State Key Laboratory of Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, China.
Syst Appl Microbiol. 2012 Jun;35(4):239-45. doi: 10.1016/j.syapm.2012.02.004. Epub 2012 Mar 29.
The genetic diversity of 88 Caragana nodule rhizobial isolates, collected from arid and semi-arid alkaline sandy soils in the north of China, was assessed by PCR-RFLP of the 16S rRNA gene and the 16S-23S IGS, as well as the phylogenies of housekeeping genes (atpD, glnII and recA) and symbiotic genes (nodC and nifH). Of the 88 strains, 69 were placed in the genus Mesorhizobium, 16 in Rhizobium and 3 in Bradyrhizobium. Mesorhizobium amorphae, Mesorhizobium septentrionale, Mesorhizobium temperatum and Rhizobium yanglingense were the four predominant microsymbionts associated with Caragana spp. in the surveyed regions, and M. septentrionale was widely distributed among the sampling sites. Phylogenies of nodC and nifH genes showed that two kinds of symbiotic genes existed, corresponding to Mesorhizobium and Rhizobium, respectively. Available phosphorous (P) and potassium (K) contents were the main soil factors correlated with the distribution of these rhizobia in the sampling regions. Positive correlations between the available higher P content/lower K content and the dominance of Mesorhizobium species (M. temperatum, M. amorphae and M. septentrionale), and between the lower P content/higher K content and the dominance of R. yanglingense were found.
从中国北方干旱半干旱碱性沙地上采集的 88 株 Caragana 根瘤菌的遗传多样性，通过 16S rRNA 基因和 16S-23S IGS 的 PCR-RFLP 分析，以及看家基因（atpD、glnII 和 recA）和共生基因（nodC 和 nifH）的系统发育进行了评估。在 88 株菌株中，69 株属于 Mesorhizobium 属，16 株属于 Rhizobium 属，3 株属于 Bradyrhizobium 属。与调查地区 Caragana spp. 相关的主要微共生菌为：Mesorhizobium amorphae、Mesorhizobium septentrionale、Mesorhizobium temperatum 和 Rhizobium yanglingense，其中 M. septentrionale 在采样地点广泛分布。nodC 和 nifH 基因的系统发育表明存在两种共生基因，分别对应于 Mesorhizobium 和 Rhizobium。可利用磷（P）和钾（K）含量是与这些根瘤菌在采样区域分布相关的主要土壤因素。可利用高 P 含量/低 K 含量与 Mesorhizobium 属（M. temperatum、M. amorphae 和 M. septentrionale）的优势呈正相关，而低 P 含量/高 K 含量与 R. yanglingense 的优势呈正相关。
