Development of a Real-Time Quantitative PCR Assay for the Assessment of Uncultured Zoosporic Fungi

Recently, molecular environmental surveys of the eukaryotic microbial community in lakes have revealed a high diversity of sequences belonging to uncultured zoosporic fungi. Although they are known as saprobes and algal parasites in freshwater systems, zoosporic fungi have been neglected in microbial food web studies. Recently, it has been suggested that zoosporic fungi, via the consumption of their zoospores by zooplankters, could transfer energy from large inedible algae and particulate organic material to higher trophic levels. However, because of their small size and their lack of distinctive morphological features, traditional microscopy does not allow the detection of fungal zoospores in the field. Hence, quantitative data on fungal zoospores in natural environments are missing. We provide a simplified step-by-step real-time quantitative PCR laboratory protocol, for the assessment of uncultured zoosporic fungi and other zoosporic microbial eukaryotes in natural samples.