Population structure analysis to explore genetic diversity and geographical distribution characteristics of wild tea plant in Guizhou Plateau

Abstract

Background Tea, the second largest consumer beverage in the world after water, is widely cultivated in tropical and subtropical areas. However, the effect of environmental factors on the distribution of wild tea plants is unclear. Results A total of 159 wild tea plants were collected from different altitudes and geological types of the Guizhou Plateau. Using the genotyping-by-sequencing method, 98,241 high-quality single nucleotide polymorphisms were identified. Genetic diversity, population structure analysis, principal component analysis, phylogenetic analysis, and linkage disequilibrium were performed. The genetic diversity of the wild tea plant population from the Silicate Rock Classes of Camellia gymnogyna was higher than that from the Carbonate Rock Classes of Camellia tachangensis. In addition, the genetic diversity of wild tea plants from the second altitude gradient was significantly higher than that of wild tea plants from the third and first altitude gradients. Two inferred pure groups (GP01 and GP02) and one inferred admixture group (GP03) were identified by population structure analysis and were verified by principal component and phylogenetic analyses. The highest differentiation coefficients were determined for GP01 vs. GP02, while the lowest differentiation coefficients were determined for GP01 vs. GP03. Conclusions This study revealed the genetic diversity and geographical distribution characteristics of wild tea plants in the Guizhou Plateau. There are significant differences in genetic diversity and evolutionary direction between Camellia tachangensis with Carbonate Rock Classes at the first altitude gradient and Camellia gymnogyna with Silicate Rock Classes at the third altitude gradient. Geological environment, soil mineral element content, soil pH, and altitude markedly contributed to the genetic differentiation between Camellia tachangensis and Camellia gymnogyna.

Genome-Wide Association Studies of Biluochun Tea Plant Populations in Dongting Mountain and Comprehensive Identification of Candidate Genes Associated with Core Agronomic Traits by Four Analysis Models

“…The results of LD analysis showed that the LD of the six subgroups was less than 1 kb, and the LD of ZW was the largest (r 2 = 500 bp), indicating that the selection pressure of these tea plants was low. Compared with Guizhou ancient tea plant (r 2 = 19.3 kb) [27], Guizhou cultivated tea plant (r 2 = 2 kb) [23] and wild tea plant (r 2 = 116 bp) [35], indicating that the selection pressure of Biluochun tea plant population was lower and Biluochun tea plant varieties may have higher genetic diversity. Therefore, they are recommended as materials for studying the evolution, origin, and breeding of tea plants.…”