This study investigates the functional role of the oxidative stress-activated mitogen-activated protein kinase (MAPK) cascade in plants, focusing on the Arabidopsis thaliana gene ANP1 and its homologue NPK1 in tobacco. The research demonstrates that H₂O₂ activates specific MAPKs, including AtMPK3 and AtMPK6, through the ANP1-mediated MAPK cascade. This cascade is crucial for stress-responsive gene expression and represses auxin signaling, establishing a molecular link between oxidative stress and auxin pathways. Transgenic tobacco plants expressing constitutively active NPK1 show enhanced tolerance to multiple environmental stresses, including freezing, heat, and salt, without activating previously described drought, cold, or abscisic acid signaling pathways. This suggests that manipulating key regulators like ANP1/NPK1 could be a strategy for engineering multiple stress tolerance in agriculture. The study also highlights the dual role of the ANP-mediated MAPK cascade in regulating gene expression and cell cycle progression, and its potential in cross-protection against various environmental stresses. The findings provide insights into the molecular mechanisms underlying oxidative stress signaling and its integration with other signaling pathways in plants.This study investigates the functional role of the oxidative stress-activated mitogen-activated protein kinase (MAPK) cascade in plants, focusing on the Arabidopsis thaliana gene ANP1 and its homologue NPK1 in tobacco. The research demonstrates that H₂O₂ activates specific MAPKs, including AtMPK3 and AtMPK6, through the ANP1-mediated MAPK cascade. This cascade is crucial for stress-responsive gene expression and represses auxin signaling, establishing a molecular link between oxidative stress and auxin pathways. Transgenic tobacco plants expressing constitutively active NPK1 show enhanced tolerance to multiple environmental stresses, including freezing, heat, and salt, without activating previously described drought, cold, or abscisic acid signaling pathways. This suggests that manipulating key regulators like ANP1/NPK1 could be a strategy for engineering multiple stress tolerance in agriculture. The study also highlights the dual role of the ANP-mediated MAPK cascade in regulating gene expression and cell cycle progression, and its potential in cross-protection against various environmental stresses. The findings provide insights into the molecular mechanisms underlying oxidative stress signaling and its integration with other signaling pathways in plants.