Detecção de espécies de Fusarium potencialmente produtoras de Micotoxinas em grãos de milho no Nordeste do Brasil

Abstract

Brazil is the thrid worldwide producer of corn kernel (Zea mays L.), only behind of the United States of América and China. The causal agents of ears and stalk rot are fungi like Stenocarpella maydis, Fusarium spp and Penicillium oxalicum, worth mentioning to the Fusarium species, specially the complex Giberrela fugikuori species. These species, usually related to ear and stalk rot are: Fusarium verticillioides (Gibberella moniliformis), Fusarium proliferatum (G. intermédia) and F. subglutinans (G. subglutinans). Other species like F. thapsinum (G. thapsina), were found in corn crop, however this specie causes high loses in sorghum crops. Recently, was described a new specie of the complex G. fugikuri, associated to corn kernels, called F. theparatum. These species are widely distributed all the world, being F. verticillioides the most frequently associated to corn crop and other grasses. To identify the Fusarium are necessaries three species concepts: morphological specie, based on similarity of morphological characters nominated morphological markers; the concept of biological specie, based on sexual compatibility between the member of the same specie; and the concept of phylogenetic specie based on genic sequences analisys. Fungi of the Fusarium gender are potential producers of many mycotoxins, being the most important the tricothecenos (vomitoxin), fumonisins, zearalenona, moniliformin and fusaric acid. These metabolites are substances that cause pulmonary edema in pigs, leukoencephalomalacia in horses and, in humans in South Africa, it was observed high incidence of esophagus cancer. When was analyzed the corn products that this population was feeding, it was found high concentrations of mycotoxis. Fusarium verticillioides species have systemic movement in seeds, roots and stalks, and can be transmitted for long distances by seeds.