头花杜鹃、陇蜀杜鹃及杜鹃属植物叶绿体基因组比较分析

Comparative analysis of the chloroplast genomes ofRhododendron capitatum , R. przewalskii ,and Rhododendron species

头花杜鹃(Rhododendron capitatum)和陇蜀杜鹃(R.przewalskii)是极具观赏价值的野生花卉和药用植物。为探讨头花杜鹃和陇蜀杜鹃叶绿体基因组的遗传结构及进化特征,该研究利用Illumina HiSeq 4000平台对头花杜鹃和陇蜀杜鹃的叶绿体全基因组进行测序,经组装和注释后,结合7个已发表的杜鹃属植物叶绿体全基因组进行比较基因组学分析和系统发育分析。结果表明:(1)头花杜鹃和陇蜀杜鹃叶绿体全基因组呈典型的环状四分体结构,均由一个大单拷贝区(105 990、109 191 bp)、一个小单拷贝区(2 617、2 606 bp)和一对反向重复区(45 825、47 516 bp)构成,全长分别为200 257、206 829 bp。(2)头花杜鹃和陇蜀杜鹃叶绿体基因组中共鉴定出263个SSR位点,大部分SSR偏好使用A/T碱基,密码子偏好使用A/U结尾。(3)杜鹃属植物叶绿体全基因组中普遍存在基因丢失以及基因组重排等结构变异现象。该研究丰富了杜鹃属植物的基因组资源,为头花杜鹃、陇蜀杜鹃的资源开发、遗传进化、育种及系统发育相关研究提供了理论参考。

Rhododendron capitatum and R.przewalskii are ornamental flowers and medicinal plants.The chloroplast genomes of R.capitatum and R.przewalskii have been sequenced using Illumina HiSeq 4000 platform to explore the genetic structure and evolution features.After assembly and annotation,comparative genomic analysis and phylogenetic analysis of the chloroplast genomes of R.capitatum and R.przewalskii were analyzed and compared with those of other Rhododendron species.The results were as follows:(1)The chloroplast genomes of R.capitatum and R.przewalskii exhibited a typical quadripartite structure,including a large single copy region(105990,109191 bp),a small single copy region(2617,2606 bp),and a pair of inverted repeat regions(45825,47516 bp).And the two Rhododendron species chloroplast genomes were 200257 bp and 206829 bp in length,respectively.(2)In addition,the 263 SSRs were detected in the chloroplast genomes of R.capitatum and R.przewalskii,most of which had A/T base preference;the codons preferred ending in A/U.(3)The chloroplast genomes of Rhododendron species exhibit structural variation such as gene loss and genomic rearrangement.The study enriches the genomic resources of Rhododendron species and provides the theoretical reference for resource exploitation,genetic evolution,breeding,and phylogeny of R.capitatum and R.przewalskii.