Detecção dos agentes etiológicos da malformação da mangueira por PCR

Abstract

Mango malformation disease in Brazil is caused by Fusarium sp. (a new Fusarium lineage in the Gibberella fujikuroi complex) and Fusarium sterilihyphosum. The conventional diagnosis of this disease is difficult due to limitation in morphological markers to differentiate between these pathogens, which have a long incubation period. Polymerase chain reaction (PCR) primers were designed for the specific detection and identification of the causal agents of mango malformation disease in Brazil, and to identify Fusarium mangiferae. Two primer sets were selected after analysis of a multiple alignment with translation elongation factor 1-α gene sequences from the target species and species in the G. fujikuroi complex. FbraF/FbraR amplifies a specific fragment of 380 bp from de DNA of F. sterilihyphosum and Fusarium sp., while FmanF/FmanR amplifies a fragment of 217 bp from F. mangiferae DNA. Primer specificity was confirmed with fungal species which colonize asymptomatic mango inflorescences. The primers FbraF/FbraR produced a detectable band with 1 fg of target DNA, while FmanF/FmanR produced a detectable band with 100 pg of target DNA. In tests using infected mango tissue the primers FbraF/FbraR were efficient for the detection of the causal agents of mango malformation in Brazil, with the confirmation of the results through the isolation of the pathogens. These primers will greatly facilitate the detection and identification of the causal agents of mango malformation, even before symptom manifestation, avoiding the dissemination of the disease within the Brazilian states and from country to country.