Background: Lysin motif (LysM) effectors are secreted by many fungal pathogens to promote host colonization by suppression of immune responses that are triggered by the fungal MAMP chitin. It has been suggested that LysM effectors inhibit chitin-triggered immunity through binding to chitin, thus preventing its recognition by plant LysM-containing immune receptors. This has been particularly well demonstrated for the LysM effector Ecp6 of the tomato leaf mold pathogen Cladosporium fulvum, which exhibits exceptionally high affinity for chitin (de Jonge et al., 2010; Sánchez-Vallet et al., 2013). However, subsequent work has revealed that many LysM effectors exhibit low chitin-binding affinity, even though they still contribute to immune suppression and fungal virulence (Tian et al., 2022). This suggests that they may suppress immunity through alternative mechanisms. We hypothesize that these LysM effectors perturb the correct formation of plant LysM immune receptor complexes (Sánchez-Vallet et al., 2015). 

Project Description: This project aims to investigate how fungal LysM effectors interfere with plant LysM receptors to suppress chitin-triggered immunity. Using biochemical and molecular biology approaches, we will characterize effector–receptor interactions, determine their effects on receptor complex formation and immune signaling, and elucidate the molecular basis of immune suppression. This project will provide new insights into fungal immune evasion and the molecular arms race between fungal pathogens and their plant hosts.