State Key Laboratory of Agrobiotechnology, Key laboratory of Agro-Microbial Resource and Application, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing 100094, China.
Microb Ecol. 2010 Feb;59(2):311-23. doi: 10.1007/s00248-009-9577-x.
The associations among rhizobia chromosomal background, nodulation genes, legume plants, and geographical regions are very attractive but still unclear. To address this question, we analyzed the interactions among rhizobia rDNA genotypes, nodC genotypes, legume genera, as well as geographical regions in the present study. Complex relationships were observed among them, which may be the genuine nature of their associations. The statistical analyses indicate that legume plant is the key factor shaping both rhizobia genetic and symbiotic diversity. In the most cases of our results, the nodC lineages are clearly associated with rhizobial genomic species, demonstrating that nodulation genes have co-evolved with chromosomal background, though the lateral transfer of nodulation genes occurred in some cases in a minority. Our results also support the hypothesis that the endemic rhizobial populations to a certain geographical area prefer to have a wide spectrum of hosts, which might be an important event for the success of both legumes and rhizobia in an isolated region.
根瘤菌的染色体背景、结瘤基因、豆科植物和地理区域之间的联系非常吸引人，但仍不清楚。为了解决这个问题，我们在本研究中分析了根瘤菌 rDNA 基因型、nodC 基因型、豆科植物属以及地理区域之间的相互作用。它们之间存在着复杂的关系，这可能是它们联系的本质。统计分析表明，豆科植物是塑造根瘤菌遗传和共生多样性的关键因素。在我们结果的大多数情况下，nodC 谱系与根瘤菌基因组种明显相关，表明尽管在某些情况下nod 基因发生了横向转移，但nod 基因与染色体背景是共同进化的。我们的研究结果还支持这样一种假设，即在特定地理区域特有的根瘤菌种群更喜欢具有广泛宿主谱的宿主，这可能是豆科植物和根瘤菌在孤立地区取得成功的一个重要事件。
