Microbial biosynthesis of wax esters during desiccation: Adaptation for colonization of the earliest terrestrial environments?

Abstract

Intense fluctuations in precipitation govern seasonal cycles of ephemeral lakes, controlling hydration stresses and producing changes in the biochemical composition of endemic microbes. The lipid compositions of emergent and desiccated mats with comparable microbial communities from evaporative alkaline lakes reveal increases in the abundance and average chain length of wax esters (WE) that may represent an evolutionary strategy to survive desiccation in evaporative environments. Subsequent rehydration naturally saponifies WE, regenerating alcohol and acid moieties that can be utilized as membrane lipids for the next viable microbial generation. The antiquity of this biosynthetic innovation suggests that WE production likely facilitated microbial migration to lake environments in the earliest terrestrial ecosystems as well as their survival through hydration-dehydration cycles.