Atividade enzimática e expressão diferencial da Superóxido Dismutase (SOD) em plantas de arroz de terras altas sob deficiência hídrica
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2014-06-30
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Universidade Federal de Goiás
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Drought is a major cause for reduced productivity in the cultivation of upland rice farming in many regions of the world. One of the consequences of the drought is the production in excess of reactive oxygen species (ROS), causing a series of oxidative damage to various biomolecules with subsequent cell death. With the function of protecting structures and functioning of cells from the damaging effects of ROS, a complex antioxidant system is activated in plants. This system consists of: (1) lipid soluble membrane-associated and tocopherols; (2) reducing water soluble compounds such as ascorbate (ASA) and glutathione (GSH) and (3) antioxidative enzymes, and superoxide dismutase (SOD) considered as a major enzymes of the antioxidant defense system. The present study aimed to evaluate the SOD in activity level via spectrophotometric method and level of gene expression via qPCR in two genotypes of upland rice (Oryza sativa japonica), Douradão and BRS Primavera, with contrasting for drought tolerance characteristics, watching the leaf and root tissue, two stages of plant development (vegetative and reproductive), grown under optimal water conditions and water deficit (100% and 50% water in the vessels), respectively. The results revealed a differential pattern of SOD activity in different tissues and developmental stages in tolerant and sensitive genotypes, and for the tolerant genotype that activity was increased only in leaf / root and vegetative/reproductive tissue, as was sensitive the leaf / reproductive and reproductive/ root. Regarding gene expression, we also observed a very different pattern of regulation in tolerant and sensitive genotypes. The CuZnSOD1, CuZnSOD4, and MnSOD genes, expression was significantly (p≤ 0.05) increased in the tolerant, the first in leaves and roots off the reproductive stage, the second vegetative stage only in leaves and the third gene in the two tissues and plant developmental stages. As for the sensitive only FeSOD1 gene had highlighted with increased expression in roots at the reproductive stage. Certainly, the different patterns of induction level of activity and / or gene expression of SOD in plants of upland rice, should be strongly considered to elucidate the cellular mechanisms of drought tolerance, aiming to support improvement programs to develop cultivars more efficient and better suited to prone areas with water deficiency.
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DEUS, K. E. Atividade enzimática e expressão diferencial da Superóxido Dismutase (SOD) em plantas de arroz de terras altas sob deficiência hídrica. 2014. 132 f. Dissertação (Mestrado em Biologia) - Universidade Federal de Goiás, Goiânia, 2014.