[ Objective ] The paper was to confirm the effect of hrpZpsg12 gene on the pathogenicity of Pseudomonas syringae pv. glycinea.[ Method] hrpZpsg12 gene was cloned from P. syringae pv. glycinea using PCR method. The knockout plasmid pKNOCK-Cm with suicide characteristics and clay pUFR034 with complementarity were used to construct the mutation vector pKNOCK477-7 and complementary vector pUFR1026-68 of hrpZpsg12 gene, the mutant 477-1 and the functional complementation unit 1026-5 of the gene was also screened out. Three strains including wild-type Psg12, mutant 477-1 and complementary unit 1026-5 were simultaneously inoculated into soybean leaves and tobacco leaves, then pathogenicity determination and hypersensitive response analysis were carried out. [ Result] All the inoculated leaves of soybean and tobacco produced reaction lesion. However, the sizes of reaction lesion were different. The lesion inoculated with Psg12 was relatively large, while the lesion inoculated with 477-1 was relatively small; the lesion of complementary unit 1026-5 was similar to wild-type Psg12.The reproduction amount of bacteria in lesions showed that the reproduction amount was the highest in wild-type Psg12, which was the lowest in mutant 477-1. The reproduction amount of complementary unit 1026-5 was similar to that of wild-type Psg12. [ Conclusion] hrpZpsg12 Gene could enhance the pathogenicity of P. syringae pr. glycinea on Soybean and produce hypersensitive response in tobacco.%[目的]明确hrpZ<,Psg12>基因对大豆细菌性斑点病菌致病性的影响.[方法]采用PCR方法从大豆细菌性斑点病菌中克隆hrpZ<,Psg12>基因,利用具有自杀特性的敲除质粒pKNOCK-Cm和具有功能互补作用的粘粒pUFR034.构建了hrpZ<,Psg12>基因的突变载体pKNOCK477-7和互补载体pUFR1026-68,并筛选出hrpZ<,Psg12>基因的突变体477-1及其功能互补子1026-5.进一步将野生型Psg12、突变体477-1和互补子1026-5等3个菌株同时接种大豆叶片和烟草叶片,进行致病性测定和过敏性反应分析.[结果]所有被接种的大豆和烟草叶片都产生了反应斑.但是,反应斑的大小有差异,Psg12菌株接种的病斑较大,477-1的较小,互补子1026-5的接近野生型菌株Psg12.病斑中细菌繁殖量分析表明,野生型菌株Psg12繁殖量最高,突变体477-1的最低,互补子1026-5的接近野生型菌株Psg12的繁殖量.[结论]hrpZ<,Psg12>基因能够增强大豆细菌性斑点病菌对大豆的致病性,并且能够在烟草上产生过敏性反应.
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