Appl Environ Microbiol. 1995 Apr;61(4):1194-200. doi: 10.1128/aem.61.4.1194-1200.1995.
Genetic structure in field populations of Bradyrhizobium japonicum isolated in Poland was determined by using several complementary techniques. Of the 10 field sites examined, only 4 contained populations of indigenous B. japonicum strains. The Polish bradyrhizobia were divided into at least two major groups on the basis of protein profiles on polyacrylamide gels, serological reaction with polyclonal antisera, repetitive extragenic palindromic PCR fingerprints of genomic DNA, and Southern hybridization analyses with nif and nod gene probes. Serological analyses indicated that 87.5% of the Polish B. japonicum isolates tested were in serogroups 123 and 129, while seven (12.5%) of the isolates tested belonged to their own unique serogroup. These seven strains also could be grouped together on the basis of repetitive extragenic palindromic PCR fingerprints, protein profiles, and Southern hybridization analyses. Cluster analyses indicated that the seven serologically undefined isolates were genetically dissimilar from the majority of the Polish B. japonicum strains. Moreover, immuno-cross-adsorption studies indicated that although the Polish B. japonicum strains reacted with polyclonal antisera prepared against strain USDA123, the majority failed to react with serogroup 123- and 129-specific antisera, suggesting that Polish bradyrhizobia comprise a unique group of root nodule bacteria which have only a few antigens in common with strains USDA123 and USDA129. Nodulation studies indicated that members of the serologically distinct group were very competitive for nodulation of Glycine max cv. Nawiko. None of the Polish serogroup 123 or 129 isolates were restricted for nodulation by USDA123- and USDA129-restricting soybean plant introduction genotypes. Taken together, our results indicate that while genetically diverse B. japonicum strains were isolated from some Polish soils, the majority of field sites contained no soybean-nodulating bacteria. In addition, despite the lack of long-term soybean production in Poland, field populations of unique B. japonicum strains are present in some Polish soils and these strains are very competitive for nodulation of currently used Polish soybean varieties.
在波兰分离的根瘤菌（Bradyrhizobium japonicum）田间种群的遗传结构，通过使用几种互补技术来确定。在所检查的 10 个田间地点中，只有 4 个地点含有土著 B. japonicum 菌株。基于聚丙烯酰胺凝胶上的蛋白质图谱、多克隆抗血清的血清学反应、基因组 DNA 的重复外回文 PCR 指纹图谱和 nif 和 nod 基因探针的 Southern 杂交分析，波兰的慢生根瘤菌被分为至少两个主要群体。血清学分析表明，测试的 87.5%的波兰 B. japonicum 分离株属于血清群 123 和 129，而测试的 7 株（12.5%）分离株属于其自身独特的血清群。这 7 个菌株也可以根据重复外回文 PCR 指纹图谱、蛋白质图谱和 Southern 杂交分析进行分组。聚类分析表明，这 7 个血清学上无法定义的分离株在遗传上与大多数波兰 B. japonicum 菌株不同。此外，免疫交叉吸附研究表明，尽管波兰 B. japonicum 菌株与针对菌株 USDA123 制备的多克隆抗血清反应，但大多数菌株与血清群 123 和 129 特异性抗血清不反应，表明波兰慢生根瘤菌包含一组独特的根瘤细菌，它们与菌株 USDA123 和 USDA129 只有少数共同抗原。结瘤研究表明，血清学上不同的组的成员在竞争结瘤 Glycine max cv. Nawiko 方面非常有竞争力。没有一个波兰血清群 123 或 129 分离株受到 USDA123 和 USDA129 限制大豆引种基因型的结瘤限制。总的来说，我们的结果表明，虽然从一些波兰土壤中分离出了遗传上多样化的 B. japonicum 菌株，但大多数田间地点都没有大豆固氮菌。此外，尽管波兰没有长期的大豆生产，但在一些波兰土壤中存在独特的 B. japonicum 菌株的田间种群，这些菌株在结瘤目前使用的波兰大豆品种方面具有很强的竞争力。
