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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: Molecular Biology and Bioinformatics for Fungal Pathogens

Location: Biological Integrated Pest Management Unit

2013 Annual Report


1a.Objectives (from AD-416):
Develop molecular tools for use in evaluating secondary metabolite potential of fungal pathogens of insects using Metarhizium as a model system.


1b.Approach (from AD-416):
Construct knockout mutants for analysis of secondary metabolite production using Agrobacterium-mediated transformation of insect pathogenic fungi, predominantly using Metarhizium. Perform bioinformatic analysis of transcriptome libraries and genome data.


3.Progress Report:

Full annotation of the Metarhizium robertsii (formerly anisopliae-ARSEF Isolate 2575) genome is greater than 95% complete, with expected completion of manual annotation shortly. The ARSEF 2575 strain was sequenced, to ~ 25X coverage, using 454 Titanium pyrosequencing and assembled (Celera) into 368 scaffolds totaling ~40 Mb. Sequence is estimated to represent at least 90% of the genome. A combination of automated gene prediction with Augustus (http://augustus.gobics.de/), fgenesh gene structure prediction software {Solovyev, 2006 #215}, blastx, and evidence based gene identification using available ESTs generated >12,200 gene models. A final count of 85 core genes involved in secondary metabolite biosynthesis were identified, encoding 16 nonribosomal peptide synthetases, 24 polyketide synthases, 9 similar to peptide synthetases , 7 hybrid synthetases, and 28 involved in terpene or steroid-like biosynthesis. Of these, 5 specific products of the nonribosomal peptide synthetases have been linked to a specific gene cluster, all from our ongoing gene deletion studies. Additionally, a master gene regulator (LaeA) deletion mutant has been prepared for analysis, as are several mutants deleted for genes that are orthologs of several uncharacterized C.heterostrophus nps mutants, including a key gene known to be involved in virulence in other pathogenic fungi, but with the secondary metabolite undescribed to date. Our plans are to use a new media formulation that appears to increase secondary metabolite expression in order to delineate the product of this pathway.


Last Modified: 7/25/2014
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