Institute of Microbiology, ETH Zurich, Wolfgang-Pauli-Strasse 10, Zurich, Switzerland.
Antonie Van Leeuwenhoek. 2012 Jan;101(1):169-83. doi: 10.1007/s10482-011-9650-6. Epub 2011 Oct 11.
Methylobacterium strains are abundantly found in the phyllosphere of plants. Morphological, physiological and chemotaxonomical properties of 12 previously isolated strains were analyzed in order to obtain a more detailed overview of the characteristics of phyllosphere colonizing Methylobacterium strains. All strains showed the typical properties of the genus Methylobacterium, including pink pigmentation, facultative methylotrophy, a fatty acid profile dominated by C18:1 ω7c, and a high G+C content of 65 mol % or more. However, some strains showed only weak growth on methanol and pigmentation varied from pale pink to red. Strains grew best under mesophilic, neutrophilic conditions and low salt (≤1%) concentrations, but variation was seen with respect to the temperature and pH range under which growth occurred. Likewise, differences were seen with respect to carbon source utilization. Some strains were versatile and utilized diverse organic acids, amino acids and sugars, while others could only metabolize a restricted number of organic acids. The strains that were most distinct from existing type strains based on 16S rRNA gene sequence analysis were selected for DNA-DNA hybridization experiments to analyze whether they are sufficiently different at the genomic level from existing type strains to justify their classification as new species. This resulted in the delineation of strain 440 and its description as Methylobacterium longum sp. nov. strain 440 (=DSM 23933(T) = CECT 7806(T)). A main characteristic of this species is the formation of relatively long rods compared to other Methylobacterium species.
甲基杆菌菌株在植物的叶际中大量存在。为了更详细地了解定殖于叶片的甲基杆菌菌株的特征，对 12 株先前分离的菌株的形态学、生理学和化学分类学特性进行了分析。所有菌株均表现出甲基杆菌属的典型特性，包括粉红色色素、兼性甲基营养型、以 C18:1 ω7c 为主的脂肪酸图谱和 65 mol%或更高的高 GC 含量。然而，一些菌株在甲醇上的生长较弱，且色素从淡粉色到红色不等。菌株在中温、中性条件和低盐（≤1%）浓度下生长最好，但在生长发生的温度和 pH 范围上存在差异。同样，在碳源利用方面也存在差异。一些菌株具有多功能性，可利用多种有机酸、氨基酸和糖，而其他菌株只能代谢有限数量的有机酸。根据 16S rRNA 基因序列分析，从最明显不同于现有模式株的菌株中选择了用于 DNA-DNA 杂交实验的菌株，以分析它们在基因组水平上是否与现有模式株足够不同，以证明它们被分类为新物种是合理的。这导致了菌株 440 的划定及其描述为长甲基杆菌。nov. 菌株 440（=DSM 23933(T)=CECT 7806(T)）。该物种的一个主要特征是与其他甲基杆菌属物种相比形成相对较长的棒状。
