2011). Species criteria: challenge and opportunity The basic rank in taxonomy of organisms is the species. Attempts to reach a consensus for a universal definition of species have been unsuccessful, and consequently over 20 different concepts have been used (Mayden 1997). For instance, the morphological species concept, the biological species concept, the ecological species concept, and the phylogenetic

species concept virtually emphasize morphological divergence, reproductive isolation, adaptation to a particular ecological niche, and nucleotide divergence respectively (Giraud et al. 2008). However, these species criteria correspond PLX4032 to the different events that occur during lineage separation and divergence, rather than to fundamental differences of what is considered to represent a species (de Queiroz 1998, 2007; Giraud et al. 2008). Morphological

species concept is the classic approach used. However, exactly what different mycologists consider to be a species can vary widely, and there are different approaches for delineating them. In addition, many morphological characters are plastic or subtle, and difficult to Dibutyryl-cAMP assess. It has been repeatedly shown that similar characters can arise from evolutionary convergence or environmental constrains (Moncalvo 2005; Hibbett 2007), and, thus, morphological species concept is, in many cases, unsatisfactory for applications. The application of biological species concept or ecological species concept 4-Aminobutyrate aminotransferase to fungi was favored between 1960–1990, and is still presently being used. However, there are still many Caspase Inhibitor VI clinical trial limitations for its application (Taylor et al. 2000; Giraud et al. 2008). Phylogenetic approaches and incorporation of molecular biological techniques, particularly the analysis of DNA nucleotide sequences have provided new information and the phylogenetic species concept is becoming a popular trend, particularly, when it is applied to asexual organisms, and connects the anamorph and teleomorphic stages

of a single species (Guarro et al. 1999; Moncalvo 2005; Hyde et al. 2011). In fungi, the sequence data from the internal transcribed spacer region of the nuclear rDNA locus (ITS) have often been used to recognize fungal phylogenetic species and may well be the DNA barcoding locus used in barcoding (Seifert 2009; Begerow et al. 2010; Jargeat et al. 2010). However, it is better to use multigene genealogy concordance than to use a single gene to recognize species (Taylor et al. 2000). The current “gold standard” genealogical concordance phylogenetic species recognition criterion has proved very useful in fungi, because it is more finely discriminating than the other criteria in many cases. Genealogical concordance phylogenetic species recognition has been practiced recently in different groups of basidiomycetes (e.g. Kauserud et al. 2006; Jargeat et al. 2010; Van de Putte et al. 2010).