RIPENING-ASSOCIATED BIOCHEMICAL TRAITS OF CANTALOUPE CHARENTAIS MELONS EXPRESSING AN ANTISENSE ACC OXIDASE TRANSGENE

Transgenic Cantaloupe Charentais melons (Cucumis melo var, cantalupens is Naud. 'Vedrantais') exhibiting strong inhibition of ethylene produc tion were used as a model to discriminate between ethylene-regulated a nd ethylene-independent ripening pathways, Compared to wild-type fruit , transgenic fruit did not undergo significant yellowing of the rind a nd softening of the flesh, However, these effects were completely reve rsed by treating transgenic fruit with 50 mu L.L-1 exogenous ethylene, Pigmentation of the flesh occurred early before the onset of the clim acteric and was thus unaffected by ethylene inhibition in transgenic f ruit, Total soluble solids accumulated at the same rate in both types of fruit until 38 days after pollination when wild-type fruit abscisse d, However, as ethylene-inhibited fruit failed to develop a peduncular abscission zone, they remained attached to the plant and accumulated higher amounts of sugars, mainly sucrose, Harvesting transgenic fruit resulted in a small hut significant increase of internal ethylene asso ciated with softening of the flesh.