Genomic comparisons of two Bacillus subtilis biocontrol strains with different modes of actions

Authors: Dunlap, Christopher; Bowman, Michael; Schisler, David

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2012
Publication Date: 8/8/2012
Citation: Dunlap, C.A., Bowman, M.J., Schisler, D.A. 2012. Genomic comparisons of two Bacillus subtilis biocontrol strains with different modes of actions [abstract]. American Phytopathological Society. Paper #133.

Interpretive Summary:

Technical Abstract: Bacillus subtilis strains AS 43.3 and OH131.1 were isolated from wheat anthers and shown to be efficacious in managing Fusarium head blight in greenhouse and some field trials. Chemical analysis of the cell-free culture supernatant identified B. subtilis strain AS 43.3 to be a potent producer of the antifungal lipopeptides: surfactin, iturin, and fengycin. In addition, strain AS 43.3 demonstrated strong antibiosis of Fusarium graminearium in competition assays. Under the same conditions, B. subtilis strain OH 131.1 produced only a small amount of the lipopeptide surfactin and did not inhibit F. graminearium in competition assays. The lack of antifungal metabolites in OH 131.1 suggested it may utilize a different mode of action than AS 43.3 or only produced them in the wheat infection court. To determine the secondary metabolite potential of each strain, we used next generation sequencing to produce assembled genome libraries with greater than 30x sequence coverage. Sequence alignments of the two genomes identified differences in the secondary metabolite pathways between the organisms. Data analysis also identified previously unknown pathways in each strain and the data suggests strain AS 43.3 may need to be reclassified as a B. amyloliquefaciens strain.