Effects of the biological activity in the antagonistic potential of soil to Fusarium Head Blight of wheat

Abstract: All soils are potentially naturally resistant or receptive to plant pathogens due to their microbial activity. In our study, we focused on the ability of agricultural soils to reduce primary inoculum of F. graminearum, the major causal agent of Fusarium Head Blight. We selected 31 wheat cultivated fields with maize as previous crop and examined soil physicochemical properties, disease symptoms in fields and mycotoxin content as well as Fusarium species present on in harvested grains. In parallel, growth of F. graminearum was evaluated in autoclaved soil samples and untreated samples incubated under controlled conditions. A significant difference was observed between the two conditions. Pathogen growth was up to 3 logs higher in autoclaved soils when compared to untreated soils. These results demonstrate a key role of soil biological activity in reducing pathogen growth. Besides, when multivariate analyses were used to correlate soil properties to the previous results, any abiotic factors seemed to have a predominant role. Our study demonstrates the key role of soil biological activity in F. graminearum repression. Further experiments are ongoing on plant model and sequencing to complete the study on soil suppressiveness.