title: Catalase plays a key role in salt stress acclimation induced by hydrogen peroxide pretreatment in maize.
abstract: Pretreatment in plants is recognized as a valuable strategy to stimulate plant defenses, leading to better plant development. This study evaluated the effects of H₂O₂ leaf spraying pretreatment on plant growth and investigated the antioxidative mechanisms involved in the response of maize plants to salt stress. It was found that salinity reduced maize seedling growth when compared to control conditions, and H₂O₂ foliar spraying was effective in minimizing this effect. Analysis of the antioxidative enzymes catalase (EC 1.11.1.6), guaiacol peroxidase (EC 1.11.1.7), ascorbate peroxidase (EC 1.11.1.1) and superoxide dismutase (EC 1.15.1.1) revealed that H₂O₂ spraying increased antioxidant enzyme activities. Catalase (CAT) was the most responsive of these enzymes to H₂O₂, with higher activity early (48 h) in the treatment, while guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) were responsive only at later stages (240 h) of treatment. Increased CAT activity appears linked to gene expression regulation. Lower malondialdehyde levels were detected in plants with higher CAT activity, which may result from the protective function of this enzyme. Overall, we can conclude that pretreatment with H₂O₂ leaf spraying was able to reduce the deleterious effects of salinity on seedling growth and lipid peroxidation. These responses could be attributed to the ability of H₂O₂ to induce antioxidant defenses, especially CAT activity.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular and Instituto Nacional de Ciência e Tecnologia em Salinidade-INCTSal/CNPq, Universidade Federal do Ceará, Caixa Postal 6039, 60440-970 Fortaleza, Ceará, Brazil.
authors.forename: Franklin Aragão
authors.initials: FA
authors.lastname: Gondim
authors.forename: Enéas
authors.initials: E
authors.lastname: Gomes-Filho
authors.forename: José Hélio
authors.initials: JH
authors.lastname: Costa
authors.forename: Nara Lídia
authors.initials: NL
authors.lastname: Mendes Alencar
authors.forename: José Tarquinio
authors.initials: JT
authors.lastname: Prisco
mesh_terms: D000064:Acclimatization / Q000187:drug effects; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008315:Malondialdehyde / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D018515:Plant Leaves; D010940:Plant Proteins / Q000378:metabolism; D055049:Salt Tolerance / Q000187:drug effects*; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D012965:Sodium Chloride / Q000009:adverse effects*; D013312:Stress, Physiological / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000502:physiology
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D012965:Sodium Chloride; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase