Aplicação de tecnologias genômicas baseadas em marcadores microssatélites para discriminação de cultivares e análise de pureza genética em feijoeiro comum.

A Embrapa Arroz e Feijão está atuando na condução de ações de pesquisa voltadas para o desenvolvimento e implementação de práticas de genotipagem molecular que possibilitem consolidar estratégias mais eficientes de proteção de cultivares e seus derivados. Novos sistemas de genotipagem utilizando análise multiplex e detecção semi-automatizada encontram-se em fase avançada de desenvolvimento, integrando locos microssatélites com elevado conteúdo informativo e poder de discriminação.bitstream/CNPAF/26008/1/comt_132.pd

A microsatellite-based consensus linkage map for species of Eucalyptus and a novel set of 230 microsatellite markers for the genus

BACKGROUND: Eucalypts are the most widely planted hardwood trees in the world occupying globally more than 18 million hectares as an important source of carbon neutral renewable energy and raw material for pulp, paper and solid wood. Quantitative Trait Loci (QTLs) in Eucalyptus have been localized on pedigree-specific RAPD or AFLP maps seriously limiting the value of such QTL mapping efforts for molecular breeding. The availability of a genus-wide genetic map with transferable microsatellite markers has become a must for the effective advancement of genomic undertakings. This report describes the development of a novel set of 230 EMBRA microsatellites, the construction of the first comprehensive microsatellite-based consensus linkage map for Eucalyptus and the consolidation of existing linkage information for other microsatellites and candidate genes mapped in other species of the genus. RESULTS: The consensus map covers ~90% of the recombining genome of Eucalyptus, involves 234 mapped EMBRA loci on 11 linkage groups, an observed length of 1,568 cM and a mean distance between markers of 8.4 cM. A compilation of all microsatellite linkage information published in Eucalyptus allowed us to establish the homology among linkage groups between this consensus map and other maps published for E. globulus. Comparative mapping analyses also resulted in the linkage group assignment of other 41 microsatellites derived from other Eucalyptus species as well as candidate genes and QTLs for wood and flowering traits published in the literature. This report significantly increases the availability of microsatellite markers and mapping information for species of Eucalyptus and corroborates the high conservation of microsatellite flanking sequences and locus ordering between species of the genus. CONCLUSION: This work represents an important step forward for Eucalyptus comparative genomics, opening stimulating perspectives for evolutionary studies and molecular breeding applications. The generalized use of an increasingly larger set of interspecific transferable markers and consensus mapping information, will allow faster and more detailed investigations of QTL synteny among species, validation of expression-QTL across variable genetic backgrounds and positioning of a growing number of candidate genes co-localized with QTLs, to be tested in association mapping experiments

Utilização de marcadores moleculares em programas de ampliação da base genética de espécies cultivadas.

Introdução; Utilização de germoplasma em programas de melhoramento genético; Determinação da variabilidade genética em acessos do banco de germoplasma; Cruzamentos amplos; Marcadores moleculares no melhoramento de plantas; Obtenção de mapas moleculares; Mapeamento de QTLs; Análise de AB-QTLs; Seleção assistida por marcadores; Considerações finais.bitstream/CNPAF/21787/1/doc_155.pd

Construção de mapa genético e análise comparativa entre cruzamentos interespecíficos de Oryza glumaepatula x Oryza sativa utilizando marcadores microssatélites.

Este trabalho objetivou: 1) desenvolver um mapa genético baseado em marcadores SSR para o cruzamento interespecífico Oryza sativa (Cica 8) x Oryza glumaepatula (RS-16); 2) avaliar a conservação da ligação e ordem dos locos SSR entre dois mapas interespecíficos, os quais possuem o parental RS-16 em comum; 3) genotipar 118 famílias na geração RC2F1 obtida a partir do cruzamento interespecífico entre Oryza sativa (Cica 8) e Oryza glumaepatula (RS-16)

Busca por sequências gênicas expressas relacionadas a características de interesse agronômico em arroz.

Este trabalho teve como objetivos: 1) Fazer uma busca por ESTs com funções relacionadas à produção e qualidade de grãos nos diversos bancos de dados de sequências genômicas expressas que contenham informações sobre gramíneas e outras espécies vegetais; 2) Desenhar pares de primers para a amplificação de regiões correspondentes aos genes de interesse identificados nos bancos de dados para posterior construção de um mapa genético transcricional para o arroz

Análise de diversidade genética em acessos de variedades asiáticas de arroz (Oryza sativa L.) do banco ativo de germoplasma da Embrapa Arroz e Feijão.

O objetivo deste trabalho foi o de caracterizar acessos asiáticos de arroz do Banco Ativo de Germoplasma da Embrapa Arroz e Feijão para o aperfeiçoamento da CNAE (Coleção Nuclear de Arroz da Embrapa)

Determination of genetic variability of traditional varieties of Brazilian rice using microsatellite markers.

The rice (Oryza sativa) breeding program of the Rice and Bean research center of the Brazilian agricultural company Empresa Brasileira de Pesquisa Agropecuária (Embrapa) is well established and provides new cultivars every year to attend the demand for improved high yielding varieties with tolerance to biotic and abiotic stresses. However, the elite genitors used to compose new populations for selection are closely related, contributing to the yield plateau reached in the last 20 years. To overcome this limit, it is necessary to broaden the genetic basis of the cultivars using diverse germplasm such as wild relatives or traditional varieties, with the latter being more practical because they are more easily crossed with elite germplasm to accelerate the recovery of modern plant types in the breeding lines. The objective of our study was to characterize the allelic diversity of 192 traditional varieties of Brazilian rice using 12 simple sequence repeat (SSR or microsatellite) markers. The germplasm was divided into 39 groups by common name similarity. A total of 176 alleles were detected, 30 of which (from 23 accessions) were exclusive. The number of alleles per marker ranged from 6 to 22, with an average of 14.6 alleles per locus. We identified 16 accessions as a mixture of pure lines or heterozygous plants. Dendrogram analysis identified six clusters of identical accessions with different common names and just one cluster with identical accessions with the same common name, indicating that SSR markers are fundamental to determining the genetic relationship between landraces. A subset of 24 landraces, representatives of the 13 similarity groups plus the 11 accessions not grouped, was the most variable set of genotypes analyzed. These accessions can be used as genitors to increase the genetic variability available to rice breeding programs

Evaluation of the number and information content of fluorescent-labeled SSR markers for rice germplasm characterization.

The use of fluorescent-labelled simple sequence repeat (SSR) markers allows the simultaneous analysis of diverse loci in multiplex series, providing an enhanced precision of the determination of the allele size when a large number of genotypes is used. Twenty-five fluorescent-labelled SSR markers were used to genotype 242 accessions of the Brazilian Rice Core Collection. Based on the Polymorphism Information Content (PIC) values of each marker, groups with 5, 10, 15 and 20 markers were formed. The average PIC values varied from 0.67 to 0.89 and the number of alleles sampled per group, from 70 to 377. In the case of rice, which has a narrow genetic base, the conclusion was drawn that it is of fundamental importance that the genotypes must be evaluated by the highest possible number of regularly spaced SSR markers in the genome, and that these, preferentially, should offer a high information content

Desenvolvimento e avaliação de marcadores SNPs de genes relacionados a proteínas de reserva de arroz.

O objetivo deste trabalho foi o de identificar associação entre polimorfismos do tipo SNP com o teor de proteína total em acessos de arroz