Multilocus phylogeny- and fruiting feature-assisted delimitation of European from a new Asian species complex and related species.

(synonym: ) is a widely cultivated edible and reportedly almost cosmopolitan mushroom species that serves as a model fungus for basidiome formation and as producer of useful natural products and enzymes. Focusing on strains from different continents, here, we present a phylogenetic analysis of this species and some adjacent taxa that employs four phylogenetic markers. In addition, we tested the strains' capability to fructify on agar media. Our analysis reveals that "" splits up into the following two well-supported monophyletic geographic lineages: a European clade and an Asian clade. The European one is closely associated with the Chinese species . In contrast, the Asian lineage, which we preliminarily designate as agg., may comprise several species (species complex) and clusters with the Pacific species (New Zealand). In addition, fruiting properties differ across and its Asian and Pacific relatives; however, strains from the Asian clade and tend to form larger basidiomes with relatively big caps and long stipes and strains from the European clade exhibit a more variable fruiting productivity with the tendency to form more basidiomes, with smaller caps and shorter stipes. Moreover, some strains showed individual fruiting patterns, such as the preference to fruit where they were exposed to injuring stimuli. In conclusion, the delimitation of the newly delimited Asian species complex from our multilocus phylogeny of "", which is supported by phenotypic data, depicts an exemplary case of biogeographic diversity within a previously thought homogeneous species of near worldwide distribution.