Concurrent selection for microbial suppression of Fusarium graminearum, Fusarium head blight and deoxynivalenol in wheat

Aim: Identify biological agents that can both control Fusarium head blight (FHB) and reduce deoxynivalenol (DON) production. Methods and Results: Concurrent screening methods were used to progressively select soil and food micro-organisms for the ability to suppress Fusarium graminearum, FHB and DON production. The micro-organisms were assessed using up to five assays including: a co-culture and dual-culture assay, all indirect impedance assay, a wheat floret assay, and two assays assessing DON production. Paenibacillus polymyxa W1-14-3 and C1-8-b gave the greatest inhibition of F. graminearum and reduction of DON production in greenhouse evaluations. Compared to a control treatment, they reduced disease severity by 56.5 and 55.4%, F. graminearum colonization of wheat heads by 58.8 and 62.4%, DON production by 84.8 and 89.4%, and increased 100-kernel weights by 56.6 and 66.9%, respectively. Conclusions: The concurrent selection has resulted in promising antagonists that may possess multiple modes of action, and have the ability to colonize wheat heads in controlled environments. Significance and Impact of the Study: A novel concurrent screening method was developed for selection of biocontrol agents for FHB. Two isolates of P. polymyxa were selected and identified. Their potential use as biocontrol agents for FHB is highlighted in this study.