Construction Of DNA Fingerprinting And Genetic Diversity Of Schisandra Chinensis Germplasm

Schisandra chinensis（Turcz.）Baill.belongs to the family Schisandraceae,the genus Schisandra,the subgenus Schisandra.Its dried fruit is a major Chinese medicinal material.S.chinensis is also widely used in health care products,cosmetics and other fields.The seeds used for the production of S.chinensis mainly come from the wild collected seeds and the seeds selected by farmers in various regions.Due to the abundant variation in the practical population,it provides rich materials for the screening of germplasm resources,but also increases the difficulty of accurate identification.In the preservation and recording of germplasm resources,the phenomenon of"different names of the same substance"or"foreign bodies with the same name"is easy to occur.In addition,with the artificial domestication and cultivation of wild resources of S.chinensis,the genetic background of S.chinensis has gradually narrowed.Therefore,it is of great significance to strengthen the research on the genetic diversity of S.chinensis germplasm resources and construct the accurate DNA fingerprint of S.chinensis germplasm identification,variety breeding and the healthy and sustainable development of the cultivation industry.In this study,106 germplasm resources of S.chinensis from 6 regions were analyzed by SSR molecular markers and genetic diversity,and DNA fingerprints were constructed.The main conclusions were as follows:（1）EST-SSR-PCR reaction system was optimized by orthogonal test.The optimal system was 16μl system:DNA20 ng,SSR positive and negative primers were 0.2μmol/L each,d NTP0.3mmol/L,Taq DNA polymerase 2U,Mg²⁺4 mmol/L.38 pairs of polymorphism primers were screened based on this system.（2）The average polymorphism information content（PIC）of 38 pairs of primers was 0.407,which had a medium level of polymorphism,which could meet the genetic diversity of Schisandra.Among 38 pairs of EST SSR polymorphism primers,35 pairs could be amplified in Schisandra sphenanthera,and the universality ratio was 92%in the same genus.Thirty-one pairs of primers were amplified in the K.chinensis,and the generality ratio among different genera was 81%.The polymorphic markers obtained in this experiment can be used to compare S.chinensis with related species.（3）Based on SSR amplification results,at the genetic similarity coefficient of 0.61,all the materials were divided into two groups.At the genetic similarity coefficient of 0.61,the cluster of S.sphenanthera and S.chinensis was classified as classⅠ,and the cluster of K.chinensis wasclassified as classⅡ.At the genetic similarity coefficient of 0.68,the cluster of classⅠwas divided into two subgroups,subgroupⅠwas the germplasm resource of S.chinensis and subgroupⅡwas the germplasm resource of S.sphenanthera.Eventually,all resources can be effectively differentiated.（4）The S.chinensis resources could be divided into three subpopulations based on population genetic structure.The Fst of three subpopulation was 0.044,Fis value was-0.051,and gene flow Nm was 5.376.The level of gene exchange among populations was high,and genetic differentiation was small.This may be closely related to strong gene flow among populations,widely distributed biological characteristics,relatively concentrated collection area and monoecious breeding mode.（5）Four pairs of SSR primers could encode the identity of 106 germplasm resources of S.chinensis.Each digital ID card included 28 loci.QR code software was used to generate the ID QR code,and the QR code information contained the name,type,source,preservation method and corresponding identity code of the germplasm resources of S.chinensis.Digital fingerprint provides an accurate and rapid molecular technology system for the identification of germplasm resources of S.chinensis,and has high application value.