Bacillus velezensis RC 218 as a biocontrol agent to reduce Fusarium head blight and deoxynivalenol accumulation: Genome sequencing and secondary metabolite cluster profiles

Authors: PALAZZINI, J - National University Of Rio Cuarto; Dunlap, Christopher; Bowman, Michael; CHULZE, S - National University Of Rio Cuarto

Submitted to: Microbiological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2016
Publication Date: 6/8/2016
Publication URL: https://handle.nal.usda.gov/10113/5301982
Citation: Palazzini, J.M., Dunlap, C.A., Bowman, M.J., Chulze, S.N. 2016. Bacillus velezensis RC 218 as a biocontrol agent to reduce Fusarium head blight and deoxynivalenol accumulation: Genome sequencing and secondary metabolite cluster profiles. Microbiological Research. 192:30-36. https://doi.org/10.1016/j.micres.2016.06.002.
DOI: https://doi.org/10.1016/j.micres.2016.06.002

Interpretive Summary: ARS researchers from Peoria, IL collaborated with Argentinian scientists to characterize the genome of a beneficial bacterium useful in controlling diseases in wheat. The research will allow us to determine how these beneficial bacteria are able to biologically control plant pathogens. The work provides a blueprint of the number and types compounds the beneficial bacteria can produce, such antifungal compounds toxic to plant pathogens. This breakthrough improves our knowledge of the mode-of-action these beneficial bacteria use, which provides insight on how we may improve their efficacy on crops in the field. Understanding how these beneficial bacteria can control plant diseases has the potential to lead to new methods of crop protection for wheat farmers.

Technical Abstract: Bacillus velezensis RC 218 was originally isolated for the anthers of wheat as a potential antagonist of Fusarium graminearium, the causal agent of Fusarium head blight. It was demonstrated to have antagonist activity against the plant pathogen with in vitro and greenhouse assays. The current study extends characterizing of B. velezensis RC 218 with a field study and genome sequencing. The field study demonstrated that B. velezensis RC 218 could reduce disease severity and the associated mycotoxin (deoxynivalenol) production, under field conditions. While the genome sequencing allowed us to accurately determine the taxonomy of the strain using a phylogenomic approach, which places it in the B. velezensis clade. In addition, the draft genome allowed us to use bioinformatics to mine the genome for potential metabolites. The genome mining allowed us to identify 9 active secondary metabolites conserved by all B. velezensis strains and one additional secondary metabolite, the lantibiotic ericin, that is unique to this strain. This represents the first confirmed production of ericin by a B. velezensis strain. The genome also allowed us to do a comparative genomics with its closest relatives and compare the secondary metabolite production of the publically available B. velezensis genomes. The results show the diversity in secondary metabolites of strains in the B. velezensis clade is driven by strains making different antibacterial compounds.