Abstract: Reaumuria trigyna, a highly xerophytic halophyte, shows strong adaption to the high saline and hyper-drought environments. Superoxide dismutase (SOD) plays an important role in withstanding these abiotic stressors. In this study, primers were designed using the known sequence of a SOD gene in the transcription database of R. trigyna. The open reading frame of the SOD gene with a size of 663 bp and encoding 220 amino acids was cloned by PCR and identified as RtSOD. The molecular weight of the protein was predicted to be 55.90 kDa and the theoretical isoelectric point was pH 5.11. The results of multiple sequence alignment analysis showed that the protein belongs to the Cu/Zn SOD family and had high homology with the SOD protein of other plants. Real-time fluorescence quantitative PCR analysis showed that NaCl, 4 ℃ temperature, polyethylene glycol, H₂O₂ and abscisic acid could induce the expression of the gene. Construction and transfer into Arabidopsis thaliana of a eukaryotic expression vector enhanced the growth rate of A. thaliana, compared to that of the wild type. In addition, antioxidant enzyme activities (SOD, peroxidase, catalase) and the content of proline were significantly higher than in wild type A. thaliana, and the contents of H₂O₂ and malondialdehyde were significantly lower than those of wild type A. thaliana under salt and drought stress. qRT-PCR analysis indicated that the expressions of stress-related genes in transgenic Arabidopsis were significantly higher than those of the wild type. The above results indicate that overexpression of RtSOD could increase the stress tolerance of transgenic plants, and further demonstrated that the RtSOD gene is involved in the response to the abiotic stress of R. trigyna and is an important component in the plant antioxidant system.

Key words: Reaumuria trigyna, superoxide dismutase, abiotic stress, transgenic Arabidopsis thaliana