A class III acidic chitinase gene was closely correlated with postharvest banana fruit ripening.

In order to understand the relationship between MaCHⅢ and banana fruit ripening,ethylene release,MaCHⅢ expression and chitinase activity were measured after ethylene and 1-MCP(1-methylcyciopropene) treatment.The results showed that under ethylene treatment,gene expression and chitinase activity decreased faster than that of naturally ripened fruit and decreased to the lowest level at 3 and 4 days after harvest(DAH),respectively.With application of 1-MCP treatment,gene expression and chitinase activity gradually increased and reached peak at the 18 and 25 DAH,respectively.On the other hand,exogenous ethylene induced ethylene biosynthesis and ethylene production and then reached peak at 3 DAH,which was 15 days earlier than naturally ripened fruits.While 1-MCP greatly suppressed ethylene biosynthesis and fruit ripening.It was suggested that this gene might negatively correlate with postharvest fruit ripening.