陕西关中地区猕猴桃溃疡病菌对CuSO4的抗性评价

为明确陕西省猕猴桃细菌性溃疡病菌（Pseudomonas syringae pv.actinidiae,Psa）对CuSO₄的抗性水平及与copA和copB基因表达量的相关性，使用最小抑菌浓度法（MIC）对分离自陕西省关中地区的84株Psa菌株对于CuSO₄的抗性进行检测。在此基础上，使用实时荧光定量PCR方法，对3株不同抗性水平Psa菌株的基因copA和copB与抗铜性的关系进行了分析。结果表明，供试的84株Psa菌株MIC分布在3.75~6.25 mmol·L^-1范围内；不同地区来源的菌株对CuSO₄的抗性表现出明显的差异，其中分离自周至的Psa菌株的抗铜水平明显高于眉县。实时荧光定量PCR分析结果显示，不同浓度CuSO₄条件诱导下，3株不同抗性水平的菌株抗铜基因copA和copB表达水平与CuSO₄浓度成正相关，且菌株的抗性水平越高，基因copA和copB相对表达水平亦越高。陕西省关中地区的Psa菌株对CuSO₄表现出较高的抗性水平，且不同地区的Psa菌株的抗性表现出明显差异；copA和copB基因参与了Psa菌株对铜离子的适应性反应。

The Evaluation of the Tolerance Level of Pseudomonas syringae pv.actinidiae to CuSO 4 in Guanzhong Area of Shaanxi Province

In order to determine the tolerance level of Pseudomonas syringae pv.actinidiae(Psa)to CuSO 4 in Shaanxi Province which is the main cultivation area of kiwifruit in China,the tolerance levels of 84 Psa strains to CuSO 4 were detected by using the minimum inhibitory concentration method(MIC).The correlations between the expression levels of copA,copB genes and the copper resistance of three strains with different tolerance levels were studied by using real-time fluorescent quantitative PCR.The results showed that 84 Psa strains showed highly tolerance to CuSO 4,and MIC ranged from 3.75 to 6.25 mmol·L-1.Significant differences in tolerance levels were observed between the strains collected from different locations.For example,the tolerance levels of the strains collected from Zhouzhi County was significantly higher than those from Meixian County.The real-time PCR results showed that the expression levels of anti-copper genes copA and copB from three strains with different tolerant levels were positively correlated with the concentration of CuSO 4,and the higher tolerance level of the strain,the higher relative expression of copA and copB genes.To sum it up,the Psa strains from Guanzhong showed high tolerance to CuSO 4,and differences in tolerance levels existed between the strains collected from different locations within the area.In addition,the copA and copB genes may be involved in the adaptive response of Psa strains to high concentration copper.