A novel signaling pathway controlling induced systemic resistance (ISR) in Arabidopsis has been identified. This pathway is triggered by nonpathogenic Pseudomonas fluorescens WCS417r bacteria and involves components of the jasmonate and ethylene response pathways. Unlike classic systemic acquired resistance (SAR), which requires salicylic acid (SA) and pathogenesis-related (PR) gene activation, ISR is independent of these factors and is regulated by the NPR1 protein. The study demonstrates that ISR requires responsiveness to both jasmonate and ethylene, and that NPR1 plays a crucial role in the expression of ISR. The signaling pathway for ISR diverges from that of SAR, indicating that NPR1 differentially regulates defense responses based on the signals involved. The research also shows that ISR is not associated with the activation of jasmonate- or ethylene-responsive genes, suggesting that the ISR pathway involves distinct mechanisms. The findings highlight the importance of jasmonate and ethylene in plant defense responses and provide insights into the complex network of signaling pathways involved in biologically induced systemic resistance.A novel signaling pathway controlling induced systemic resistance (ISR) in Arabidopsis has been identified. This pathway is triggered by nonpathogenic Pseudomonas fluorescens WCS417r bacteria and involves components of the jasmonate and ethylene response pathways. Unlike classic systemic acquired resistance (SAR), which requires salicylic acid (SA) and pathogenesis-related (PR) gene activation, ISR is independent of these factors and is regulated by the NPR1 protein. The study demonstrates that ISR requires responsiveness to both jasmonate and ethylene, and that NPR1 plays a crucial role in the expression of ISR. The signaling pathway for ISR diverges from that of SAR, indicating that NPR1 differentially regulates defense responses based on the signals involved. The research also shows that ISR is not associated with the activation of jasmonate- or ethylene-responsive genes, suggesting that the ISR pathway involves distinct mechanisms. The findings highlight the importance of jasmonate and ethylene in plant defense responses and provide insights into the complex network of signaling pathways involved in biologically induced systemic resistance.