A research team has mapped genetic variation underlying catechin composition and galloylation across a diverse collection of tea plants. By integrating genome-wide genotyping, chemical profiling and gene-expression analysis, the researchers identified 48 genetic loci and 13 candidate genes associated with major catechins and gallic acid. The findings show that tea catechin profiles are shaped by coordinated regulation of precursor supply, phenylpropanoid metabolism, flavonoid modification and cellular transport. These genetic resources could support marker-assisted breeding of tea cultivars with targeted catechin profiles, distinctive flavors, enhanced nutritional properties and improved suitability for different processing methods.
Catechins are the principal polyphenolic compounds in tea leaves and major contributors to tea's taste, nutritional value and processing quality. They are generally divided into nongalloylated catechins, including catechin, gallocatechin, epicatechin and epigallocatechin, and galloylated catechins, particularly epicatechin gallate and epigallocatechin gallate. Although the core pathways responsible for catechin biosynthesis have been extensively studied, the genetic mechanisms driving natural differences among tea populations—especially the balance between galloylated and nongalloylated catechins—remain incompletely understood. Conventional mapping approaches often examine limited genetic diversity and produce broad genomic intervals, creating a need for population-scale analyses capable of locating genes more precisely.
A study ( DOI:10.48130/bpr-0026-0036 ) published in Beverage Plant Research on 26 August 2026 by Qinfei Song's & Suzhen Niu's team, Guizhou University, reports genetic loci and candidate genes that help explain natural variation in catechin accumulation among tea plants.
The researchers analyzed 329 tea accessions collected from 31 counties and districts in Guizhou Province, China, comprising 187 accessions of Camellia sinensis, 85 of C. tachangensis and 57 of C. remotiserrata. Fresh shoots consisting of one bud and two leaves were collected under standardized growing conditions. High-performance liquid chromatography was used to quantify gallic acid and seven detectable catechin monomers, while genotyping-by-sequencing generated 318.2 gigabases of clean sequence data. After quality filtering, the team retained 102,538 high-quality single-nucleotide polymorphisms. Population-structure, phylogenetic, principal-component, genetic-diversity and linkage-disequilibrium analyses showed that the germplasm could be divided into five ancestral populations and one admixed group. Positive Tajima's D values across all six groups suggested that bottlenecks and/or balancing selection contributed to their genetic history. Chemical profiling revealed pronounced diversity among accessions and species. C. tachangensis displayed the lowest median epigallocatechin gallate content but the highest median epicatechin gallate content, as well as the largest proportion of nongalloylated catechins. Correlation analysis further indicated that catechin components are interconnected rather than independently regulated. Using trait-specific general, mixed and compressed mixed linear models, the researchers identified 48 significant loci associated with gallic acid and catechin traits; individual loci explained 6.71%–13.33% of phenotypic variation. Functional annotation of genes within 50 kilobases of these loci yielded 13 candidates involved in phenylpropanoid and shikimate metabolism, sucrose transport, flavonoid modification and metabolite storage. Reverse-transcription quantitative PCR provided additional support for four candidates: CsUGT73C2 expression was positively correlated with epigallocatechin gallate, CsPAL with epicatechin gallate and CsCCR2 with epigallocatechin, whereas CsSUT5 was negatively correlated with epicatechin. One locus, S6_43615287, was associated with both gallic acid and epicatechin gallate, suggesting a possible pleiotropic role in coordinating precursor availability and galloylated catechin production.
Overall, the study presents catechin composition as a complex trait governed by interacting biosynthetic, regulatory and transport processes. The identified loci and candidate genes offer promising molecular markers for selecting tea plants with high epigallocatechin gallate, high epicatechin gallate or other desirable chemical profiles. Functional studies using gene silencing, transient overexpression or genome editing will still be needed to confirm causality, but the results establish a valuable foundation for precision breeding and the development of new tea cultivars combining superior quality with distinctive flavor characteristics.
