A unique tea germplasm rich in theacrine and EGCG3"Me: a multi-omics perspective
Theacrine and EGCG3"Me are important secondary metabolites in tea, which play important health effects and unique flavor. However, tea plant germplasms naturally rich in both theacrine and EGCG3"Me are rare. In this study, a unique tea cultivar resource Anxi Kucha(AXKC) that is rich in both secondary metabolites was discovered for the first time. In the targeted data, among the three samples tested, only theacrine was detected in AXKC, with a content of 17.44mg/g. Among the catechin components, the EGCG3"Me content of AXKC reached the highest among the three samples tested, which was 11.25mg/g. Through proteomics and transcriptomics, it was identified that the key pathways for the synthesis of theacrine and EGCG3"Me were the purine metabolism pathway and the flavonoid biosynthesis pathway, respectively. Combined proteome-transcriptome-metabolome analysis showed that SAMS3, APRT1, IMPDH, and TCS1 were the main enzymes promoting theacrine synthesis; CHI1, CHI2, FLS2 and LAR1 were the main enzymes that promote the synthesis of EGCG3"Me. The results of transcription factor analysis showed that MYB4 and bHLH74 had positive regulatory effects on the synthesis of theacrine and EGCG3"Me.