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以水稻黄单胞菌水稻致病变种 (Xanthomonasoryzaepv .oryzae)的毒性菌株PXO99A和无毒菌株PXO99A(pBUavrXa1 0 F1 ) ,检测液体培养中菌体超氧化物歧化酶 (SOD)活性变化 ,以说明SOD与菌株致病性的关系。结果表明 ,菌体SOD活性高峰出现于延迟期末 ,之后下降 ;毒性菌株SOD活性高于无毒菌株。两个菌株的SOD活性的胞内定位均以胞质为主 ,占总活性的 70 %以上 ;酶体周质中SOD活性占总活性的 2 0 %～ 30 %。以 50～ 80 0 μmol/L外源O-2 处理细菌培养物 1h ,可诱导菌体中SOD活性的增加。其中以 2 0 0 μmol/LO-2 处理SOD活性最高 ;1 2h菌龄培养物的诱导效果优于 2 4h培养物 ;对毒性菌株SOD的诱导作用更为明显。外源O-2 处理后细菌存活率明显降低 ,2 4h培养物的存活率下降大于 1 2h培养物 ;毒性菌株存活率下降大于无毒菌株。
The change of superoxide dismutase (SOD) activity in the liquid culture was detected using PXO99A and PXO99A (pBUavrXa1 0 F1), a virulent strain of Xanthomonas oryzae virulent strain, to demonstrate that SOD Relationship with the pathogenicity of the strain. The results showed that the peak of SOD activity appeared at the end of the delay period and then decreased. The SOD activity of the virulent strain was higher than that of the non-toxic strain. The intracellular localization of SOD activity in both strains was mainly in the cytoplasm, accounting for more than 70% of the total activity. The SOD activity in the periplasm of the two strains accounted for 20% -30% of the total activity. Bacterial culture was treated with 50 ~ 80 0 μmol / L exogenous O-2 for 1 h, which could induce the increase of SOD activity. Among them, the highest SOD activity was treated with 200 μmol / L LO-2; the induction effect of 12-h culture was superior to that of 24-h culture; the induction of SOD was more obvious. Survival rate of bacteria decreased significantly after treated with exogenous O-2, and the survival rate of 24 h culture decreased more than that of 12 h culture. The survival rate of virulent strain decreased more than that of non-toxic strain.