Identification and Functional Characterization of Genes Involved in Abscisic Acid and Brassinosteroid Catabolism in Grapevine

在加拿大，葡萄莓主要用于生产增值产品，如葡萄酒。酿酒葡萄主要产于安大略省和不列颠哥伦比亚省，以及魁北克省和新斯科舍省。作为一种经济上重要的食品，色素葡萄（“红”）富含抗氧化化合物，对人体健康有许多好处。水果生理学家将成熟分为两类，更年期和非更年期。少数农业上重要的水果是非更年期的，包括葡萄藤浆果。非更年期水果在成熟初期不表现出呼吸和植物激素乙烯的增加，这是许多更年期水果物种的特征。不同于在更年期成熟起始的乙烯信号转导级联，控制非更年期成熟的分子机制尚不清楚。来自葡萄藤的证据表明，控制非更年期成熟起始（葡萄栽培家称之为“veraison”）的主要激素是植物激素、脱落酸和油菜素类固醇，而乙烯显然起着次要的辅助作用。在这个项目中，我们将确定控制这些激素修饰的基因，这些基因使它们在植物细胞中失活，并表征这些基因在调节葡萄浆果变异中的潜在作用。通过更好地了解激素代谢和其他调控激素作用的机制，我们可以确定分子靶标：1)开发成熟开始的生物标志物，葡萄种植者已经指出这将是一个有益的管理工具；2)通过基因改造缩短葡萄从结实到成熟的时间，这是加拿大凉爽气候葡萄栽培所需要的。

Grapevine berries are commercially cultivated primarily for value added products such as wines in Canada. Wine grapes are produced mainly in Ontario and British Columbia, as well as Quebec and Nova Scotia. As well as being an economically important food product, pigmented ('red') grapes are rich in antioxidant compounds which have numerous reported human health benefits. Fruit physiologists classify ripening into two categories, climacteric and non-climacteric. A small number of agriculturally important fruits are non-climacteric, including grapevine berries. Non-climacteric fruits do not exhibit increases in respiration and the production of the plant hormone, ethylene, at the onset of ripening that are characteristic of the many climacteric fruit species. Unlike the well-characterized ethylene signal transduction cascade in climacteric ripening initiation, the molecular mechanisms underlying the control of non-climacteric ripening are poorly understood. Evidence from grapevine suggests that the principal hormones controlling non-climacteric ripening initiation (called 'veraison' by viticulturists) are the plant hormones, abscisic acid and brassinosteroids, while ethylene apparently plays a minor, additive role. In this project, we will identify genes controlling modifications to these hormones which make them inactive in plant cells and characterize potential roles for these genes in regulating veraison in grapevine berries. By better understanding hormone metabolism and other regulatory mechanisms controlling hormone action at veraison, we can identify molecular targets for: 1) developing biomarkers for ripening onset, which viticulturists have indicated would be a beneficial management tool and 2) genetically modifying grapevine to shorten the time from fruit set to veraison, which is desirable for cool climate viticulture in Canada.