Research On Genetic Diversity Of Myrtle Germplasm Resources Based On SNP

In China,myrtle(Rhodomyrtus tomentisa(Ait)Hassk)is widely distributed in South China.It is a traditional Chinese medicine resource,a fine new garden plant for flower and fruit observation and a new fruit economic crop for Rural Revitalization.Through the collection of Geographical Provenances and Habitat Analysis of myrtle in China,and the analysis of genetic diversity and gene sequencing within and among wild Myrtle provenances,we can explore the geographical genetic differences and the influence of habitat,reveal the characteristics of genetic diversity and the mechanism of variation,and provide theoretical basis and production guidance for further introduction and domestication of myrtle.This paper uses a new generation of molecular marker technology SNP(Single Nucleotide Polymorphisms)to genetically analyze the genetic differences of 179 wild R.tomentosa plants from 20 provinces in China:Using MEGA X software,based on neighbor joining method,using Kimura 2-parameter model,bootstrap repeated 1000 times,the phylogenetic tree of each sample was constructed.Based on SNP and admixture software,the population structure of the samples was analyzed.The cluster number(k value)of the samples was assumed to be 1-20.The cluster results are cross validated,and the optimal number of clusters is determined according to the estimation of cross validation error rate.Based on SNP and eigensoft software,principal component analysis was carried out to get the principal component clustering of samples.Through PCA analysis,we compared the close relationship of myrtle provenances,and divided myrtle materials from 20 provenances into groups according to their relationship,and assisted with evolutionary analysis.Based on the climatic characteristics of the provenance,the environmental causes of genetic diversity of myrtle were discussed,and the mechanism of genetic variation of geographical provenance was analyzed.The results were as follows:1.Taking the guava(Psidium guajava)genome as the reference genome,determined to use Rsa I+Hae III restriction enzyme digestion,the digestion efficiency reached 95.72%,obtained 2,276,088 SLAF tags,the average sequencingdepth is 11.86 x,among them,466,228 were polymorphic SLAF tags,and a total of3,787,540 population SNPs were obtained;2.The construction of a phylogenetic tree shows that the populations of Fuzhou,Pingyang,and Quanzhou in the northern margin of the distribution of Myrtle are located at the most base position and are relatively old in terms of evolutionary relationship,while the populations of Baise,Fangchenggang,and Nanning in the west are more evolved,reveals the path of the occurrence and expansion of Myrtle in our country;3.The cluster analysis of the population structure of all myrtle provenances shows that when the group number K is 8,the cross-validation error rate is the lowest,and the provenances of myrtle nationwide are divided into 8 subgroups;4.The principal component analysis based on the degree of SNP difference shows that the country myrtle can be divided into 7 groups.The above research results have laid a certain foundation for further research on the development and utilization of Myrtle.