DNA Barcoding Identification And Ecological Suitability Of Important Medicinal Plants Of Orchidaceae

Orchidaceae is one of the largest and most evolution families in the angiosperms.There are approximately 800 genera worldwide with around 20 000～35 000 species.Many species of orchids can be used as herbal medicines.Some factors such as the damage of ecologic environment,overexploitation and late investigation on wild medicinal plants of Orchidaceae caused the habitat destruction and the resource decreased dramatically.Many medicinal plants of Orchidaceae exist only small differences because of their highly evolved morphology.Therefore,it is difficult to identify them from morphologic characters.It is in urgent need of exploring more effective identification methods which are suitable for identifying medicinal plants of Orchidaceae.In the studies,some important medicinal plants of Orchidaceae were studied by using DNA barcoding molecular identification method,exploring the feasibility of this method and promoting the identification studies of medicinal plants of Orchidaceae.The medicinal plants of Orchidaceae are a research hotspot in recent years.Due to lack of relevant studies about the ecological suitability of medicinal plants of Orchidaceae,the quality of medicinal plants which were not cultivated in the suitable areas were often not meet pharmacopoeia standards.In view of the practical problems,the studies hope to seek a convenient method to solve the problems and provide scientific support on the introduction of medicinal plants of Orchidaceae.The studies of the efficient identification and ecological suitability of medicinal plants of Orchidaceae were done by using the DNA barcoding molecular identification and global geographic information system for medicinal plant(GMPGIS),in addition,a new species of the genus Odontochilus of Orchidaceae which were found basing on the field investigation,identification and ecological suitability were studied.1.The studies of DNA barcoding molecular identification of medicinal plants of OrchidaceaeIn the studies,DNA barcoding molecular identification method was used to validate the traditional morphological classification of medicinal plants of Orchidaceae.163 samples of 135 species belong to 49 genera which have been confirmed by morphological identification were collected.Candidate sequences,including matK,psbA-trnH and ITS2 sequences,were amplified,bidirectionally sequenced,and assembled.All the sequences were blasted to GenBank database at NCBI,then analyized by Neighbor-joining tree method by MEGA 7.0.The results showed that the DNAs of 163 samples were successfully extracted.The amplification efficiency of matK,psbA-trnH and ITS2 sequences were 100%,100%and 98.77%,respectively.487 sequences of medicinal plants of Orchidaceae were obtained,345 sequences of which matched corresponding sequences in the GenBank database and 142 sequences were new sequences.These sequences of medicinal plants of Orchidaceae which are-committed to the GenBank database can enrich the species sequence information in the GenBank database and promote the studies of DNA barcoding molecular identification of medicinal plants of Orchidaceae.The phylogenetic trees of medicinal plants of Orchidaceae which were constructed with the matK sequences,psbA-trnH sequences,ITS2 sequences by using the Neighbor-joining method showed that most of the species clustered into one clade respectively.The species that were gotten together could become the emphasis species in the further study of genetic relationship.The phylogenetic trees of medicinal plants of Orchidaceae could explain genetic relationship of some species.The phylogenetic tree of medicinal plants of Orchidaceae which were constructed with the matK sequences was better than the trees of psbA-trnH and ITS2 sequences.In conclusion,the matK,psbA-trnH and ITS2 sequences were complementary to each other and suitable for identification of medicinal plants of Orchidaceae.DNA barcoding can be used as an auxiliary means for identification of medicinal plants of Orchidaceae.With the support of relevant websites,the 2-dimensional bar codes of 133 species of medicinal plants of Orchidaceae which contain their ITS2 sequence information were made respectively.It could help people who use mobile terminals,such as the Android mobile phone,iPhone users get corresponding DNA barcoding sequence information of medicinal plants of Orchidaceae more easily and conveniently.It could also provide convenience and the research foundation for the further research of medicinal plants of Orchidaceae.2.The studies of ecological suitability of important medicinal plants of OrchidaceaeDue to the demand for medicinal plants of Orchidaceae is increasing,the excavation of the wild resources of medicinal plants of Orchidaceae have become more serious.Therefore,it is in urgent need for the research of ecological suitability of medicinal plants of Orchidaceae.After that,it can get the suitable growing regions of the species and increase the cultivation.By using cultivated species instead of wild species,it can meet the market supply and reduce the excavation of wild medicinal plants of Orchidaceae.The ecological suitability of 19 species of medicinal plants of Orchidaceae which are the most representative among the 135 species were studied by using global geographic information system for medicinal plant(GMPGIS).First,the studies obtained 2 725 latitude and longitude information of the 19 species of important medicinal plants of Orchidaceae in China through carrying out field investigation(obtaining the latitude and longitude point by using the global position system)and querying the related literatures and databases.After importing 2 725 latitude and longitude information into GMPGIS,the shape files of distribution points of each species of medicinal plants of Orchidaceae in China were generated.With the support of basic geographic information database,climate database,medicinal plants distributed spatial database,etc.,the ecological suitability of 19 species of medicinal plants of Orchidaceae were studied by using GMPGIS.The studies have gotten the diagrams of the ecological factor value range of main growth areas,the distribution points and the distribution maps of maximum ecological similarity areas of 19 species of medicinal plants of Orchidaceae in China.The studies have gotten the suitable wildlife tending and the cultivation areas of the 19 species in China by carrying out ecological suitability zoning.In the studies,the distribution areas of maximum ecological similarity of the 19 species in China included all the distribution areas which were recorded in the Flora of China.The maximum ecological similarity areas and the ecological factor value of main growth areas were consistent with the results reported in related research literatures.In addition,the studies have gotten the new suitable distribution regions which were not recorded in the previous literatures.The ecological suitability zoning of 19 species of medicinal plants of Orchidaceae which are rare and endangered were conducted in the studies.It could provide basic data and references for wildlife tending,introduction and cultivation and regionalization of medicinal material producting of these medicinal plants of Orchidaceae in China.The studies about the ecological suitability of important medicinal plants of Orchidaceae by using GMPGIS has some reference significance for reasonable arrangement of production range and expanding production range of other medicinal plants.The study results could also provide some help for the breeding of these species and provide scientific basis for breeding local suitable cultivars,such as breeding drought-resistant cultivars in arid areas.3.The studies of a new species of the genus Odontochilus of Orchidaceae from ChinaBased on the field investigation,identification and studying ecological suitability,we discovered a new species of the genus Odontochilus of Orchidaceae,namely Odontochilus napoensis H.Tang et Y.F.Huang sp.nov..The new species was only found in limestone evergreen broad-leaved forest,Napo county,southwestern Guangxi,China,which lies in the Sino-Vietnamese border region.This new species could probably also distribute on limestone areas of Northern Vietnam.In the studies,the related research about the new species such as morphological description,comparing it with other similar species,protection and utilization,prediction of potential distribution were conducted.These studies would help people to know this new species and conduct related research and conservation as early as possible.The studies could provide significant basic data and research methods for efficient identification,wildlife tending,regionalization of medicinal plants of Orchidaceae in China.The research results have some practical meaning for the conservation and sustainable exploitation of medicinal plants of Orchidaceae.