Canadian Food Inspection Agency, Charlottetown, Canada.
Phytopathology. 2012 Oct;102(10):937-47. doi: 10.1094/PHYTO-04-12-0083-R.
Pectobacterium atrosepticum, P. carotovorum subsp. brasiliensis, P. carotovorum subsp. carotovorum, and P. wasabiae were detected in potato stems with blackleg symptoms using species- and subspecies-specific polymerase chain reaction (PCR). The tests included a new assay for P. wasabiae based on the phytase gene sequence. Identification of isolates from diseased stems by biochemical or physiological characterization, PCR, and multi-locus sequence typing (MLST) largely confirmed the PCR detection of Pectobacterium spp. in stem samples. P. atrosepticum was most commonly present but was the sole Pectobacterium sp. detected in only 52% of the diseased stems. P. wasabiae was most frequently present in combination with P. atrosepticum and was the sole Pectobacterium sp. detected in 13% of diseased stems. Pathogenicity of P. wasabiae on potato and its capacity to cause blackleg disease were demonstrated by stem inoculation and its isolation as the sole Pectobacterium sp. from field-grown diseased plants produced from inoculated seed tubers. Incidence of P. carotovorum subsp. brasiliensis was low in diseased stems, and the ability of Canadian strains to cause blackleg in plants grown from inoculated tubers was not confirmed. Canadian isolates of P. carotovorum subsp. brasiliensis differed from Brazilian isolates in diagnostic biochemical tests but conformed to the subspecies in PCR specificity and typing by MLST.
马铃薯青枯病假单胞菌、胡萝卜软腐果胶杆菌亚种巴西软腐亚种、胡萝卜软腐果胶杆菌亚种胡萝卜软腐亚种和稻生欧文氏菌在出现黑胫病症状的马铃薯茎中使用种特异性和亚种特异性聚合酶链反应（PCR）进行了检测。该测试包括了一种基于植酸酶基因序列的稻生欧文氏菌新检测方法。通过生化或生理特征、PCR 和多位点序列分型（MLST）对患病茎中的分离物进行鉴定，在很大程度上证实了 PCR 对茎样本中果胶杆菌属的检测。马铃薯青枯病假单胞菌最为常见，但在 52%的患病茎中仅检测到该种果胶杆菌。稻生欧文氏菌最常与马铃薯青枯病假单胞菌共同存在，在 13%的患病茎中仅检测到该种果胶杆菌。稻生欧文氏菌对马铃薯的致病性及其引起黑胫病的能力通过茎接种得到了证实，并且从接种过的种薯生长的田间患病植物中仅分离出稻生欧文氏菌。患病茎中胡萝卜软腐果胶杆菌亚种巴西软腐亚种的发病率较低，且加拿大菌株在接种过的块茎中引起黑胫病的能力尚未得到证实。加拿大的胡萝卜软腐果胶杆菌亚种巴西软腐亚种与巴西的分离株在诊断生化试验中存在差异，但在 PCR 特异性和 MLST 分型方面符合该亚种。
