The role of 2-oxoglutarate dehydrogenase during water deficit and recovery in Arabidopsis thaliana

• Ano de defesa: 2018
• Autor(a) principal: Vargas, Jonas Rafael
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Arabidopsis thaliana; Metabolismo; Balanço hidrológico; Krebs, Ciclo de; Prolina; Genes; Proteínas; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/28278

To deal with periods of water limitation, plants use different mechanisms. Among them, stomatal closure and proline accumulation are the major ones during stress exposure. After stress, proline is degraded releasing glutamate in the mitochondrial matrix. The glutamate is metabolized by different metabolic pathways and may: (i) participate in nitrogen metabolism, being used for ammonia assimilation under the action of enzymes like Glutamine synthetase (GS) and Glutamine 2-oxoglutarate aminotransferase (GOGAT), (ii) being reintroduced in the tricarboxylic acid cycle (TCA cycle) as succinate via GABA shunt activity or (iii) enter the TCA cycle as 2-oxoglutarate (2-OG) when undergoing the action of the enzyme glutamate dehydrogenase. 2-OG is converted into succinyl-CoA by the action of the enzyme 2-oxoglutarate dehydrogenase (2-OGDH). In order to understand the importance of 2-OGDH during water deficit and stress release, two T-DNA insertion lines with low expression of the E1 subunit of 2-OGDH encoding gene, e1-ogdh1.1 and 1.2 were submitted to drought conditions for 22 days and then, after rewatering, three days of recovery period. This work revealed that the TCA cycle goes through downregulation in such a way that allows plants to cope with water deficit and that following recovery period its activity is reestablished. Furthermore, it was observed that the reduction in the activity of 2-OGDH did not demonstrate great impact in the metabolism during the implementation and recovery of water deficit. Keywords: abiotic stress; metabolism; proline; TCA cycle; 2-OGDH.