Endophytic Metarhizium anisopliae is a potential biocontrol agent against wheat Fusarium head blight caused by Fusarium graminearum

Fusarium graminearum causes Fusarium head blight (FHB) in wheat, resulting in severe yield losses. Further, it produces mycotoxins, which can have adverse effects on human health. This study aimed to assess the biocontrol efficacy of Metarhizium anisopliae against F. graminearum causing FHB in wheat. M. anisopliae significantly inhibited F. graminearum mycelial growth in the dual culture test, resulting in hyphal deformation at the site of its hyphal tips. Similar effects were observed with a 1% concentration of broth filtrates from M. anisopliae on mycelial growth and hyphal morphology of F. graminearum. However, the same was not observed for its volatiles. Furthermore, a 1% concentration of broth filtrates impeded conidial germination of F. graminearum . The colonisation ability of M. anisopliae on wheat roots was validated through eGFP -labelled M. anisopliae strain Ma-eGFP. The positive effects of M. anisopliae on seedling growth and single-spike weight of wheat were recorded. However, no noticeable effect on the 1000-seed weight of wheat was observed. Results from field experiments revealed that treating wheat seeds with the seed coating agent of M. anisopliae and spraying wheat heads with M. anisopliae conidia suspension resulted in a significant control efficacy of 38.6% and 40.1% at the early flowering period of wheat, respectively. These findings suggest that M. anisopliae is a promising biocontrol agent against F. graminearum causing FHB in wheat, and may fight against FHB by producing fungistatic secondary metabolites, enhancing wheat growth, and eliciting wheat defence responses.