Integrated Volatile Metabolomics and Transcriptomics Analyses Revealed the Regulatory Mechanism of Aroma Compound Synthesis Induced by Microenvironmental Changes in Purple Tea Leaves

Abstract

Tea plants with distinct leaf colours, such as purple, have attracted attention for their potential economic and flavour-related benefits. To investigate how purple mutations influence aroma composition, we analyzed 64 tea germplasms (Camellia sinensis) with varying degrees of purple pigmentation, integrating microenvironmental data, volatile metabolomics and transcriptomics. Purple tea exhibited reduced accumulation of volatile phenylpropanoids/benzenoids (VPBs), higher surface temperatures and enrichment of stress-responsive genes, leading to increased levels of fatty acid-derived volatiles (FADVs) and volatile terpenoids (VTs). We identified CsWRKY70 as a central regulator of aroma biosynthesis, with its expression upregulated under heat stress, activating CsLOX3 and CsTPS13 to promote FADVs and VTs accumulation. These findings demonstrate that purple leaf mutations influence aroma composition by modulating the phenylpropanoid pathway and altering the leaf microenvironment, providing new insights into the interplay between leaf colour, environmental stress and flavour potential in tea plants.