GENETIC POTENTIAL FOR TOXICITY: BLOOMS OF CYANOBACTERIA IN THE ITAIPU RESERVOIR, BRAZIL

Cyanobacteria are algae of great importance to environmental and public health because they produce toxins, such as microcystins. The same species of cyanobacteria may show microcystin- producing and non-microcystin-producing genotypes, which are impossible to differentiate based on morphological characteristics. The presence of the mcyA gene has been used as an indirect diagnosis for the identification of microcystin-producing cyanobacteria. The aim of this work was to evaluate if the blooms of cyanobacteria in the Itaipu reservoir present a microcystin-producing genotype. To that end, the phycocyanin intergenic spacer (PC-IGS) and partial mcyA gene were amplified and sequenced. The presence of these genes was observed in all the samples, indicating the toxicological potential of the blooms of cyanobacteria in the Itaipu reservoir. The phylogenetic analyses of sequences from cyanobacteria blooms isolated from the Itaipu reservoir and sequences available in GenBank demonstrated the genetic similarity between samples from Itaipu and species from the Microcystis genus.