Caracterização fisiológica e expressão de genes relacionados à resistência ao déficit hídrico em soja

• Ano de defesa: 2009
• Autor(a) principal: Gomes, Wellington Silva
• Orientador(a): Oliveira, Aluízio Borém de
• Banca de defesa: Campos, André Narvaes da Rocha , Carneiro, José Eustáquio de Souza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Estresse hídrico; Soja; Estresse oxidativo; Expressão gênica; SnRKs
• Palavras-chave em Inglês: Water stress; Oxidative stress; Gene expression; SnRKs
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4705

Drought tolerance in plants is a complex trait, the result of a set of mechanisms that work to prevent or tolerate periods of drought. Water stress is one of the most important environmental factors that induce physiological changes, such as reduced water potential in the cell, stomatal closure and the development of oxidative processes by the formation of reactive oxygen species (EROs). The antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POX) are efficient suppressors of ROS. Two soybean cultivars (BR-16 and Embrapa 48), with contrasting responses to water stress were studied using the technique of Real-Time PCR to identify genes that may exhibit differences in expression during periods of drought. Physiological characterization of the genotypes showed significant differences between them. There was considerable increase in lipid peroxidation in the sensitiven genotype, while in the tolerant, the amount of MDA (formed malonic aldehyde) was significantly equal to control irrigation. The increased activity of antioxidant enzymes, SOD and POX, was significant only in the susceptible genotype, on the potentials of -1.5 MPa for a first and -3.0 MPa for the second. The genotype BR-16, when subjected to water stress, showed increased gene expression for genes OST1, SnRK2.2 and SnRK2.3. In contrast, the genotype Embrapa 48 showed no change in expression levels for any of the four genes tested. The tolerance of the genotype Embrapa 48 is not related to gene expression, nor with the increased activity of antioxidant enzymes, analyzed here. This indicates the need to better understand the biochemical processes, physiological and molecular processes involved in tolerance of this genotype to water deficit. The study of expression of these genes and identification of genes responsible for increased tolerance in the genotype Embrapa 48 may be used in breeding programs aimed at obtaining plants tolerant to drought.