内蒙古林草过渡区欧亚绣线菊和土庄绣线菊叶绿体基因组比较研究

Comparative analyses on chloroplast genome between Spiraea media and Spiraea pubescens in the forest-grass transition zone of Inner Mongolia,northern China

【目的】我国是绣线菊属植物的现代分布和分化中心,欧亚绣线菊和土庄绣线菊是同域分布在内蒙古林草过渡区的两种绣线菊属植物,分析两个物种的叶绿体基因组差异可为鉴定同属植物亲缘关系提供依据。【方法】本研究采用二代测序技术,利用Illumina Novaseq 6000平台,通过组装、注释后得到两个物种完整的叶绿体全基因组序列,并利用生物信息学方法分析其序列结构并构建系统发育树。【结果】结果显示:欧亚绣线菊叶绿体序列全长为155916 bp,总GC含量为36.72%,土庄绣线菊叶绿体序列全长为155942 bp,总GC含量为36.76%。二者均注释得到130个基因,其中111个基因是独有的,包含78个蛋白质编码基因、29个tRNA基因和4个rRNA基因。欧亚绣线菊和土庄绣线菊分别检测到238和241个简单重复序列,以A或U结尾的密码子偏好性大于以G或C结尾的密码子偏好性,基因组变异区域主要分布于非编码区域。二者编码亮氨酸的密码子含量最多,半胱氨酸密码子含量最低。系统发育树结果显示:欧亚绣线菊和土庄绣线菊构成姐妹类群,存在较近的亲缘关系,绣线菊属与鲜卑花属亲缘关系较近,呈姐妹类群关系。【结论】研究结果可为绣线菊属植物的系统发育、分类鉴定和资源开发利用等相关研究提供基础资料。

[Objective]China is the modern distribution and differentiation center of Spiraea plants.S.media and S.pubescens are sympatric species of Spiraea distributed in the forest-grass transition zone of Inner Mongolia,northern China.Analysis of chloroplast genomic differences between the two species can provide a basis for identifying plant relatives in the same genus.[Method]In this study,the complete chloroplast genome sequences of the two species were obtained by assembly and annotation using secondgeneration sequencing technology and Illumina Novaseq 6000 platform,and the sequence structures were analyzed using bioinformatics methods to construct phylogenetic trees.[Result]The total length of chloroplast genome of S.media was 155916 bp with 36.72% total GC content,and the total length of chloroplast genome of S.pubescens was 155942 bp with 36.76% total GC content.Both were annotated to obtain 130 genes,111 of which were unique,containing 78 protein-coding genes,29 tRNA genes and 4 rRNA genes.S.media and S.pubescens detected 238 and 241 simple repeats,respectively,with codon preference ending in A or U over codon preference ending in G or C and the genomic variation regions were mainly distributed in non-coding regions.They were both with the largest number of codons encoding leucine and the least number of codons encoding cysteine.The phylogenetic tree showed that these two species formed a sister group,and had a relatively close relation.Spiraea and Sibiraea were closely related,showing a sister group relationship.[Conclusion]The results of the study can provide basic information for the phylogeny,taxonomic identification and resource development and utilization of Spiraea.