Development of a novel TaqMan qPCR assay for rapid detection and quantification of Gymnodinium catenatum for application to harmful algal bloom monitoring in coastal areas of Tunisia

Gymnodinium catenatum is a dinoflagellate known to cause paralytic shellfish poisoning (PSP), commonly associated with human muscular paralysis, neurological symptoms, and, in extreme cases, death. In the present work, we developed a real-time PCR-based assay for the rapid detection of the toxic microalgal species, G. catenatum, in environmental bivalve mollusc samples as well as seawater samples. G. catenatum-specific primers and probe were designed on the ITS1-5.8S-ITS2 rDNA region. Hydrolysis probe qPCR assay was optimized. ITS1-5.8S-ITS2 rDNA region copy numbers per G. catenatum cell genome were estimated to be 122.73 +/- 5.54 copies/cell, allowing cell quantification. The application of the optimized qPCR assay for G. catenatum detection and quantification in field samples has been conducted, revealing high sensitivity (detection of around 1.310(5) cells/L of seawater samples. Thus, the designed hydrolysis probe qPCR assay could be considered an efficient tool for phytoplankton monitoring whilst ensuring accuracy and sensitivity and providing cost and time savings.

Automated summary

In this study, a real-time PCR-based assay was developed for rapid detection of toxic microalgal species G. catenatum in environmental samples. The optimized qPCR assay showed high sensitivity and accuracy in detecting and quantifying G. catenatum in bivalve mollusc and seawater samples, offering time and cost savings.