Knockout mutations in the genes encoding phosphate transporters impair adaptation of Saccharomyces cerevisiae to ethanol consumption

Phosphate transporters in yeast cells are responsible for phosphorus homeostasis, and also indirectly involved in the regulation of various adaptive processes. One of these processes is the adaptation to ethanol consumption, which requires significant changes in phosphorus metabolism. We demonstrated that knockout mutations in the genes encoding phosphate transporters PHO87, PHO89, PHO90 and PHO91 impair adaptation of Saccharomyces cerevisiae to ethanol consumption at ethanol concentration of 4%. For these mutant strains an extension of the lag phase and in a decrease in the growth rate at the active stage was observed when the cells were cultivated in the medium with 4% ethanol. Mutant cells differ in the content of inorganic polyphosphates, but not orthophosphate, from the parental strain: they contain less long-chain polyphosphates when cultivated on ethanol, but not on glucose. When cultivated on a medium containing 4% ethanol, a strain with a knockout mutation in the PHO84 gene, encoding the transporter of phosphate and divalent metals, as well as knockout strains for the PHM6 and PHM7 genes, responsible for the polyphosphate overplus, did not show any growth differences compared with parent strain in a medium with 4% ethanol. The possible role of phosphate transporters and inorganic polyphosphates in the adaptation of yeast to ethanol consumption is discussed.