Other interesting, putatively pathogenicity-related dermatophyte genes have been identified recently in a broad transcriptome

approach in A. benhamiae during the interaction with human keratinocytes (Burmester et al., 2011). In comparison with many other fungi, dermatophytes have been shown to be less amenable to genetic manipulation. As a result, site-directed mutagenesis in dermatophyte species has been evidenced only in a very small number of cases. This drawback is assumed to be a result of both low transformation frequency and inefficient check details homologous integration, processes that are indispensable for targeted genetic manipulations. The first successful transformation of a dermatophyte has been described in 1989 by Gonzalez et al. (1989) in T. mentagrophytes (Table 1). The transformation protocol applied was based on a standard protoplast/polyethylene glycol (PEG)-mediated procedure that has been established widely in filamentous fungi,

for example Aspergillus nidulans, Neurospora crassa and others (for a review, see Fincham, 1989; Weld et al., 2006). As a marker for the selection of T. mentagrophytes transformants, the system used the bacterial hygromycin B phosphotransferase gene hph. Plasmid DNA was stably integrated into the fungal genome with varying integration sites and numbers of insertions in the resulting transformants. Thereafter, no further attempts on dermatophyte transformation have been reported until 2004, when Kaufman et al. (2004) described PEG-mediated SB431542 price protoplast transformation and restriction-enzyme-mediated integration in T. mentagrophytes, using the hph gene as a selectable marker and the gene

encoding the enhanced green fluorescent protein (eGFP) as a reporter. PEG-mediated transformation and transformant selection via hygromycin resistance was further demonstrated in M. canis (Yamada et al., 2005, 2006; Vermout et al., 2007) and T. rubrum (Fachin et al., 2006; Ferreira-Nozawa et al., 2006). Different other drugs/dominant markers have meanwhile RANTES been proven successful for the selection of transformants in T. mentagrophytes, i.e. two other aminoglycoside antibiotics/resistance genes, nourseothricin/Streptomyces noursei nourseothricin acetyltransferase gene nat1 (Alshahni et al., 2010) and geneticin (G-418)/Escherichia coli neomycin phosphotransferase gene neo (Yamada et al., 2008). The latter marker as well as hph were also used successfully in A. benhamiae (Grumbt et al., 2011). Besides PEG-mediated protoplast transformation, other techniques facilitating gene transfer were also meanwhile adopted in dermatophytes. A promising Agrobacterium tumefaciens-mediated transformation (ATMT) system was established recently for T. mentagrophytes (Yamada et al., 2009b). ATMT has already strongly advanced functional genomics in various filamentous fungi before (for a review, see Michielse et al.