Prey preference and cell wall-mediated resistance shape predation efficiency in Saccharomycopsis schoenii

Microbial antagonism, including predation and competition, shapes microbial community diversity and dynamics. Saccharomycopsis schoenii, a unicellular predatory yeast, serves as a distinct model for bona fide fungal predation, characterized by penetration pegs that enable predation. This study examined prey preferences of S. schoenii within wine-associated yeast consortia and assessed the role of prey adhesion and cell wall features in modulating predation efficiency. Predation assays revealed species-specific dynamics, with Saccharomyces cerevisiae showing pronounced susceptibility and Torulaspora delbrueckii displaying resistance indicative of density-dependent prey switching. Expression of prey Flo-adhesins in S. cerevisiae did not affect predation outcomes, highlighting that prey adhesion phenotypes are not primary determinants of susceptibility. In contrast, S. cerevisiae VIN13-related mutant strains with increased cell wall chitin showed variable resistance phenotypes, suggesting that chitin contributes to resistance, but that broader cell wall remodelling and structural features are relevant factors independent of chitin levels. While these findings provide a mechanistic framework for understanding predator-prey interactions and prey resistance, the ecological and evolutionary significance of these interactions remains uncertain due to the rarity of Saccharomycopsis species in natural communities. Ultimately, these results emphasize the importance of integrating laboratory and ecological perspectives to fully comprehend the evolutionary implications of fungal predatory behaviour.