The processed root of Wikstroemia indica, also known as Wikstroemiae Radix (WR), is known as a time-honored traditional herbal medicine demonstrating health-promoting properties. Although W. indica is valuable, its molecular information on this medicinal plant is limited. In this study, we reported the complete chloroplast (cp) genome sequences of W. indica and its congener, W. nutans, the latter of which is highly identical to W. indica in both their natural distributions and morphological characteristics. The cp genomes of W. indica and W. nutans were 151,746 bp and 149,776 bp in size, respectively, and were predicted to contain the same number of genes, including 78 protein-coding, 37 tRNA, and eight rRNA genes. Genome comparison of W. indica showed that mutational hotspots were present despite low intraspecific variations were detected between two different accessions. Although phylogenetic analyses revealed that the two closely-related species of Wikstroemia were sisters, presence of variations in the sequence and mutational hotspots demarcated these two species apart. To authenticate commercial WR products sold in the market, three sets of novel indel markers and two sets of novel DNA barcoding markers from the cp genome sequences were developed. However, only the indel marker ndhK-trnV and the DNA barcoding marker, ccsA-psaC were proven useful in discriminating W. indica from W. nutans; while the former is even capable to delimit W. indica from adulterants of other related species. The findings of this study are useful for the molecular development of W. indica and also contribute to the effort in species authentication, trade monitoring and drug regulation in the local herbal industry.

Wikstroemia indica的加工根，也称为Wikstroemiae Radix（WR），是一种历史悠久的传统草药，具有促进健康的特性。尽管印度W（W。indica）很有价值，但其在这种药用植物上的分子信息有限。在这项研究中，我们报告了W. indica及其同类物W. nutans的完整叶绿体（cp）基因组序列，后者在自然分布和形态特征上均与W. indica高度相同。W. indica和W. nutans的cp基因组大小分别为151,746 bp和149,776 bp，预计包含相同数目的基因，包括78个蛋白质编码基因，37个tRNA和8个rRNA基因。W. indica的基因组比较显示，尽管在两个不同种质之间检测到低种内变异，但仍存在突变热点。尽管系统发育分析表明，维克斯血病的两个密切相关物种是姐妹，但序列变异和突变热点的存在将这两个物种区分开来。为了验证在市场上出售的商业WR产品，开发了三套来自cp基因组序列的新型indel标记和两套新型DNA条形码标记。但是，只有插入缺失标记ndh K-事实证明，trn V和DNA条形码标记ccs A- psa C可用于区分印度W. nutans和W. nutans。而前者甚至有能力从其他相关物种的掺假物中划定印度W。这项研究的发现对于印度W的分子发育是有用的，并且还有助于当地草药行业在物种鉴定，贸易监测和药物监管方面的努力。