Molecular characterisation of the Cu/Zn superoxide dismutase gene (ZjSOD1) induced by salt stress in Zoysia japonica

NaCl was used to evaluate the molecular response to salt stress in Zoysia japonica. A 452-bp cDNA clone, which showed high similarity to other plant Cu/Zn superoxide dismutase (SOD) gene sequences, was selected and designated Zoysia japonica Cu/Zn superoxide dismutase 1 (ZjSOD1). Southern blot analysis showed the presence of at least two copies of the ZjSOD1 gene in Z. japonica. ZjSOD1 transcripts increased with exposure to a high salt concentration (300 mM NaCl). ZjSOD1 transcript levels increased in non-immersed tissues such as stolons and their tips, as well as in stolon tissue that had been immersed in 300 mM NaCl for 36 h. The highest level of ZjSOD1 gene expression was observed in stolon tips. However, ZjSOD1 transcript levels were higher in immersed stolons than in non-immersed stolons, or their tips, during the salt stress treatment. Molecular characterisation of the ZjSOD1 gene may provide clues about the response mechanism to salt stress in the stolons of Z. japonica and other turfgrasses.