Bacterial signals N-acyl homoserine lactones induce the changes of morphology and ethanol tolerance in Saccharomyces cerevisiae

The bacterial quorum sensing signals N-acyl homoserine lactone (AHL) signals are able to regulate a diverse array of physiological activities, such as symbiosis, virulence and biofilm formation, depending on population density. Recently, it has been discovered that the bacterial quorum sensing (QS) signal molecules can induce extensive response of higher eukaryotes including plants and mammalian cells. However, little is known about the response of fungi reacting to these bacterial signals. Here we showed that Saccharomyces cerevisiae, as an ancient eukaryote and widely used for alcoholic beverage and bioethanol production, exposed to short-chain 3-OC(6)-HSL and long-chain C(12)-HSL appeared obvious changes in morphology and ethanol tolerance. AHLs could increase the frequency of cells with bipolar and multipolar buds, and these changes did not present distinct differences when induced by different types (3-OC(6)-HSL and C(12)-HSL) and varied concentrations (200 nM and 2 μM) of AHLs. Further investigation by flow cytometer displayed that the cells untreated by AHLs reduced cell size (decreased FSC) and enhanced intracellular density (increased in SSC), compared with the AHLs-induced cells after incubation 6 h. In addition, the long-chain C(12)-HSL could slightly increase the ethanol tolerance of S. cerevisiae while the short-chain HSL obviously decreased it. Our study would be valuable to further research on the interaction between prokaryotic and eukaryotic microbes, and be reference for industrial production of bioethanol.