Similaridade gen?tica entre variedades de arroz utilizando RAPD e avalia??o da cin?tica de absor??o e de express?o de transportadores de nitrato

• Ano de defesa: 2010
• Autor(a) principal: Ara?jo, Osm?rio Jos? Lima de
• Orientador(a): Souza, Sonia Regina de
• Banca de defesa: Cabral, Luiz Mors, Mauad, Munir
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Agronomia - Ci?ncia do Solo
• Departamento: Instituto de Agronomia
• País: Brasil
• Palavras-chave em Português: Oryza sativa; Express?o g?nica; Absor??o de nitrato
• Palavras-chave em Inglês: Oryza sativa; Gene expression; Nitrate uptake
• Área do conhecimento CNPq: Agronomia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/jspui/3863

The largest efficiency of N uptake from low concentrations in the solution, and the capacity of accumulation of this nutrient could propitiate a larger stock of N in the vegetative period, which during the grains development would be the responsible for the largest protein in the grains of the traditional rice (Oryza sativa) varieties. Thus, in this study, to identify the metabolic mechanisms responsible for this efficiency 56 traditional rice varieties and 10 improved varieties were compared for their genetic similarities, using the RADP technique. Among the two main groups obtained, the contrasting varieties IAC-47, Bico Ganga and Revenda were selected to represent the Group I, and Manteiga for Group II. It was also considered the crude proteins content of the grains. The varieties were evaluated for the kinetic parameters of absorption of nitrate and kinetics of expression of the genes that codify high affinity nitrate transporters. The genetic similarity resulted in two great groups: Group I and Group II. The group I was shown to be quite heterogeneous as for the origin of the analyzed varieties. All of the improved varieties were contained in the Group I. Most of the varieties named Lageado, originated from the germoplasm bank were in the Group I. The group II contained exclusively varieties form farms in the State of Maranh?o, what suggests a narrow genetic base of the varieties. The rice varieties with thinnest and longest grains (with larger relationship length width ? L/W) were in the Group I, while in the Group II they were more rounded, in other words, with the smallest relationships L/W. The varieties Revenda and Manteiga presented larger expression of high affinity transporters OsNRT2.1 and 2.2, in all times. When compared the kinetics of absorption of nitrate with the expression of the transporters it was observed that the variety IAC-47 presented the smallest Vm?x, and that there was not great increase of the expression of NRT2.1. the variety IAC-47, despite of belonging to the same grouping of genetic similarity of the variety Revenda and both with similar size of grain and length/width ratios, presented only 65% of genetic similarity. Therefore the results showed that the rice variety Revenda has mechanisms that propitiate larger capacity of nitrate absorption when it is available to the plant.