Identificaçăo e validaçăo de marcadores moleculares associados a variaçőes no teor de amilose e temperatura de gelatinizaçăo em grăos de arroz (Oryza sativa L.)
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2009-06-22
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Universidade Federal de Goiás
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The synthesis of starch involves the interaction a complex cascade of genes. Alterations in these genes can change the final composition of starch and alter the quality of the rice grain after cooking. The quality of grain is influenced by the physico-chemical properties of starch. Through the associative mapping is possible to identify genes related to a quantitative trait and, therefore, using molecular markers of this gene as tools for assisted selection in breeding programs using access genebanks.This work had as objective identify and validate the association between amylose content (TA) and gelatinization temperature (TG) with molecular markers microsatellites and SNP of genes involved in starch metabolic route.Were used 242 accessions of rice core collection of Embrapa Arroz e Feijão, separated according to cropping system upland and lowland.The accessions were also classified for TA, based on the analysis conducted in 2004 and 2005, and TG analysis in 2007. The genetic analyzes were conducted using 36 molecular markers, 7 are those described in the literature, three microsatellite (SSR), 1 Sequence Tagged Sites (STS), 2 cleaved amplified polymorphic Sequence (CAPS) and the set of pairs of F7-F22-R1-R21 primers. The other markers were developed for this work in the Biotechnology laboratory of the Embrapa Arroz e Feijão, 6 markers are based on SSR and 26 SNP.For SSR markers were identified 70 alleles, with an average of 8.75 alleles per locus. The genetic diversity (He) was higher for access to lowland (0.72) compared to accesses with upland, that had a mean of 0.55. Found SNP/Indel 10 markers when the mini core collection was sequenced. The nucleotide diversity was low, with an average of 0.0054. CA-2 marker gene which expresses the enzyme glucose-6-phosphate isomerase, showed the greatest number of polymorphisms, with 9 SNP/Indel. Based on the genetic similarity dendrogram constructed with data from the SSR loci,was found genetic difference in the cropping system and the TA. Nine markers were significantly associated (p <0.05) with one of the characteristics. These six markers were associated with TA. The marker W2R, the waxy gene, was the one that best explained the variation of TA (82%). Eight markers were associated with TG. The F7-F22-R1-R21 together best explained the variation (66%).The factorial correspondence analysis has shown that the set of SSR loci literature together coms developed for this work are efficient in allocating access between TA classes. This work allowed the identification of not random associations between loci and starch characteristics of economic interest. Validating markers described in the literature and new markers, opening new prospects for the use of these markers in the early selection for TA and TG in rice.
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OLIVEIRA, L. K. Identificaçăo e validaçăo de marcadores moleculares associados a variaçőes no teor de amilose e temperatura de gelatinizaçăo em grăos de arroz (Oryza sativa L.). 2009. 98 f. Dissertação (Mestrado em Biologia) - Universidade Federal de Goiás, Goiânia, 2009.