title: Symbiotic association between soybean plants and Bradyrhizobium japonicum develops oxidative stress and heme oxygenase-1 induction at early stages.
abstract: We have previously demonstrated that the induction of heme oxygenase-1 (HO-1) (EC 1.14.99.3) plays a protective role against oxidative stress in leaves and nodules of soybean plants subjected to cadmium, UV-B radiation, and salt stress. Here, we investigated HO-1, localization and their relationship with oxidative stress in different growth stages of soybean plants roots inoculated with Bradyrhizobium japonicum (3, 5, 7, 10, and 20 days post-inoculation) and nodules. After 7 days of inoculation, we observed a 70% increase in thiobarbituric acid-reactive substances that correlates with an enhancement in the gene expression of HO-1, catalase, and superoxide dismutase. Furthermore, the inhibition of HO-1 activity by Zn-protoporphyrin IX produced an increase in lipid peroxidation and a decrease in glutathione content suggesting that, in this symbiotic process, HO-1 may act as a signal molecule that protects the root against oxidative stress. We determined, for the first time, the tissular localization of HO-1 in nodules by electron-microscope examination. These results undoubtedly demonstrated that this enzyme is localized only in the plant tissue and its overexpression may play an important role as antioxidant defense in the plant. Moreover, we demonstrate that, in roots, HO-1 is induced by oxidative stress produced by inoculation of B. japonicum and exerts an antioxidant response against it.
authors: Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
authors: Carla G
authors: CG
authors: Zilli
authors: Diego M
authors: DM
authors: Santa Cruz
authors: Ariel H
authors: AH
authors: Polizio
authors: María L
authors: ML
authors: Tomaro
authors: Karina B
authors: KB
authors: Balestrasse
mesh_terms: D020369:Bradyrhizobium / Q000187:drug effects / Q000201:enzymology*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress; D017319:Photosensitizing Agents / Q000494:pharmacology; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011524:Protoporphyrins / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012492:Salts / Q000494:pharmacology; D013025:Glycine max / Q000187:drug effects / Q000201:enzymology*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013559:Symbiosis; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D017319:Photosensitizing Agents; D011524:Protoporphyrins; D012333:RNA, Messenger; D018749:RNA, Plant; D012492:Salts; D017392:Thiobarbituric Acid Reactive Substances; C028025:protoporphyrin IX; D002374:Catalase; D051547:Heme Oxygenase-1; D013482:Superoxide Dismutase; D005978:Glutathione