Three symbionts involved in interspecific plant-soil feedback: epichloid endophytes and mycorrhizal fungi affect the performance of rhizobia-legume symbiosis

Abstract

Aims Plants interact by modifying soil conditions in plant-soil feedback processes. Foliar endophytes of grasses exert multiple effects on host rhizosphere with potential consequences on plant-soil feedback. Here, we hypothesize that the grass-endophyte symbiosis impairs soil symbiotic potential, and in turn influences legume performance and nitrogen acquisition. Methods Soil was conditioned in pots, growing Lolium multiflorum with or without the fungal endophyte Epichloë and with or without arbuscular mycorrhizal fungi (AMF). Then, Trifolium repens grew in all types of conditioned soils with high or low rhizobia availability. Results Endophyte soil conditioning reduced AMF spores number and rhizobial nodules (−27 % and −38 %, respectively). Seedling survival was lower in endophyteconditioned soil and higher in mycorrhizal soils (−27 % and +24 %, respectively). High rhizobia-availability allowed greater growth and nitrogen acquisition, independent of soil conditioning. Low rhizobia-availability allowed both effects only in endophyte-conditioned soil. Conclusion Endophyte-induced changes in soil (i) hindered symbiotic potential by reducing AMF spore availability or rhizobia nodulation, (ii) impaired legume survival irrespective of belowground symbionts presence, but (iii) mimicked rhizobia effects, enhancing growth and nitrogen fixation in poorly nodulated plants. Our results show that shoot and root symbionts can be interactively involved in interspecific plant-soil feedback.

Soil microbial communities alter conspecific and congeneric competition consistent with patterns of field coexistence in three Trifolium congeners

“…The net effects of these microbes on Trifolium hosts were highly variable and depended on the host species and the source (native or introduced range) of the microbes and hosts (Shelby et al, ). Moreover, the combined effects of AMF and other microbes have been shown to interact and thus alter both the benefits received by Trifolium and PSFs (Alho, Carvalho, Brito, & Goss, ; García‐Parisi, Lattanzi, Grimoldi, Druille, & Omacini, ). Rhizobia and AMF together reduce the competitive suppression of Trifolium species by grasses (Hall, ; Thompson, Turkington, & Holl, ; Wagg, Jansa, & Stadler, ).…”

Removal of Soil Microbes Alters Interspecific Competitiveness of Epichloë Endophyte-Infected over Endophyte-Free Leymus chinensis

“…In natural systems, plants often experience direct competition with neighbouring plants and simultaneous complex interactions with soil biota [43]. Epichloë endophyte colonization can shape communities of soil biota [44][45][46][47][48] and influence subsequent plant growth and survival [49][50][51][52]. Can simultaneous occurrence of foliar Epichloë endophytes and soil microbes affect the competitivity of the host grasses?…”

Plant performance response to eight different types of symbiosis

“…There is much scope for strengthening our understanding of plant symbioses through understanding symbioses as a risk–benefit trade‐off in plants, for example via the extension to symbioses of the risk preference framework in plants (Dener et al ., ); testing the comparisons between different symbioses on similar focal plants, simultaneously or at different stages during the life cycle of the plants (Bagyaraj et al ., ; Larimer et al ., ; García‐Parisi et al ., ); expressing plant performance with a standardized measurement (such as mass or height), rather than various proxies such as the number of leaves or the leaf area, and so on; extending the comparison between symbioses to other components of plant fitness (fecundity and survival; Gaur & Adholeya, ; Gibert et al ., ).…”