Biofilm formation by rhizobacteria in response to water-limiting conditions

Abstract

Bacterial biofilms are relevant to agricultural, environmental, industrial, and medical research areas. Biofilm formation is instrumental in the development of a microniche that protects soil bacteria (rhizobacteria) against a variety of physical and chemical stress factors. Biofilm composition varies depending on the bacteria–host plant system. The major components of biofilms are water and bacterial cells, followed by matrix exopolysaccharides, which provide (i) a physical barrier against diffusion of antibiotics, defensive substances, or other adverse host plant compounds; and (ii) protection against environmental stress factors, including UV radiation, pH changes, osmotic stress, and desiccation. This chapter summarizes our current knowledge of biofilm formation by rhizobia in response to water-limiting conditions.