Transcriptome analysis reveals ethylene-mediated defense responses toFusarium oxysporumf. sp.cucumerinuminfection inCucumis sativusL.

Background Fusariumwilt, caused byFusarium oxysporumf. sp.cucumerinum(Foc), is a severe disease affecting cucumber (Cucumis sativusL.) production worldwide, but mechanisms underlyingFusariumwilt resistance in cucumber remain unknown. To better understand of the defense mechanisms elicited in response to Foc inoculation, RNA sequencing-based transcriptomic profiling of responses of theFusariumwilt-resistant cucumber line 'Rijiecheng' at 0, 24, 48, 96, and 192 h after Foc inoculation was performed. Results We identified 4116 genes that were differentially expressed between 0 h and other time points after inoculation. All ethylene-related and pathogenesis-related genes from the differentially expressed genes were filtered out. Real-time PCR analysis showed that ethylene-related genes were induced in response to Foc infection. Importantly, after Foc infection and exogenous application of ethephon, a donor of ethylene, the ethylene-related genes were highly expressed. In response to exogenous ethephon treatment in conjunction with Foc inoculation, the infection resistance of cucumber seedlings was enhanced and endogenous ethylene biosynthesis increased dramatically. Conclusion Collectively, ethylene signaling pathways play a positive role in regulating the defense response of cucumber to Foc infection. The results provide insight into the cucumberFusariumwilt defense mechanisms and provide valuable information for breeding new cucumber cultivars with enhancedFusariumwilt tolerance.