Inhibition of the Growth of Fusarium tricinctum and Reduction of Its Enniatin Production by Erwinia gerundensis Isolated from Barley Kernels

Fusarium tricinctum is among the pathogenic fungi that contaminate cereal crops, including barley. It produces toxic metabolites such as enniatins (ENNs) that affect the quality and safety of barley-based products such as malt and beer, thus representing a significant concern for the cereal industries. Therefore, it is critical to reduce Fusarium spp. development and enniatin contamination in cereal-based products. Fungicides are commonly used during agricultural practices, but they are facing growing fungal resistance and environmental and health concerns. Hence, there is need to define environmentally friendly control strategies. This study highlights the ability of a bacterial strain isolated from barley kernels, namely Erwinia gerundensis 6E4, to inhibit the growth of Fusarium tricinctum and to reduce its toxigenic potential. First, E. gerundensis 6E4 exhibited a significant fungistatic activity against pathogenic fungal strains during co-cultures, with fungal growth reduced by up to 100% on Petri dishes and by about 69% in liquid medium. The bacterial strain also led to a drastic reduction (74 to 100%) of ENNs production by F. tricinctum strains over 72 h co-cultures. Based on these results, our study supports the use of E. gerundensis 6E4 as a biocontrol agent in strategies aiming at reducing the presence of Fusarium tricinctum and enniatins in cereal-based products, or as a food and feed supplement for the bio-detoxification of enniatins.