Reduced water availability influences the dynamics, development, and ultrastructural properties of Pseudomonas putida biofilms.

Pseudomonas putida strain mt-2 unsaturated biofilm formation proceeds through three distinct developmental phases, culminating in the formation of a microcolony. The form and severity of reduced water availability alter cell morphology, which influences microcolony size and ultrastructure. The dehydration (matric stress) treatments resulted in biofilms comprised of smaller cells, but they were taller and more porous and had a thicker extracellular polysaccharide layer at the air interface. In the solute stress treatments, cell filamentation occurred more frequently in the presence of high concentrations of ionic (but not nonionic) solutes, and these filamented cells drastically altered the biofilm architecture.