Metabolomic and Transcriptome Analysis of the Inhibitory Effects of Bacillus subtilis Strain Z‑14 against Fusarium oxysporum Causing Vascular Wilt Diseases in Cucumber

Controlling cucumber Fusarium wilt caused by Fusarium
oxysporum f. sp. cucumerinum (FOC) with Bacillus strains is a hot research
topic. However, the molecular mechanism of Bacillus underlying the biocontrol of cucumber wilt is rarely reported. In
this study, B. subtilis strain Z-14
showed significant antagonistic activity against FOC, and the control effect reached 88.46% via pot experiment. Microscopic
observations showed that strain Z-14 induced the expansion and breakage
of FOC hyphae. The cell wall thickness was uneven,
and the organelle structure was degraded. The combined analysis of
metabolome and transcriptome showed that strain Z-14 inhibited the FOC infection by inhibiting the synthesis of cell wall and
cell membrane, energy metabolism, and amino acid synthesis of FOC mycelium, inhibiting the clearance of reactive oxygen
species (ROS) and the secretion of cell wall-degrading enzymes (CWDEs),
thereby affecting mitogen-activated protein kinase (MAPK) signal transduction
and inhibiting the transport function.