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Correlations between the ascorbate‐glutathione pathway and effectiveness in legume root nodules
Author(s) -
Dalton David A.,
Langeberg Lorene,
Treneman Nancy C.
Publication year - 1993
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1993.tb01743.x
Subject(s) - root nodule , legume , glutathione reductase , biochemistry , glutathione , reductase , chemistry , antioxidant , tripeptide , peroxidase , nad+ kinase , nitrogen fixation , enzyme , biology , glutathione peroxidase , botany , amino acid , nitrogen , organic chemistry
Legume root nodules use the ascorbate‐glutathione pathway to remove harmful H 2 O 2 . In the present study. effective and ineffective nodules from soybean and alfalfa were compared with regard to this pathway. Effective nodules had higher activity of all 4 enzymes (ascorbate peroxidase, EC 1. 11. 1. 11: monodehydroascorbate reductase, EC 1. 6. 5. 4: dehydroascorbate reductase, EC 1. 8. 5. 1: and glutathione reductase, EC 1. 6. 4. 2). The concentration of thiol tripeptides (primarily homoglutathione) was about 1 m M in effective nodules – a level 3–4‐fold higher than in ineffective nodules. Effective nodules contained higher levels of NAD + . NADP + and NADPH. but not of NADH or ascorbate. The increased capacity for peroxide scavenging in effective nodules as compared to ineffective nodules emphasizes the important protective role that this pathway may play in processes related to nitrogen fixation.