The molecular mechanism for the ethylene regulation of postharvest button mushrooms maturation and senescence

The button mushroom (Agaricus bisporus) produces ethylene and respiration climacteric bursts coupling with rapidly maturation and senescence during postharvest storage. However, the molecular mechanism for the ethylene regulation of button mushroom maturation and senescence is still unclear. In this study, postharvest button mushrooms were treated with ethephon and the plant ethylene receptor inhibitor 1-methylcyclopropene (1-MCP), and the results showed that ethylene accelerated postharvest mushroom maturation and senescence and upregulated maturation- and senescence-related genes, which was in contrast to the effect of 1-MCP. Plant ethylene response elements were predicted in the promoter regions of all 19 maturation- and senescence-related genes in the button mushroom, and the 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO) gene promoter region contained three ethylene response elements, which all expressed the GUS gene in transgenic onion epidermal cells by exogenous ethylene induction. The ACO gene was also highly expressed in postharvest mushrooms by ethylene induction. The results suggest that the ethylene response elements harbored in the promoter regions of the maturation- and senescence-related genes are probably responsible for the ethylene and respiration bursts as well as maturation and senescence of the postharvest button mushroom. The molecular mechanism for the ethylene regulation of postharvest button mushroom maturation and senescence may be similar to that of climacteric fruits.