Genome-wide association analysis identified molecular markers associated with important tea flavor-related metabolites

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.

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

“…It provides numerous cultural, health and economic benefits [ 1 ]. Tea extracts are rich in secondary metabolites [ 2 ], including polyphenol, theanine, caffeine, polysaccharides and volatile oils. These substances are antioxidant, stimulant, diuretic, hypoglycemic and immunomodulatory [ 2 – 6 ].…”

“…Tea extracts are rich in secondary metabolites [ 2 ], including polyphenol, theanine, caffeine, polysaccharides and volatile oils. These substances are antioxidant, stimulant, diuretic, hypoglycemic and immunomodulatory [ 2 – 6 ]. Tea plants originated in southwestern China, and are cultivated in over 60 and spread to over 160 countries.…”

Applications of Genomic Tools in Plant Breeding: Crop Biofortification

“…Fatty acids [173] HPLC-DAD Isoflavones [174] HPLC-MS Aminoacids, isoflavones, lipids, organic acids [175] Tea Camellia sinensis L. HPLC Theanine, caffeine, catechins [176] HPLC-PDA Amino acids, caffeine, catechins [177] Tomato S. lycopersicum GC-MS Organic acids, sugars [178] GC-MS Amino acids, organic acid ‡ ‡ , sugars [179] HPLC-MS/MS Alkaloids ‡ ‡ ‡ [180] GC-MS Fatty acids, lipids, carotenoids (i.e., tocopherols and tocotrienols: vitamin E) [181] Wheat T. aestivum HPLC-ESI-QTRAP-MS/MS Amino acids, (poly)amines, flavonoids, organic acids, sugars, vitamins, etc.…”

Combining novel technologies with interdisciplinary basic research to enhance horticultural crops

“…For example, GWAS of tomatine content, peel color, flavor formation, etc., has been conducted in tomato (Burgos et al., 2021; Tieman et al., 2017; Zhu et al., 2018). For tea trees, researchers carried out GWAS to discover functional loci related to tea flavonoids, catechins, and amino acids (Fang et al., 2021; Yamashita et al., 2020; Zhang et al., 2020b). For instance, Zhang et al.…”