Metabolic engineering of wine grapes with improved flavonoid-based health properties

花青素是一种天然的类黄酮化合物，可以使苹果、葡萄、蓝莓和乌藨子等几十种不同水果的表皮呈现红色到紫色。在植物中已经鉴定出超过600种不同的花青素。 许多对人类的健康益处最近被归因于特定的花青素提取物，包括抗癌特性，治疗糖尿病视网膜病变，以及降低血压，防止LDL氧化和增强免疫系统的益处，包括减少炎症。这些健康益处的机制与抗氧化剂，抗炎和抗肿瘤特性有关。先前的研究表明，不同植物物种的果实优先积累特定类型的花青素，导致显著不同的生物活性能力以及可变的色素强度和色调。 例如，“甘蔗”果实如乌藨子积累衍生自二氢槲皮素前体的花青素，所述花青素具有比在商业上重要的欧洲酿酒葡萄品种中合成的那些上级的抗氧化性质，所述欧洲酿酒葡萄品种主要是二氢杨梅素型。虽然以前的工作一直致力于从甘蔗果实和葡萄浆果的总花青素提取物的抗氧化活性的特征，在甘蔗果实中的花青素化合物的明显更健康的比例的生产的分子生物学基础仍然未知。 我的实验室将：1）确定与重要的酿酒葡萄栽培品种黑比诺相比，在具有报道的最高天然抗氧化能力的甘蔗果实物种黑树莓中优先产生二氢槲皮素型类黄酮的分子基础，以及2）研究代谢工程酿酒葡萄以相对于二氢杨梅素型类黄酮增加二氢槲皮素型类黄酮的产生的手段。 我的实验室预计，这些信息将在长期的未来对现有的葡萄和其他红莓品种的商业品种进行基因内修饰，以增加消费者的健康益处。

Anthocyanins are naturally occurring flavonoid compounds that impart red to purple colours to skins of dozens of different fruits such as apples, grapes, blueberries, and raspberries. Over 600 different anthocyanins have been identified in plants. Numerous health benefits for humans have recently been attributed to specific anthocyanin extracts, including anti-cancer properties, treatment of diabetic retinopathy, and benefits towards reduced blood pressure, protection against LDL oxidation, and boosts to the immune system including reduced inflammation. The mechanisms underlying these health benefits are associated with antioxidant, anti-inflammatory, and anti-tumour properties. Previous studies have shown that fruits from different plant species preferentially accumulate particular types of anthocyanins, resulting in significantly different bioactive capacities as well as variable pigment intensities and hues. For example, "cane" fruits such as raspberries accumulate anthocyanins derived from a dihydroquercitin precursor that have superior antioxidant properties to those synthesized in commercially important European wine grape varieties, which are predominantly dihydromyricetin-type. While previous work has been devoted to characterizing antioxidant activities of total anthocyanin extracts from cane fruits and grape berries, the molecular biology underlying the production of the apparently healthier proportions of anthocyanin compounds in cane fruit remains unknown. My lab will: 1) determine the molecular basis for preferential production of dihydroquercitin-type flavonoids in a cane fruit species with reported highest natural antioxidant capacity, black raspberry, in comparison to the important wine grape cultivar, Pinot Noir, and 2) investigate means to metabolically engineer wine grape to increase the production of dihydroquercitin-type flavonoids relative to dihydromyricetin-type flavonoids. My lab anticipates that this information will be useful in the long-term future for intragenic modification of existing commercial cultivars of grape and other red-berry species for increased health benefits to consumers.