24-Epibrassinolide regulates volatile metabolic pathways to improve tomato flavor quality during postharvest storage

The effects of 24-epibrassinolide (EBL) on flavor quality and regulation networks of volatile metabolism genes were investigated in tomato fruit. The results showed that EBL treatment affected the accumulation of carotenoid-derived volatiles via the regulation on carotenoid contents and expression levels of lycopene metabolic genes. Meanwhile, EBL treatment uplifted the level of salicylaldehyde, while decreased that of methyl salicylate (MeSA) by regulating MeSA metabolic genes. WGCNA was performed based on 2473 differential expressed genes and 27 volatiles to obtain 11 volatile connected modules and hub genes in these modules. Modules MEpurple and MEred had significant connections with the biosynthesis of β-ionone and MeSA. BAM1, the hub gene of MEred, was involved in β-ionone metabolic pathway. PIF3, the hub gene of MEpurple, had a direct connection with MeSA metabolic pathway. Taken together, the EBL application has the potential to improve the quality characteristics of tomato during postharvest storage via the volatile regulation network.