Nitrogenase and antioxidant enzyme activities in Phaseolus vulgaris nodules formed by Rhizobium tropici isogenic strains with varying tolerance to salt stress

• Published in: Journal of plant physiology Vol. 161; no. 3; pp. 329 - 338
• Main Authors: Tejera, Noel A., Campos, Rosario, Sanjuan, Juan, Lluch, Carmen
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 01.03.2004; Elsevier; Elsevier Science Ltd
• Subjects: amino acids; Antioxidant enzymatic defenses; antioxidants; Antioxidants - metabolism; beans; Biological and medical sciences; carbohydrate content; catalase; common bean root nodules; enzyme activity; Fundamental and applied biological sciences. Psychology; Genes, Fungal; glutathione dehydrogenase (ascorbate); mutants; Mutation; nitrogenase; Nitrogenase - metabolism; oxidative stress; Parasitism and symbiosis; Phaseolus - enzymology; Phaseolus - microbiology; Phaseolus vulgaris; Plant physiology and development; plant proteins; Rhizobium tropici; Rhizobium tropici - drug effects; Rhizobium tropici - genetics; Rhizobium tropici - physiology; root nodules; salt stress; salt tolerance; Sodium Chloride - pharmacology; superoxide dismutase; Symbiosis; Symbiosis - drug effects; Symbiosis - genetics; Symbiosis - physiology; Antioxidant enzymatic defenses; salt stress; Phaseolus vulgaris; common bean root nodules; oxidative stress; Growth; Superoxide dismutase; Plant nodule; Catalase; Dicotyledones; Angiospermae; Nitrogen fixation; Symbiosis; Enzyme; Tolerance; Antioxidant; Stress; Salinity; Leguminosae; Peroxidases; Nitrogenase; Spermatophyta; Oxidoreductases; Mutation; Reductase
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1078/0176-1617-01050

Common bean plants inoculated with salt-tolerant Rhizobium tropici wild-type strain CIAT899 formed a more active symbiosis than did its decreased salt-tolerance (DST) mutant derivatives (HB8, HB10, HB12 and HB13). The mutants formed partially effective (HB10, HB12) or almost ineffective (HB8, HB13) nodules (Fix d) under non-saline conditions. The DST mutant formed nodules that accumulated more proline than did the wild-type nodules, while soluble sugars were accumulated mainly in ineffective nodules. Under salt stress, plant growth, nitrogen fixation, and the activities of the antioxidant defense enzymes of nodules were affected in all symbioses tested. Overall, mutant nodules showed lower antioxidant enzyme activities than wild-type nodules. Levels of nodule catalase appeared to correlate with symbiotic nitrogen-fixing efficiency. Superoxide dismutase and dehydroascorbate reductase seem to function in the molecular mechanisms underlying the tolerance of nodules to salinity.