细辛叶绿体基因组结构特征与系统进化分析

Characteristics and phylogenetic analysis of chloroplast genome of medicinal plant Asari Radix et Rhizoma

目的以细辛药材为材料,采用高通量测序和生物信息学技术组装完整的叶绿体基因组序列,明确其结构特征、系统发育位置。方法基于Illumina测序平台对细辛叶绿体基因组序列进行结构特征分析;同时,采用最大似然法(maximum likelihood,ML)构建马兜铃科的系统发育关系。结果华细辛和辽细辛叶绿体基因组全长为160521~160555 bp,表现出典型的四分体结构,且两者叶绿体基因组GC含量均为38.5%。细辛叶绿体基因组包含128个基因,其中85个蛋白质编码基因,34个t RNA基因,8个r RNA基因。此外,系统发育分析结果显示,基于完整的叶绿体基因组和蛋白编码数据集构建的拓扑树一致,细辛属物种和马蹄香属物种形成一个支持率的单系分支。结论细辛叶绿体基因组测序、组装、结构特征分析,发现其大小介于Asarum bracteolata和A.sieboldii var.seoulense之间,IR区存在rpl16、rps19、ycf1、rpl23等基因扩张,研究结果丰富了细辛属植物遗传资源,为该属物种分子鉴定、系统发育以及野生资源保护与开发利用等研究提供理论基础。

Objective The complete chloroplast genome of medicinal plant Xixin(Asari Radix et Rhizoma)sequenced and assembled by high-throughput sequencing and bioinformatics technology to confirm the genome structure characteristics,phylogenetic relationship and its evolutionary status.Methods The Illumina sequencing platform was used to perform characterization of the complete chloroplast genome sequence of Asari Radix et Rhizoma;Meanwhile,the maximum likelihood(ML)was used to construct the phylogenetic relationship of Aristolochiaceae.Results The results indicated that the whole length of Huaxixin(Asarum sieboldii Miq.)and Liaoxixin[A.heterotropoides Fr.Schmidt var.mandshuricum(Maxim.)Kitag.]plastid was 160521-160555 bp,showing a typical tetrad structure.The GC contents of the chloroplast genome were 38.5%.The plastid genome contains 128 genes,including 85 protein-coding genes,34 tRNA genes,and 8 rRNA genes.Furthermore,phylogenetic analysis indicated that topological trees recovered from the complete plastid genome and protein-coding datasets were consistent,suggesting that Asarum and Saruma species constitute a high support monophyletic clade.Conclusion Sequencing,assembly and structural analysis of Asari Radix et Rhizoma chloroplast genome in this study indicated that its size was between A.bracteolata and A.sieboldii var.seoulense,and rpl16,rps19,ycf1 and rpl23 genes were expanded in IR region.All research findings not only enriched the genetic resources of Asarum,but also provided a theoretical basis for the molecular identification,phylogeny,and protection,development and utilization of wild resources of this genus.