Phylogeny and distribution of extra-slow-growing Bradyrhizobium japonicum harboring high copy numbers of RSalpha, RSbeta and IS1631.
Phylogeny and distribution of extra-slow-growing Bradyrhizobium japonicum harboring high copy numbers of RSalpha, RSbeta and IS1631.
复制标题
DOI：
10.1016/s0168-6496(03)00009-6
复制
发表时间：
2003-05
影响因子：
4.2
通讯作者：
R. Sameshima;Tsuyoshi Isawa;M. Sadowsky;T. Hamada;H. Kasai;A. Shutsrirung;H. Mitsui;K. Minamisawa
中科院分区：
文献类型：
--
作者：
R. Sameshima;Tsuyoshi Isawa;M. Sadowsky;T. Hamada;H. Kasai;A. Shutsrirung;H. Mitsui;K. Minamisawa
我们先前报道了从日本三个现场获得的超慢生长慢生根瘤菌分离株，命名为具有高度重复序列的菌株，具有高拷贝数的插入序列RSα和RSβ。以RS-α、RS-β和IS1631为探针，对美国、日本、韩国、泰国和中国的样品进行Southern杂交检测，发现日本、中国和美国样品中有HRS菌株，而韩国和泰国样品中未发现HRS菌株。根据rRs(16S rRNA基因)的拷贝数对RSα和RSβ的拷贝数进行了分析，结果表明，RS菌株可分为两大类。A组成员具有较高的RSα拷贝数(平均值±S.D.)，较低的RSβ序列数(平均值±S.D.，30±13)和极低的生长速度(平均倍增时间±S.D.，27±9h)。而B组为RSβ拷贝数高的菌株(平均值为93±6)，RSα拷贝数低的菌株。这些HRS毒株分组与基于rrS和gyrBand血清群的系统发育聚类(110/122和123/135)有很好的相关性。B的增长率。日本血吸虫株还与RSα拷贝数呈正相关。讨论了这些发现的生态、进化和生物技术方面的影响。
We previously reported that extra-slow-growingBradyrhizobium japonicumisolates obtained from three field sites in Japan, designated as HRS (highly reiterated sequence-possessing) strains, have high copy numbers of the insertion sequences RSα and RSβ. When strain collections in the USA, Japan, Korea, Thailand and China were examined by Southern hybridization using RSα, RSβ and IS1631as probes, HRS strains were found in the Japanese, Chinese, and American collections, but not in the Korean and Thai ones. Copy number analyses of RSα and RSβ, calibrated with the copy number ofrrs(16S rRNA gene), indicated that the HRS stains can be divided into two major groups. Group A is comprised of members with a high copy number of RSα (mean±S.D., 139±27), a low number of RSβ (mean±S.D., 30±13) sequences, and extremely slow growth rates (mean doubling time±S.D., 27±9 h). In contrast, group B is comprised of strains with a high copy number of RSβ (mean±S.D., 93±6) and a lower number of RSα. These groupings of HRS strains were well correlated with phylogenetic clusters based onrrs,gyrBand serogroups (110/122 and 123/135). Growth rate ofB. japonicumstrains was also correlated exclusively with RSα copy number. The ecological, evolutionary and biotechnological implications of the findings are discussed.