Osmoadaptation in rhizobia: ectoine-induced salt tolerance

Autor: Mohamed Jebbar, R. Talibart, Théophile Bernard, H. Wroblewski, Carlos Blanco, S. Himdi-Kabbab, Gwenola Gouesbet
Přispěvatelé: Université de Rennes (UR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), University of Rennes
Předmět:
Time Factors
[SDE.MCG]Environmental Sciences/Global Changes
Biology
Ectoine
Microbiology
03 medical and health sciences
chemistry.chemical_compound
Ectoine transport
Betaine
[SDV.EE.ECO]Life Sciences [q-bio]/Ecology
environment/Ecosystems
Glutamates
Species Specificity
[SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Genomics [q-bio.GN]
[SDV.BV]Life Sciences [q-bio]/Vegetal Biology
[SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Biochemistry [q-bio.BM]
Molecular Biology
030304 developmental biology
Aspartic Acid
0303 health sciences
Osmotic concentration
030306 microbiology
Osmolar Concentration
Amino Acids
Diamino
Biological Transport
[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry
Molecular Biology/Molecular biology
Trehalose
Culture Media
Kinetics
chemistry
Biochemistry
Osmolyte
Glycine
Osmoprotectant
[SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology
[SDE.BE]Environmental Sciences/Biodiversity and Ecology
Carrier Proteins
Rhizobium
Sinorhizobium meliloti
Research Article
Zdroj: Europe PubMed Central
Journal of Bacteriology
Journal of Bacteriology, 1994, 176 (17), pp.5210-5217. ⟨10.1128/jb.176.17.5210-5217.1994⟩
Journal of Bacteriology, American Society for Microbiology, 1994, 176 (17), pp.5210-5217. ⟨10.1128/jb.176.17.5210-5217.1994⟩
Scopus-Elsevier
ISSN: 0021-9193
1098-5530
DOI: 10.1128/jb.176.17.5210-5217.1994⟩
Popis: International audience; After having shown that ectoine (a tetrahydropyrimidine) displays osmoprotective properties towards Escherichia coli (M. Jebbar, R. Talibart, K. Gloux, T. Bernard, and Blanco, J. Bacteriol. 174:5027-5035, 1992), we have investigated the involvement of this molecule in the osmotic adaptation of Rhizobium meliloti. Ectoine appeared almost as effective as glycine betaine in improving the growth of R. meliloti under adverse osmotic conditions (0.5 M NaCl). Moreover, improvement of growth of rhizobial strains insensitive to glycine betaine was also observed. Ectoine transport proved inducible, periplasmic protein dependent, and, as shown by competition experiments, distinct from the transport of glycine betaine. Medium osmolarity had little effect on the uptake characteristics, since the rate of influx increased from 12 to only 20 nmol min-1 mg of protein-1 when NaCl concentrations were raised from 0 to 0.3 or 0.5 M, with a constant of transport of 80 microM. Natural-abundance 13C-nuclear magnetic resonance and radiolabelling assays showed that ectoine, unlike glycine betaine, is not intracellularly accumulated and, as a consequence, does not repress the synthesis of endogenous compatible solutes (glutamate, N-acetylglutaminylglutamine amide, and trehalose). Furthermore, the strong rise in glutamate content in cells osmotically stressed in the presence of ectoine suggests that, instead of being involved in osmotic balance restoration, ectoine should play a key role in triggering the synthesis of endogenous osmolytes. Hence, we believe that there are at least two distinct classes of osmoprotectants: those such as glycine betaine or glutamate, which act as genuine osmolytes, and those such as ectoine, which act as chemical mediators.
Databáze: OpenAIRE
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