Screening of Endophytic Bacteria from Wheat Roots for Biocontrol Potential Against Gaeumannomyces graminis var. tritici

Abstract

Take-all disease caused by Gaeumannomyces graminis var. tritici is one of the most destructive root diseases of wheat, leading to severe yield losses in cereal-based production systems. The present study aimed to screen and evaluate endophytic bacteria isolated from wheat roots for their biocontrol potential against the pathogen under laboratory and greenhouse conditions. Healthy wheat root samples were collected, and endophytic bacteria were isolated following surface sterilization procedures. A total of bacterial isolates were obtained and screened for antagonistic activity against G. graminis var. tritici using dual culture assays. Significant variability in antifungal activity was observed among isolates, with several strains exhibiting strong inhibition of mycelial growth. Promising isolates were further evaluated for plant growth–promoting traits, including production of hydrolytic enzymes, siderophores, and indole-3-acetic acid. In vivo greenhouse experiments demonstrated that selected bacterial strains reduced disease severity and improved root and shoot growth compared to untreated controls. Mechanistic studies suggested that antibiosis, competition for nutrients, and induced systemic resistance contributed to pathogen suppression. Molecular identification based on 16S rRNA gene sequencing revealed that the most effective isolates belonged to genera commonly associated with plant growth promotion and biocontrol activity. Disease suppression was most pronounced under conditions favorable for pathogen development, indicating strong bioprotective potential of selected endophytes. The study highlights the importance of wheat-associated endophytic bacteria as a sustainable alternative to chemical fungicides for managing take-all disease. Overall, the findings demonstrate that root-associated endophytic bacteria possess significant biocontrol potential against G. graminis var. tritici and can be integrated into eco-friendly disease management strategies for sustainable wheat production systems.