“…However, the osmotrophic lifestyle of Aspergillus , i.e., extracellular digestion of complex substrates achieved by a plethora of secreted hydrolytic enzymes (Kobayashi et al, 2007; Monod et al, 2009) and followed by uptake of breakdown products via numerous transporters, impedes a comprehensive analysis (Yoon et al, 2009). To assist in assessing any relevance of cellular functions that are encoded by multiple genes, progress was made with respect to gene targeting approaches that allows repetitive targeting of all members of a gene family to abolish any redundantly encoded cellular function (d’Enfert, 1996; Krappmann and Braus, 2003; Krappmann et al, 2005; Nielsen et al, 2006; Forment et al, 2006; Hartmann et al, 2010). By developing genetic markers, recombinase-driven excision of which can be achieved in fungo , marker rescue became feasible to allow recurring rounds of gene targeting in a straight-forward manner.…”