Effects of salinity on protein and lipopolysaccharide pattern in a salt-tolerant strain of Mesorhizobium ciceri

Aims: To characterize the physiological and metabolic responses of Mesorhiz obium ciceri strain ch-191 to salt stress, investigating the changes induce d by salinity in protein and lipopolysaccharide profiles, as well as determ ining the accumulation of amino acids, glutamate and proline. Methods and Results: Strain ch-191 of M. ciceri was grown with different Na Cl concentrations. Protein and lipopolysaccharide patterns were determined by electrophoresis. The strain ch-191 tolerated up to 200 mmol l(-1) NaCl, although higher salt dosages limited its growth and induced changes in the protein profile. The most noteworthy change in the LPS-I pattern was the de crease in the slowest band and the appearance of an intermediate mobility b and. The accumulation of proline in response to salt stress surpassed that of glutamate. Conclusions: The protein profile showed major alterations at salinity level s which inhibited growth. However, the alterations in the LPS profile and a ccumulation of compatible solutes were evident from the lowest levels, sugg esting that these changes may constitute adaptative responses to salt, allo wing normal growth. Significance and Impact of the Study: The selection and characterization of salt-tolerant strains, which also show efficient symbiotic performance und er salinity, may constitute a strategy for improving Cicer arietinum-Mesorh izobium ciceri symbiosis in adverse environments.