The Structure and Evolution of Beta-Rhizobial Symbiotic Genes Deduced from Their Complete GenomesZheng JZ1, Wang R1, Liu RR1, Chen JJ1, Wei Q1, Wu XY1, Pang XW1, James EK2 and Liu XY1*
- *Corresponding Author:
- XiaoYun Liu
Key Laboratory of Microbial Diversity Research and Application of Hebei Province
College of Life Sciences
Baoding 100072, PR China
E-mail: [email protected]
Received Date: March 03, 2016; Accepted Date: March 14, 2017; Published Date: March 24, 2017
Citation: Zheng JZ, Wang R, Liu RR, Chen JJ, Wei Q, et al. (2017) The Structure and Evolution of Beta-Rhizobial Symbiotic Genes Deduced from Their Complete Genomes. Immunome Res 13:131. doi: 10.4172/17457580.1000131
Copyright: © 2017 Zheng JZ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract Nitrogen-fixing Rhizobia were discovered more than 100 years ago. They are classified into two clades, Alphaand Beta-rhizobia. Their symbiotic function is remarkable, but its origin and evolution has been confusing from a phylogenetic perspective. In this study, we make use of 33 publicly available complete genome sequences downloaded from NCBI, which consist of bacteria and archaea, and focus on 10 strains, constructing symbiotic structural maps for them based on their genomes and previous gene annotations. Phylogenies of the symbiosisessential genes nodA and nifH were examined. Although large incongruities with some hypotheses from previous studies were detected by the present study, we support the general concept that Beta-rhizobia were the original symbionts of legumes, but that their symbotic genes originated from a common ancestor to the Alpha-rhizobia. We also confirm that the spread and maintenance of symbiotic genes occurred mainly through vertical transmission, with lateral transfer playing a significant, albeit supporting, role.