McGhee Gayle C, Schnabel Elise L, Maxson-Stein Kimberly, Jones Beatrix, Stromberg Verlyn K, Lacy George H, Jones Alan L
Department of Plant Pathology, Michigan State University, East Lansing 48824-1312, USA.
Appl Environ Microbiol. 2002 Dec;68(12):6182-92. doi: 10.1128/AEM.68.12.6182-6192.2002.
The plant pathogen Erwinia pyrifoliae has been classified as a separate species from Erwinia amylovora based in part on differences in molecular properties. In this study, these and other molecular properties were examined for E. pyrifoliae and for additional strains of E. amylovora, including strains from brambles (Rubus spp.). The nucleotide composition of the internal transcribed spacer (ITS) region was determined for six of the seven 16S-23S rRNA operons detected in these species with a 16S rRNA gene probe. Each species contained four operons with a tRNA(Glu) gene and two with tRNA(Ile) and tRNA(Ala) genes, and analysis of the operons from five strains of E. amylovora indicated a high degree of ITS variability among them. One tRNA(Glu)-containing operon from E. pyrifoliae Ep1/96 was identical to one in E. amylovora Ea110, but three tRNA(Glu) operons and two tRNA(Ile) and tRNA(Ala) operons from E. pyrifoliae contained unique nucleotide changes. When groEL sequences were used for species-specific identification, E. pyrifoliae and E. amylovora were the closest phylogenetic relatives among a set of 12 bacterial species. The placement of E. pyrifoliae distinct from E. amylovora corroborated molecular hybridization data indicating low DNA-DNA similarity between them. Determination of the nucleotide sequence of plasmid pEP36 from E. pyrifoliae Ep1/96 revealed a number of presumptive genes that matched genes previously found in pEA29 from E. amylovora and similar organization for the genes and origins of replication. Also, pEP36 and pEA29 were incompatible with clones containing the reciprocal origin regions. Finally, the ColE1-like plasmid pEP2.6 from strain Ep1/96 contained sequences found in small plasmids in E. amylovora strains IL-5 and IH3-1.
植物病原菌梨火疫欧文氏菌已被分类为与解淀粉欧文氏菌不同的物种，部分依据是分子特性的差异。在本研究中，对梨火疫欧文氏菌以及解淀粉欧文氏菌的其他菌株，包括来自悬钩子属（悬钩子属植物）的菌株，检测了这些以及其他分子特性。用16S rRNA基因探针确定了在这些物种中检测到的7个16S - 23S rRNA操纵子中的6个的内部转录间隔区（ITS）区域的核苷酸组成。每个物种都含有4个带有tRNA(Glu)基因的操纵子和2个带有tRNA(Ile)和tRNA(Ala)基因的操纵子，对5株解淀粉欧文氏菌的操纵子分析表明它们之间的ITS存在高度变异性。梨火疫欧文氏菌Ep1/96的一个含tRNA(Glu)的操纵子与解淀粉欧文氏菌Ea110中的一个相同，但梨火疫欧文氏菌的3个tRNA(Glu)操纵子以及2个tRNA(Ile)和tRNA(Ala)操纵子含有独特的核苷酸变化。当使用groEL序列进行物种特异性鉴定时，在一组12种细菌中，梨火疫欧文氏菌和解淀粉欧文氏菌是亲缘关系最近的系统发育亲属。梨火疫欧文氏菌与解淀粉欧文氏菌不同的分类位置证实了分子杂交数据，表明它们之间的DNA - DNA相似性较低。对梨火疫欧文氏菌Ep1/96的质粒pEP36的核苷酸序列测定揭示了一些推测基因，这些基因与先前在解淀粉欧文氏菌的pEA29中发现的基因匹配，并且基因和复制起点的组织相似。此外，pEP36和pEA29与含有相互起源区域的克隆不相容。最后，来自菌株Ep1/96的ColE1样质粒pEP2.6含有在解淀粉欧文氏菌菌株IL - 5和IH3 - 1的小质粒中发现的序列。
