Disruption of trehalose production in Escherichia coli K-12 does not confer sensitivity to SDS-EDTA-induced outer membrane stress

Abstract

Trehalose, a glucose disaccharide, has been reported to play a role in stabilizing the cell envelope of Escherichia coli under numerous forms of abiotic stress. The exact manner by which trehalose contributes to this stability remains under investigation, though a recent paper suggested that it stabilizes the outer membrane component of the cell envelope in response to a variety of environmental stressors, including the presence of SDS and EDTA. We sought to validate these findings with a more robust approach to the SDS-EDTA assay. A key enzyme in the biosynthetic pathway of trehalose is OtsA, a trehalose-6-phosphate synthase, as otsA mutants are unable to synthesize trehalose. We hypothesized that otsA deletion mutants would be hindered in their ability to stabilize the outer membrane, increasing their susceptibility to SDS-EDTA-induced stress. To test this hypothesis, we performed basal growth rate analyses and SDS-EDTA assays. We report that mutants with a disrupted trehalose biosynthesis pathway were not more sensitive to either form of membrane stress (SDS or EDTA) relative to the wild type. These findings suggest that trehalose may not promote outer membrane stability of E. coli during SDS-EDTA stress.