Metabolic and physiological characteristics of salt-tolerant strains of Bradyrhizobium spp.

Biochemical and physiological characteristics of salt-tolerant (88 mM, 264 mM and 440 mM NaCl) strains of Bradyrhizobium were evaluated according to t heir capacity for using different carbon sources, growth rate, resistance t o antibiotics, plasmid profile and exopolysaccharide production. Salt-toler ant strains significantly enhance their capacity to oxidize C sources (abou t 75-85 compounds) by increasing growth rate and exopolysaccharide producti on involved in adhesion, resulting in a greater adapting capacity to coloni ze unfavorable saline environments. However, salt stress could work as a cu ring agent and thus the gene stability would become critical for the biolog ical nitrogen-fixation information present in plasmids, as is the case in R hizobium.