Biocontrol potential of anthracnose in sorghum by Bacillus spp. and its lipopeptide extracts

Abstract

Climate change is increasing constraints on crop production and reinforcing the need for sustainable alternatives to chemical disease control. Sorghum is a drought-tolerant crop of increasing importance. However, anthracnose caused by Colletotrichum sublineola remains its most destructive disease, and no biological control products are currently registered for its management. This study evaluated bacterial isolates as potential biological control agents against sorghum anthracnose. Bacteria isolated from honey were identified as Bacillus spp. based on 16S rDNA sequencing and screened for antifungal activity in vitro . Four isolates inhibited mycelial growth of C. sublineola by more than 67%. Lipopeptide extraction and characterization confirmed the production of surfactin, fengycin, and iturin. Greenhouse assays demonstrated that bacterial cell suspensions reduced symptomatic leaf area by 40%, whereas lipopeptide extracts reduced disease severity by 77% and significantly increased the chlorophyll index. The most effective treatments were further evaluated under field conditions, confirming their effects on disease suppression and plant physiological performance. Three Bacillus isolates showed strong potential for biological control of sorghum anthracnose using both talc-based formulations and lipopeptide extracts. Further studies are required to optimize formulation stability and assess long-term field efficacy.

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