Fig. 1

Schematic diagram depicting plasmids utilized to test activity of promoters during extremely low A. niger growth. For plasmids pCH8.1, pFW4.4 and pEN1, the promoter for the antifungal protein from A. niger (Panafp) and the corresponding terminator (Tanafp) were used. In the other three plasmids (pPK4.1, pFW2.52, pEN2) the promoter PhfbD and terminator ThfbD were utilized. These ~1000 bp promoter and terminator regions ensure homologous integration of exogenous DNA cassettes at the respective native locus via a double crossover event. In all plasmids, termination of transcription of the gene of interest was attained using the terminator of tryptophan synthase of Aspergillus nidulans, Ttrpc. All plasmids utilized the short version of pyrG (spyrG _AO ) for selection of transformants, with exception of pFW2.52, which encoded the hygromycin resistance gene (hygR). a For facile intracellular reporting of promoter activity, plasmids CH8.1 and PK4.1 encode the modified luciferase gene mluc [16]. b Plasmids FW4.4 and FW2.52 contain the afp gene encoding the A. giganteus antifungal protein and additionally the signal sequence for secretion of the respective genes (SSanafp and SShfbD). c For expression of the thermal hysteresis protein gene from the spruce budworm C. fumiferana, the codon optimized (for A. niger) thp gene was utilized in plasmids EN1 and EN2