Genetic Ecology of Bradyrhizobium japonicum in soils

利用4个DNA杂交探针，对日本6个地区特有的日本慢生根瘤菌进行了鉴定；nifDK, nodDYAB, hup， RS-alpha和RS- beta。观察了rs特异性杂交（rs指纹）的多样性。rs指纹图谱与nif和hup基因型相关，并与田间位置和种植历史相关。根据nodDYAB杂交结果，田间分离菌株可分为A、B、c 3个主要类群。A、B类群产生的nod代谢产物相似，包括NodBj-V，均有甲基聚焦。仅从siratro中分离出的C组菌株与大豆不相容，产生不同的nod代谢物。对于结点，我们构建了简单的关系。建立了本地慢生根瘤菌的遗传生态学方法。

The isolates of Bradyrhizobium japonicum indigenous to six field in Japan were characterized by using four DNA hybridization probes from the species; nifDK, nodDYAB, hup, RS-alpha, and RS- beta. Diversity in RS-specific hybridization (RS-fingerprint) were observed. The RS-fingerprints were correlated with the nif and hup genotypes, and with the location of field including cropping history. According to nodDYAB hybridization, the field isolates were classified into three main group A, B and C. The group A and B produced similar nod metabolites including NodBj-V with methyl fucose. The group C isolates, which were separated only from siratro, were incompatible with soybeans,and produced different nod metabolites. As for nodulation, we constructed simple relationship. As a result, we established the method of genetic ecology for indigenous bradyrhizobia.