Background: Plants defend themselves against pathogens through innate immune responses, but also through recruitment of beneficial microorganisms. In turn, pathogens try to overcome these defences through the secretion of effector proteins. We have recently shown that plant pathogenic fungi produce antimicrobial proteins (AMPs) to suppress antagonistic microbes, thereby promoting their persistence during different phases of host colonization (Mesny et al., 2024; 2026). For example, the soil-borne fungal pathogen Verticillium dahliae secretes antimicrobial proteins (AMPs) to antagonize microbial competitors at different life stages. Its genome encodes hundreds of predicted AMP genes. Interestingly, AMP gene expression seems to be manipulated by soil bacteria: while some of AMP genes are repressed, others are induced (Zhu et al., 2026). However, the molecular mechanisms by which soil bacteria affect fungal AMP gene expression remain unknown.

Project Description: This project aims to elucidate the molecular mechanisms by which soil bacteria induce AMP expression in V. dahliae. Comparative transcriptomic analyses will identify bacteria-induced AMP genes, followed by functional characterization of selected candidates. Soil bacterial community profiling will be conducted to identify key bacterial taxa associated with AMP induction, and the roles of selected bacterial taxa will be validated through co-culture assays with V. dahliae. Finally, the signalling mechanisms underlying bacteria-induced AMP expression will be investigated. In this way, we will dissect the microbiome-mediated regulation of AMP expression in fungal pathogens and contribute to the development of microbiome-based strategies for sustainable disease control.