Caracterização molecular de cultivares de soja por meio de um sistema de genotipagem fluorescente utilizando marcadores microssatélites com cauda estendida universal

• Ano de defesa: 2011
• Autor(a) principal: Ribeiro, Carlos Alexandre Gomes
• Orientador(a): Barros, Everaldo Gonçalves de
• Banca de defesa: Piovesan, Newton Deniz
• 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: Soja - Melhoramento genético; Microssatélites (Genética); Genética vegetal; Polimorfismo (Genética)
• Palavras-chave em Inglês: Soy - Breeding; Microsatellite (genetics); Plant genetics; Polymorphism (Genetics)
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS
• Link de acesso: http://locus.ufv.br/handle/123456789/4803

Identification of soybean cultivars in Brazil is currently based on 30 morphological descriptors. Microsatellite markers are widely used for determination of genetic diversity, paternity tests, varietal purity and genetic mapping. Some variations of the conventional technique for microsatellite genotyping have been developed in order to match the speed and automation of current techniques with quality and low cost. Among them, there is a multiplex genotyping system in semi-automatic DNA sequencers, using universal tail extended primers (UTEP). This study aimed to standardize a robust system of semi-automatic molecular genotyping based on the UTEP methodology for soybean identification, to evaluate differences between this method and the conventional genotyping system using polyacrylamide gel electrophoresis and to characterize 30 soybean cultivars with a set of selected markers, estimating their allelic frequencies. These descriptors can be used as genotypic tool for cultivar identification and provide subsidies for the protection of intellectual property, determination and testing of varietal purity. Thirty commercial soybean cultivars were evaluated with a group of 22 microsatellite markers described in the literature. Genotyping was performed in a semi-automatic sequencer (UTEP) or by polyacrylamide gel electrophoresis (conventional). Among the loci analyzed, 13 were selected because they presented good amplification profiles, with few stutter products, and a large number of alleles. The allelic profile of each cultivar was first defined by the genotyping conventional system, and then by the semi- automated sequencer. For the UTEP genotyping methodology, the total number of alleles found was 50, ranging from 2 (Satt045) to 7 (Satt005). The polymorphic information content (PIC) ranged from 0.40 (Satt045) to 0.74 (Satt005) with an average of 0.62. For the conventional method the number of alleles found was 38 with a range of 2 (Satt045, Satt070 and AF162283) to 5 (Satt005) alleles. The PIC had a range 0.39 (Satt045) to 0.67 (Satt079), with an average of 0.56. The values of probability for random identity differed between the methods being <10-5 (UTEP) and <10-4 (conventional). Despite slight differences, there was a high correlation between genetic dissimilarity matrices obtained by the two methods (0.8026), and the groups formed also showed high similarity among them and they were coherent with the phenotypic data used for varietal registration and with the genealogies of the cultivars. In addition to the high sensitivity for detection of alleles of very close sizes, the UTEP method allowed a more accurate identification of amplification artifacts. The marker selected for both methods allowed the distinction of all cultivars analyzed. The UTEP method has a low cost when compared to common techniques of fluorescence tagging, in addition, its high accuracy makes this an advantageous method for cultivar characterization and determination of genetic purity. The set of markers tested in this work can be used as a set of genotype descriptors complementary to the phenotypic descriptors already used for cultivar protection in distinctness tests.