661 resultados para blast
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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2016
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Blast is a major disease of rice in Brazil, the largest rice-producing country outside Asia. This study aimed to assess the genetic structure and mating-type frequency in a contemporary Pyricularia oryzae population, which caused widespread epidemics during the 2012/13 season in the Brazilian lowland subtropical region. Symptomatic leaves and panicles were sampled at flooded rice fields in the states of Rio Grande do Sul (RS, 34 fields) and Santa Catarina (SC, 21 fields). The polymorphism at ten simple sequence repeats (SSR or microsatellite) loci and the presence of MAT1-1 or MAT1-2 idiomorphs were assessed in a population comprised of 187 isolates. Only the MAT1-2 idiomorph was found and 162 genotypes were identified by the SSR analysis. A discriminant analysis of principal components (DAPC) of SSR data resolved four genetic groups, which were strongly associated with the cultivar of origin of the isolates. There was high level of genotypic diversity and moderate level of gene diversity regardless whether isolates were grouped in subpopulations based on geographic region, cultivar host or cultivar within region. While regional subpopulations were weakly differentiated, high genetic differentiation was found among subpopulations comprised of isolates from different cultivars. The data suggest that the rice blast pathogen population in southern Brazil is comprised of clonal lineages that are adapting to specific cultivar hosts. Farmers should avoid the use of susceptible cultivars over large areas and breeders should focus at enlarging the genetic basis of new cultivars.
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O feijão-de-metro é uma hortaliça amplamente cultivada nos municípios da região metropolitana de Belém. Diversas doenças podem comprometer a sua produtividade, dentre elas as viroses. Recentemente, foi detectado o Cucumber mosaic virus (CMV) em vagens de feijão-de-metro provenientes do município de Castanhal-PA. Este trabalho teve como objetivo identificar o subgrupo do CMV detectado em vagens de feijão-de-metro, por meio de RT-PCR, sequenciamento do ácido nucléico e análise utilizando o programa Blast, ClustalW e MEGA 7.0. Para isso, foi feita a extração de ácidos nucleicos total a partir de folhas de fumo inoculado com o isolado. Posteriormente, foi realizado o RT-PCR utilizando os primers específicos (CMV-CPR e CMV-CPF). A partir da análise da filogenia foi observado que o isolado formou um clado com os acessos do subgrupo IB de CMV.