Kerala Forest Research Institute, Peechi, Thrissur, Kerala, India.
Kerala Forest Research Institute, Peechi, Thrissur, Kerala, India.
Comput Biol Chem. 2021 Apr;91:107438. doi: 10.1016/j.compbiolchem.2021.107438. Epub 2021 Jan 19.
The genus Salacia (Celastraceae) consists of many important medicinal plants used mainly against type II diabetes. Segregation and delimitation of species is difficult based on morphological features alone. DNA barcoding is the most effective and emerging method of molecular identification. It was reported that ITS2 has better discriminating power in the genus Salacia in comparison to other barcode loci. This paper describe the analysis of sequence and structural information of ITS2 to discriminate the species of Salacia. A total of 8 species of Salacia in South India and the available sequences in NCBI database were taken for the present study. NJ method based phylogenetic trees were constructed using MEGAX with primary sequence as well as using sequence and secondary structural information. Primary structure based phylogeny did not give much information whereas the dendrogram based on sequence and structural information was more informative to decipher the phylogeny of South Asian species of Salacia. The present study revealed some interesting facts regarding the genus. Secondary structure of the ITS2 sequence of S. chinensis reported from Kerala differs consistently from that of S. chinensis reported from other parts of India and of South Asia. Probably the S. chinensis in Kerala, India has diverged a lot from the original S. chinensis. ITS2 sequence of S. reticulata reported from Sri Lanka was identical to S. chinensis reported by other groups from Thailand and Udupi, India. The molecular level identity of ITS2 sequence of S. chinensis with S. reticulata suggest merger of the two species. ITS2 sequence of S. beddomei is only reported from Kerala, India showed it to be identical to S. macrosperma. This observation points to a mistaken identity of S. beddomei which could be elusive from Kerala. Phylogenetic trees constructed based on sequence and structural features of ITS2 suggest that the ancestor species of S.chinensis diversified in two evolutionary lines. One line leads to the present day S. chinensis and the other line further diversified and lead to the rest of the present day Salacia species.
藤黄科（Celastraceae）的 Salacia 属包含许多重要的药用植物，主要用于治疗 II 型糖尿病。仅基于形态特征对物种进行分离和划定是困难的。DNA 条形码是最有效和新兴的分子鉴定方法。据报道，与其他条形码基因座相比，ITS2 在 Salacia 属中具有更好的区分能力。本文描述了分析 ITS2 的序列和结构信息以区分 Salacia 物种的方法。本研究共选取了印度南部的 8 种 Salacia 物种和 NCBI 数据库中的可用序列。使用 MEGAX 基于主要序列以及序列和二级结构信息构建了 NJ 方法的系统发育树。基于主要结构的系统发育树没有提供太多信息，而基于序列和结构信息的系统发育树更有助于解析南亚 Salacia 物种的系统发育。本研究揭示了一些关于该属的有趣事实。来自喀拉拉邦的中华青牛胆（S. chinensis）的 ITS2 序列的二级结构与来自印度其他地区和南亚的中华青牛胆的 ITS2 序列始终不同。可能印度喀拉拉邦的中华青牛胆与原来的中华青牛胆有很大的差异。来自斯里兰卡的 Salacia reticulata 的 ITS2 序列与其他组从泰国和印度乌代浦报告的 S. chinensis 相同。ITS2 序列的分子水平同一性表明中华青牛胆和 Salacia reticulata 已合并为一个物种。来自印度喀拉拉邦的 S. beddomei 的 ITS2 序列仅被报道，它与 S. macrosperma 相同。这一观察结果表明 S. beddomei 的身份可能有误，可能难以从喀拉拉邦发现。基于 ITS2 序列和结构特征构建的系统发育树表明，中华青牛胆的祖先物种在两条进化线上多样化。一条线导致了现在的中华青牛胆，另一条线进一步多样化，导致了现在其余的 Salacia 物种。
