Du XH, Zhao Q, Yang ZL, Hansen K, Taşkın H, Büyükalaca HS, Dewsbury D, Moncalvo J-M, Douhan GW, Robert VARG, Crous PW, Rehner SA, Rooney AP, Sink S, O’DonnellK.

Abstract: Arguably more mycophiles hunt true morels (Morchella) during their brief fruiting season each spring in the Northern Hemisphere than any other wild edible fungus. Concerns about overharvesting by individual collectors and commercial enterprises make it essential that science-based management practices and conservation policies are developed to insure the sustainability of commercial harvests and to protect and preserve morel species diversity. Therefore, the primary objectives of the present study were to: (i) investigate the utility of the ITS rDNA fungal ‘barcode’ locus for identifying Morchella species, using phylogenetic species previously inferred from multilocus DNA sequence data as a reference; and (ii) clarify ‘insufficiently identified’ sequences and determine whether the named sequences in GenBank were identified correctly. Towards this end, we generated 660 Morchella ITS rDNA sequences and downloaded 246 additional ones generated by other researchers from GenBank using emerencia (http://www.emerencia.org) and analyzed them phylogenetically. Three major findings emerged: (i) ITS rDNA sequences were useful in identifying 47/62 (75.8%) of the known phylospecies; however, they failed to identify 12 of the 22 species within the species-rich Elata Subclade, and two closely related species in the Esculenta Clade; (ii) at least 66% of the named Morchella sequences in GenBank are misidentified; and (iii) ITS rDNA sequences of up to six putatively novel Morchella species were represented in GenBank. Recognizing the need for a dedicated web-accessible reference database to facilitate the rapid identification of known and novel species, we constructed Morchella MLST (http://www.cbs.knaw.nl/morchella/) which can be queried using ITS rDNA sequences and those of the four other genes used in our prior multilocus molecular systematic studies of this charismatic genus.

Keywords: Ascomycota, biodiversity, biogeography, emerencia, GCPSR, GenBank, phylogeny, species limits