TY - JOUR
T1 - Genetic divergence among Bradyrhizobium strains nodulating wild and cultivated Kummerowia spp. in China
AU - Ji, Zhaojun
AU - Liu, Tianyan
AU - Zhang, Jixing
AU - Yan, Hui
AU - Wang, Entao
AU - Cui, Qingguo
AU - Chen, Wenxin
AU - Chen, Wenfeng
N1 - Publisher Copyright:
© 2018 Elsevier GmbH
PY - 2019/3
Y1 - 2019/3
N2 - Distribution of rhizobial species is affected by geographical isolation and selected by leguminous hosts, however, little is known about the molecular evolution of rhizobia nodulating the same legume in different eco-environments. In present study, the microevolution of Bradyrhizobium associated with the leguminous grass Kummerowia grown in exurban areas and cultivated in urban areas in China was investigated. Total 14 genospecies, including seven new groups, were identified based on a concatenated sequence analysis of taxonomic markers (SMc00019, truA and thrA) for 94 representative strains. Results demonstrated that lower levels of nucleotide diversity were found in the strains isolated from urban areas compared with those isolated from exurban areas, based on the evolutional analyses of three housekeeping genes (atpD, glnII and recA), two symbiosis-related genes (nodC and nifH), and the taxonomic markers. Moreover, compared with urban areas, gene exchange and recombination occurred more frequently among the genospecies isolated from exurban areas, regardless of the geographical distribution. Finally, the evolutionary lineage of Bradyrhizobium strains isolated from urban areas was independent of that of the strains isolated from exurban areas. In summary, the evolutionary history of Kummerowia bradyrhizobia may have been gradually segregated to different evolutionary lineages, irrespective of distinct biogeography.
AB - Distribution of rhizobial species is affected by geographical isolation and selected by leguminous hosts, however, little is known about the molecular evolution of rhizobia nodulating the same legume in different eco-environments. In present study, the microevolution of Bradyrhizobium associated with the leguminous grass Kummerowia grown in exurban areas and cultivated in urban areas in China was investigated. Total 14 genospecies, including seven new groups, were identified based on a concatenated sequence analysis of taxonomic markers (SMc00019, truA and thrA) for 94 representative strains. Results demonstrated that lower levels of nucleotide diversity were found in the strains isolated from urban areas compared with those isolated from exurban areas, based on the evolutional analyses of three housekeeping genes (atpD, glnII and recA), two symbiosis-related genes (nodC and nifH), and the taxonomic markers. Moreover, compared with urban areas, gene exchange and recombination occurred more frequently among the genospecies isolated from exurban areas, regardless of the geographical distribution. Finally, the evolutionary lineage of Bradyrhizobium strains isolated from urban areas was independent of that of the strains isolated from exurban areas. In summary, the evolutionary history of Kummerowia bradyrhizobia may have been gradually segregated to different evolutionary lineages, irrespective of distinct biogeography.
KW - Bradyrhizobium
KW - Kummerowia
KW - Microevolution
KW - Phylogeny
KW - Recombination
KW - Urban segregation
UR - http://www.scopus.com/inward/record.url?scp=85055026140&partnerID=8YFLogxK
U2 - 10.1016/j.syapm.2018.10.003
DO - 10.1016/j.syapm.2018.10.003
M3 - Artículo
C2 - 30343835
SN - 0723-2020
VL - 42
SP - 223
EP - 231
JO - Systematic and Applied Microbiology
JF - Systematic and Applied Microbiology
IS - 2
ER -