Modification of tomato fruit ripening by transformation with sense or antisense chimeric 1-aminocyclopropane-1-carboxylate synthase genes

摘要

Ethylene controls tomato ripening. The rate-limiting step in ethylene biosynthesis is catalysed by ACC synthase. In this study, ripening characteristics of tomatoes transformed with the ACC synthase gene in sense or antisense orientation were examined. Tomato plants (cv. Ailsa Craig) were transformed by Agrobacterium tumefaciens. Forty-three independent antisense and 26 sense transformants were obtained. Changes in surface colour of these tomato fruits were measured by a colour difference meter. Amarked retardation in red colour development was observed in one antisense transformant and was reversed by treatment of fruits with ethylene. Four transformants with sense ACC synthase gene showed similar retardation of ripening, due to co-suppression.The effect was also reversed by ethylene. Genetic analyses of the selfed progenies indicated that these transgenes were stably inherited. Both antisense and sense gene constructs were effective for down-regulation of ACC synthase in tomato fruits, and are expected to improve the shelf-life and quality of tomatoes.