Yeast Killer Toxin

Yeasts can exhibit a killer phenotype by producing and secreting proteins with a lethal effect on sensitive strains, called killer toxins. To date, about 100 killer yeast species from diverse phylogenetic origins have been described, and several killer toxins have been investigated for their antimicrobial power, in particular against pathogenic microorganisms. Killer toxins show a broad spectrum of activity against bacteria, yeast, and protozoa. The action mechanism of the killer toxins is based on interference with the vital cellular processes, such as cell wall and membrane integrity, DNA replication, or mRNA translation. Over the last decades, killer toxins and killer yeasts have been well characterized and have found interesting and advantageous applications in the food and feed industries, as well as in the biological control of plant pathogens and as insect vectors of human diseases. Killer yeasts can combat contaminating microorganisms in the production of wine, beer, and bread, or act as bio-control agents in the preservation of foods. Moreover, killer toxins and their derived-peptides are involved in the development of novel drugs for the treatment of human and plant–fungal infections. Advanced studies on the deep characterization of killer toxins and biotechnology applications of killer yeasts and killer toxins will be the focus of the Special Issue titled Yeast Killer Toxin.