Identification of hepatotoxin-producing cyanobacteria by DNA-chip

We developed a new tool to detect and identify hepatotoxin-producing cyanobacteria of the genera Anabaena, Microcystis, Planktothrix, Nostoc and Nodularia. Genus-specific probe pairs were designed for the detection of the microcystin (mcyE) and nodularin synthetase genes (ndaF) of these five genera to be used with a DNA-chip. The method couples a ligation detection reaction, in which the polymerase chain reaction (PCR)-amplified mcyE/ndaF genes are recognized by the probe pairs, with a hybridization on a universal microarray. All the probe pairs specifically detected the corresponding mcyE/ndaF gene sequences when DNA from the microcystin- or nodularin-producing cyanobacterial strains were used as template in the PCR. Furthermore, the strict specificity of detection enabled identification of the potential hepatotoxin producers. The specificity, sensitivity and ability of the DNA-chip in simultaneously detecting all the main hepatotoxin producers make this method suitable for highthroughput analysis and monitoring of environmental samples.