The Agrobacterium fabrum efflux pump PecM serves as a critical metabolic relief valve to maintain cellular homeostasis

Accumulating proteins included glutathione S-transferase and glutathione-dependent peroxiredoxin, both of which protect from oxidative stress. Consistent with this observation, the pecM disrupted strain was more resistant to oxidative stress. Across the genes and proteins detected in both datasets, there was no overall linear relationship, as reflected in a Pearson correlation of ~0.

A marked depletion of bS21C, which is a component of the small ribosomal subunit was observed; as one of three paralogs, its differential expression suggests the possibility that ribosome heterogeneity is part of adaptation to stress. Taken together, our data suggest that absence of PecM imposes a 4-hydroxybenzaldehyde-induced oxidative or electrophile stress, and that PecM serves as a critical metabolic relief valve to maintain cellular homeostasis.