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利用MT选择性培养基从加拿大进境油菜籽样品中分离到2株细菌分离物2305-1和5309-1,对分离物进行致病性测定、LOPAT测试、Biolog测试、hrp Z和cfl基因序列分析,以及多位点序列分析。结果表明:2株分离物人工接种油菜、花椰菜和番茄幼苗都能引起典型黑斑症状;LOPAT测试和Biolog测试结果与丁香假单胞菌(Pseudomonas syringae)的各项生理指标一致;hrp Z基因序列与十字花科黑斑病菌(P.syringae pv.maculicola)和番茄细菌性叶斑病菌(P.syringae pv.tomato)的序列相似性均为99.18%~100%;cfl基因序列分析表明分离物2305-1和5309-1基因组中存在冠毒素合成基因;选择gyr B、rop D、glt A、gap1、acn B和pgi 6个看家基因进行多位点序列分析,系统发育树显示分离物2305-1和5309-1均与P.syringae pv.maculicola聚在一起。根据试验结果将分离物2305-1和5309-1鉴定为十字花科黑斑病菌P.syringae pv.maculicola。
Two bacterial isolates, 2305-1 and 5309-1, were isolated from Canadian rapeseed samples using MT selective media. The isolates were tested for pathogenicity, LOPAT test, Biolog test, hrp Z and cfl gene sequences Analysis, and multi-site sequence analysis. The results showed that the two isolates were able to induce typical black spot by artificial inoculation of rapeseed, cauliflower and tomato seedlings. The results of LOPAT and Biolog were consistent with the physiological indexes of Pseudomonas syringae. The hrp Z gene sequence The sequence similarity to P. syringae pv. Maculicola and P. syringae pv.tomato was 99.18% -100%. Sequence analysis of cfl gene showed that the isolates 2305 -1 and 5309-1 genes. The six housekeeping genes gyr B, rop D, glt A, gap1, acn B and pgi were selected for multi-locus sequence analysis. The phylogenetic tree showed that the isolates 2305- 1 and 5309-1 are together with P. syringae pv. Maculicola. According to the test results, isolates 2305-1 and 5309-1 were identified as P. syringae pv. Maculicola.