Phylogeography Of The Relict Plant Castanopsis Kawakamii

Castanopsis kawakamii(Fagaceae,Castanopsis),is endangered plant of the national third-grade protection of China,is endemic to southern boundary of the mid-subtropical region in China and is relic of Tertiary.Based on the previous research,because of the change of natural environment,destroy by human beings,and it own genetics feature,now the Castanopsis kawakamii population face the decline stage,the adult tree had death,seedling recruitment difficulties.Our research group had do systemic research in order to find the reason of it endangered from physiological to biochemical aspects,showed that the biological reasons is one of the main factors affecting its endangered.Therefore,this study selected sampling all around China;we collected 168 sampling from 22 populations to do the research.Select cpDNA(trnL-trnF,rpL 16)and nrDNA(ITS 1-4)fragment to do gene markers for all individuals.To study the population genetic diversity,origin and evolution of history and geography,population,endangered mechanism of Castanopsis kawakamii.Combined with the present situation of population ecology,put forward the corresponding measures of protection.In order to solve the present situation of endangered Castanopsis kawakamii from genetics,to ensure the sustainable development of Castanopsis kawakamii population,the protection of biodiversity in china.The main results are as follows:(1)Population Genetic Diversity Analysis of Castanopsis kawakamiiBased on the genetics analysis of Castanopsis kawakamii population found that:ITS 1-4 data analysis showed that the Nst(0.631)is greater than the Gst(0.515),illustrate that the genetic structure of Castanopsis kawakamii population is obvious;AMOVA analysis showed that,the genetic differentiation among population and within populations was high on nrDNA and cpDNA data:ITS 1-4 series,Fst=0.510,showed that in the geographical distribution area,there are certain degree of genetic differentiation among population and within populations,and the genetic differentiation among the populations is higher,and the gene flow is frequent;cpDNA sequence:Fst=0.550,showed that the genetic differentiation distributed in both populations and within populations.The high level may be caused by its breeding system,human disturbance and genetic drift.(2)Phylogenetic analysis of Castanopsis kawakamiiThrough the analysis of ITS 1-4 and cpDNA sequence data,the gene flow between Castanopsis kawakamii populations were Nm=0.240,0.205,were less than 1,indicates the presence of genetic exchange between Castanopsis kawakamii population were low.There are 15 haplotypes among 22 Castanopsis kawakamii populations.An cpDNA combined fragment were mainly clustered into 4 branches,its relationship with approximately ITS 1-4.The Nanping unique haplotypes NR3 and NR2 were clustered together firstly,and then to the north of Guangdong the widely distributed NR1 together;Zhangping in the middle region Sanming and Xunwu,affect the distribution of the haplotypes of the two;the distribution of haplotype inference of Taiwan area in Fujian province of Castanopsis kawakamii is spread over the past;in the southern region,Guangxi its unique haplotype NR4 first and regional wide distribution of haplotype NR 14 together,and then with the Hainan unique haplotype NR13 together.Through the analysis we can see,there is a clear differentiation of Castanopsis kawakamii distributed in China,mainly divided into the Fujian-Taiwan area and Guangxi area,Guangdong two differentiation zones.(3)Phylogeographic pattern of Castanopsis kawakamiiThe Castanopsis kawakamii populations of nrDNA MDA analysis,MDA analysis found that Castanopsis kawakamii curve and the curve is not consistent with the expected squared error;P of SSD and HRag were less than 0.05,significantly,with the rapid expansion of Tajima model;Tajima's D test and Fu's Fs was negative and a non significant.The Castanopsis kawakamii populations of cpDNA MDA analysis,MDA analysis found that Castanopsis kawakamii curve and the curve is almost entirely consistent with expectations,showing a single peak;P of SSD and HRag were greater than 0.05,is not obvious,with the rapid expansion of the model;Tajima's D and Fu's Fs were negative and are not significant.Arlequin estimated that Castanopsis kawakamii expansion time was 1 Mya.Based on the cpDNA data analysis shows Castanopsis kawakamii,about 1000000 years ago,the rapid expansion of the event occurred,during the period of Castanopsis kawakamii genetic differentiation may lead to the increase of Castanopsis kawakamii population,genetic diversity.The island of Taiwan and connected to the mainland called "Dongshan" bridge,until only 10000 years ago was completely submerged.After the formation of Taiwan Island,genetic exchanges on the mainland and Castanopsis kawakamii is blocked,the Taiwan area in the genetic variation of the Castanopsis kawakamii is to retain the original haplotypes but also produced a new haplotype.In Hainan Island about 400000 years ago in Hainan Island and Mainland China are connected,plants and animals can be the bridge for migration and diffusion,in about 10000 years ago during the last glacial period,Hainan Island and the mainland has been completely water interval.In the long course of evolution,Hainan within populations of Castanopsis kawakamii genetic inheritance of the Guangxi populations of the haplotype at the same time,but also by environmental selection and genetic drift caused the unique haplotypes.