Premium
Monitoring toxigenic Microcystis strains in the Missisquoi bay, Quebec, by PCR targeting multiple toxic gene loci
Author(s) -
Ngwa Felexce,
Madramootoo Chandra,
Jabaji Suha
Publication year - 2014
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.21770
Subject(s) - microcystis , microcystin , biology , genotype , cyanobacteria , gene , veterinary medicine , genetics , medicine , bacteria
The increasing incidence of mixed assemblages of toxic and nontoxic cyanobacterial blooms in Quebec's freshwater bodies over the last decade, coupled with inherent inadequacies of current monitoring approaches, warrants development of sensitive and reliable tools for assessing the toxigenic potential of these water blooms. In this study, we applied three independent polymerase chain reaction (PCR) assays that simultaneously target the microcystin synthetase ( mcy ) genes A, E, and G to rapidly and reliably detect and quantify potentially toxic Microcystis genotypes in the Missisquoi bay, Quebec, Canada. Linear regressions of quantitative PCR threshold cycles ( C t ) against the logarithm of their respective Microcystis cell number equivalents resulted in highly significant linear curves with coefficients of determination ( R 2 ) greater than 0.99 ( p < 0.0001, n = 6) and reaction efficiencies of 91.0, 95.8, and 92.7%, respectively, for the mcy A, mcy E, and mcy G‐based quantitative real‐time PCR (qPCR) assays. The three assays successfully estimated potential microcystin‐producing Microcystis genotypes from all field samples. The proportions of Microcystis mcy A, mcy E, and mcy G genotypes to total Microcystis cell counts showed substantial spatial variability ranging between 1.7–21.6%, 1.9–11.2%, and 2.2–22.6%, respectively. Correlation of microscopically determined total Microcystis counts to qPCR‐based Microcystis mcy A, mcy E, or mcy G cell number equivalents resulted in highly significant associations with R 2 > 0.90. Thus, PCR‐based assays targeting the mcy A, mcy G, and/or mcy E genes can serve as powerful screening tools for rapid and sensitive estimation of microcystin‐producing Microcystis genotypes in freshwater water bodies. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 440–451, 2014.