Sclerotinia sclerotiorum circumvents flavonoid defenses by catabolizing flavonol glycosides and aglycones
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Date
Authors
Chen, Jingyuan
Ullah, Chhana
Reichelt, Michael
Gershenzon, Jonathan
Hammerbacher, Almuth
Journal Title
Journal ISSN
Volume Title
Publisher
American Society of Plant Biologists
Abstract
Flavonols are widely distributed plant metabolites that inhibit microbial growth. Yet many pathogens cause disease in flavonol-containing plant tissues. We investigated how Sclerotinia sclerotiorum, a necrotrophic fungal pathogen that causes disease in a range of economically important crop species, is able to successfully infect flavonol-rich tissues of Arabidopsis (Arabidopsis thaliana). Infection of rosette stage Arabidopsis with a virulent S. sclerotiorum strain led to the selective hydrolysis of flavonol glycosidic linkages and the inducible degradation of flavonol aglycones to phloroglucinol carboxylic and phenolic acids. By chemical analysis of fungal biotransformation products and a search of the S. sclerotiorum genome sequence, we identified a quercetin dioxygenase gene (QDO) and characterized the encoded protein, which catalyzed cleavage of the flavonol carbon skeleton. QDO deletion lines degraded flavonols with much lower efficiency and were less pathogenic on Arabidopsis leaves than wild-type S. sclerotiorum, indicating the importance of flavonol degradation in fungal virulence. In the absence of QDO, flavonols exhibited toxicity toward S. sclerotiorum, demonstrating the potential roles of these phenolic compounds in protecting plants against pathogens.
Description
Keywords
Flavonols, Plant metabolites, Sclerotinia sclerotiorum, Arabidopsis (Arabidopsis thaliana), Quercetin dioxygenase gene (QDO), Site-specific response, Beta-glucosidase, Metabolism, Pathogenicity, Detoxification, Host, Quercetin, Degradation, Accumulation
Sustainable Development Goals
Citation
Chen, J.Y., Ullah, C., Reichelt, M., Gershenzon, J. & Hammerbacher, A. 2019, 'Sclerotinia sclerotiorum circumvents flavonoid defenses by catabolizing flavonol glycosides and aglycones', Plant Physiology, vol. 180, no. 4, pp. 1975-1987.