萝藦叶绿体基因组结构及进化发育分析

Analysis of chloroplast genome structure and evolutionarydevelopment of Metaplexis japonica

萝藦(Metaplexis japonica(Thunb.)Makino),具有一定的食用价值和药用价值。本研究目的是获得萝藦叶绿体基因组拼接,分析叶绿体基因组序列特征,确定其在近缘物种中的系统进化关系。研究方法是利用Illumina平台对萝藦叶绿体基因组进行高通量测序,使用一系列生物信息学分析方法,完成基因组拼接和基因注释,分析重复序列特征。结合萝藦多个近缘物种,分析边界基因的变异,构建多物种系统进化树。结果表明,萝藦叶绿体基因组是典型的环状四分体结构,全长157 081 bp, GC含量是36.49%。共注释132个基因,包含有45个光合作用相关基因、74个自我复制相关基因、6个其他基因和7个功能未知基因。鉴定得到271个简单重复序列(SSR)位点,其中以单碱基重复为主,其次是三碱基重复。多物种比较和系统进化分析证实,萝藦属于鹅绒藤属,与马利筋属和牛角瓜属是进化上更近的属间植物。

Abstrct:Metaplexis japonica(Thunb.)Makino has certain edible and medicinal value.The purpose of this study is to obtain the chloroplast genome splicing of Metaplexis japonica,analyze the sequence characteristics of the chloroplast genome,and determine its phylogenetic relationship in related species.The research method is to use the Illumina platform for high-throughput sequencing of the chloroplast genome of Metaplexis japonica,using a series of bioinformatics analysis methods to complete genome splicing and gene annotation,and analyze repeat sequence characteristics.Combining multiple closely related species of Metaplexis japonica,analyzing the variation of boundary genes,a multi species phylogenetic tree was constructed.The results showed that the chloroplast genome of Metaplexis japonica is a typical circular tetrad structure,with a total length of 157081 bp and a GC content of 36.49%.A total of 132 genes were annotated,including 45 photosynthesis related genes,74 self replication related genes,6 other genes,and 7 functionally unknown genes.In total,271 simple repeat sequence(SSR)loci were identified,with single base repeats being the main sequence,followed by triple base repeats.Multiple species comparison and phylogenetic analysis have confirmed that Metaplexis japonica belongs to the genus Cynanchum,and shows a closer relation to the genera Asclepias and Calotropis.