Population Structure Analysis Revealed Water or Ancient Hub-induced Genetic Diversity of Cultivated-type Tea Plants in Guizhou Plateau

Abstract

Background Tea plants originated from the southwest of China. Guizhou is one of the origin center of tea plants, which is rich in tea plant germplasm resources. However, the distribution characteristics and transmission model of tea plant were still unclear. Results We collected 253 cultivated-type tea plant accessions from Guizhou plateau and analyzed the genetic diversity, PCA, phylogenetic, population structure, LD, and development of core collection using the genotyping-by-sequencing (GBS) approach. A total of 112,072 high-quality SNPs were identified, which was further used to analyze the genetic diversity and population structure. In this study, we found that the genetic diversity in cultivated-type tea accessions of PR Basin were significantly higher than that in cultivated-type tea accessions of YR Basin. Moreover, four groups, including three pure groups (CG-1, CG-2 and CG-3) and one admixture group (CG-4), were identified based on population structure analysis, which was verified by PAC and phylogenetic analysis. Our results showed that the highest GD and Fst values were found in CG-2 vs CG-3, followed by CG-1 vs CG-2 and CG-1 vs CG-3. The lowest GD and Fst values were detected in CG-4 vs CG-1, CG-4 vs CG-2, and CG-4 vs CG-3. Conclusions This study provided the evidence to confirm the contribution of PR and YR Basins and ancient hub road section to the transmission of cultivated-type tea accessions in Guizhou plateau. The genetic diversity, population structure and core collection revealed by our study will benefit further genetic studies, germplasm protection, and breeding.