o Bacillus velezensis RC218 as a biocontrol agent against Fusarium Head Blight of wheat: revealing genome insights and metabolite profile production

PALAZZINI, J. M.

Conferencia; Microbes for life; 2021

Bacillus velezensis RC218was originally isolated from wheat anthers as a potential antagonist of Fusarium graminearum sensu stricto, thecausal agent of Fusarium head blight (FHB) in Argentina. We demonstrated theability of B. velezensis RC218 toreduce disease severity and DON accumulation in vitro, under greenhouse and field trials. The current presentationextends characterizing B. velezensis RC218by genome sequencing and secondary metabolite production. Secondary metaboliteclusters were identified with antiSMASH3.0 or direct blasting. Culturesupernatants containing secondary metabolites were analyzed by LC-MS. The fieldstudy demonstrated that B. velezensis RC218 could reduce FHB severity and the associated mycotoxin (deoxynivalenol)production to undetectable levels. The genome sequencing allowed us toaccurately determine the taxonomy of the strain using a phylogenomic approach,which places it in the B. velezensisclade. The genome mining allowed us to identify 9 active secondary metabolitesconserved by all B. velezensis strainsand one additional secondary metabolite, the lantibiotic ericin, which isunique to this strain. This represents the first confirmed production of ericinby a B. velezensis strain. Biocontrolactivity can be related to the production of several lipopeptides, from thesurfactin, fengycin and iturin families. Microbiome analysis also demonstratedthat application of the bioicontrol on spikes does not impact nativepopulations dynamics.