Extracellular factors involved in biofilm matrix formation by Rhizobium leguminosarum

PATRICIA L. ABDIAN (CORRESPONDING AUTHOR); ANGELES ZORREGUIETA

The Perfect Slime: Microbial Extracellular Polymeric Substances (EPS)

IWA Publishing Group

Lugar: Londres; Año: 2016; p. 227 - 247

Rhizobia are soil bacteria that play an important role in biological nitrogen fixation through their symbiotic interaction with legumes. Rhizobia grow in varied environmental conditions during their life cycle and are able to produce different types of biofilms. Rhizobial biofilm formation may represent an advantageous way to survive long periods of nutrient starvation or desiccation when bacteria encounter the bulk soil, but it may also aid in the interaction with the host plant, increasing the inoculum of bacteria on plant tissues susceptible to infection. Many of the extracellular polymeric substances (EPS) produced by rhizobia have been previously studied in the context of the symbiotic interaction with the legume host, but only in some cases their importance in biofilm matrix formation have been determined. The best characterized polymers are exopolysaccharides, and although several secreted proteins were identified only a few were linked to matrix formation. This chapter summarizes most of the cell associated or extracellular components (exopolysaccharides, capsular polysaccharides, lipopolysaccharide, proteins) produced by several rhizobial species that have been involved in biofilm matrix development. Other components such as glucomannan, flagella and Nod factors are also discussed, as recent evidence points them as polymers/compounds that participate in biofilm matrix formation or attachment to different surfaces.