Exopolysaccharide production in a mean to tolerate salinity by Rhizobium meliloti nodulating Mucuna pruriens Linn. plant

Abstract

The Rhizobial strains isolated from Mucuna pruriens Linn. plants were screened for the sodium chloride tolerance and exopolysaccharide productions in a salinity stressed medium containing up to 800 mM salt. The maximum growth was observed at 200 mM NaCl. Exopolysaccharide production was found to be directly proportional along with increasing NaCl concentration compared to control (Without salt). The nodulation activity of salt adapted Rhizobia with the host plant was limited up to 40 mM in vivo. Compared with control, the isolates retained their survival by increasing the EPS secretion thereby tolerating the salinity stress to a limited extent.