Biocontrol Potential of Bacillus stercoris Strain DXQ-1 Against Rice Blast Fungus Guy11

Fungal diseases severely threaten global agriculture, while conventional chemical fungicides face increasing restrictions due to environmental and safety concerns. In this study, we isolated a soil-derived <i>Bacillus stercoris</i> strain, DXQ-1, exhibiting strong antagonistic activity against plant pathogenic fungi, notably <i>Magnaporthe oryzae</i>, the causal agent of rice blast. Scanning electron microscopy revealed that DXQ-1 disrupts fungal hyphae and inhibits conidial germination, with a 24 h crude broth treatment reducing germination to 83.33% and completely blocking appressoria formation. LC-MS-based metabolomic analysis identified key antifungal components, including lipids (35.83%), organic acid derivatives (22.15%), and small bioactive molecules (e.g., Leu-Pro, LPE 15:0). After optimizing fermentation conditions (LB medium, pH 7.0, 28 °C, 48 h), the broth showed >90% inhibition against <i>M. oryzae</i> and <i>Nigrospora oryzae</i> and retained high thermal (68 °C, 1 h) and UV (4 h) stability. Field trials demonstrated effective disease control and significant promotion of rice growth, increasing plant height (17.7%), fresh weight (53.3%), and dry weight (33.3%). These findings highlight DXQ-1 as a promising biocontrol agent, offering a sustainable and effective alternative for managing fungal diseases in crops.