Tolerance of Mesorhizobium type strains to different environmental stresses

• Published in: Antonie van Leeuwenhoek Vol. 99; no. 3; pp. 651 - 662
• Main Authors: Laranjo, Marta, Oliveira, Solange
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-03-2011; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Alphaproteobacteria - drug effects; Alphaproteobacteria - genetics; Alphaproteobacteria - metabolism; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Biomedical and Life Sciences; Blotting, Northern; Electrophoresis, Polyacrylamide Gel; Environmental conditions; Environmental stress; Fundamental and applied biological sciences. Psychology; Gene expression; groEL; Heat tolerance; Hydrogen-Ion Concentration; Life Sciences; Medical Microbiology; Mesorhizobium; Mesorhizobium ciceri; Mesorhizobium huakuii; Microbiology; Original Paper; Plant Sciences; Proteins; Salt; Salts; Sodium chloride; Sodium Chloride - pharmacology; Soil Science & Conservation; Stress; Stress response; Symbiosis; Temperature; pH; Salt; Temperature; Stress; Environment; groEL; Mesorhizobium; Strain
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1007/s10482-010-9539-9

The symbiosis between rhizobia and legumes is affected by different environmental conditions. Our aims were to evaluate stress tolerance of Mesorhizobium species and investigate species-specific stress response mechanisms. Tolerance of Mesorhizobium type strains to temperature, salt and pH stress was evaluated. Mesorhizobium thiogangeticum showed highest growth with 1.5% NaCl and Mesorhizobium ciceri at pH 5. Mesorhizobium plurifarium showed higher growth at 37°C. SDS-PAGE analysis revealed changes in the protein profiles, namely the overexpression of a 60 kDa protein, following heat stress. Under salt stress, five overexpressed proteins were identified in M. plurifarium and M. thiogangeticum. Northern analysis revealed an increase in groEL expression in Mesorhizobium huakuii and Mesorhizobium septentrionale after heat shock; by contrast, a decrease was detected in Mesorhizobium albiziae and M. thiogangeticum, upon salt shock. A high diversity in tolerance to temperature, salt and pH stress was detected among Mesorhizobium species. M. thiogangeticum and M. ciceri are moderately halophilic and acidophilic, respectively. Several proteins, overproduced in different strains, may be involved in stress tolerance. groEL expression increased upon heat and decreased upon salt shock. To our knowledge, this is the first study focusing tolerance to temperature, salt and pH stress, as well as groEL expression, in Mesorhizobium type strains.