Title: Identification of a hybrid PKS-NRPS required for the biosynthesis of NG-391 and NG-393 metabolites in Metarhizium anisopliae Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 16, 2009
Publication Date: August 16, 2009
Citation: Donzelli, B., Krasnoff, S., Churchill, A., Vandenberg, J.D., Gibson, D.M. 2009. Identification of a hybrid PKS-NRPS required for the biosynthesis of NG-391 and NG-393 metabolites in Metarhizium anisopliae. Meeting Abstract. p.20. Technical Abstract: A 19,818 kb genomic region harboring six predicted ORFs was identified in <i> M. anisopliae</i> ARSEF 2575. The ORF4 CDS, putatively encoding a hybrid polyketide synthase/nonribosomal peptide synthetase (PKS-NRPS) was targeted using Agrobacterium-mediated gene knockout. Homologous, but not heterologous, recombinants failed to produce detectable levels of the fusarin-like compounds NG-391 and NG-393, indicating the involvement of this locus in their biosynthesis. ORF4 deletion mutants had no significant changes in virulence levels against <i>Spodoptera exigua</i> larvae and in resistance to H2O2-generated oxidative stress compared to the wild type. The use of the ORF4 promoter-sGFP reporter fusion showed that the gene is transcriptionally regulated and expressed <i>in vitro</i> during early exponential growth; inoculum amount also affected expression, indicating a correlation with growth phase. RT-PCR performed using total RNA extracted during the fungal interaction within the <i>S. exigua</i> host revealed that ORF4 is expressed during the infection process.