous researches and the Genbank and other relevant databases.Then we used these sequences as query sequences to perform multiple Blast searches against plants whole-genome to retrieve GPDH-like sequences and identify the new members of the GPDH protein family in plants.Then we constructed the phylogenetic tree and performed gene structure and protein motif analyses,functional divergence,Ka/Ks ratio and adaptive evolution analyses.As a result,a total of 75 GPDH members were identified to belong to 2 clades and 3 monophyletic lineages,indicating that the GPDH genes arose from two ancestral GPDH genes.Functional divergence analyses showed that significant amino acid site-specific selective constraints acted on the different clades of GPDH genes.Adaptive evolution analyses and Ka/Ks ratioanalyses demonstrated that GPDH genes were subject to strong purifying selection after their species-specific duplications and that rapid evolution occurred with a high degree of evolutionary dynamics in GPDH genes.In conclusion,this study provides a better understanding of the evolutionary history and diversity of the GPDH gene family in plants,and offeres a foundation for further biochemical and genome-wide analyses and genetic studies of the GPDH gene family in plants.Moreover,the findings in this work provide insight into the function and evolution of this gene family in plant and pave the way for studies in other species.