Biofilm Formation and Biosurfactant Activity in Plant-Associated Bacteria

Biofilms are structurally complex communities of microbial cells that adhere to a surface and are surrounded by an extracellular polymeric matrix. Biofilm formation plays important roles in attachment and colonization of plant surfaces by both beneficial bacteria (e.g. plant growth-promoting rhizobacteria) and phytopathogenic bacteria. During the process of biofilm development and maturation, surface-attached cells undergo aggregation to form microcolonies. Biosurfactants are produced by many plant-associated bacterial species and play essential roles in bacterial motility, signaling, biofilm formation and control of plant-bacteria interactions. In this chapter, we review the biochemical and genetic mechanisms that underlie biofilm formation and biosurfactant activity in beneficial (symbiotic) bacteria and phytopathogenic bacteria, particularly Pseudomonas species.