Provenance Identification Of Two Medicinal Dendrobium Species Based On High-throughput Sequencing Technology

There are nearly 80 species of Dendrobium Swartz in China,50 of which have long been used in traditional medicines.Because of the high medicinal value,the medicinal Dendrobium industry has been developing rapidly in recent years,and the mature cultivation and breeding techniques have also come into being.However,at the same time,the medicinal Dendrobium product quality was shoddy.A large number of medicinal Dendrobium products in the market have lost their active ingredients and of variable quality,and there is no effective means of identification.Dendrobium catenatum（D.officinale）and D.huoshanense are valuable genuine herbs.Traditional methods for identification by morphology,spectroscopy,and chromatography are difficult to identify the sources of the two species.As the rapid development of molecular biology,researchers have made some progress in the interspecific identification of Dendrobium by gene fragments,but it is difficult to conduct the intraspecific identification of the medicinal Dendrobium species.In this study,we used the reduced representation sequencing（RAD-seq）approach to perform high-throughput sequencing of 31 provenances of D.catenatum and 3 provenances of D.huoshanense.We obtained high quality SNP data sets by mapped to reference genome and quality control.and then constructed phylogenetic tree,conducted principal component analysis,genetic structure analysis and population genetic differentiation analysis.The main conclusions are as follows:1.RAD-seq technology can provide large amount of genome sequence information.In this study,485 Gb clean data were obtained and 688518 high quality SNPs were selected after filtration.2.In the phylogenetic tree constructed by the maximum likelihood method,for most of the provenances of D.catenatum,individuals of the same provenance clustered together with high support values,except that individuals of three groups from Zhejiang Wuyi,Zhejiang Lishui,and Zhejiang Zhangzhou.At the same time,the distribution of D.catenatum samples in the phylogenetic tree is closely related to their geographical locations.3.In principal component analysis,three provenances of D.huoshanense can be clearly distinguished,and most of the provenances of D.catenatum can be distinguished.For example,D.catenatum samples in Guangxi Shihuo plantation（GXSHTPa33）can be clearly distinguished from the other provenances.4.Through population genetic structure analysis,we found that all samples can be divided into four subgroups,of which D.huoshanense is a single group,D.catenatum can be divided into three groups,and each group is closely related to the distribution of sampling sites.5.By analyzing interspecific genetic differentiation,the result showed that a high level of intraspecific genetic diversity and genetic differentiation,further proving that the three groups classification by the provenance of D.catenatum in the genetic structure analysis is reasonable.6.A genetic information database of D.catenatum and D.huoshanense was established,which confirmed that the application of RAD-seq technology in the identification of medicinal Dendrobium from different provenances was feasible.This study provides a new idea for the development of the identification technology of medicinal Dendrobium species,and it also lays a solid foundation for the breeding of fine Dendrobium provenances.