Evolution and taxonomy of native mesorhizobia nodulating medicinal Glycyrrhiza species in China.
Previously, 159 bacterial strains were isolated from the root nodules of wild perennial Glycyrrhiza legume species grown on 40 sites in central and north-western China, in which 57 strains were classified as "true symbionts" belonging to the genus Mesorhizobium based on amplified fragment length polymorphism (AFLP) genomic fingerprinting and partial sequences of the 16S rRNA gene [20]. In the present work, the phylogeny of Glycyrrhiza nodulating mesorhizobia was further examined by multilocus sequence analysis (MLSA). The concatenated gene tree of three housekeeping genes (16S rRNA, recA, and rpoB) of 59 strains including the 29 mesorhizobial test strains and 30 type mesorhizobial species, was constructed applying the maximum likelihood method and Bayesian inference. In the concatenated gene tree, the 29 test strains were distributed in seven separate clades. Seventeen test strains clustered with Mesorhizobium tianshanense, Mesorhizobium temperatum, Mesorhizobium muleiense, and Mesorhizobium alhagi with high bootstrap support (BS>85%). Eight test strains did not cluster with any of the described Mesorhizobium species. Based on the results, we proposed these eight test strains might belong to a putative new species of the genus Mesorhizobium. The sequences of three accessory genes (nodA, nodC, and nifH) of the test strains were also analyzed and were compared with those of representatives of the 30 described mesorhizobial species. The results showed that mesorhizobia involved in symbiosis with Glycyrrhiza plants probably have acquired some genetic material from other rhizobia in co-evolution with Glycyrrhiza and other legume species.
University of Helsinki, Department of Environmental Sciences, Helsinki, Finland. Electronic address: s.abdollah.mousavi@gmail.com.
Seyed Abdollah
SA
Mousavi
University of Helsinki, Department of Food and Environmental Sciences, Helsinki, Finland; Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Li
L
Li
Northwest A&F University, College of Life Sciences, Yangling, Shaanxi, China.
Gehong
G
Wei
University of Helsinki, Department of Food and Environmental Sciences, Helsinki, Finland.
Leena
L
Räsänen
University of Helsinki, Department of Environmental Sciences, Helsinki, Finland.
Kristina
K
Lindström
D000217:Acyltransferases / Q000235:genetics; D054458:Amplified Fragment Length Polymorphism Analysis; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D006035:Glycyrrhiza / Q000382:microbiology*; D059128:Mesorhizobium / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D058885:Multilocus Sequence Typing; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D012231:Rhizobium / Q000145:classification / Q000302:isolation & purification*; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C029130:nitrogenase reductase; D000217:Acyltransferases; C060770:NodA protein, Rhizobiales; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales; D011938:Rec A Recombinases; D012321:DNA-Directed RNA Polymerases
Accessory genes; Glycyrrhiza; Housekeeping genes; MLSA; Mesorhizobium