Spatial variation in AMF communities and soil properties correlates with leaf and root allelopathic potential in...

Allelopathy is a key driver of plant invasion. However, how arbuscular mycorrhizal fungal (AMF) communities and abiotic factors associated with plant-soil interactions (PSIs) influence plant chemistry and allelopathic potential remains poorly understood. We examined the allelopathic potential of leaf and root extracts of Solidago canadensis from 18 invaded quadrats across six sites using a Raphanus sativus bioassay. We then analyzed the associations among invasion intensity, AMF communities, soil abiotic properties, plant chemistry, and allelopathy. Results indicated significant spatial heterogeneity in leaf and root chemistry and their allelopathic strength. AMF community metrics and soil abiotic properties within the invaded communities were significantly correlated with variations in leaf and root chemistry (e.g., phenols and flavonoids), both of which were strongly linked to allelopathic potential. Leaf chemistry showed stronger allelopathic inhibition than root chemistry and was more responsive to variations in the soil environment. Our partial least squares path modeling supported a hypothesized PSI framework in which the degree of S. canadensis invasion was negatively associated with changes in the AMF community; together with soil abiotic factors, these were correlated with shifts in allelochemical production and allelopathic potential. These findings outline a correlative network through which invasive plants may modify soil biota and chemistry, a process potentially linked to their ecological dominance.