Flavonoids in plant-environment interactions and stress responses

This review explores the multifaceted roles of low-molecular-weight secondary metabolites, such as flavonoids, which are ubiquitous in plants. Flavonoids perform diverse functions, particularly in various physiological processes crucial for plant health. In the context of plant-environment interactions, flavonoid-based allelochemicals exhibit a dual nature, demonstrating stimulatory activity at low concentrations and inhibitory effects at higher concentrations. The involvement of flavonoids in defense mechanisms against bacterial and fungal pathogens underscores their vital role in enhancing plant resilience. Additionally, flavonoids serve as efficient signaling compounds in establishing symbiotic relationships between plants and various microorganisms, including rhizobia, the actinobacterium Frankia, and mycorrhizae. These interactions contribute significantly to the overall health and nutrient acquisition strategies of host plants. Flavonoids also play a pivotal role in mitigating stress-associated chemical changes caused by biotic and abiotic factors, thus providing stress protection. Notably, flavonoids exhibit antioxidative activity, detoxifying reactive oxygen species produced under stress conditions. This antioxidative capability helps alleviate stress-induced oxidative damage. Collectively, these findings underscore the importance of flavonoids in orchestrating plant-environment interactions and highlight their multifunctional role in stress mitigation. This review consolidates and emphasizes the current understanding of flavonoids, providing valuable insights for researchers and practitioners in plant biology, agriculture, and environmental science.