Targeted Metabolomics Analysis of Plant Pathogen Ralstonia solanacearum Towards Bacillus amyloliquefaciens

Ralstonia solanacearum, a soil-borne Gram-negative bacterial pathogen, causes crop wilt, posing a serious threat to global food security through significant agricultural losses. While Bacillus amyloliquefaciens has emerged as a promising biocontrol agent, its effectiveness in rescuing or fully protecting crops from this pathogen remains limited, and the mechanisms underlying their interactions are poorly understood. This study investigated how R. solanacearum responds to substances released by B. amyloliquefaciens BNC5 by analyzing changes in intracellular lipid metabolites using targeted metabolomics. Culturing R. solanacearum in casamino acid-peptone-glucose medium supplemented with 15% B. amyloliquefaciens supernatant for 24 h significantly increased the levels of fatty acids and phosphatidylethanolamines compared to control cultures without the supernatant. Other lipid metabolites, including monoacylglycerols, diacylglycerols, triacylglycerols, and phosphatidylglycerols showed minimal or no statistically significant changes. These substantial changes in R. solanacearum's signaling and membrane lipid composition in response to B. amyloliquefaciens substances suggest that alterations in these pathways may influence the pathogen’s sensitivity and defensive mechanism to biocontrol agents, presenting new opportunities for developing effective management strategies.