Functional Genomic Analysis of Fruit Flavor and Nutrition Pathways

水果是人类饮食的主要成分，提供了很大一部分维生素、矿物质、抗氧化剂和纤维。虽然风味和营养成分具有明显的积极人类利益的潜力，但由于它们通常复杂的生物合成和调节途径，它们被证明是很难通过传统育种改变的特征。许多水果中的“风味”是糖、酸和多种挥发性化合物之间复杂相互作用的产物。这些化合物的合成和积累是许多基因协同活动的结果。在许多情况下，这些化合物的合成途径尚未建立。该计划将重点关注这些化合物新陈代谢的关键基因的表达，以便能够识别水果风味和营养成分的关键调节因素，并最终通过许多可能的途径进行操作。具体地说，该计划将在一系列广泛的种质中应用基因表达谱，以1)绘制控制风味和营养的重要成分水平的调控电路，以及2)识别编码参与这些成分新陈代谢的酶的基因。番茄果实成熟过程中表达的大多数基因的表达水平将与由突变体、转基因和重组自交系组成的不同种质中特定代谢物的丰度相关。生物信息学将被用来识别其表达与目标化合物的外观相关的基因。这些标记作为化学成分预测指标的价值将通过遗传图谱和转基因操作来检验。这些实验将产生广泛的影响，1)绘制控制风味和营养代谢途径的关键步骤，2)确定与风味和营养关键成分的调节或代谢有关的特定基因，3)为育种和改良水果品质提供有用的工具，4)建立相关的代谢物和全球基因表达的公共数据库，供广泛的成熟相关研究使用。

Fruits are major components of the human diet contributing a large portion of vitamins, minerals, antioxidants, and fiber. While flavor and nutrition composition have clear potential for positive human benefit, they have proven to be difficult traits to modify via traditional breeding due to their generally complex biosynthetic and regulatory pathways. "Flavor" in many fruits is the product of a complex interaction among sugars, acids and multiple volatile compounds. Synthesis and accumulation of these compounds is the result of coordinated activity of many genes. In many cases, the pathways for synthesis of these compounds have yet to be established. This program will focus on the expression of the genes critical for metabolism of these compounds so that key regulators of fruit flavor and nutrient composition can be identified and eventually manipulated via the many possible routes available. Specifically, the program will apply gene expression profiling to an extensive set of germplasm to 1) map regulatory circuits controlling the levels of important components of flavor and nutrition, and 2) identify genes encoding enzymes involved in metabolism of these components. Levels of expression of most of the genes expressed during tomato fruit ripening will be correlated with the abundances of specific metabolites in a diverse set of germplasm consisting of mutants, transgenic and recombinant inbred lines. Bioinformatics will be used to identify genes whose expression is linked to appearance of target compounds. The value of these markers as predictors of chemical composition will be tested by genetic mapping and transgenic manipulation. These experiments will have broad impact by 1) mapping critical steps controlling flavor and nutrition metabolic pathways, 2) identifying specific genes involved in either regulation or metabolism of critical components of flavor and nutrition, 3) providing useful tools for breeding and engineering improved fruit quality, and 4) establishing a correlative public database of metabolites and global gene expression that will be accessible for a broad array of ripening-related studies.