| The control of tea plant diseases and insect pests has always been a hot field in the research of sustainable development of tea industry.The annual production reduction of tea caused by diseases and insect pests is 15%～20%,which seriously affects the yield and quality of tea.Applying insecticides for control is an effective measure,but a large amount of insecticides will lead to a series of problems,such as environmental pollution,increased pest resistance,and decreased insecticidal effect.Jasmonic acid(JA)is an important anti-insect factor,which can induce the expression of a series of anti-insect genes to resist insect pests.Tea polyphenols(TP)and Caffeine(CAF)are important phenols in tea plant,which can induce resistance and avoid insects.Therefore,it is of great significance to explore the molecular mechanism of insect resistance factors such as jasmonic acid,tea polyphenol and caffeine in germplasm resources of local tea plants in Guizhou province,and to mine important insect resistance candidate genes for breeding new insect resistance varieties of tea plants through marker-assisted selection.In this study,350 local tea germplasm resources in Guizhou are selected through Genotyping-by-Sequencing(GBS).100,720 high-quality Single nucleotide polymorphism(SNP)were identified at the genomic level.The contents of jasmonic acid,tea polyphenol and caffeine in 350 tea plant germplasm materials from Guizhou Province were analyzed by ultra performance liquid chromatography(UPLC),and the correlation analysis between the contents of jasmonic acid,tea polyphenols and caffeine and the number of wormholes,the analysis of genetic diversity,genetic differentiation and population structure of tea plant population were carried out,as well as the Genome-wide association studies(GWASs)between the genotypes of germplasm resources of tea plant in Guizhou and the contents of jasmonic acid,tea polyphenols,caffeine and the number of wormholes and candidate gene prediction.The main research results are as follows:(1)Through the analysis of the correlation between the contents of jasmonic acid,tea polyphenol and caffeine and the number of wormholes in 350 Guizhou local tea germplasm resource populations,the results showed that the jasmonic acid content was negatively correlated with the number of wormholes,and the tea polyphenol content was negatively correlated with the number of wormholes.(2)Through the analysis of the population structure and genetic diversity of 350 tea germplasm resources in Guizhou,the results showed that 350 tea germplasm resources were divided into 5 pure subgroups and 1 mixed group,and the observed heterozygosity(Ho),nucleotide polymorphism(π)of G 01 population were the highest among the five inferred populations.And the Tajima’s D of the 5 inferred populations were all greater than 0.(3)Through the analysis of the genetic differentiation among 350 populations of Guizhou tea germplasm resources showed that the genetic differentiation between G 04 and G 05 populations was larger,and there was little genetic differentiation between G02 and G 03.(4)Through the analysis of genome-wide association study on the genotypes and phenotypic traits of jasmonic acid content,tea polyphenol content,caffeine content and wormhole number of 350 tea germplasm resources from Guizhou.The results showed that jasmonic acid content was associated with 30 SNPs.A total of 79 SNPs markers were associated with tea polyphenol content.The caffeine content was associated with15 SNPs markers.The number of wormholes was associated with a total of 19 SNPs markers.(5)Through the predict candidate genes of 350 local tea germplasm resources in Guizhou.The results showed that a total of 10 candidate genes were found near 7 SNPs significantly correlated with jasmonic acid content,among which TEA001467.1 and TEA006436.1 genes may be correlated with jasmonic acid content.A total of 37 candidate genes were found near 27 SNPs that were significantly correlated with tea polyphenol content,among which TEA004424.1 and TEA025120.1 genes might be correlated with tea polyphenol content.A total of 6 candidate genes were found near 15 SNPs which were significantly correlated with theobroine content,among which TEA007160.1 gene might be correlated with theobroine content.A total of 12 candidate genes were found near 7 SNPs that were significantly correlated with the number of wormholes,among which TEA013488.1 and TEA033038.1 genes might be correlated with the number of wormholes. |
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