Kim W S, Hildebrand M, Jock S, Geider K
Max-Planck-Institut für Zellbiologie, Rosenhof, 68526 Ladenburg, Germany.
Microbiology (Reading). 2001 Nov;147(Pt 11):2951-9. doi: 10.1099/00221287-147-11-2951.
Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen. These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did not give the expected PCR signals with several primer pairs specific for Erwinia amylovora. The isolates tested positive with PCR primers designed to detect the novel pear pathogen Erwinia pyrifoliae, which was isolated from Nashi pear trees in South Korea. The nucleotide sequence analysis of a DNA fragment preceding the gene cluster for exopolysaccharide synthesis revealed a closer relationship to Erwinia pyrifoliae than to Erwinia amylovora. Plasmid profiles, protein patterns and genomic DNA analysed by PFGE after XbaI and SpeI digestion were different than Erwinia amylovora. Experiments with strains of Erwinia amylovora isolated from raspberry (Rubus sp.), Erwinia mallotivora and Enterobacter pyrinus also did not reveal a relationship between these bacteria and the Japanese Erwinia strains. The latter are not identical to Erwinia pyrifoliae, but possess many similar features to this pathogen that causes Asian pear blight. It is concluded that pathogenic bacteria isolated in Japan from pear trees with symptoms resembling fire blight are possibly different from Erwinia amylovora.
从日本患坏死症状（类似火疫病）的梨树上分离出的几种欧文氏菌菌株，最初被鉴定为梨火疫欧文氏菌，现对其与火疫病病原菌的关系进行重新研究。这些分离株在未成熟梨切片上产生菌脓，在MM2Cu琼脂平板上呈黏液状，但不合成果聚糖，并且用几种针对梨火疫欧文氏菌的特异性引物对未给出预期的PCR信号。这些分离株用设计用于检测新型梨病原菌梨欧文氏菌的PCR引物检测呈阳性，该病原菌是从韩国的二十世纪梨树上分离得到的。对胞外多糖合成基因簇之前的一个DNA片段进行核苷酸序列分析表明，其与梨欧文氏菌的关系比与梨火疫欧文氏菌的关系更近。经XbaI和SpeI酶切后通过PFGE分析的质粒图谱、蛋白质图谱和基因组DNA与梨火疫欧文氏菌不同。用从树莓（悬钩子属）分离出的梨火疫欧文氏菌菌株、苹果欧文氏菌和梨肠杆菌进行的实验也未揭示这些细菌与日本欧文氏菌菌株之间的关系。后者与梨欧文氏菌并不相同，但具有许多与这种引起亚洲梨疫病的病原菌相似的特征。得出的结论是，在日本从有类似火疫病症状的梨树上分离出的病原菌可能与梨火疫欧文氏菌不同。
