Residence-time-dependent shifts in plant–soil feedback strategies from mutualism to pathogen regulation in a vigorous invasive plant

We conducted a two-phase common garden experiment to assess PSF effects on the invasiveness of Galinsoga quadriradiata and explore microbial mechanisms across the central and edge populations.The edge populations of G. quadriradiata exhibited stronger overall PSF than the central populations.

PSF significantly influenced plant growth, resource allocation, leaf functional traits, and life-history strategies, with central populations tending to allocate more resources to aboveground structures to enhance light competition, whereas edge populations exhibited greater belowground resource allocation and expanded their temporal niche by accelerating seed maturation. Crucially, the microbial mechanisms underlying PSF diverged between population types: PSF in the central populations was primarily associated with pathogen-related microbial traits, while PSF in the edge populations was more strongly linked to arbuscular mycorrhizal fungi (AMF).