Porcel Rosa, Barea José Miguel, Ruiz-Lozano Juan Manuel
Departamento de Microbiología del Suelo y Sistemas Simbióticos. Estación Experimental del Zaidín (CSIC), Profesor Albareda n°1, E-18008 Granada, Spain.
New Phytol. 2003 Jan;157(1):135-143. doi: 10.1046/j.1469-8137.2003.00658.x.
• The mechanisms by which the mycorrhizal symbiosis protects soybean ( Glycine max ) plants against premature nodule senescence induced by drought stress is investigated here by evaluating the activity of a set of antioxidant enzymes in relation to nodule senescence. • Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activity was determined in well watered or drought-stressed soybean plants inoculated with Bradyrrhizobium japonicum alone or in combination with Glomus mosseae . • In roots, only GR activity was higher in mycorrhizal than in non-mycorrhizal plants. The other antioxidant activities were similar, or lower (APX), in droughted, mycorrhizal plants than in the corresponding nonmycorrhizal ones. Similarly, in nodules, SOD, CAT and APX activities were lower in droughted, mycorrhizal plants than in nonmycorrhizal plants whereas, again, GR activity was higher in nodules from mycorrhizal plants. • We propose that the consistently higher GR activity in roots and nodules of mycorrhizal plants might have contributed to decreased oxidative damage to biomolecules, which are involved in premature nodule senescence. Additional drought-avoidance mechanisms induced by the AM symbiosis might also contribute to the lower oxidative stress in mycorrhizal plants.
• 本研究通过评估一组抗氧化酶的活性与根瘤衰老的关系，探讨了菌根共生保护大豆（Glycine max）植株免受干旱胁迫诱导的根瘤早衰的机制。
• 在单独接种慢生根瘤菌或与摩西球囊霉联合接种的充分浇水或干旱胁迫的大豆植株中，测定了超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）的活性。
• 在根中，菌根植物的GR活性仅高于非菌根植物。在干旱的菌根植物中，其他抗氧化活性与相应的非菌根植物相似或较低（APX）。同样，在根瘤中，干旱的菌根植物的SOD、CAT和APX活性低于非菌根植物，而菌根植物根瘤中的GR活性再次较高。
• 我们认为，菌根植物根和根瘤中持续较高的GR活性可能有助于减少对参与根瘤早衰的生物分子的氧化损伤。丛枝菌根共生诱导的额外避旱机制也可能有助于降低菌根植物的氧化应激。
