Yeasts collectively extend the limits of habitable temperatures

The conventional view is that high temperatures cause microorganisms to replicate slowly or die, both autonomously. We show that budding yeasts, despite being single-celled organisms, collectively combat rising temperatures [1]. By cooperating, yeasts help each other and their future generations to replicate and avoid population extinction at high temperatures. As a consequence, even at the same temperature, a yeast population can exponentially grow, never grow or grow after unpredictable durations (hours to days) of stasis, depending on its population density. We measured a phase diagram which summarizes, as a function of both the temperature and the starting population density, when yeasts can replicate and when they cannot. These features arise from yeasts secreting and extracellularly accumulating a heat-damage preventing antioxidant (glutathione). We show that the secretion of glutathione, which eliminates harmful extracellular chemicals, is both necessary and sufficient for yeasts to survive high temperatures. Our study demonstrates how organisms can cooperatively define and extend the boundaries of life-permitting temperatures.

[1] Laman Trip, D.S., Youk, H. Yeasts collectively extend the limits of habitable temperatures by secreting glutathione. Nat Microbiol (2020).