Plant-soil feedbacks play critical roles in species invasions but are rarely investigated at the intraspecific level. We studied plant-soil feedbacks in three predominant North American lineages of a globally distributed plant species, Phragmites australis. We used field surveys and a common garden experiment to analyze the total and active microbial communities in the rhizosphere of P. australis stands from Native, Introduced and Gulf (uncertain origin) lineages, to examine lineage specific controls on rhizosphere microbial communities.
Regardless of where samples were collected in the United States, within-lineage microbial communities were similar, but were distinct among lineages, even those growing sympatrically. The distinct microbial community structure associated with Introduced lineage populations suggest that novel associations may facilitate invasion. Structural equation modeling of the common garden experiment also provides evidence that P. australis lineage engineers the rhizosphere microbial community.