Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: March 15, 2011
Citation: Donzelli, B., Krasnoff, S., Churchill, A.L., Gibson, D.M. 2011. NRPS4 is responsible for the biosynthesis of destruxins in Metarhizium robertsii ARSEF 2575. Fungal Genetics Conference Proceedings. p. 263. Technical Abstract: Destruxins (DTXs) are a family of cyclic depsipeptides that include > 35 members produced by Ascomycetous fungi belonging to several different taxa. These metabolites display a plethora of biological activities including toxicity against insects, depolarization of Ca2+ gradient across the plasma membrane and negative effects on both cellular and humoral immune responses in insects. Strains belonging to the genus Metarhizium are copious producers of these metabolites which have been traditionally considered as likely contributors to virulence. We have identified an NRPS-encoding gene from the M. robertsii ARSEF 2575 genome. The gene is predicted to produce a 7,884 aa protein harboring 6 full modules, and it is expressed both in vitro and during the interaction with the Spodoptera exigua (beet armyworm) host. Mutants produced by Agrobacterium-mediated gene knockout failed to produce DTXs. A preliminary phenotypic characterization of 3 independently generated DTX null mutants did not reveal significant changes in their phenotype. Preliminary pathogenicity tests indicate that DTX null mutants do not differ significantly in virulence as compared to wild type.