Strategies for enhancement of bioactive flavonol glycosides in plants

增强植物中生物活性黄酮醇苷的策略

• 批准号: RGPIN-2015-03950
• 负责人: Bozzo, Gale
• 金额: $ 1.75万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679999
• 关键词: Strategies; enhancement; bioactive; flavonol; glycosides

Flavonols (e.g. quercetin) are well known phytochemicals. Their incorporation in the human diet may prevent accumulation of damaging radicals associated with chronic diseases including Alzheimer's. Approximately 5% of Canadians over the age of 65 are diagnosed with some form of dementia. Flavonols offer a preventative measure to offset the $33 billion spent annually to treat these disorders in Canada. In the human diet, flavonols are not as available as their glycosides, forms which tend to predominate across vegetative (e.g. onion, kale, broccoli) and fruit (e.g. apple, grape, pepper, tomato) tissues. In plants, flavonols exists as conjugates of one or more sugars, including monoglycosides, diglycosides and bisglycosides (e.g. quercetin 3-O-ß-glucoside-7-O-a-rhamnoside). The physiological roles of these compounds in plants are not yet clear, but evidence suggests they are linked to growth, environmental stress, and plant-insect interactions. Plant accumulation of flavonol bisglycosides occurs in response to environmental perturbations, including UV-B light, chilling, nutrient deficiencies, and is dependent upon transcriptional regulation of the biosynthetic pathway. Flavonol preservation in plants, including foodstuffs, is not solely dependent upon biosynthetic processes as losses on the order of 1-35% per day are typical, including during postharvest handling. Enhanced levels of flavonol bisglycosides may be achieved by minimizing their degradation in planta, processes that are little understood. ***Over the past 6 years, my laboratory has established the biochemical evidence for the loss of flavonol bisglycosides and their related molecules from plants. Our current research focuses on characterizing this catabolism in Arabidopsis thaliana, a model plant for flavonol biochemistry due to the availability of genetic mutants. A highlight of our research includes the identification of an enzymatic component, specifically a ß-glucosidase, as a possible first step in the loss of these bioactive compounds. We are interested in elucidation of the complete flavonol bisglycoside catabolism pathway in plants. Our laboratory uses cutting edge analytical chemistry platforms together with physiology, classical biochemistry and biotechnology to identify the genes/enzymes associated with the turnover of these important small molecules. In addition to providing unique training opportunities for students in biochemistry, molecular biology and analytical chemistry, this research aims to enhance knowledge of plant flavonol catabolism. Moreover, this novel research provides potential tools for genetic engineering and molecular breeding strategies targeting flavonol biofortification in economically important crop plants.***********

黄酮醇（例如槲皮素）是众所周知的植物化学物质。将它们纳入人类饮食中可以防止与阿尔茨海默病等慢性疾病相关的破坏性自由基的积累。大约 5% 65 岁以上的加拿大人被诊断患有某种形式的痴呆症。黄酮醇提供了一种预防措施，可以抵消加拿大每年用于治疗这些疾病的 330 亿美元的费用。在人类饮食中，黄酮醇不像其糖苷那样容易获得，黄酮醇的形式往往在植物（例如洋葱、羽衣甘蓝、西兰花）和水果（例如苹果、葡萄、胡椒、番茄）组织中占主导地位。在植物中，黄酮醇以一种或多种糖的缀合物形式存在，包括单糖苷、二糖苷和双糖苷（例如槲皮素 3-O-ß-葡萄糖苷-7-O-a-鼠李糖苷）。这些化合物在植物中的生理作用尚不清楚，但有证据表明它们与生长、环境压力和植物与昆虫的相互作用有关。植物积累黄酮醇双糖苷是为了响应环境扰动，包括 UV-B 光、寒冷、营养缺乏，并且依赖于生物合成途径的转录调节。植物（包括食品）中黄酮醇的保存不仅仅取决于生物合成过程，因为每天的损失量通常约为 1-35%，包括在采后处理过程中。通过最大限度地减少黄酮醇双糖苷在植物中的降解，可以提高黄酮醇双糖苷的水平，这一过程尚不清楚。 ***在过去的六年里，我的实验室已经建立了植物中黄酮醇双糖苷及其相关分子损失的生化证据。我们目前的研究重点是表征拟南芥中的这种分解代谢，由于存在基因突变体，拟南芥是黄酮醇生物化学的模型植物。 我们研究的一个亮点包括鉴定一种酶成分，特别是β-葡萄糖苷酶，作为失去这些生物活性化合物的可能的第一步。 我们对阐明植物中完整的黄酮醇双糖苷分解代谢途径感兴趣。我们的实验室使用尖端的分析化学平台以及生理学、经典生物化学和生物技术来识别与这些重要小分子的周转相关的基因/酶。除了为生物化学、分子生物学和分析化学领域的学生提供独特的培训机会外，这项研究还旨在增强对植物黄酮醇分解代谢的了解。此外，这项新颖的研究为针对经济重要作物中的黄酮醇生物强化的基因工程和分子育种策略提供了潜在的工具。 **********