9362031 Dunsmuir Flavor in tomato fruit is associated with high levels of both sugars and acids. It is known that the level of malic acid in the fruit declines by 50% with fruit ripening and that this reduction is thought to be mediated by a cytosolic NADP dependent malic enzyme (NADP-ME). The tomato NADP-ME genes which are expressed in the pericarp during ripening by using a heterologous probe for NADP-ME from maize will be isolated and characterized. Once isolated, the tomato genes will be used in genetic engineering experiments so that the induction of NADP-ME which occurs during ripening would be reduced or inhibited and higher malic acid levels would persist within the ripe fruit. In parallel higher levels of the same enzyme in the fruit will be engineered in order to gain insight into mechanisms which regulate acid levels in the fruit. %%% The anticipated outcome of this research would be the ability to directly engineer the acid levels in fruit which could significantly affect the flavor of tomatoes in the treatment of processing tomatoes. ***
