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

Abstract

Aims: To characterize the physiological and metabolic responses of Mesorhizobium ciceri strain ch-191 to salt stress, investigating the changes induced by salinity in protein and lipopolysaccharide pro®les, as well as determining the accumulation of amino acids, glutamate and proline. Methods and Results: Strain ch-191 of M. ciceri was grown with different NaCl 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 pro®le. The most noteworthy change in the LPS-I pattern was the decrease in the slowest band and the appearance of an intermediate mobility band. The accumulation of proline in response to salt stress surpassed that of glutamate. Conclusions: The protein pro®le showed major alterations at salinity levels which inhibited growth. However, the alterations in the LPS pro®le and accumulation of compatible solutes were evident from the lowest levels, suggesting that these changes may constitute adaptative responses to salt, allowing normal growth. Signi®cance and Impact of the Study: The selection and characterization of salt-tolerant strains, which also show ef®cient symbiotic performance under salinity, may constitute a strategy for improving Cicer arietinum±Mesorhizobium ciceri symbiosis in adverse environments.

Salt stress manifestation on plants, mechanism of salt tolerance and potassium role in alleviating it: a review

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Development of Pigeon Pea Inoculated With Rhizobium Isolated From Cowpea Trap Host Plants

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Transcriptome Profiling Reveals the Importance of Plasmid pSymB for Osmoadaptation of Sinorhizobium meliloti

“…Rhizobia may use distinct mechanisms for osmotic adaptation when they are exposed to salt stress, such as intracellular accumulation of low-molecularweight organic solutes (osmolytes), including amino acids, sugars and polyamines, or accumulation of ions (i.e., K ϩ ) (37,66). Other salt-induced responses in rhizobia are changes in cell morphology and size and modifications in the pattern of extracellular polysaccharides (30,31,54,66). The latter responses may have an impact on the symbiotic interaction because exopolysaccharides and lipopolysaccharides (LPS) are very important for the development of root nodules.…”