Molecular characterization of microcystin-producing cyanobacteria from Romanian fresh waters

Abstract

In this study the molecular analysis of 24 potentially toxic cyanobacterial strains of genus Microcystis isolated from Romania is presented. The toxic potential was assessed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), which indicated that five out of the 24 strains are able to produce microcystins. Beside this, the strains were shown to produce various peptides, including aeruginosins, microginins or cyanopeptolins. Identification of potentially toxic Microcystis strains by PCR was performed using primers described in known literature. These primers occasionally generated amplification products in non-microcystin-producing strains. New primers were designed, and the amplification of a mcyD gene fragment exclusively in microcystin-producing strains certified the high specificity of these new primers for microcystin-producing cells. All of the five microcystin-producing strains were shown to possess four characteristic parts of the gene cluster responsible for microcystin synthesis (mcyA, mcyB, mcyD and mcyE). The 16S–23S rDNA ITS sequence was used to confirm the taxonomic identification of the strains and their relationship to strains from outside Romania.