The quantitative real-time PCR applications in the monitoring of marine harmful algal bloom (HAB) species

Abstract

In the last decade, various molecular methods (e.g., fluorescent hybridization assay, sandwich hybridization assay, automatized biosensor detection, real-time PCR assay) have been developed and implemented for accurate and specific identification and estimation of marine toxic microalgal species. This review focuses on the recent quantitative real-time PCR (qrt-PCR) technology developed for the control and monitoring of the most important taxonomic phytoplankton groups producing biotoxins with relevant negative impact on human health, the marine environment, and related economic activities. The high specificity and sensitivity of the qrt-PCR methods determined by the adequate choice of the genomic target gene, nucleic acid purification protocol, quantification through the standard curve, and type of chemical detection method make them highly efficient and therefore applicable to harmful algal bloom phenomena. Recent development of qrt-PCR-based assays using the target gene of toxins, such as saxitoxin compounds, has allowed more precise quantification of toxigenic species (i.e., Alexandrium catenella) abundance. These studies focus only on toxin-producing species in the marine environment. Therefore, qrt-PCR technology seems to offer the advantages of understanding the ecology of harmful algal bloom species and facilitating the management of their outbreaks.

Fig. 1

Examples of amplification plots generated from dilutions of a target sequence (LSU rDNA from Ostreopsis cf. ovata) cloned into a plasmid (a) and from O. cf. ovata cell dilutions (b). The corresponding standard curves (c, d) were obtained by the correlation of C _t values and log₁₀ input plasmid copies or environmental cell number, respectively. Adapted from Perini et al. (2011)