Employing a polyphasic taxonomy in Talaromyces

Abstract

Talaromyces is an important and diverse genus. Its species have positive and/or negative impacts on humans and animals. On the negative side, many Talaromyces species are associated with food spoilage and mycotoxin production, while some are opportunistic pathogens for animals and humans. On the positive side, many species are exploited in biotechnology for the production of novel enzymes, antibiotics, anti-tumour agents and food colourants, while some species are used as bio-control agents. The diversity within the genus and its importance make correct identifications in Talaromyces crucial. This was the focus of this project and in the process we have established a polyphasic approach for working with the genus. This means that Talaromyces species can now be identified using morphology or multi-gene sequences. Morphological identifications may be tricky, as it often needs an experienced worker. This is evident from studies employing only morphological identifications, which lead to numerous misidentifications. The DNA barcoding initiative lead to more studies employing sequence-based identifications. However, for accurate identifications using only DNA sequences, the correct genes should be amplified and the sequences should be compared to a verified and trustworthy dataset. One goal of our study was to supply this dataset for Talaromyces. Also, BenA was proposed as a secondary barcode marker to ITS. In this study we provide verified sequence datasets for both ITS and BenA for the accepted 88 Talaromyces species. These sequences will not only be crucial for future identifications, but also for exploring for new species. From our studies on the T. verruculosus species complex and section Islandici the number of accepted species will soon rise to 97. Additionally, we have found a number of supposedly new species that will be described in future papers. Talaromyces species can be found in a wide range of substrates all over the world. It is clear that there are many more Talaromyces species in nature waiting to be discovered and this study has made a big contribution towards discovering the true diversity in Talaromyces.