Pesquisa Agropecuária Brasileira

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/9886

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Resultados da Pesquisa

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    Study of simple sequence repeat markers from coffee expressed sequences associated to leaf miner resistance
    (Empresa Brasileira de Pesquisa Agropecuária - Embrapa, 2007-03) Pinto, Fernanda de Oliveira; Maluf, Mirian Perez; Guerreiro-Filho, Oliveiro
    The objective of this work was to identify expressed simple sequence repeats (SSR) markers associated to leaf miner resistance in coffee progenies. Identification of SSR markers was accomplished by directed searches on the Brazilian Coffee Expressed Sequence Tags (EST) database. Sequence analysis of 32 selected SSR loci showed that 65% repeats are of tetra-, 21% of tri- and 14% of dinucleotides. Also, expressed SSR are localized frequently in the 5’–UTR of gene transcript. Moreover, most of the genes containing SSR are associated with defense mechanisms. Polymorphisms were analyzed in progenies segregating for resistance to the leaf miner and corresponding to advanced generations of a Coffea arabica x Coffea racemosa hybrid. Frequency of SSR alleles was 2.1 per locus. However, no polymorphism associated with leaf miner resistance was identified. These results suggest that marker-assisted selection in coffee breeding should be performed on the initial cross, in which genetic variability is still significant.
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    Gene expression profile during coffee fruit development and identification of candidate markers for phenological stages
    (Empresa Brasileira de Pesquisa Agropecuária - Embrapa, 2012-07) Gaspari‐Pezzopane, Cristiana de; Bonturi, Nemailla; Guerreiro Filho, Oliveiro; Favarin, José Laércio; Maluf, Mirian Perez
    The objective of this work was to identify genes that could be used as suitable markers for molecular recognition of phenological stages during coffee (Coffea arabica) fruit development. Four cultivars were evaluated as to their differential expression of genes associated to fruit development and maturation processes. Gene expression was characterized by both semi‐quantitative and quantitative RT‐PCR, in fruit harvested at seven different developmental stages, during three different seasons. No size polymorphisms or differential expression were observed among the cultivars for the evaluated genes; however, distinct expression profiles along fruit development were determined for each gene. Four out of the 28 evaluated genes exhibited a regular expression profile in all cultivars and harvest seasons, and, therefore, they were validated as candidate phenological markers of coffee fruit. The gene α‐galactosidase can be used as a marker of green stage, caffeine synthase as a marker of transition to green and yellowish‐green stages, and isocitrate lyase and ethylene receptor 3 as markers of late maturation.