Genetic structure of Fusarium verticillioides populations and occurrence of fumonisins in maize grown in Southern Brazil

The fumonisins are a group of mycotoxins produced primarily by Fusarium spp. There are several different forms of fumonisins, among them fumonisins B1 and B2 are the most common and economically important forms in maize. The aim of this study was to investigate the presence of fumonisins and Fusarium spp. in kernels of four maize genotypes grown in two Southern Brazilian locations. Fumonisins B1 and B2 were detected in all samples, with levels ranging from 0.4 to 9.1 μg × g−1. Of the 3840 maize kernels examined, 77.0% were infected with Fusarium spp., and F. verticillioides was the most prevalent species (98.1%). In addition, we found that approximately 95% of the isolates of F. verticillioides harbor essential genes for fumonisin biosynthesis (FUM1 and FUM8). Next, we investigated the genetic structure of F. verticillioides populations based on molecular data generated by the AFLP technique, which revealed a high genetic variability. Statistical analyses have shown that a significant part of the genetic differentiation was associated with the maize growing location.