Waswa Emmanuel Nyongesa, Mkala Elijah Mbandi, Odago Wyclif Ochieng, Amenu Sara Getachew, Mutinda Elizabeth Syowai, Muthui Samuel Wamburu, Ding Shi-Xiong, Hu Guang-Wan, Wang Qing-Feng
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China.
Front Plant Sci. 2023 Jun 16;14:1179510. doi: 10.3389/fpls.2023.1179510. eCollection 2023.
L. is found in the family Viburnaceae (syn. Adoxaceae) and encompasses approximately 29 accepted species. The complex morphology of these species has caused continued confusion concerning their nomenclature, classification, and identification. Despite previous attempts to resolve taxonomic complexities in the genus, there are still unclear phylogenetic relationships among several species. In this study, the newly obtained plastome of Hance. as well as the populations of L., Blume, and Wall. ex DC were sequenced, and their sizes, structural similarity, gene order, gene number, and guanine-cytosine (GC) contents were analyzed. The phylogenetic analyses were conducted using the whole chloroplast genomes and protein-coding genes (PCGs). The findings revealed that the chloroplast genomes of species exhibited typical quadripartite double-stranded DNA molecules. Their lengths ranged from 158,012 base pairs (bp) () to 158,716 bp ( L). Each genome comprised a pair of inverted repeats (IRs), which separated the large single-copy (LSC) and small single-copy (SSC) regions. In addition, the plastomes contained 132 genes, encompassing 87 protein-coding, 37 tRNA, and four rRNA genes. In the simple sequence repeat (SSR) analysis, A/T mononucleotides had the highest proportion, with the most repetitive sequences observed in . The comparative genome analyses showed high similarities in structure, order, and gene contents. The hypervariable regions in the studied chloroplast genomes were , , , , , and , which may be used as candidate barcodes for species discrimination in genus. Phylogenetic analyses supported the monophyly of and revealed the separation of and populations. Lindl. was nested within in the same clade, collaborating their conspecific treatment. These outcomes indicate that the chloroplast genome of plants is a valuable genetic resource for resolving taxonomic discrepancies at the lower taxonomic levels and can be applied in molecular evolutionary studies.
荚蒾属植物属于五福花科（同义词：接骨木科），包含约29个公认的物种。这些物种复杂的形态导致了它们在命名、分类和鉴定方面一直存在混淆。尽管此前曾试图解决该属的分类复杂性问题，但仍有几个物种之间的系统发育关系不明确。在本研究中，对新获得的荚蒾属植物的叶绿体基因组以及荚蒾属、荚蒾属、荚蒾属和荚蒾属的种群进行了测序，并分析了它们的大小、结构相似性、基因顺序、基因数量和鸟嘌呤-胞嘧啶（GC）含量。使用整个叶绿体基因组和蛋白质编码基因（PCG）进行系统发育分析。研究结果表明，荚蒾属物种的叶绿体基因组呈现典型的四分体双链DNA分子。它们的长度范围从158,012碱基对（bp）（荚蒾属）到158,716 bp（荚蒾属）。每个基因组都包含一对反向重复序列（IR），将大单拷贝（LSC）和小单拷贝（SSC）区域分开。此外，叶绿体基因组包含132个基因，包括87个蛋白质编码基因、37个tRNA基因和4个rRNA基因。在简单序列重复（SSR）分析中，A/T单核苷酸比例最高，在荚蒾属中观察到的重复序列最多。比较基因组分析表明，它们在结构、顺序和基因含量方面具有高度相似性。所研究的叶绿体基因组中的高变区为、、、、和，这些区域可作为荚蒾属物种鉴定的候选条形码。系统发育分析支持荚蒾属的单系性，并揭示了荚蒾属和荚蒾属种群的分离。荚蒾属植物嵌套在同一分支中的荚蒾属内，支持它们的同种处理。这些结果表明，荚蒾属植物的叶绿体基因组是解决较低分类水平上分类差异的宝贵遗传资源，可应用于分子进化研究。
