Lineage overwhelms environmental conditions in determining rhizosphere bacterial community structure in a cosmopolitan invasive plant

LAURA A. MEYERSON; JIM CRONIN; JENNIFER BOWEN; WARWICK ALLEN; KLÁRA PYKOVÁ; JOSÉ L. HIERRO; DIEGO VILLARREAL; JAN CUDA; PETR PYSEK

Congreso; NEOBIOTA 2018 10th International Conference on Biological Invasions New Directions in Invasion Biology; 2018

Plant-microbe interactions play critical roles in species invasionsbut are rarely investigated at the intraspecific level. We studiedthese interactions in three lineages of a globally distributed modelplant species, Phragmites australis. We used field surveys anda common garden experiment to analyze the total and activebacterial communities in the rhizosphere of P. australis standsfrom Native, Invasive, and Gulf lineages to determine whetherthere were lineage-specific controls on rhizosphere bacteria. Weshow that regardless of sampling location across the continentalUnited States, within-lineage bacterial communities are similar,but are distinct among lineages, results that were reproducedin a complementary common garden experiment. Further, ourresults indicate that the rate of bacterial community turnoverwith distance is lineage-specific. Invasive P. australis rhizospherebacterial communities had significantly lower abundances ofpathways involved in antimicrobial biosynthesis and degradation,suggesting a lower exposure to enemy attack than for the Nativeand Gulf lineages. However, lineage and not rhizosphere bacterialcommunities influenced individual plant growth in our commongarden experiment. We concluded that lineage is critical fordetermination of both rhizosphere bacterial communities andplant fitness in North America. The next steps in our researchare to expand our study to the global scale and sample in SouthAmerica, Austral-Asia, Europe, and Africa. We are including otherspecies in the genus Phragmites and we will collect samples notonly for rhizosphere soil but also leaf tissue for both fungi andbacteria. Because environmental change is likely to favor someplant genotypes over others, understanding bottom-up changesdue to microbial communities is critical in predicting ecosystemresponses and community reorganization.