Climacteric fruit ripening: Ethylene-dependent and independentudregulation of ripening pathways in melon fruit

摘要

Cantaloupe melons have a typical climacteric behaviour with ethylene playing a major role in the regulation of the ripening process andudaffecting the ripening rate. Crossing of Cantaloupe Charentais melon with a non-climacteric melon indicated that the climacteric character isudgenetically dominant and conferred by two duplicated loci only. However, other experiments made by crossing two non-climacteric melonsudhave generated climacteric fruit, indicating that different and complex genetic regulation exists for the climacteric character. Suppression ofudethylene production by antisense ACC oxidase RNA in Charentais melon has shown that, while many ripening pathways were regulated byudethylene (synthesis of aroma volatiles, respiratory climacteric and degreening of the rind), some were ethylene-independent (initiation ofudclimacteric, sugar accumulation, loss of acidity and coloration of the pulp). Softening of the flesh comprised both ethylene-dependent andudindependent components that were correlated with differential regulation of cell wall degrading genes. These results indicate that climactericud(ethylene-dependent) and non-climacteric (ethylene-independent) regulation coexist during climacteric fruit ripening. In addition, ethylenesuppressedudmelons allowed demonstrating that the various ethylene-dependent events exhibited differential sensitivity to ethylene and thatudethylene was promoting sensitivity to chilling injury. Throughout this review, the data generated with melon are compared with thoseudobtained with tomato and other fruit.udud