Quantitative detection of G. catenatum by qPCR based on the rDNA-ITS and sxtA4 genes

Blooms of Gymnodinium catenatum occur annually in southern Tasmania, particularly the Huon Estuary, D'Entrecasteaux Channel and Port Esperance. To detect the presence of G. catenatum in the environment a G. catenatum-specific quantitative PCR assays were established targeting the rDNA-ITS (ITS1-5.8S-ITS2) region and combined with a qPCR targeting the A4 domain of the saxitoxin synthetase gene (sxtA4). The G. catenatum rDNA-ITS primer specificity was tested against related gymnodinoids including G. nolleri and G. microreticulatum and were capable of detecting the presence of the saxitoxin-producing species in the water environment at concentrations below routine light microscopic detection. This assays are being developed as an early warning of the potential PST toxicity in the water environmental.