Development Of SSR Markers Based On The Camellia Sinensis Transcriptome And Genetic Diversity Analysis Of Some Camellia Genus Plants

The accumulation of genetic variation in the evolution of camellia genus plant makes it show rich genetic diversity at the DNA molecular level.In this study,the SSR locus search was performed based on the transcriptome data of Camellia sinensis,and the bioinformatics analysis was performed on the sequence containing the SSR locus.The development SSR molecular marker primers were carried out.The genetic diversities of camellia genus plants were analyzed by using the developed primers.The main findings are as follows:1.MIS A software was used to search the transcriptome data of Camellia sinensis,and 10,078 SSR sites matching the screening parameters were found in 9,508 Unigene.The frequency of occurrence(SSR-containing Unigene/total Unigene)was 6.49%,and the frequency of occurrence(SSR number/total number of Unigene)is 7.23%.The average distance between each SSR site was 2.85 kb.2.The SSR-containing Unigenes in the transcriptome data of Camellia sinensis were compared with the nr protein database and the KEGG database,and the annotation information of 17,267 and 1,866 was obtained.The comprehensive statistical analysis of the annotation information shows that the annotated SSR-containing Unigenes were mainly related to cellular metabolism.3.The SSR locus information statistics showed that the number of dinucleotide repeat elements were the highest,accounting for 43.1%of the total SSR loci.The number of repetitions of each type of nucleotide element were mainly 5～9 times.The number of AG/CT and A/T nucleotide types were large(3,584),and the total proportion of total SSR was 67.76%.The lengths of SSR components were concentrated at 12～30 bp,with 8,823,accounting for 83.4%.4.Primer 3.0 was used to design primers in batches.A total of 38 pairs of primers including various types of nucleotide elements were randomly selected for subsequent screening.A total of 24 pairs of primers could amplify the target bands,and 16 pairs of primers were obtained after polymorphism screening.The development rate of polymorphic primers was 42.11%,covering one to six nucleotide elements,and the number of polymorphic primers containing dinucleotide elements was the largest.5.The genetic diversity of 20 camellia genus plants were analyzed by polymorphic primers.The results showed that the observed number of alleles was 3.3125;the effective number of alleles was 2.65;the Shannon’s Information index was 1.039;and the average Nei’s genetic diversity index was 0.61.The UPGMA method was used to cluster the samples.The results showed that the samples were divided into two groups at 0.38 Nei’s genetic distance.The clustering of the samples was basically consistent with the geographical information.