Effects Of Road Corridor And Forest Landscape Pattern On Population Property And Genetic Structure Of Ageratina Adenophora

Ageratina adenophora is one of the most noxious worldwide weeds.It was introduced into Yunnan province from the border of Burma in the last century and has invaded many provinces in China,especially in the southwest part.Its populations were easily spread along roads and rivers,which put serious impact on the ecological environment.In this paper,the genetic diversity and population genome structure of the invasive species,A.adenophora were surveyed by SSR,AFLP,and Rad-seq sequencing at local landscape scale,in order to understand genetic and genomic variation of A.adenophora populations under different road density,landscape pattern and landscape resistance.This study might provide a theoretical basis and genetic background for the control of A.adenophora.The main results were as follows:1.A.adenophora was significantly affected by the tree layer of the forest communitie.Forest types had no significant effect on the distribution of A.adenophora.The distance from road was the most important factor on the distribution of A.adenophora in natural forests,but it had no significant effect on cultivated forests.2.8 pairs of SSR and 4 pairs of AFLP polymorphic primers were used to conduct PCR amplification for 600 individuals of 25 populations,and all sites were monomorphic.Ten populations in different landscape typeswere chosen,and a total of 50 individuals,5 in each population for RAD-seq sequencing.?The results showed that the percentage of polymorphic(PPB)= 63.854-68.585,average allele frequency(P)= 0.782-0.785,expected heterozygosity(He)= 0.25672-0.26227,observed heterozygosity(Ho)= 0.565-0.571,nucleotide diversity(Pi)= 0.2908-0.3034.The largest genetic differentiation among populations was between the population in Quercus aliena forest and roadside population,POP24.The lowest genetic differentiation was those of POP3 and Cupressus duclouxiana forest.3.Ten populations were clustered by "ADMIXTURE" into,two typical landscape populations.The one type was evergreen broad-leaved forests and deciduous oak forest,which were primitive forests.The another,type of populations were inside coniferous forests and,plantations,and the roadside one,which human disturbance were stronger.4.PPB,Pi,and P were not significantly different among the ten populations in different road density,except Ho.Landscape metrics were unrelated to genomic polymorphisms of A.adenophora.In addition,there was no significant correlation between the landscape resistance and the genetic diversity of A.adenophora.At local scale,landscape pattern had no obvious impact population of genetic diversity of A.adenophora.