| In this study,250 natural populations of aging walnut in Xinjiang were used to establish 30 gene pools.Molecular marker-assisted selection test was conducted for tannin traits in aging walnut population by AFLP markers with rich polymorphism,co-dominant inheritance,good reduplication and simple operation,and to identify and classify high and low tannin populations.At the same time using GWAS data(genome-wide association analysis)analysis and SNP marker for aging walnut groups to analyze the genetic diversity and population structure,the tannin traits phenotypic and SNP loci mixed linear model(MLM),dig up significantly associated with tannin traits loci,and 100 KB of significant association loci candidate genes for mining area,the main results were as follows:(1)AFLP amplification results showed that a total of 553 statistical bands were obtained,of which 474 bands were polymorphic,and the average percentage of polymorphic bands was 85.47%.The number of alleles in 30 gene pools was 2.0-2.02,with an average of 2.00.The number of effective alleles was 1.41-1.58,with an average of 1.52.The genetic diversity was 0.29-0.35,with an average of 0.31.Shannon information index was 0.40-0.52,with an average of 0.47.Among them,specific bands such as E11-M2-59,E9-M2-216 and E9-M2-59 can be used to preliminarily identify walnut populations with high and low tannins.According to the results of cluster analysis including tannins,can direct clustering analysis,the high tannin groups directly when clustering worshiping a value of 0.20,can be in 30 old walnut gene Chi Zu is divided into three categories,the genetic distance between gene pool sample is bigger,the genetic variation between the groups of various also more abundant,and found that the clustering results with clustering analysis is more uniform tannins.(2)By comparing BWA with the used reference genome(jrserr＿genomes.FASTA)in the GWAS experiment,the average data volume is 10.96 GB,and the average sequencing depth is 20.49×.For the diversity analysis of re-sequenced species,the average Mapping rate is 96.38%,the average permutation Mapping rate is 88.37%,and the Mapping rate is greater than 85.00%.Through the coverage analysis of the reference genome 1-10×(with at least 1-10 base coverage),the average genome coverage was 95.60%,1×coverage was 95.95%,4×coverage was 94.07%,87.44%,and 10× coverage was 85.89%.The detection degree of the bases on the genome was high,and the distribution of the bases was uniform,and the sequencing results were good.(3)The results of PCA analysis showed that the clustering of aging walnut population was relatively clear in the principal components PCA1-PCA2 and PCA1-PCA3.Wild walnut in Yili of Xinjiang was separately clustered into one category,the aging walnut and cultivated walnut varieties were cross-mixed with each other,and the cultivated walnut in PCA2-PCA3,both Yili walnut and aged walnut had a dispersed mixed distribution.The results of population genetic structure showed that the population could be divided into five subpopulations,among which some old walnuts in Wenshu Tianshan Shenmu Temple of Aksu showed close genetic relationship.The LD distance of Yili wild,Hotan,Aksu and Kashgar was in order.The existence of such high LD was caused by the accumulation of recombinational events after gene mutation and allele formation due to the particularity of the environment.(4)Correlation analysis results showed that translocon at the outer membrane of chloroplasts was found in the two SNPs regions.Translocon at the outer membrane of chloroplasts(Jr8DG00136900,Jr8DG00137100),glutathione S-transfer ase(Jr8DG00137000),DENN domain and WD repeat-containing protein;Jr8DG00138300,Jr8DG00138400),five functional genes that may be associated with t he accumulation of tannins. |
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