Salt and oxidative stress: similar and specific responses and their relation to salt tolerance in Citrus

• Published in: Planta 1997-12, Vol.203 (4), p.460-469
• Main Authors: Gueta-Dahan, Y, Yaniv, Z, Zilinskas, B.A, Ben-Hayyim, G
• Format: Article
• Language: English
• Subjects: ABA; Abscisic Acid - pharmacology; Absorption. Translocation of ions and substances. Permeability; ACIDE GRAS; ACIDOS GRASOS; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; ANTIOXIDANTES; ANTIOXIDANTS; ANTIOXYDANT; Ascorbate Peroxidases; ASCORBATPEROXIDASE; Biological and medical sciences; CAL; CALLO; CALLUS; Cell Line; CELLS; CELLULE; CELULAS; CITRUS; Citrus - drug effects; Citrus - metabolism; Culture Media - pharmacology; Cultured cells; Economic plant physiology; ENZIMAS; ENZYME; ENZYMES; ENZYMIC ACTIVITY; ESTRES; FATTY ACIDS; Fundamental and applied biological sciences. Psychology; GLUTATHION PEROXYDASE; GLUTATHIONE PEROXIDASE; Glutathione Peroxidase - metabolism; GLUTATHIONREDUKTASE; GLUTATION PEROXIDASA; Hydrogen Peroxide - metabolism; LIPIDE; LIPIDOS; LIPIDS; MODELE; MODELOS; Nutrition. Photosynthesis. Respiration. Metabolism; Oxidative Stress; OXIDATIVER STRESS; Paraquat - pharmacology; Peas; PEROXIDASAS; PEROXIDASES; Peroxidases - drug effects; Peroxidases - metabolism; PEROXYDASE; Plant physiology and development; Plants; Protein isoforms; PROTEINAS; PROTEINE; PROTEINS; SALT TOLERANCE; SALZSTRESS; Sodium Chloride - pharmacology; STRESS; SUPEROXIDE DISMUTASE; Superoxide Dismutase - drug effects; Superoxide Dismutase - metabolism; Superoxides; SUPEROXIDO DISMUTASA; SUPEROXYDE DISMUTASE; Table salt; TOLERANCE AU SEL; TOLERANCIA A LA SAL; TOXICIDAD; TOXICITE; TOXICITY; Water and solutes. Absorption, translocation and permeability
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250050215

Salt damage to plants has been attributed to a combination of several factors including mainly osmotic stress and the accumulation of toxic ions. Recent findings in our laboratory showed that phospholipid hydroperoxide glutathione peroxidase (PHGPX), an enzyme active in the cellular antioxidant system, was induced by salt in citrus cells and mainly in roots of plants. Following this observation we studied the two most important enzymes active in elimination of reactive oxygen species, namely, superoxide dismutase (SOD) and ascorbate peroxidase (APX), to determine whether a general oxidative stress is induced by salt. While Cu/Zn-SOD activity and cytosolic APX protein level were similarly induced by salt and methyl viologen, the response of PHGPX and other APX isozymes was either specific to salt or methyl viologen, respectively. Unlike PHGPX, cytosolic APX and Cu/Zn-SOD were not induced by exogenously added abscisic acid. Salt induced a significant increase in SOD activity which was not matched by the subsequent enzyme APX. We suggest that the excess of H2O2 interacts with lipids to form hydroperoxides which in turn induce and are removed by PHGPX. Ascorbate peroxidase seems to be a key enzyme in determining salt tolerance in citrus as its constitutive activity in salt-sensitive callus is far below the activity observed in salt-tolerant callus, while the activities of other enzymes involved in the defence against oxidative stress, namely SOD, glutathione reductase and PHGPX, are essentially similar.