Investigating the impact of flavonoids on aspergillus flavus: Insights into cell wall damage and biofilms

Authors: Castano-Duque, Lina; Lebar, Matthew; Mack, Brian; Lohmar, Jessica; Carter-Wientjes, Carol

Submitted to: The Journal of Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2024
Publication Date: 9/23/2024
Citation: Castano-Duque, L.M., Lebar, M.D., Mack, B.M., Lohmar, J.M., Carter Wientjes, C.H. 2024. Investigating the impact of flavonoids on aspergillus flavus: Insights into cell wall damage and biofilms. The Journal of Fungi. 10(9). 665. https://doi.org/10.3390/jof10090665.
DOI: https://doi.org/10.3390/jof10090665

Interpretive Summary: Aspergillus flavus, a fungus known for producing carcinogenic toxins called aflatoxins, poses significant threats to both agriculture and global health. Flavonoids, plant-derived compounds, inhibit A. flavus proliferation and mitigate aflatoxin production. In this study, we conducted a comprehensive investigation using various analytical techniques, focusing on three flavonoids - apigenin, luteolin, and quercetin – applied to A. flavus NRRL 3357. Our findings revealed the following key insights: 1) glycosylated luteolin led to a 10% reduction in maximum fungal growth capacity; 2) quercetin affected cell wall integrity by triggering extreme mycelial collapse, while apigenin and luteolin caused peeling of the outer layer of cell wall; 3) luteolin exhibited the highest antioxidant capacity in the environment compared to apigenin and quercetin; 4) osmotic stress assays did not reveal morphological defects; 5) flavonoids promoted cell adherence, which is a precursor for biofilm formation; and 6) RNA sequencing analysis revealed that flavonoids impact expression of putative cell wall and plasma membrane biosynthesis genes. This study enhances our understanding of flavonoid-mediated effects on A. flavus and provides insights for future research of cell wall and biofilm formation that can impact agricultural practices and health management.

Technical Abstract: Aspergillus flavus, a fungus known for producing carcinogenic toxins called aflatoxins, poses significant threats to both agriculture and global health. Flavonoids, plant-derived com-pounds, inhibit A. flavus proliferation and mitigate aflatoxin production. The precise molecular and physical mechanisms underlying these effects remain poorly understood. In this study, we conducted a comprehensive investigation using various analytical techniques, focusing on three flavonoids - apigenin, luteolin, and quercetin – applied to A. flavus NRRL 3357. Our findings re-vealed the following key insights: 1) glycosylated luteolin led to a 10% reduction in maximum fungal growth capacity; 2) quercetin affected cell wall integrity by triggering extreme mycelial collapse, while apigenin and luteolin caused peeling of the outer layer of cell wall; 3) luteolin exhibited the highest antioxidant capacity in the environment compared to apigenin and quercetin; 4) osmotic stress assays did not reveal morphological defects; 5) flavonoids promoted cell ad-herence, which is a precursor for biofilm formation; and 6) RNA sequencing analysis revealed that flavonoids impact expression of putative cell wall and plasma membrane biosynthesis genes. This study enhances our understanding of flavonoid-mediated effects on A. flavus and provides insights for future research of cell wall and biofilm formation that can impact agricultural practices and health management.