Study On Conservation Genetics Of Toxicodendron Vernicifluum F.A. Barkley In China

Toxicodendron vernicifluum（Stokes）F.A.Barkley is Tertiary relict plant,it was originally grew in China,it is classified as a kind of deciduous macrophanerophytes also the subdivision of the Toxicodendron which belongs to the Anacardiaceae.T.vernicifluum has economic,ecological and cultural value.China is rich of T.vernicifluum resources,however in recent years,due to environmental changes and human activities,its wild resources have been destroyed and urgently need to be protected.In this study,modern molecular biology techniques were applied to study the population genetic of the species,aiming to reveal its genetic background,as well as to provide theory and technological support for its protection.In this study,18 pairs of EST-SSR primers were used to conduct population genetic analysis on 520 wild sumac individuals from 26 populations collected from 15 provinces.The results showed that:（1）The observed number of alleles（A）of 18 pairs of primers is 3.111,the index of heterozygosity observation（H_O）is 0.764,while index of heterozygosity expectation（H_E）is 0.572,Shannon’s information index（I）is 0.943.Otherwise,0.571 for the index of total genetic diversity（H_T）,0.497 for the average index of primers’polymorphism information content（PIC）,and 9 of 18 pairs of primers’index of PIC is higher than 0.5.The above results indicated the polymorphism of EST-SSR primers in this research was high.（2）The results of genetic diversity analysis showed that T.vernicifluum had high genetic diversity at the population and species levels.（3）0.296 6（>0.25）for the genetic differentiation among populations(F_ST),and the gene flow（N_m）is 0.567（<1）,it indicated that the level of gene exchange between populations was low,the genetic differentiation was large,and the genetic variation mainly came from within the population.The results of mantel test showed that there’s definite relativity between the genetic and geographic distance（r=0.598,P=0.01<0.05）.（4）The results of Bayesian cluster analysis,adjacency cluster analysis and PCA analysis were basically the same.26 populations were divided into three groups in Central China,East China and southwest China.（5）While the testing results from BOTTLENECK confirmed all the 26 populations have experienced the bottleneck effects.T.vernicifluum is widely distributed in China,and its life-history characteristics such as sexual reproduction mode and insect-borne pollination have accumulated rich genetic diversity in the population of T.vernicifluum.At the same time,restricted by factors such as climate change,geographic isolation,bottleneck effect,and habitat fragmentation,gene flow cannot resist the influence of genetic drift,resulting in significant genetic differentiation of T.vernicifluum populations.In view of the rich genetic diversity of T.vernicifluum and the significant genetic differentiation of populations,we believe that the protection of T.vernicifluum should be based on in situ protection,focusing on the protection of populations in Mts.Qinling-Bashan Area and Southwest China.