Genetic Diversity And Evolvement Of Natural Populations In Aquilaria Sinensis (lour.) Gilg

Aquilaria sinensis(Lour.) Gilg,species in Thymelaeaceae,is one of the valuable medicinal plants uniquely native in China.But its natural resource has been over destroyed,and to be endangeried species listed in China Plants Red Book.Hardly any knowledge about the total amount of resources and population genetic diversity has been reported.In this study,total of 115 accessions include of 112 A.sinensis and 3 D.axillaris nearly relative species in 11 geographic natural populations have been collected basecd on full investigation to the distribution districts of A.sinensis.Integrating ISSR and SRAP marker systems were used to take examination and evaluation of the whole genetic diversity level and differention among the natural populations with NTSYS-pc,POPGENE32 and Mega2 softwares.Originally,it revealed that the genetic classification,diversity paramaters and the evolution relationship among different populatiuons in A.sinensis.It also has been discussed that the cause of endangering and the possible strategies to conserve.The main results got are as followings:(1) Throughout selection and better large amount of ISSR and SRAP primers and its amplified conditions,each 20 pairs of primers have been choiced and set up the effective ISSR and SRAP analysis system in A.sinensis first timely,that will contribute to relative researches methodologilly.(2) Combining to ISSR and SRAP marker data,total of 818 alleles have been found,average 20.45 alleles per primer and there are 567 polymorphic alleles with ratio of 69.32%.With the enrich diversity loci,it revealed that the genetic classification of population is coincide to the geography distribution with some of the crosses,such as the 5 genetic and geograpgic populations of A.sinensis:Jianfengling-Maogan clade,Bawang-nanyanwan clade, Wuzhishan-limuling clade,Diaoluoshan clade and Guangdong clade.PCA analysis further showed that there are three large scale level geographic distribution zones of A.sinensis,they are Hainan group,Guangdong group and among them of Hainan Diaoluoshan group.(3) The intra-group and total genetic diversity parameters have been estimated based on geographic population classification.Among the 7 populations,the genetic diversity index(Ⅰ) of Jianfengling,Bawang and Guangdong are little higher(0.2954,0.2859,0.2938) than others. The current genetic diversity of whole population is low(h=0.2397,I=0.3582),indicating that less genetic diversity in population A.sinensis means it was reaching to or in the endangered state theoretically,and need pay attentation to conservation.(4) Integrated ISSR and SRAP allele imformation described the genetic differentiation and gene flow among the 7 populations.Coefficient of gene differentiation among populations was 0.2147(Gst),which means 21.47%of total genetic variation residented among populations.Gene flow among populations was relatively restricted(Nm=1.8292).The relationship of the geographic groups:Primaryly,there are two bigger groups,Jiangfengling (Pop1) and Maogan(Pop2) sub-group constructed the first group;the second group consist of three sub-groups,DIAOLUOSHAN(Pop6) and GUANGDONG(Pop7) sub-group,BAWANG (Pop4) and WUZHISHAN(Pop5) sub-group,NANYANWAN(Pop3) sub-group.(5) According to evolutionary analysis using D.axillaris to be root,it is indicated that among the 11 natural populations,some of the DIAOLUOSHAN,WUZHISHAN and LIMUSHAN accessions were first branched,and they will be the originally types;The others alphbitically were GUANGDONG accessions,Hainan DIAOLUOSHAN accessions,NANYANWAN and BAWANG accessions,and then JIANFENGLING and MAOGAN accessions.The latest branched Hainan Jianfengling and Maogan types are the younger developed populations with higher diversity.They could be the hot spot to take the in situ conservation.In the paper,the rationale of endangering and the available conservative strategies have been discussed according to revealed genetic diversity level and distribution of whole resources in A.sinensis.However,what about the relationship between molecular genetic diversity to the economic traits has not been studied,and it need take test and evaluation in physiology,biochemistry and genomics level in the further work,to benefit to use and industrialization of A.sinensis species.