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

在加拿大，葡萄藤浆果的商业化种植主要用于增值产品，如葡萄酒。 酿酒葡萄主要产于安大略和不列颠哥伦比亚省，以及魁北克和新斯科舍省。 作为一种经济上重要的食品，色素（“红”）葡萄富含抗氧化化合物，对人类健康有许多好处。 果实生理学家将成熟分为两类，跃变型和非跃变型。 少数农业上重要的水果是非跃变型的，包括葡萄藤浆果。 非跃变型果实在成熟开始时不表现出呼吸作用和植物激素乙烯产生的增加，这是许多跃变型果实物种的特征。 与跃变型成熟启动中的乙烯信号转导级联不同，非跃变型成熟控制的分子机制知之甚少。 来自葡萄藤的证据表明，控制非跃变型成熟开始（被葡萄栽培学家称为“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加性作用。 在这个项目中，我们将确定基因控制这些激素的修饰，使它们在植物细胞中失活，并表征这些基因在葡萄藤浆果中调节veraison的潜在作用。 通过更好地了解激素代谢和其他控制veraison激素作用的调节机制，我们可以确定分子靶点： 1)开发成熟开始的生物标志物，葡萄栽培学家指出这将是一种有益的管理工具，2）转基因葡萄缩短从坐果到变熟的时间，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.