College of Pharmacy, Hubei University of Chinese Medicine, Wuhan 430065, China.
Hubei Institute for Drug Control, Wuhan 430012, China.
Molecules. 2018 Oct 30;23(11):2811. doi: 10.3390/molecules23112811.
Rhubarb is an important ingredient in traditional Chinese medicine known as . However, this common name refers to three different botanical species with different pharmacological effects. To facilitate the genetic identification of these three species for their more precise application in Chinese medicine we here want to provide chloroplast sequences with specific identification sites that are easy to amplify. We therefore sequenced the complete chloroplast genomes of all three species and then screened those for suitable sequences describing the three species. The length of the three chloroplast genomes ranged from 161,053 bp to 161,541 bp, with a total of 131 encoded genes including 31 tRNA, eight rRNA and 92 protein-coding sequences. The simple repeat sequence analysis indicated the differences existed in these species, phylogenetic analyses showed the chloroplast genome can be used as an ultra-barcode to distinguish the three botanical species of rhubarb, the variation of the non-coding regions is higher than that of the protein coding regions, and the variations in single-copy region are higher than that in inverted repeat. Twenty-one specific primer pairs were designed and eight specific identification sites were experimentally confirmed that can be used as special DNA barcodes for the identification of the three species based on the highly variable regions. This study provides a molecular basis for precise medicinal plant selection, and supplies the groundwork for the next investigation of the closely related Rheum species comparing and correctly identification on these important medicinal species.
大黄是一种重要的中药成分，被称为 。然而，这个常见的名称指的是三种具有不同药理作用的不同植物物种。为了促进这三种物种的遗传鉴定，以便更精确地应用于中药，我们在这里提供具有特定识别位点、易于扩增的叶绿体序列。因此，我们对这三种物种的完整叶绿体基因组进行了测序，然后筛选出适合描述这三种物种的序列。三种叶绿体基因组的长度从 161,053bp 到 161,541bp 不等，总共编码了 131 个基因，包括 31 个 tRNA、8 个 rRNA 和 92 个蛋白编码序列。简单重复序列分析表明这些物种存在差异，系统发育分析表明叶绿体基因组可作为超条形码用于区分大黄的三种植物物种，非编码区的变异高于蛋白编码区，单拷贝区的变异高于反向重复区。设计了 21 对特异性引物，并通过实验证实了 8 个特异性识别位点，可用于基于高度可变区的三种物种的鉴定。这项研究为精确选择药用植物提供了分子基础，并为下一个对这些重要药用物种进行比较和正确鉴定的亲缘 Rheum 物种的研究提供了基础。
