Extracellular factors involved in biofilm matrix formation by rhizobia

ABDIAN, P; ZORREGUIETA, A

The perfect slime: microbial extracellular polymeric substances (EPS)

IWA Publishing

Año: 2016; p. 1 - 4

Rhizobia are soil bacteriathat play an important role in biological nitrogen fixation through theirsymbiotic interaction with legumes. Rhizobia grow in varied environmentalconditions during their life cycle and are able to produce different types ofbiofilms. Rhizobial biofilm formation may represent an advantageous way tosurvive long periods of nutrient starvation or desiccation when bacteria encounterthe 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. Manyof the extracellular polymeric substances (EPS) produced by rhizobia have beenpreviously studied in the context of the symbiotic interaction with the legumehost, but only in some cases their importance in biofilm matrix formation havebeen determined. The best characterized polymers are exopolysaccharides, andalthough several secreted proteins were identified only a few were linked to matrixformation. This chapter summarizes most of the cell associated or extracellularcomponents (exopolysaccharides, capsular polysaccharides, lipopolysaccharide,proteins) produced by several rhizobial species that have been involved in biofilmmatrix development. Other components such as glucomannan, flagella and Nodfactors are also discussed, as recent evidence points them as polymers/compoundsthat participate in biofilm matrix formation or attachment to differentsurfaces.