Ornithine decarboxylase is involved in methyl jasmonate-regulated postharvest quality retention in button mushrooms (Agaricus bisporus)

BACKGROUND In the present study, we investigated the role of ornithine decarboxylase (ODC) in the methyl jasmonate (MeJA)-regulated postharvest quality maintenance of Agaricus bisporus (J. E. Kange) Imbach button mushrooms by pretreating mushrooms with a specific irreversible inhibitor called alpha-difluoromethylornithine (DFMO) before exposure to MeJA vapor. RESULTS Mushrooms were treated with 0 or 100 mu mol L-1 MeJA or a combination of 120 mu mol L-1 DFMO and 100 mu mol L-1 MeJA, respectively, before storage at 4 degrees C for 21 days. Treatment with MeJA alone induced the increase in ODC activity whereas this effect was greatly suppressed by pretreatment with DFMO. alpha-Difluoromethylornithine strongly attenuated the effect of MeJA on decreasing cap opening, slowing the decline rate of soluble protein and total sugar, and accumulating total phenolics and flavonoids. alpha-Difluoromethylornithine pretreatment also counteracted the ability of MeJA to inhibit polyphenol oxidase and lipoxygenase activities, and malondialdehyde production, and to stimulate superoxide dismutase and catalase activities. It also largely downregulated MeJA-induced accumulation of free putrescine (Put). CONCLUSION These results reveal that ODC is involved in MeJA-regulated postharvest quality retention of button mushrooms, and this involvement is likely to be associated with Put levels. (c) 2018 Society of Chemical Industry