Flavonoids, strigolactones, and beyond: scaling plant‐arbuscular mycorrhizal fungi communication towards community‐level dynamics

Arbuscular mycorrhizal fungi (AMF) are key drivers of plant growth and nutrition, shaping the relationship between plant diversity and ecosystem productivity. In agroecosystems, AMF generally benefit crops but often have neutral or even negative effects on weeds, yet the mechanisms underlying these contrasting interactions remain poorly understood. In this Viewpoint, we propose a plant community-level framework to investigate interactions between multiple crop and weed species and diverse AMF taxa, focusing on chemically mediated communication via root exudates, particularly flavonoids (FLVs) and strigolactones (SLs). These compounds can act as 'cry for help' signals that recruit beneficial soil microorganisms to alleviate environmental stress. We found that their composition varies widely among plant families, with crops typically producing more diverse and functionally distinctive FLV profiles than weeds. Similar patterns, though less documented, appear for SLs. Different FLV subclasses elicit contrasting AMF responses, influencing spore germination, hyphal growth, and root colonization. Notably, FLVs with stronger positive effects on AMF are more common in crops, whereas those with neutral effects tend to dominate in weeds. Our results are consistent with the idea that such molecular cues may shape AMF recruitment and could potentially feed back into plant community dynamics, although this hypothesis should be explicitly tested.