Transcriptome analysis reveals the effect of short-term sunlight on aroma metabolism in postharvest leaves of oolong tea(Camellia sinensis)

Tea (Camellia sinensis (L.)) is an important economic plant. Light is the earliest external signal factor during the postharvest processing of oolong tea, and the solar withering is an indispensable process for aroma formation. In this study, Tieguanyin was used to analyze the effect of sunlight on aroma metabolism, which indicated that the main aroma compounds were significantly increased during solar withering for 15 min compared to the indoor withering. In addition, differentially expressed genes related to aroma metabolism were identified and quantified using the high-throughput Illumina RNA-Seq technology. The expression levels of key regulatory genes were consistent with the results from the gas chromatography-time of flight mass spectrometry (GC-TOF-MS) analysis, especially in terpenoid metabolic pathway, which showed that aroma metabolism could significantly respond to the short-term light, while its expression level was easily inhibited by the up-regulation of heat shock protein. Taken together, those data provides further insights into the mechanisms, contributing to aroma metabolism of tea plant.