The complete chloroplast genome sequence and phylogenetic analysis of the Bichetii grass Chlorophytum laxum (Asparagaceae)

Chlorophytum laxum of Asparagaceae is a valuable ornamental plant native to the tropical regions of Asia, Africa, and Australia. The plant also has medicinal properties and is used as source for folk medicine. Despite being commercially important, genetic studies of C. laxum are still limited. To expand the genomic information of this plant species, we sequenced, assembled, and characterized its complete chloroplast genome. The chloroplast genome was 153,678 bp in length, with a large single-copy region (83,225 bp) and a small single-copy region (18,031 bp) separated by a pair of inverted repeat regions (26,211 bp each). A total of 127 genes were predicted, including 81 protein-coding, 38 tRNA, and eight rRNA genes. The overall GC content was 37.3%. Based on current sampling size, phylogenetic analysis using the maximum likelihood based on the complete chloroplast genome sequence revealed that the relationship in Chlorophytum is well resolved; C. laxum was closely related to C. rhizopendulum.

天门冬科（Asparagaceae）松叶吊兰（Chlorophytum laxum）是一种极具观赏价值的原生植物，其自然分布范围涵盖亚洲、非洲与澳大利亚的热带区域。该植物兼具药用价值，可作为民间医药的原料来源。尽管其具备重要的商业价值，但针对C. laxum的遗传学研究仍较为有限。为拓展该物种的基因组信息储备，我们对其完整叶绿体基因组（chloroplast genome）开展了测序、组装与特征分析工作。该叶绿体基因组全长153678 bp，包含一个大单拷贝区（large single-copy region，83225 bp）与一个小单拷贝区（small single-copy region，18031 bp），二者由一对反向重复区（inverted repeat regions，每个长26211 bp）分隔。研究共预测得到127个基因，其中包括81个蛋白编码基因、38个转运RNA（transfer RNA，tRNA）基因以及8个核糖体RNA（ribosomal RNA，rRNA）基因。整体GC含量为37.3%。基于现有采样规模，利用基于完整叶绿体基因组序列的最大似然法（maximum likelihood）开展的系统发育分析显示，吊兰属（Chlorophytum）内的物种演化关系得到了较好解析；松叶吊兰与C. rhizopendulum亲缘关系密切。