BMOL Seminar Series: Dr. Paul Rowley

Presenter Information

Speaker: Dr. Paul Rowley, Associate Professor of Biological Sciences at University of Idaho

Short Description of Research: Dr. Rowley’s research interests are centered on the complex interactions that occur between a virus and its host. The Rowley laboratory aims to better understand how antifungal proteins (called “killer toxins”) interact with fungal cells. The laboratory uses the model eukaryote Saccharomyces cerevisiae and pathogenic fungi to understand how killer toxins attack fungal cells and mechanisms of resistance.

Seminar Details

Host: Dr. Juliette Tinker, Biological Sciences

Title: Exploring the Lethal Arsenal of Killer Yeasts for Biotechnology and Beyond

Abstract: Yeasts, traditionally known for their role in studying fundamental biological processes, fermentation, and biotechnology, are a source of antifungal proteins named killer toxins. We have recently completed a comprehensive study of killer toxin production by 1,270 strains of the brewer’s yeast Saccharomyces cerevisiae and found that 50% produce killer toxins. This large collection of 638 diverse killer yeasts has enabled the discovery of killer toxins that can prevent the growth of medically and commercially important species of yeasts. Specifically, the opportunistic fungal pathogen Candida glabrata is uniquely susceptible to killer toxins produced by Saccharomyces yeasts. Due to the absence of killer toxin resistance in C. glabrata, it was possible to investigate the evolution of killer toxin resistance. Of the K1 toxin-resistant clones isolated, we found that growth rate and morphology were largely unaffected but had increased sensitivity to detergents and were avirulent. Whole-genome sequencing revealed novel genes involved in killer toxin resistance, including those critical for vesicle trafficking and cell wall morphogenesis. Moreover, we have observed membrane and organelle composition changes associated with K1 resistance that are linked to the mislocalization of a critical killer toxin receptor. We have also found that spoilage yeasts associated with contamination events in craft breweries are also susceptible to killer yeasts. In a simulated industrial-scale contamination event we find that killer yeasts can prevent hyperattenuation of beer. The future development of brewer’s yeasts that produce killer toxins will be important to reduce commercial losses due to diastatic yeast contamination. This work provides a unique mechanistic insight into killer toxin resistance in an opportunistic human pathogen and the feasibility of applying killer yeast on an industrial scale.

Publications Related to Talk:

• The Species-Specific Acquisition and Diversification of a K1-like Family of Killer Toxins in Budding Yeasts of the Saccharomycotina
• The prevalence of killer yeasts and double-stranded RNAs in the budding yeast Saccharomyces cerevisiae