Delay of postharvest ripening and senescence of tomato fruit through virus-induced LeACS2 gene silencing

Plant virus-induced gene silencing (VIGS) is currently a powerful tool for the study of gene function in plants. Here we report the silencing of LeACS2 by vacuum-infiltration and the tobacco rattle virus (TRV)-based VIGS method, which leads to a significant delay of the postharvest ripening and senescence of tomato fruit. Harvested mature green tomato fruit were vacuum-infiltrated with Agrobacterium strain GV3101 containing pTRV1 and pTRV2-LeACS2. Because of the silencing of LeACS2, the ethylene climacteric and pigment changes were clearly delayed. The onset of fruit ripening and senescence was significantly postponed, and transcription of LeACS2 and ACC synthase activity were also suppressed in treated tomato fruit during storage. The silencing of LeACS2 by vacuum infiltration, however, did not alter the contents assayed at the end of storage. Our results indicate that vacuum infiltration is a highly efficient TRV-based VIGS method to silence LeACS2 in harvested tomato fruit. It can obviously delay ripening and senescence, and is a potential method for postharvest preservation of tomato fruit.