Glutathione and Homoglutathione Synthesis in Legume Root Nodules

• Published in: Plant physiology (Bethesda) Vol. 121; no. 3; pp. 879 - 888
• Main Authors: Manuel A. Matamoros, Jose F. Moran, Iturbe-Ormaetxe, Iñaki, Maria C. Rubio, Becana, Manuel
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.11.1999; American Society of Plant Biologists
• Subjects: Age; Agronomy. Soil science and plant productions; Alfalfa; Amino Acid Sequence; Beans; Biological and medical sciences; Chromatography, High Pressure Liquid; DNA, Complementary; Economic plant physiology; Enzymes; Fabaceae - genetics; Fabaceae - metabolism; Fundamental and applied biological sciences. Psychology; Glutathione - analogs & derivatives; Glutathione - biosynthesis; Glutathione Synthase - chemistry; Glutathione Synthase - genetics; Glutathione Synthase - metabolism; Glycine max; Leaves; Legumes; Liquid chromatography; Molecular Sequence Data; Nodules; Parasitism and symbiosis; Peas; Peptide Synthases - chemistry; Peptide Synthases - genetics; Peptide Synthases - metabolism; Phaseolus vulgaris; Plant age; Plant physiology and development; Plant Roots - metabolism; Plant-Microbe and Plant-Insect Interactions; Plants; Plants, Medicinal; Sequence Alignment; Sequence Homology, Amino Acid; Soybeans; Species Specificity; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Thiols; Vigna radiata; Vigna unguiculata; Symbiosis; Glutamate-cysteine ligase; Symbionte; Thiol; Carbon-nitrogen ligases; Enzyme; Tissue specificity; Biosynthesis; Plant nodule; Rhizobium; Concentration; Leguminosae; Ligases; Dicotyledones; Angiospermae; Bacteria; Spermatophyta; Rhizobiaceae; Glutathione
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.121.3.879

High-performance liquid chromatography (HPLC) with fluorescence detection was used to study thiol metabolism in legume nodules. Glutathione (GSH) was the major non-protein thiol in all indeterminate nodules examined, as well as in the determinate nodules of cowpea (Vigna unguiculata), whereas homoglutathione (hGSH) predominated in soybean (Glycine max), bean (Phaseolus vulgaris), and mungbean (Vigna radiata) nodules. All nodules had greater thiol concentrations than the leaves and roots of the same plants because of active thiol synthesis in nodule tissue. The correlation between thiol tripeptides and the activities of glutathione synthetase (GSHS) and homoglutathione synthetase (hGSHS) in the nodules of eight legumes, and the contrasting thiol contents and activities in alfalfa (Medicago sativa) leaves (98% hGSH, 100% hGSHS) and nodules (72% GSH, 80% GSHS) indicated that the distribution of GSH and hGSH is determined by specific synthetases. Thiol contents and synthesis decreased with both natural and induced nodule senescence, and were also reduced in the senescent zone of indeterminate nodules. Thiols and GSHS were especially abundant in the meristematic and infected zones of pea (Pisum sativum) nodules. Thiols and γ-glutamylcysteinyl synthetase were also more abundant in the infected zone of bean nodules, but hGSHS was predominant in the cortex. Isolation of full-length cDNA sequences coding for γ-glutamylcysteinyl synthetase from legume nodules revealed that they are highly homologous to those from other higher plants.