Three symbionts mediate indirect plant-soil feedback: Epichloid endophytes and mycorrhizal fungi affect the performance of rhizobia-legume symbiosis

GARCIA PARISI, PA; LATTANZI, F; GRIMOLDI, A; OMACINI M

PLANT AND SOIL

SPRINGER

Lugar: Berlin; Año: 2017 vol. 412 p. 151 - 162

0032-079X

Aims:Plants interact by modifying soil conditions in plant-soil feedback processes.Foliar endophytes of grasses exert multiple effects on host rhizosphere withpotential consequences on plant-soil feedback. Here, we hypothesize that thegrass-endophyte symbiosis impairs soil symbiotic potential, and in turninfluences legume performance and nitrogen acquisition.Methods: Soil wasconditioned in pots, growing Lolium multiflorum with or without the fungalendophyte Epichloë and with or without arbuscular mycorrhizal fungi (AMF).Then, Trifolium repens grew in all types of conditioned soils with high or lowrhizobia availability.Results: Endophyte soil conditioning reduced AMF sporesnumber and rhizobial nodules (-27% and -38%, respectively). Seedling survivalwas lower in endophyte-conditioned soil and higher in mycorrhizal soils (-27 %and +24%, respectively). High rhizobia-availability allowed greater growth andnitrogen acquisition, independent of soil conditioning. Lowrhizobia-availability allowed both effects only in endophyte-conditioned soil.Conclusion: Endophyte-induced changes in soil (i) hindered symbionts potentialby impairing AMF spores availability or rhizobia nodulation, (ii) impairedlegume survival irrespective of belowground symbionts presence, but (iii) mimickedrhizobia effects, enhancing growth and nitrogen fixation in poorly nodulatedplants. Our results show that shoot and root symbionts can be interactivelyinvolved in interspecific plant-soil feedbacks.