Genomic organization of Bradyrhizobium flagellar systems

ALTHABEGOITI, MJ; MONGIARDINI, EJ; QUELAS, JI; LODEIRO, AR

Córdoba

Congreso; XI Congreso Argentino de Microbiología General (SAMIGE); 2015

Asociación Argentina de Microbiología (AAM)

Bacterial motility is an important trait for processes such as adherence to host cells, host cell invasion, protein secretion, and biofilm formation. Bradyrhizobium diazoefficiens and B. japonicum can live into plant nodules as a symbiont, or in a planktonic, free-living state in the soil, where they can swim and swarm self-propelled by their flagellar systems. Bradyrhizobium is the only rhizobium specie that posses two flagellar systems, both expressed independently with a different sets of genes. B. diazoefficiens USDA 110 and B. japonicum USDA 6 possess a subpolar flagellum and some lateral flagella (Althabegoiti et al., 2008, 2011, Althabegoiti, unpublished, Kanbe et al. 2007). Other not related species such as Vibrio parahaemoliticus, Aeromonas hydrophila, Chromobacterium violaceum, Rhodobacter shaeroides, Rhodopseudomonas palustris and Azospirillum brasilense posses also two flagellar systems. In these species the lateral flagella were described as only required for motility on surfaces while in B. diazoefficiens USDA 110 both flagellar types are expressed in liquid medium and seems not to play an exclusive role in the different types of displacements, swimming or swarming. Therefore, elucidation of the roles of these two flagellar systems in Bradyrhizobium requires more investigation. A possible approach to understand the biological functions is a comparative study of the genomic organization of these systems between Bradyrhizobium and also with the most related specie R. palustris.