Identification and characterization of key genes and signal transduction pathways enabling necrotrophic mycoparasitism of predator yeasts of the genus Saccharomycopsis.

Predacious yeasts are a unique group of yeasts that share the ability to kill other fungal cells via forming a penetration peg and feeding on the cellular content of the prey. We have begun to study the molecular mechanisms of this process as it harbors potential to use these yeasts as biocontrol agents against fungal pathogens. Predacious yeasts belong to the CTG-clade, i.e. there is a reassignment of the CTG codon to encode serine instead of leucine. This project has three objectives: (i)Establishment of molecular genetic tools for working with predator yeasts (use of antibiotic resistance markers for gene deletions, fluorescent proteins and staining techniques, analysis of mating type and sexual sporulation). Of key importance is the introduction of routine procedures for the targeted deletion. (ii) We have obtained high quality genomic and
transcriptomic information on Saccharomycopis schoenii grown under different conditions, incl.during predation on Saccharomyces cerevisiae. This has identified several genes upregulated specifically when predator yeasts are in contact with prey, incl. cell wall lytic enzymes, proteases and permeases but also cell surface signaling genes. Characterization of these genes aims at identifying genes required for predation process. (iii) Finally, based on our long-standing
experience in fungal morphogenesis we aim to analyze the role of the actin cytoskeleton and its regulators on penetration peg formation in the predator yeast S. schoenii.