Shorten spreading duration enhance the quality of summer Meitan Cuiya tea.

Meitan Cuiya (MTCY), a representative green tea from Guizhou, China, may exhibit lower quality in summer due to increased bitterness and astringency. Spreading is a common method to enhance tea quality, but its impact on summer MTCY remains unclear. This study combined transcriptomics and volatile metabolomics to investigate the effects of spreading duration on quality of summer fresh tea leaves and MTCY. Results showed that spreading time shortened to 4 h improved the taste of MTCY, due to lower catechins and higher theanine levels. This duration also yielded woody floral scent in MTCY, marked by high levels of -Cubebol, linalool, -linalool oxide. Transcriptomic analysis linked the 4-h spreading to proteasome activities. Aroma formation was related to diterpenoid and flavonoid biosynthesis. Additionally, gibberellins and auxin were associated with quality formation in fresh tea leaves. This research lays a foundation for improving quality of fresh tea leaves and MTCY in summer.