P. nalgiovense carries a gene which is homologous to the paf gene of P. chrysogenum which codes for an antifungal peptide.

Penicillium nalgiovense is related to P. chrysogenum. P. chrysogenum carries the paf gene (Penicillium antifungal peptide) with homology to the afp gene of Aspergillus giganteus. This gene codes for a peptide with antifungal activity. Based on the sequence of the published P. chrysogenum paf gene primers were generated. By the use of these primers a PCR product of the expected length could be isolated from strains of P. nalgiovense. This fragment was sequenced and compared to the sequence of the paf gene of P. chrysogenum. According to the results P. nalgiovense carries a gene (naf = P. nalgiovense antifungal peptide) which is highly homologous to the paf gene of P. chrysogenum. The gene also codes for a preproprotein with the same processing sites as the paf gene, suggesting that the mature product is also a 55 amino acid (aa) peptide. The naf gene has three amino acid exchanges compared to the paf gene, which however do not influence the amino acid sequence of the mature peptide. It also carries two introns at the same positions, however, the sequence differences between the introns are higher than between the coding regions. When P. nalgiovense were grown on plates containing other food-relevant fungi it showed weak antifungal activity.