DNA Barcoding of the Economically Important Leucocalocybe mongolica to Prevent Mushroom Mislabeling

Abstract

Morphological identification of the L. mongolica species, which is traded in edible wild mushroom markets, can be challenging for citizens and mycologists who are not experts on this fungal group. For the exploration of a rapid and reliable approach of L. mongolica species discrimination, nuclear ribosomal internal transcribed spacer (ITS), which is the proposed universal DNA barcode for fungi, was tested in this study to investigate the feasibility of discriminating L. mongolica from 11 low-priced mushrooms that are frequently mislabeled and sold as the former in markets in North China (Inner Mongolia and Hebei Province). The appropriate intra- and inter-specific sequence divergences are considered to be important criteria for judging the suitability of the candidate DNA marker. ITS sequence showed high species identification levels within and among the 12 species. The largest intra-specific ITS variation among the investigated taxa was 2.2%, and the smallest inter-specific variation was 5.9%, which was much higher than the intra-specific variation. No overlap was observed. ITS successfully discriminated L. mongolica from the confusing mushrooms. Thus, we present ITS as the DNA barcode for the famous, expensive mushroom and its frauds or easily mislabeled fungi.