Respostas das enzimas antioxidantes em abacaxizeiro após injúria foliar
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Data
2013-02-22
Autores
Nascimento, Vitor de Laia
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Universidade Federal do Espírito Santo
Resumo
The pineapple (Ananas comosus var. comosus) is a tropical fruit of the most produced in the world. The Brazil stands out worldwide in the production of this fruit and the Espirito Santo state are showing potential national productivity.Diseases are limiting factors for the achievement of an optimum productivity in any crop. The pineapple is a plant that can be affected by various diseases caused by fungi, bacteria and viruses, especially in economic importance fusariosis. The hypersensitivity responses are the first events that occur in the cells of plants in response to biotic and abiotic stresses. There synthesis of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl (OH-) and superoxide (O2 -) that can produce oxidative damage in living beings as a form of protection. The plants have a well-developed defense system against ROS comprising a complex array of enzymatic and non-enzymatic antioxidants that protect cells from oxidative damage. The infection process of Fusarium pineapple is dependent on mechanical stress, foliar wound. The literature demonstrates that the cultivar (cv) Vitória, resistant to fusarium wilt has accelerated healing compared to a susceptible cv, Peróla. Increased expression and activity of antioxidant enzymes is correlated with plant defense to pathogens and pests. The objective was to characterize the differential response between two cultivars of pineapple, Vitória and Peróla, to the oxidative stress generated by foliar wound. For it was determined the concentration of total soluble protein of the two cvs, Vitória and Peróla, with and without foliar wound, quantified and compared the activity of superoxide dismutase (SOD - EC 1.15.1.1), ascorbate peroxidase (APX - EC 1.11.1.11) and catalase (CAT - EC 1.11.1.6) after treatment of foliar wound at different times and characterized the profiles of total soluble proteins and isozymes of SOD and CAT in SDS-PAGE at the times in which there is better response. Initially we have no difference of total soluble proteins between cvs and treatments for the times analyzed. It was also demonstrated that the antioxidant enzymes cv Vitória exhibit significant difference in activity compared to the Pérola. Vitória/ s SOD showed a peak response at 15 minutes after injury. APX showed differential response to Vitória at 30 and 45 minutes after foliar wound. Already / Vitória/ CAT peaked differential response at 45 minutes. The analysis on SDS-PAGE with patterns of SOD and CAT, at 15, 30 and 45 minutes after foliar wound showed no difference between the enzymes quantitatively analyzed. Cultivar / Vitória/ presents correlation between the activity of antioxidant enzymes and response to foliar wound. However the activity was not directly related to the enzymes concentration. Since there is no difference in protein expression we suggest that enzymes regulators and cofactors are important in these mechanisms
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Palavras-chave
Enzymology , Oxidative stress , Mechanical stress , Estresse mecânico , Foliar wound , Injúria foliar , Ananas comosus var. comosus
Citação
NASCIMENTO, Vitor de Laia. Respostas das enzimas antioxidantes em abacaxizeiro após injúria foliar. 2013. 60 f. Dissertação (Mestrado em Biologia Vegetal) - Universidade Federal do Espírito Santo, Centro de Ciências Humanas e Naturais, Vitória, 2013.