Flavonoids Are Intra- and Inter-Kingdom Modulator Signals

Abstract

Flavonoids are a broad class of secondary metabolites with multifaceted functionalities for plant homeostasis and are involved in facing both biotic and abiotic stresses to sustain plant growth and health. Furthermore, they were discovered as mediators of plant networking with the surrounding environment, showing a surprising ability to perform as signaling compounds for a multitrophic inter-kingdom level of communication that influences the plant host at the phytobiome scale. Flavonoids orchestrate plant-neighboring plant allelopathic interactions, recruit beneficial bacteria and mycorrhizal fungi, counteract pathogen outbreak, influence soil microbiome and affect plant physiology to improve its resilience to fluctuating environmental conditions. This review focuses on the diversified spectrum of flavonoid functions in plants under a variety of stresses in the modulation of plant morphogenesis in response to environmental clues, as well as their role as inter-kingdom signaling molecules with micro- and macroorganisms. Regarding the latter, the review addresses flavonoids as key phytochemicals in the human diet, considering their abundance in fruits and edible plants. Recent evidence highlights their role as nutraceuticals, probiotics and as promising new drugs for the treatment of several pathologies.

The Role of Plant Growth-Promoting Microorganisms (PGPMs) and Their Feasibility in Hydroponics and Vertical Farming

“…Plants communicate with microorganisms via cell growth phases, where the roots contribute to the rhizospheric environment via the lysis of root cells, polysaccharides, and volatile organic carbon that activates the symbiotic interaction with PGPMs [ 21 , 22 ]. Thus, plants communicate with microorganisms during their growth period through their root exudates and secretion of the various signaling molecules that stimulate and promote the survival of the microorganisms, increasing the degradation and transformation of organic pollutants [ 23 ].…”

Natural compounds protect against the pathogenesis of osteoarthritis by mediating the NRF2/ARE signaling

“…Flavonoids have various pharmacological activities, including anti-inflammation, anti-oxidation, anti-cancer, anti-apoptosis, and bone system protection ( Ghitti et al, 2022 ). Natural flavonoids provide health-benefiting effects against chronic diseases, such as OA.…”

Flavonoids as Aglycones in Retaining Glycosidase-Catalyzed Reactions: Prospects for Green Chemistry

“…They are ubiquitous secondary metabolites produced in plants and fungi . In plants, they are involved in various functions that are associated with color and pigmentation, resistance to drought conditions, increased salt and UV-light stress, the presence of heavy metals in the soil, defense against herbivorous insects, and inhibition of certain disease-causing bacterial and fungal organisms. − For example, a high flavonoid content in tomato plants has been shown to confer resistance to the whitefly Bemisia tabaci , which feeds on these plants and can thus transmit plant viruses . On the other hand, high levels of flavonoids can harm beneficial organisms such as Orius sauteri , which are used for biological control of pests in tomato plants .…”

“…On the other hand, high levels of flavonoids can harm beneficial organisms such as Orius sauteri , which are used for biological control of pests in tomato plants . Flavonoids, as cell wall components, are also involved in plant defense against fungal pathogens, as has been shown in several pathosystems. , In addition, flavonoid glycosides and their aglycones play multiple roles in interactions between roots and microbial communities and may act as mediators in symbiotic interactions between nitrogen-fixing Rhizobia and legume roots …”

“…11,12 In addition, flavonoid glycosides and their aglycones play multiple roles in interactions between roots and microbial communities 13 and may act as mediators in symbiotic interactions between nitrogen-fixing Rhizobia and legume roots. 7 Most flavonoids in plants are glycosylated, linked to the carbohydrate moiety usually at position C-3 or C-7, forming Oglycosides (glucosides, rhamnosides, rutinosides, galactosides or arabinosides). 14 Moreover, flavonoid C-glycosides and additional linking positions of the glycosyl moieties are also known.…”