Author contributions
FV and AM conceived the idea. FV performed microbiological experiments, transcriptomic and statistical analyses. IP performed bioinformatic analysis of RNA-Seq data. NA, NJ, MM helped in setting microbiological experiments. PB guided the experiments with fungal strains. PEC provided fungal strains and guided interpretation of fungal-related data. KDA, LK, RS, KP provided support, guidance and data interpretation for plant experiments, metabolomic analysis and assays of rhizobial phenotypes. AM and FV interpreted the whole set of data and drafted the manuscript. All authors contributed in the writing of the final version of the manuscript.