SBIR Phase II: Engineering of Acidity in Tomato Fruit through NADP-Malic Enzyme

9500360番茄果实中的邓斯穆尔风味与高水平的糖和酸有关。众所周知，果实中苹果酸的含量随着果实的成熟下降了50%，这种下降被认为是由胞质NADP-苹果酸酶(NADP-ME)介导的。该项目将尝试通过有针对性的基因抑制来特别降低番茄果实中NADP-ME的水平。将产生一些果实特异性NADP-ME水平降低的转基因番茄品系，并对这些品系的生化和感官特性进行检测。被鉴定为成熟果实苹果酸水平升高和感官特性改善的转基因品系，然后将在田间进行评估，以确定是否存在任何有害的农艺影响，并识别将用于育种计划的抑制品系。这项研究的预期结果是，能够直接控制番茄水果中的酸水平，这可能会显著影响番茄的味道，并可能导致开发一种直接改变番茄、葡萄和菠萝等水果中酸水平的技术方法。这可以改善生鲜市场和加工水果的风味。

9500360 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 per cent with ripening and this reduction is thought to be mediated by cytosolic NADP-malic enzyme (NADP-ME). This project will attempt to specifically decrease the levels of the NADP-ME in the tomato fruit using targeted gene suppression. A number of transgenic tomato lines will be generated with diminished levels of the fruit-specific NADP-ME and the biochemical and sensory properties of these lines will be examined. Transgenic lines which are identified as having elevated malic acid levels in the ripe fruit and improved sensory properties, will then be evaluated in the field to determine whether there are any deleterious agronomic effects and to identify suppressed lines which would be used in breeding programs. The anticipated outcome of this research is the ability to directly engineer the acid levels in tomato fruit which could significantly effect the flavor of tomatoes and could result in the development of a technical approach for the directed alteration of acid levels in fruit such as tomatoes, grapes and pineapples. This could improve flavor for fresh market and processed fruits.