Nonribosomal Peptide Synthetase GenespesLandpes1Are Essential for Fumigaclavine C Production in Aspergillus fumigatus

摘要: ABSTRACTThe identity of metabolites encoded by the majority of nonribosomal peptide synthetases in the opportunistic pathogen,Aspergillus fumigatus, remains outstanding. We found that the nonribosomal peptide (NRP) synthetases PesL and Pes1 were essential for fumigaclavine C biosynthesis, the end product of the complex ergot alkaloid (EA) pathway inA. fumigatus. Deletion of eitherpesL(ΔpesL) orpes1(Δpes1) resulted in complete loss of fumigaclavine C biosynthesis, relatively increased production of fumitremorgins such as TR-2, fumitremorgin C and verruculogen, increased sensitivity to H2O2, and increased sensitivity to the antifungals, voriconazole, and amphotericin B. Deletion ofpesLresulted in severely reduced virulence in an invertebrate infection model (P< 0.001). These findings indicate that NRP synthesis plays an essential role in mediating the final prenylation step of the EA pathway, despite the apparent absence of NRP synthetases in the proposed EA biosynthetic cluster forA. fumigatus. Liquid chromatography/diode array detection/mass spectrometry analysis also revealed the presence of fumiquinazolines A to F in bothA. fumigatuswild-type and ΔpesLstrains. This observation suggests that alternative NRP synthetases can also function in fumiquinazoline biosynthesis, since PesL has been shown to mediate fumiquinazoline biosynthesisin vitro. Furthermore, we provide here the first direct link between EA biosynthesis and virulence, in agreement with the observed toxicity associated with EA exposure. Finally, we demonstrate a possible cluster cross-talk phenomenon, a theme which is beginning to emerge in the literature.