Striking up the conversation: quorum sensing in fungi

Abstract

Quorum sensing is a form of communication observed in different species of microbes. Numerous studies have shown the ability of bacteria and fungi to carry out quorum sensing by releasing specific molecules to enable communication in a large population. Quorum sensing has been shown to influence growth, morphology, and other factors pertaining to virulence in pathogenic microbes. In this review, we address three important fungal species and explain how each fungus has a unique and dynamic way of communicating. Candida albicans is an opportunistic pathogen, or one that is part of the normal microbiota that can become pathogenic and cause several diseases. Here, we address two quorum sensing molecules (QSMs) identified by investigators. These chemicals are tyrosol and farnesol, which act together to control cellular growth, morphology and biofilm production. Another opportunistic fungal pathogen, Cryptococcus neoformans, has been shown to display quorum sensing activity by using pantothenic acid as well as a peptide called quorum sensing-like peptide 1. These molecules have both been shown to control growth rates of C. neoformans. Saccharomyces cerevisiae is another dimorphic fungus that uses QSMs, although it is nonpathogenic. Using two aromatic alcohols, phenylethanol and tryptophol, S. cerevisiae can alter pseudohyphal growth in diploid cells as well as invasive growth in haploid cells. By understanding more about the ways these organisms communicate, we present the potential for new and better targets for the treatment of fungal infections.