Perfil protéico e uso de marcadores moleculares relacionados à qualidade de panificação em trigo

• Ano de defesa: 2010
• Autor(a) principal: Dias, Renata de Oliveira
• Orientador(a): Souza, Moacil Alves de
• Banca de defesa: Motoike, Sérgio Yoshimitsu , Barbosa, Marcio Henrique Pereira , Machado, Juarez Campolina
• 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: Triticum aestivum L.; Gluteninas; Gliadinas; Marcadores moleculares; SDS-PAGE; SE-HPLC; Teste de panificação
• Palavras-chave em Inglês: Triticum aestivum L.; Glutenins; Gliadins; Molecular markers; SDS-PAGE; SE-HPLC; Baking tests
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL
• Link de acesso: http://locus.ufv.br/handle/123456789/4723

Wheat is one of the principal cereals in the world and is processed into a wide range of products. In recent decades researchers have shown concern over acquisition of cultivars with good baking quality, a characteristic which initially refers to the protein composition of the endosperm, composed principally of the proteins making up gluten. Various methodologies have been employed in the evaluation of this characteristic, including SDS-PAGE (polyacrylamide gel electrophoresis), SE-HPLC (size exclusion high performance liquid chromatography), baking tests and employment of genetic markers. In an attempt to compare the different existing methodologies and propose a strategy for wheat genetic improvement programs based on industrial quality, four different techniques were tests with 45 national cultivars. Six allele-specific markers were used for verification of the presence of the HMW subunits: Glu-D1-1d (5+10) and Glu-B1-2a (7+8), one LMW subunit: Glu-A3d, the presence or absence of 1B/1R translocation: by the presence of Glu-B1 (long arm of the wheat chromosome) or ω- secalin (gene of the short arm of rye) and puroindoline (Pinb-D1b). Also employed where SDS-PAGE, SE-HPLC and baking test methods. As a result of applying the markers, the presence in the genotypes observed was: 71% for subunit Glu-D1-1d (5+10), 16% for Glu-B1-2a (7+8), 60% for Glu-B1 (absence of translocation) and 8% for Pinb-D1b and Glu-A3d. The results of SDS-PAGE suggested a prevalence of the subunits 2* and 1 in chromosome 1A; 7+8, 7+9 and 17+18 in 1B; and 5+10 in 1D. The average values of SE-HPLC were 35.99% and 44.99% for the polymeric protein in protein (PPP) and unextractable polymeric protein (UPP), respectively, and 1.29 for the ratio between gliadins and glutenins (GLI/GLU), with significant variation among the genotypes (p≤0.05). The baking test also showed a significant difference (p≤0.05) between the cultivars under the same conditions. The UPP data were independent of the PPP percentage data, signifying that a portion of the unextractable polymeric protein (UPP) does not depend on the greater percentage of total polymeric proteins. However there was a positive correlation between the score of HMW subunits, evaluated by SDSPAGE, and the UPP values; this indicates that scoring has apparently been efficient in classifying the genotypes of greatest quality. The cultivars without translocation with rye also showed better results for UPP, PPP and GLI/GLU in relation to those possessing translocation. The GLI/LGU ratio is correlated with the specific volume of the bread, but apparently does not guarantee quality of the qualitative characteristics, which may indicate the action of gliadins in extensibility, but with a lack of structure in the gluten network. These results corroborate for the selection of HMW subunits 5+10, cultivars without translocation with rye, with high values of UPP and an appropriate GLI/GLU ratio with the objective of obtaining greater wheat baking quality.