Characterization of the complete plastid genome and phylogenetic analysis of <i>Oreocharis argyreia</i> var. <i>angustifolia</i> (Gesneriaceae)

Oreocharis argyreia var. angustifolia of Gesneriaceae is widely distributed in South China, including Guangdong, Guangxi, Hunan, and Jiangxi provinces. However, genetic information of this species is limited, further contributing to the taxonomic complications surrounding this species. Thus, in this study, we assembled and characterized the complete chloroplast genome of O. argyreia var. angustifolia as a genomic resource for future studies. The complete plastid genome was 154,675 bp in size, with a pair of inverted repeat regions of 25,329 bp each, separating the 85,977-bp large and 18,040-bp small single copy regions. A total of 131 genes were predicted, consisting of 86 protein-coding, 37 tRNA, and eight rRNA genes. The overall GC content was 37.6%. Phylogenetic analysis based on 79 shared unique CDS resulted in a fully resolved phylogenetic tree using both the maximum likelihood and Bayesian inference methods. Based on current circumscription, both methods indicated that Oreocharis is monophyletic; O. argyreia var. angustifolia diverged after O. chienii, which then followed by the divergence of the other three species included namely, O. continifolia, O. esquirolii, and O. mileensis. The genomic data obtained will be useful for future studies on the phylogenetics and evolution of Gesneriaceae.苦苣苔科（Gesneriaceae）银叶马铃苣苔狭叶变种（Oreocharis argyreia var. angustifolia）在华南地区分布广泛，涵盖广东、广西、湖南及江西各省。然而，该物种的遗传信息仍较为匮乏，进一步加剧了其分类学上的复杂性。为此，本研究完成了银叶马铃苣苔狭叶变种的完整叶绿体基因组组装与注释，为后续相关研究提供基因组学资源。该完整质体基因组全长154675 bp，包含一对长度均为25329 bp的反向重复区，二者分别分隔开总长85977 bp的大单拷贝区与18040 bp的小单拷贝区。共预测得到131个基因，其中包括86个蛋白编码基因、37个转运RNA（tRNA）基因以及8个核糖体RNA（rRNA）基因。整体GC含量为37.6%。基于79个共享的独特编码序列（CDS）开展系统发育分析，通过最大似然法与贝叶斯推断法均得到了分辨率完整的系统发育树。依据当前的分类界定，两种分析方法均表明马铃苣苔属（Oreocharis）为单系类群；银叶马铃苣苔狭叶变种在陈氏马铃苣苔（O. chienii）之后分化，随后其余三个供试物种，即连叶马铃苣苔（O. continifolia）、云贵马铃苣苔（O. esquirolii）与米洛马铃苣苔（O. mileensis）相继分化。本研究获得的基因组数据将为后续苦苣苔科植物的系统发育与进化研究提供有力支撑。