LhSBP1 Gene of Liriodendron Hybrid Enhances the Cold Resistance of Plants by Regulating ROS Metabolism

Selenium-Binding Protein 1 (SBP1), involved in selenium metabolism, contributes to plant stress response. However, it is currently unknown whether the SBP1 protein from <i>Liriodendron</i> hybrid (LhSBP1) plays a role in response to cold stress. In this study, transgenic overexpression lines of <i>LhSBP1</i> in <i>Arabidopsis thaliana</i> and <i>Populus deltoides × P. euramericana</i> cv. 'Nanlin 895', were used as materials to conduct phenotypic observations and physiological and biochemical determinations under cold stress. The results showed that the full-length CDS sequence of <i>LhSBP1</i> gene was cloned, with a length of 1467 bp, encoding 488 amino acids. Under cold stress, physiological and biochemical indexes showed that the contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in transgenic <i>Arabidopsis</i> were lower, with the contents of hydrogen peroxide (H₂O₂) and superoxide anion (O₂^-) being 0.72 and 0.71 times those of the wild type, respectively, and the MDA content was 0.53 times that of the wild type. Compared with the wild type, the activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased by 1.2, 1.75, and 1.48 times respectively, and the soluble protein content increased by 1.41 times, which significantly improved the cold tolerance of <i>Arabidopsis</i>. The contents of H₂O₂, O₂^-, and MDA in <i>LhSBP1</i> transgenic 'Nanlin 895' poplar were 0.63 and 0.67 times and 0.6 times those of wild type, respectively. The activities of SOD, POD and CAT were increased by 1.37, 1.48, and 1.44 times, and the soluble protein was increased by 1.28 times, which significantly improved the cold tolerance of 'Nanlin 895' poplar. Taken together, this study utilized two model plant systems to demonstrate the positive and conserved functions of <i>LhSBP1</i> in plant cold tolerance defense response, which provided valuable genetic resources for the breeding of cold-tolerance woody plants.