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Article|01 Mar 2021|OPEN
Genome-wide association analysis identified molecular markers associated with important tea flavor-related metabolites
Kaixing Fang1, Zhiqiang Xia2,3, Hongjian Li1, Xiaohui Jiang1, Dandan Qin1, Qiushuang Wang1, Qing Wang1, Chendong Pan1, Bo Li1 & Hualing Wu1,
1Tea Research Institute, Guangdong Academy of Agricultural Sciences; Guangdong Key Laboratory of Tea Plant Resources Innovation & Utilization, Guangzhou 510640, China
2Institute of Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 570100, China
3Hainan University, Haikou 570228, China

Horticulture Research 8,
Article number: 42 (2021)
doi: 10.1038/hortres.2021.42
Views: 347

Received: 01 Jul 2020
Revised: 15 Dec 2020
Accepted: 17 Dec 2020
Published online: 01 Mar 2021

Abstract

The characteristic secondary metabolites in tea (theanine, caffeine, and catechins) are important factors contributing to unique tea flavors. However, there has been relatively little research on molecular markers related to these metabolites. Thus, we conducted a genome-wide association analysis of the levels of these tea flavor-related metabolites in three seasons. The theanine, caffeine, and catechin levels in Population 1 comprising 191 tea plant germplasms were examined, which revealed that their heritability exceeded 0.5 in the analyzed seasons, with the following rank order (highest to lowest heritabilities): (+)-catechin > (−)-gallocatechin gallate > caffeine = (−)-epicatechin > (−)-epigallocatechin-3-gallate > theanine > (−)-epigallocatechin > (−)-epicatechin-3-gallate > catechin gallate > (+)-gallocatechin. The SNPs detected by amplified-fragment SNP and methylation sequencing divided Population 1 into three groups and seven subgroups. An association analysis yielded 307 SNP markers related to theanine, caffeine, and catechins that were common to all three seasons. Some of the markers were pleiotropic. The functional annotation of 180 key genes at the SNP loci revealed that FLS, UGT, MYB, and WD40 domain-containing proteins, as well as ATP-binding cassette transporters, may be important for catechin synthesis. KEGG and GO analyses indicated that these genes are associated with metabolic pathways and secondary metabolite biosynthesis. Moreover, in Population 2 (98 tea plant germplasm resources), 30 candidate SNPs were verified, including 17 SNPs that were significantly or extremely significantly associated with specific metabolite levels. These results will provide a foundation for future research on important flavor-related metabolites and may help accelerate the breeding of new tea varieties.