Discovery, Characterization, and Application of Broad-Spectrum Antimicrobial Peptide AtR905 from <i>Aspergillus terreus</i> as a Biocontrol Agent

This study investigates a novel antimicrobial peptide AtR905 derived from the endophytic fungus <i>Aspergillus terreus</i>, which was successfully expressed in <i>Bacillus subtilis</i>, purified, and characterized, and highlighted as a promising potential biocontrol agent against various plant pathogens. The results indicated AtR905 exhibited broad-spectrum antimicrobial activities against key pathogens such as <i>Ralstonia solanacearum</i> and <i>Clavibacter michiganensis</i> with very low minimal inhibitory concentrations (MICs). Stability tests confirmed that AtR905 retains its antimicrobial properties under varying thermal, pH, and UV conditions. The Oxford Cup test indicated that AtR905 showed obvious fungicidal activity against six plant pathogenic fungi, especially <i>Rhizoctonia solani</i> and <i>Botrytis cinerea</i>. Additionally, in vivo experimental demonstrated AtR905 could effectively control the <i>B. cinerea</i> on tobacco leaves and <i>R. solanacearum</i> on tomato plants. Scanning electron microscopy revealed significant membrane disruption in bacterial cells treated with AtR905. These findings suggest that AtR905 is a promising candidate for sustainable plant disease management, potentially reducing the reliance on chemical pesticides and mitigating the issue of antibiotic resistance in agricultural settings. Further research is needed to evaluate the long-term field applicability and ecological impacts of AtR905.