<i>SlMAPK1/2/3</i>and Antioxidant Enzymes Are Associated with H₂O₂-Induced Chilling Tolerance in Tomato Plants

Abstract

Hydrogen peroxide (H₂O₂) acts as a signaling molecule in response to cold stress. Mitogen-activated protein kinases (MAPKs) and C-repeat/dehydration-responsive factor (CBF) play important roles in cold response regulation. To investigate the roles of MAPKs and CBF in H₂O₂-induced chilling tolerance, tomato (Solanum lycopersicum cv. Ailsa Craig) plants were treated with 1 mM H₂O₂ before chilling treatment. The results showed that H₂O₂ treatment protected subcellular structure, increased concentrations of abscisic acid (ABA), zeatin riboside (ZR), and methyl jasmonate (MeJA), but decreased the concentration of gibberellic acid (GA₃). Furthermore, 1 mM H₂O₂ treatment enhanced the activities of antioxidant enzymes. Meanwhile, relative expressions of SlMAPK1/2/3 and SlCBF1 in H₂O₂-treated plants were higher than those in the control. Our findings suggest that H₂O₂ treatment might enhance the chilling tolerance of tomato plants by activating SlMAPK1/2/3 and SlCBF1 gene expression and by regulating phytohormone concentrations and antioxidant enzyme activities.