Regulatory mechanism of methyl jasmonate and methyl dihydrojasmonate in enhancing aroma in 'Cabernet Gernischt' via the lipoxygenase pathway

BACKGROUND The present study explored the effects of pre-harvest methyl jasmonates spraying on the volatiles of 'Cabernet Gernischt' grapes through the lipoxygenase pathway. Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry and an enzyme-linked immunosorbent assay were utilized to analyze volatile metabolites and key enzyme activities following methyl jasmonates application. Total RNA extraction and cDNA library construction were followed by transcriptome sequencing. RESULTS The application of 0.1 mmol L-1 methyl jasmonate and 5 mmol L-1 methyl dihydrojasmonate significantly increased the levels of C6 compounds in 'Cabernet Gernischt' berries, and also enhanced the utilization of unsaturated fatty acids as precursors in the lipoxygenase-hydroperoxides lyase pathway. The up-regulated expression of VvADH1, VvADH2, VvHPL and VvLOX2S genes led to modulations in enzyme activity, thereby enhancing the berries's aromatic profile. There was a significant correlation between linoleic and linolenic acids (i.e. the precursors of the lipoxygenase pathway) and the activities and metabolites of key enzymes. CONCLUSION The optimal concentration of methyl jasmonates treatment favorably influences the accumulation of green leaf volatiles in 'Cabernet Gernischt' grape. (c) 2024 Society of Chemical Industry.