Seed Priming with Antagonistic Bacteria for Managing Fusarium Crown and Root Rot in Durum Wheat

Durum wheat is increasingly threatened by Fusarium diseases, including Fusarium Crown Rot (FCR) and Fusarium Root Rot (FRR), caused primarily by Fusarium culmorum, F. graminearum, and F. pseudograminearum. These pathogens reduce yield, by causing pre- and post-emergence damping-off and induce symptoms including stem and root browning, as well as severe growth stunting. Traditional control methods, including agronomic practices and seed treatments with fungicides, face limitations due to pathogen resistance and environmental concerns, emphasizing the need for sustainable, microbiologically-driven alternatives, particularly in organic farming. This study evaluates beneficial bacteria as biocontrol agents for efficacy in controlling Fusarium disease in durum wheat. An in vitro screening of 89 bacterial strains against a panel of Fusarium isolates, specifically Fusarium culmorum (Fc383, Fc401, Fc820, Fc1126, Fc1435, Fc1674), F. graminearum (Fg566, Fg913, Fg919), and F. pseudograminearum (Fp1139, Fp1140), identified promising candidates, including Bacillus, Pseudomonas, and lactic acid bacteria (LAB). Seed biopriming with Bacillus amyloliquefaciens MA8 and two strains of Lactiplantibacillus plantarum (5H1 and HB23) effectively suppressed Fusarium infection in vitro. Lp. plantarum HB23 demonstrated in vivo the highest biocontrol efficacy against Fc1126 and Fc566 strains, reducing disease severity by 44.4% and 49.2%, respectively. Metabolomic profiling revealed bacterial production of antifungal compounds, including surfactin and fengycin from Bacillus and benzoic and hydrocinnamic acids from Lactobacillaceae. This study demonstrates Lp. plantarum as an effective biopriming agent against F. culmorum and F. graminearum in durum wheat, confirming that seed treatment with BCAs is a viable alternative to chemical fungicides, especially in organic agriculture.