Soil transplantation: complex interplay between soil microbes and the local environment.

Soil transplantation, the introduction of co-adapted soil microbes to maintain plant-microbe interactions in novel environments, is increasingly used to mitigate climate change effects on plants. However, it yields variable outcomes. We performed a reciprocal transplantation experiment at three elevations, plus a glasshouse experiment, where seedlings of three species were grown in rhizosphere soils from conspecific individuals collected from their original (home soil) or transplanted (away soil) sites. There were idiosyncratic patterns of plant growth for both effects of transplantation to new sites with their origin soils and for home vs away soils at new sites. These patterns likely reflect species-specific changes in the relative abundance of soil fungal pathogens across elevations. After transplantation, only a subset of taxa in the home soils persisted, and the compositional similarity in plant rhizosphere communities (in home soils) decreased with increasing elevation differences between the original and transplanted sites. Furthermore, the growth rate of transplanted plants was influenced by taxa from both home soils and local environments. Glasshouse experiment results did not predict patterns in the field transplantation experiment. Our findings underscore the interplay between soil microbes and the local environment in shaping plant-soil interactions following transplantation.