Translation elongation factor 1-α gene as a potential taxonomic and identification marker in dermatophytes

Intra- and interspecies variations of the translation elongation factor 1-alpha (Tef-1 alpha) gene were evaluated as a new identification marker in a wide range of dermatophytes, which included 167 strains of 30 species. An optimized pan-dermatophyte primer pair was designed, and the target was sequenced. Consensus sequences were used for multiple alignment and phylogenetic tree analysis and the levels of intra-and interspecific nucleotide polymorphism were assessed. Between species, the analyzed part of the Tef-1 alpha gene varied in length from 709 to 769 nucleotides. Significant numbers of species including Trichophyton rubrum, T. tonsurans, T. schoenleinii, T. concentricum, T. violaceum, Epidermophyton floccosum, Microsporum ferrugineum, M. canis, M. audouinii, T. equinum, T. eriotrephon, and T. erinacei were invariant in Tef-1 alpha and had sufficient barcoding distance with neighboring species. Although overall consistency was found between ITS phylogeny as the current molecular marker of dermatophytes and Tef-1 alpha, a higher discriminatory power of Tef-1 alpha appeared particularly useful in some clades of closely related species such as the A. vanbreuseghemii, T. rubrum, A. benhamiae, and A. otae complexes. Nevertheless, we stress that a single gene can not specify species borderlines among dermatophytes and multiple lines of evidence based on a multilocus inquiry may ascertain an incontrovertible evaluation of kinship.