Locality identification of Chinese medicinal plant Scutellaria baicalensis (Lamiaceae) population-level DNA barcoding

Abstract

Scutellaria baicalensis is an important traditional Chinese medicine and Scutellaria flavonoids have received worldwide attention in recent years. It is the basis of controlling quality of S. baicalensis to develop a reliable genetic marker system used to identify locality of origin. Because of the characteristics of maternal inherited and high-rate of evolution, the cpDNA intergenic spacer can effectively elucidate the degree of genetic variation in different areas of the same species (populations), which can be used as the population-level DNA barcoding to locality identify. In this study, we have used the molecular phylogeography analysis for the three cpDNA intergenic spacers atpB-rbcL, trnL-trnF and psbA-trnH of 17 wild populations from different localities, which reveals the 20 haplotypes, including 13 polymorphic sites and constitutes a shallow gene tree. The authers have divided the haplotypes of S. baicalensis into three grades of population-level DNA barcoding according to the frequence and geographic distribution: 3 highest-frequency haplotypes as area-population-level DNA barcoding, 3 haplotypes were mainly shared by 2-3 adjacent populations as region-population-level DNA barcoding, and there are also 8 unique-population haplotypes as unique-population-level DNA barcoding. The result of this study reveals that population-level DNA barcoding is a reliable genetic marker used to locality identify of S. baicalensis.