ANTISENSE EXPRESSION OF HETEROLOGOUS MUSA ACUMINATA ACC OXIDASE cDNA IN TOMATO (SOLANUM LYCOPERSICUM L.) FOR DELAYED RIPENING

Abstract

Over-ripening causes post-harvest losses in various climacteric fruits including tomatoes.. Antisense of banana 1-aminocyclopropane-1-carboxylate ACC oxidase (MaACO) cDNA was developed and expressed in tomato to silence the expression of its tomato counterpart, thereby to impede ethylene synthesis. Eleven putative transformants events were confirmed by PCR amplification, of which three events were able to bear ripened fruits. PCR confirmed T1 plants were selected for raising the T2 population. Reverse transcription-PCR analysis confirmed the expression of the antisense MaACO RNA in T2 tomato plants. Delay in ripening was observed in the transgenic tomato, with 46.3 days required to attain red ripe stage as against 35.7 days in control plants. Higher titratable acidity (mean 0.76%) was observed during ripening in transgenic fruits over control fruits (mean 0.49%), indicating lower ethylene concentration in transgenic tomato. These results suggest the antisense expression of banana ACO is effective in delaying fruit ripening in tomato.