Roles of flavonoid compounds in determining the shelf life of tomato fruit

• Main Author: Zhang, Yang
• Published: University of East Anglia 2013
• Subjects: 570
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601052

This thesis examines the role of flavonoid compounds in determining the shelf life of tomato fruit. Shelf life is one of the most important traits for tomato industry. Although there are many approaches to enhance the post-harvest performance of tomato fruit, most of them would have side effects such as reducing fruit quality. My work showed that accumulation of anthocyanins in tomato fruit by over expressing Delila and Rosea 1, two transcriptional factors from Antirrhinum majus, can extend tomato shelf life significantly. Compared to WT tomato fruit, the anthocyanin-enriched purple fruit have double the shelf life including delayed over-ripening and reduced susceptibility to the fungal pathogen, Botrytis cinerea. My data indicate that the delayed over-ripening is associated with the high antioxidant capacity of purple tomato and the reduced susceptibility to B. cinerea is due to the high scavenging ability of anthocyanins. Using Aft/Aft atv/atv, a conventionally bred tomato variety which accumulates anthoycanin predominantly in the skin, I showed that accumulation of anthocyanins in tomato skin can be sufficient to extend fruit shelf life. The scientific findings from transgenic crop studies can provide new strategies for conventional breeding improved fruit quality. My research also revealed that, as a general principle, flavonoids extend tomato shelf life. For ripening and over-ripening, increasing total antioxidant capacity by accumulating flavonoids of different types can delay these processes. To reduce susceptibility to B. cinerea, however, the effects of different flavonoids depend on their scavenging abilities, which are determined by their molecular structures. Taken together these findings demonstrate that increasing total antioxidant capacity by accumulating different flavonoid compounds offers a general strategy to delay over-ripening of tomato fruit. However, to reduce susceptibility to B. cinerea, flavonoid compounds with high scavenging activity should be used.