conclusions
The herein presented protocols for PCR and sample pre-processing exhibit a number of features that make them useful diagnostic tools. They are sensitive, quick, cost-effective and can function with a variety of samples that may be difficult to identify morphologically. For future studies it will be important to continue evaluating the specificity of the APHA1 assay by testing additional taxa (and different isolates of each species) – especially some of the non-European deadly Amanitas (see Table 2 of ESM-2). In addition, it will be interesting to test the ability to detect the target fungi in buccal swab samples and oral fluid. With particular respect to a forensic context, rapid identification of fungal species by DNA-based methods offers a wide array of potential applications. Apart from its use for the detection of poisonous or illicit hallucinogenic mushrooms [46], similar techniques may be developed for the analysis of fungal spores that can be exploited as indicators of association and locality [47]. Single cell sensitivity enables amplification of minute amounts of target traces. Therefore, pre-laboratory contamination of questioned samples (e.g. through airborne dispersal of spores) has to be considered, and the common prevention strategies of forensic DNA laboratories against contaminations (including
negative controls; unidirectional workflow; strict separation of sample pre-processing/DNA-extraction, PCR set-up and post-amplification; filter-tips; PCR workstations with UV/HEPA filters etc.) are required. In the future, the development of multiplex assays (e.g. TaqMan qPCR) may not only further increase the speed of diagnostic testing and reduce the amount of samples needed, but may also allow the simultaneous detection of different (even unrelated taxa) and the use of internal controls (e.g. universal primers or additional species-specific primers), respectively. Furthermore, relative quantitation (e.g. the amount of target template versus total basidiomycetes DNA) may provide a better basis for the interpretation of complex samples than merely a qualitative result.
Conflicts of interest
The authors declare that they do not have any known conflict of interest.
Acknowledgements
We kindly thank EOA Dr. Michael Moser (Klinikum Klagenfurt, Dept. of Emergency Medicine), Dr. Ch. Goed and SpOA Dr. Andrea Jaeger (Department of Paediatrics, Gottfried von Preyer'sches Kinderspital, Vienna) for providing case samples and background informations. Thanks to Günter Frühwirth (Vienna Food Inspection and Market Authority, Municipal Department 59) for the fresh A. phalloides specimens.