Nourseothricin acetyltransferase: a new dominant selectable marker for the dermatophyte Trichophyton mentagrophytes

Dermatophytes are filamentous fungi that colonize the keratinized layer of human and animal skin. The availability of several selectable markers for dermatophyte gene manipulation would provide important tools to understand the genetic properties of this fungal group. In this study, we report the nourseothricin resistance gene nat1 that confers resistance to the aminoglycoside antibiotic nourseothricin as a dominant marker in Trichophyton mentagrophytes. The NAT cassette was introduced into T. mentagrophytes by the Agrobacterium tumefaciens-mediated transformation (ATMA) method. Transformation occurred at a frequency of 78 transformants per 1 x 10(7) cells. Molecular analysis showed integration of the NAT cassette into the genomic DNA of T. mentagrophytes. This study presents the nourseothricin resistance gene nat1 as a useful selectable marker for selection of T. mentagrophytes.