Arabidopsis thaliana exudates induce growth and proteomic changes in Gluconacetobacter diazotrophicus.

Our results revealed the induction of bacterial growth in response to cocultivation. Comparative proteomic analysis identified 450 bacterial proteins, with 39 up-accumulated, and 12 down-accumulated in response to cocultivation. Among the up-accumulated pathways, the metabolism of pentoses and protein synthesis were highlighted. Proteins potentially relevant to bacterial growth response such as ABC-F-Etta, ClpX, Zwf, MetE, AcnA, IlvC, and AccC were also increased. Reverse genetics analysis, using insertion mutants, revealed that the lack of ABC-F-Etta and AccC proteins severely affects G. diazotrophicus response to cocultivation. Our data demonstrated that specific mechanisms are activated in the bacterial response to plant exudates, indicating the essential role of "ribosomal activity" and "fatty acid biosynthesis" in such a process. This is the first study to demonstrate the participation of EttA and AccC proteins in plant-bacteria interactions, and open new perspectives for understanding the initial steps of such associations.