Antimicrobial effectors secreted by plant-colonizing fungi and their role in endophytism

• Applicant: Dr. Fantin Mesny
• Subject Area: Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 508411006

In nature, plant tissues are colonized by a wide diversity of micro-organisms, including bacteria, fungi and oomycetes, collectively forming their microbiota. Microbes that live within plant tissues are described as endophytes. Fungi constitute important members of the plant microbiota, and shape plant fitness and distribution worldwide. To colonize a plant host, they employ a variety of mechanisms, including the secretion of small proteins referred to as effectors. Effectors have a wide diversity of functions, and are notably known to manipulate host immunity. The fungal species Verticillium dahliae was recently shown to secrete effectors with antimicrobial activities, in order to modulate plant microbiota. By inhibiting the growth of bacterial and fungal competitors, these effectors facilitate the colonization of plant roots by V. dahliae. Here, we aim to determine how common the exploitation of antimicrobial effectors is among fungal endophytes. We will therefore (1) develop an algorithm predicting antimicrobial activity of fungal effectors; (2) study the conservation and evolution of antimicrobial effectors in a broad panel of plant-associated fungi, including endophytes; (3) assess how fungi secreting different sets of antimicrobial effectors impact endophytic plant microbiota. The expected outcome of this project is the discovery and functional validation of antimicrobial effectors with a strong impact on microbial communities, thus playing key roles in fungal endophytism.

• DFG Programme: WBP Position