Beauveria bassiana rewires molecular mechanisms related to growth and defense in tomato

Plant roots can exploit beneficial associations with soil-inhabiting microbes, promoting growth and expanding theimmune capacity of the host plant. In this work, we aimed to provide new information on changes occurring in tomato interacting with the beneficial fungus Beauveria bassiana. The tomato leaf proteome revealed perturbed molecular pathways during the establishment of the plant-fungus relationship. In the early stages of colonization (5-7 d),proteins related to defense responses to the fungus were down-regulated and proteins related to calcium transportwere up-regulated. At later time points (12-19 d after colonization), up-regulation of molecular pathways linked to protein/amino acid turnover and to biosynthesis of energy compounds suggests beneficial interaction enhancing plantgrowth and development. At the later stage, the profile of leaf hormones and related compounds was also investigated, highlighting up-regulation of those related to plant growth and defense. Finally, B. bassiana colonization wasfound to improve plant resistance to Botrytis cinerea, impacting plant oxidative damage. Overall, our findings furtherexpand current knowledge on the possible mechanisms underlying the beneficial role of B. bassiana in tomato plants.