Co-inoculation of legumes with rhizobia and field soil microbial communities results in host specific responses
In the legume-rhizobia symbiosis, rhizobia bacteria fix nitrogen for legume plant hosts in exchange for carbon. We investigated how inoculation with field soil microbial communities affects the rhizobia-legume symbiosis across different legume species. 13 Medicago species were grown under 2 inoculation treatments: inoculation with rhizobia (R+), inoculation with microbes from a field soil community (F+), and a combined treatment (R+F+). Plant growth outcomes and rhizobial nodulation were measured and analyzed. M. rigiduloides and M. rotata could not survive in any treatment, M. coronata, littoralis, lupulina, rigidula, and truncatula generally benefited from rhizobial inoculation, while M. arabica, M. murex, and M. noeana generally suffered. The findings indicate that host specificity and soil community should be considered in agricultural and restoration applications.