Metabolite signatures of diverse Camellia sinensis tea populations

Xiaomin Yu,Zhenbiao Yang,Jiajing Xiao,Qianlin Chao,Zhijun Fu,Yuan Yu,Jun Lin,Liang Chen,Jianqiang Ma,Yuzhen Lin,Si Chen,Qiongqiong Zhou,Ruizi Li,Renyi Liu

doi:10.1038/s41467-020-19441-1

Abstract

The tea plant (Camellia sinensis) presents an excellent system to study evolution and diversification of the numerous classes, types and variable contents of specialized metabolites. Here, we investigate the relationship among C. sinensis phylogenetic groups and specialized metabolites using transcriptomic and metabolomic data on the fresh leaves collected from 136 representative tea accessions in China. We obtain 925,854 high-quality single-nucleotide polymorphisms (SNPs) enabling the refined grouping of the sampled tea accessions into five major clades. Untargeted metabolomic analyses detect 129 and 199 annotated metabolites that are differentially accumulated in different tea groups in positive and negative ionization modes, respectively. Each phylogenetic group contains signature metabolites. In particular, CSA tea accessions are featured with high accumulation of diverse classes of flavonoid compounds, such as flavanols, flavonol mono-/di-glycosides, proanthocyanidin dimers, and phenolic acids. Our results provide insights into the genetic and metabolite diversity and are useful for accelerated tea plant breeding.

Highlights

The tea plant (Camellia sinensis) presents an excellent system to study evolution and diversification of the numerous classes, types and variable contents of specialized metabolites
By analyzing transcriptomic and metabolomic data from 136 representative tea accessions in China, we were able to classify these accessions into five phylogenetic groups/populations, identify over 8000 polymorphic markers that can be used for marker-assisted breeding, explore the dynamic variations in metabolite compositions and gene expression, and identify dozens of signature metabolites that are highly accumulated in one group of tea accessions but not in other groups
Our results show that there exists a high level of metabolite diversity in different tea populations and accessions, which can be explored to investigate the underlying regulatory mechanisms and guide molecular breeding for tea improvement

Summary

Introduction

The tea plant (Camellia sinensis) presents an excellent system to study evolution and diversification of the numerous classes, types and variable contents of specialized metabolites. We investigate the relationship among C. sinensis phylogenetic groups and specialized metabolites using transcriptomic and metabolomic data on the fresh leaves collected from 136 representative tea accessions in China. A recent study, using 6,252,201 single-nucleotide polymorphism (SNP) markers obtained from genome-resequencing data, separated 81 collected accessions into three clusters (CSS, CSA, and wild type)[35]. The smaller number of clusters revealed by this study is most likely because only 81 accessions were evaluated, among which only 58 were cultivated accessions To resolve this discrepancy, a comprehensive evaluation of genetic diversity and population structure of a larger number of representative tea accessions, especially cultivated tea accessions, using genome-wide markers such as SNPs is needed

Methods

Results

Conclusion