密花香薷叶绿体基因组结构及系统进化分析

Characterization of chloroplast genome structure and phyletic evolution of Elsholtzia densa

目的基于高通量测序获得药用资源植物密花香薷Elsholtzia densa叶绿体基因组序列,分析了叶绿体基因组结构及特征,为研究密花香薷资源分类及系统进化奠定了基础。方法以密花香薷叶片为材料,利用改良的CTAB法提取DNA;采用二代测序技术Illumina NovaSeq平台对叶绿体基因组进行测序;以广藿香叶绿体基因组为参考序列,进行序列组装和矫正,得到完整叶绿体基因组序列;利用生物信息学方法分析密花香薷叶绿体基因组特征并进行系统发育分析。结果获得密花香薷完整叶绿体基因组序列全长149095bp,GC含量37.92%,注释到130个基因,其中包括85个蛋白质编码基因,8个rRNA基因和37个tRNA基因;密花香薷叶绿体基因组中共检测到28个散在重复序列,串联重复序列共检测到191个,单核苷酸重复序列最多,共114个;系统发育结果表明,密花香薷和其他唇形科植物聚合在一起形成一个分支结构,紫苏属植物和香薷属植物亲缘关系较近。结论建立了适于香薷属植物叶绿体基因组测序及其特征分析的方法,丰富了唇形科植物遗传资源,为密花香薷分子标记开发及唇形科属种间系统发育分析研究提供了理论基础。

Objective The choroplast genome sequence of Elsholtzia densa in medicinal plants was obtained through high-throughput sequencing,and characterization of chloroplast genome structure was analyzed.This study lays the groundwork for resource classification and phyletic evolution of E.densa.Methods The total genomic DNA was extracted from the leaves of E.densa using improved CTAB method,and the sequencing process was performed by the platform of Illumina NovaSeq which was from second generation sequencing technique.After sequence assembly and correction was executed by Pogostemon cablin chloroplast genome as a reference,the complete chloroplast genome sequence was obtained.The characterization of chloroplas genome in E.densa and phyletic evolution were analyzed with the method of bioinformatics.Results The complete chloroplast genome of E.densa was 149 095 bp in length and the total GC content of the genome was 37.92%.A number of 130 genes were detected,including 85 protein-coding genes,37 tRNA genes and eight ribosomal RNA genes.A total of 28 interspersed repetitive sequence and 191 polymorphic simple-sequence repeat loci were identified.The single nucleotide repeats had the greatest number of 114.The result of phylogenetic tree showed that plants in Perilla had a close relationship with E.densa and all species in Lamiaceae were grouped into one branch in this study.Conclusion The suitable approach for studying sequencing and characterization of chloroplast genome in Elsholtzia was established,and all research findings in this study not only enriched the genetic resources of Lamiaceae,but also laid the theoretical basis foundation for the development of molecular markers and studying on the systematic evolution of interspecific in Lamiaceae.