Population sequencing enhances understanding of tea plant evolution

Tea is an economically important plant characterized by a large genome size and high heterozygosity and species diversity. In this study, we assemble a 3.26-Gb high-quality chromosome-scale genome for tea using the 'Longjing 43' cultivar of Camellia sinensis var. sinensis. Population resequencing of 139 tea accessions from around the world is used to investigate the evolution of tea and to reveal the phylogenetic relationships among tea accessions. With the spread of tea cultivation, hybridization has increased the heterozygosity and wide-ranging gene flow among tea populations. Population genetics and transcriptomics analyses reveal that during domestication, the selection for disease resistance and flavor in C. sinensis var. sinensis populations has been stronger than that in C. sinensis var. assamica populations. The data compiled in this study provide resources for the marker-assisted breeding of tea and can serve as a basis for further research on the genetics and evolution of tea.