Liu Hongmei, Fang Chengxin, Zhang Tingmo, Guo Li, Ye Qiang
State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu, 611137, People's Republic of China.
AMB Express. 2019 Apr 19;9(1):53. doi: 10.1186/s13568-019-0767-8.
Owing to their significant medicinal and edible values, the natural Dendrobium species have underdone over-collection and habitat destruction, and cultivated species emerged for candidates. However, these Dendrobium plants are similar in shape to be easily confused, leading to extreme difficulties for identification based on their morphological and chemical features. In this study, the rDNA ITS region sequence analysis was developed for rapid and accurate identification of thirteen wild and cultivated Dendrobium species belonging to two sections Formosae and Chrysotoxae. By cloning and sequencing the rDNA ITS region genes from 13 Dendrobium species, the phylogenetic relationships among them were analyzed. Results showed that the variation of the ITS region, together with the lengths and Guanine and Cytosine contents of ITS, 5.8s rDNA, ITS1 and ITS2 sequences occurred in the tested Dendrobium species, and which from section Chrysotoxae was higher than that from section Formsae. Phylogenetic analysis based on neighbor-joining and maximum p-arsimony trees indicated that the Dendrobium species of sections Formosae and Chrysotoxae could be well divided into two groups. A majority of Dendrobium species exhibited distinctive ITS2 secondary structures, while for those with close genetic relationships were similar. Therefore, the ITS2 region sequence analysis is simple, quick, and highly reliable that can be used as an effective tool for molecular identification and classification, as well as the reconstruction of the phylogeny of wild and cultivated Dendrobium species belonging to different sections.
由于其显著的药用和食用价值，天然石斛物种遭到过度采集和栖息地破坏，因此出现了人工栽培品种作为替代。然而，这些石斛植物形态相似，容易混淆，基于其形态和化学特征进行鉴定极具难度。在本研究中，开发了rDNA ITS区域序列分析方法，用于快速准确鉴定属于福尔摩沙组和金钗组两个组的13种野生和栽培石斛物种。通过克隆和测序13种石斛物种的rDNA ITS区域基因，分析了它们之间的系统发育关系。结果表明，受试石斛物种的ITS区域存在变异，ITS、5.8s rDNA、ITS1和ITS2序列的长度以及鸟嘌呤和胞嘧啶含量也发生了变化，且金钗组的变化高于福尔摩沙组。基于邻接法和最大简约树的系统发育分析表明，福尔摩沙组和金钗组的石斛物种可以很好地分为两组。大多数石斛物种表现出独特的ITS2二级结构，而亲缘关系较近的物种则相似。因此，ITS2区域序列分析简单、快速且高度可靠，可作为分子鉴定和分类以及重建不同组野生和栽培石斛物种系统发育的有效工具。
