Extreme Osmotolerance and Halotolerance in Food-Relevant Yeasts and the Role of Glycerol-Dependent Cell Individuality.

摘要: Osmotolerance or halotolerance are used to describe resistance sugars and salt, only respectively. Here, a comprehensive screen of more than 600 different yeast isolates revealed that osmosensitive species were equally affected by NaCl glucose. However, the relative toxicity salt became increasingly prominent in osmoresistant species. We confirmed growth inhibition glucose laboratory strain Saccharomyces cerevisiae occurred at lower water activity (Aw) (NaCl), pre-growth high levels gave enhanced cross-resistance either. Salt was largely due osmotic stress but with an additive enhancement effects relevant cation. Almost all from also noted exhibit hetero-resistance both sugar, whereby concentrations restricted small minority cells within clonal populations. Rare resistant colonies required for up 28 days become visible. This cell individuality marked possible further reflection ion effect. In cases, heteroresistance S. strikingly dependent on GPD1 gene product, important glycerol synthesis. contrast, tps1Δ deletant impaired trehalose showed altered MIC no change heteroresistance. Effects evident chronic (but not acute) stress, particularly low Aw foods. The study reports diverse osmotolerance phenotypes across extensive panel isolates, indicates Gpd1-dependent synthesis is key determinant enabling rare subpopulations Aw, brought about particular salt.