Excitation of filamentous growth in Dekkera spp. by quorum sensing aromatic alcohols 2-phenylethanol and tryptophol

Abstract Fungi from the genus Dekkera, also known as Brettanomyces, are significant contaminants in commercial beer and wine production, and when present unintentionally, these non-domesticated yeasts result in the development of undesirable sensorial characteristics, in part due to the production of volatile phenols and acetate esters. The persistence of Dekkera spp. in industrial manufacturing environments can be attributed to its strong bioadhesive properties, allowing it to attach to various surfaces and form biofilms, which often contribute to recurrent contaminations. In other fungi, the yeast-to-filamentous transition is pivotal in enhancing bioadhesive properties, a process tightly regulated by density-dependent quorum-sensing mechanisms. However, there is no documented evidence regarding the influence of fungal quorum-sensing compounds on the yeast-to-filamentous transition in Dekkera, nor is there any evidence of existing quorum-sensing circuits in this genus. In this investigation, two Dekkera spp. were cultivated on a modified nitrogen-limiting synthetic low-ammonium dextrose medium supplemented with exogenous concentrations of quorum-sensing molecules 2-phenylethanol and tryptophol. Following cultivation, whole colonies were imaged and analyzed with a whole colony filamentation algorithm to quantify their filamentation. Our results demonstrate that the quorum-sensing compounds 2-phenylethanol and tryptophol significantly promote the yeast-to-filamentous transition in Dekkera spp., underscoring the broader presence of quorum-regulated social behaviors within this genus.