Rapid on-site monitoring of cylindrospermopsin-producers in reservoirs using quantitative PCR

Recently the cyanobacterium Cylindrospermopsis raciborskii has become a major concern in water quality monitoring and control perspective due to the toxicity of cylindrospermopsin. To minimize the harmful effects of cylindrospermopsin, an effective and efficient on-site monitoring method of C. raciborskii is needed to assess the risk of public health and activities associated with drinking and recreational water. Although bio-molecular detection methods have become popular because of its specificity and speed, only very few studies have focused on the quick monitoring of cylindrospermopsin-producers in reservoirs. In this study, we tested quantitative polymerase chain reaction (qPCR) method coupled with microwave pretreatment for the extraction and quantification of targeted DNA, including rpoC1 for total C. raciborskii and polyketide synthase (pks) for cylindrospermopsin-producer. The method was successfully tested with laboratory cultures and then applied to 10 reservoirs in Taiwan. It was found that the method was able to quantify total C. raciborskii and cylindrospermopsin producers within 2 h after sampling with detection limit at about 1,000 cells mL^-1. Total C. raciborskii (rpoC1) and cylindrospermopsin producer (pks) were detected in 3 and 2 reservoirs, respectively, all in Kinmen Island. Microscopic measurement and cylindrospermopsin concentrations measured in the reservoir samples were in accordance with the detection of total and toxigenic C. raciborskii cells, respectively. This study successfully showed the applicability of the qPCR method for rapid on-site detection of C. raciborskii in reservoirs. In addition, the results also suggest that cylindrospermopsin is an important cyanotoxin in the reservoirs in Kinmen Island.