Comparing activated sludge fungal community population diversity using denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism

We compared the relative values of denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) for profiling fungal communities in wastewater treatment plants using both ITS and 18S rRNA gene fragments as phylogenetic markers. A similar number of fungal ribotypes was obtained with both methods for the same treatment plant when the ITS primer set was used, while a greater number of ribotypes was obtained with T-RFLP compared to DGGE with the 18S rRNA primer set. Non-metric multi-dimensional scaling of presence/absence data and analysis of similarity showed that both methods could distinguish between the different plant communities at a statistically significant level (p < 0.05), regardless of which phylogenetic marker was used. The data suggest that both methods can be used preferably together to profile activated sludge fungal communities. A comparison of profiles generated with both these phylogenetic markers based on the number of ribotypes/bands, suggests that the 18S rRNA region is more discriminatory than the ITS region. Detected differences in fungal community compositions between plants probably reflect differences in their influent compositions and operational parameters.