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 methyl jasmonate and 5 mmol L 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. © 2024 Society of Chemical Industry.