Study on the growth inhibition and mechanism of bacillus subtilis B579 metabolites on fusarium oxysporum

FENG Jinghan; FAN Zongqiang; ZHENG Lixue; CHEN Zihan; LIU Chenke; WANG HUI; PENG Xiangqian; CHEN Fang

doi:10.19728/j.issn1672-6634.2025010007

Abstract：Objective:To investigate the inhibitory mechanism of Bacillus subtilis B579 against Fusariu-moxysporum.Methods:Co-culture and metabolomics techniques combined with plate inhibition test were used to screen out the differential metabolites with antibacterial effect.The effects of differential metabo-lites on the extracellular relative conductivity,malondialdehyde content,soluble protein content,and cata-lase activity of Fusarium oxysporum mycelium were determined,and the control effiency of these metabo-lites on cucumber Fusarium wilt were explored.Result:Under co-culture conditions(B579 and patho-gen),48 differential metabolites were found to be highly secreted by B579.Among the 15 differential me-tabolites tested,trans-cinnamic acid(CA)and palmitic acid(PA)had the strongest inhibitory activity.At the three treatment concentrations,both CA and PA showed the strongest inhibitory activity at 50 μg/mL,resulting in inhibition zone diameters of 0.63 and 1.27 cm,respectively.In liquid culture,the extra-cellular relative conductivity,malondialdehyde content,and catalase activity of CA and PA(50 μg/mL)treated cells were significantly increased,while the intracellular soluble protein content was significantly decreased.The pot experiment showed that the application of CA and PA achieved the disease control effi-ciency against cucumber wilt,reaching 67.58％and 47.29％respectively.Conclusion:CA and PA screened under co-culture conditions can cause oxidative damage to the cell membrane of pathogenic bacte-ria,resulting in loss of membrane integrity and enhanced permeability,inhibiting the growth of pathogenic bacteria,thus effectively preventing and treating Fusariumoxysporum.