Abstract: 【Objective】 In this study,the sod gene deletion strain was constructed to elucidate the effect of sod gene on the anti-oxidative stress ability of Listeria monocytogenes 10403S.【Method】 The sod gene deletion strain was constructed by homologous recombination method.The growth ability of parent strain 10403S,deletion strain 10403SΔsod and complemented strain 10403S CΔsod were analyzed by growth test.The effect of sod gene on oxidative stress of Listeria monocytogenes was determined by oxidative stress test.The effect of oxidative stress on SOD protein expression was determined by Western blotting.【Result】 The results of PCR showed that the target fragments of 10403SΔsod and 10403SCΔsod were 1 468 and 1 875 bp,respectively,deletion strain 10403SΔsod and complemented strain 10403S CΔsod were successfully constructed.The results of growth test showed that sod gene deletion did not affect the growth ability of 10403S.The results of anti-oxidative stress test showed that sod gene deletion reduced the anti-oxidative stress ability of 10403S under the condition of 20 mmol/L H₂O₂(P＜0.01).The results of Western blotting showed that the expression level of SOD protein of Listeria monocytogenes was significantly up-regulated under oxidative stress (P＜0.01).【Conclusion】 The deletion of sod gene did not affect the normal growth of Listeria monocytogenes 10403S,but it could lead to a decrease in oxidative stress ability,and the expression level of SOD protein in 10403S was significantly increased under the condition of 20 mmol/L H₂O₂.

Key words: Listeria monocytogenes; superoxide dismutase (SOD); oxidative stress; polyclonal antibody