To better understand the first steps of recognition and interaction of plants towardsits close environment, the early reaction of the model plant M. truncatula towards the symbiontR. irregularis or the pathogen A. euteiches was analyzed. This was done by analyzing thetranscriptome and secondary metabolites of root exudates at 2/ 12 and 12 hrs after microbialcontact, respectively. The transcriptomic data revealed that many genes were regulated in a similar way after treatmentwith the symbiont or the pathogen, while the intensity of the regulated gene expressiondiffered clearly. A. euteiches had a much stronger impact than R. irregularison the number of regulated genes. For analysis of roots exudates, plants were cultivated in an aeroponic system, which allowed aneasy exudate collection. Untargeted LC-MS analysis revealed major differences betweenexudate patterns of roots in contact with R. irregularis or A. euteiches. Both treatments hada much stronger impact on root exudation than the genotype(wtvs dmi3).