Phylogeny of Symbiotic Genes and the Symbiotic Properties of Rhizobia Specific to Astragalus glycyphyllos L.
The phylogeny of symbiotic genes of Astragalus glycyphyllos L. (liquorice milkvetch) nodule isolates was studied by comparative sequence analysis of nodA, nodC, nodH and nifH loci. In all these genes phylograms, liquorice milkvetch rhizobia (closely related to bacteria of three species, i.e. Mesorhizobium amorphae, Mesorhizobium septentrionale and Mesorhizobium ciceri) formed one clearly separate cluster suggesting the horizontal transfer of symbiotic genes from a single ancestor to the bacteria being studied. The high sequence similarity of the symbiotic genes of A. glycyphyllos rhizobia (99-100% in the case of nodAC and nifH genes, and 98-99% in the case of nodH one) points to the relatively recent (in evolutionary scale) lateral transfer of these genes. In the nodACH and nifH phylograms, A. glycyphyllos nodule isolates were grouped together with the genus Mesorhizobium species in one monophyletic clade, close to M. ciceri, Mesorhizobium opportunistum and Mesorhizobium australicum symbiovar biserrulae bacteria, which correlates with the close relationship of these rhizobia host plants. Plant tests revealed the narrow host range of A. glycyphyllos rhizobia. They formed effective symbiotic interactions with their native host (A. glycyphyllos) and Amorpha fruticosa but not with 11 other fabacean species. The nodules induced on A. glycyphyllos roots were indeterminate with apical, persistent meristem, an age gradient of nodule tissues and cortical vascular bundles. To reflect the symbiosis-adaptive phenotype of rhizobia, specific for A. glycyphyllos, we propose for these bacteria the new symbiovar "glycyphyllae", based on nodA and nodC genes sequences.
Department of Veterinary Microbiology, University of Life Sciences, 13 Akademicka st. 20-950 Lublin, Poland.
Sebastian
S
Gnat
Department of Genetics and Microbiology, University of Maria Curie-Skłodowska, 19 Akademicka st., 20-033 Lublin, Poland.
Wanda
W
Małek
Department of Genetics and Evolution, University of Białystok, 1J Ciołkowskiego st., 15-245 Białystok, Poland.
Ewa
E
Oleńska
Department of Genetics and Microbiology, University of Maria Curie-Skłodowska, 19 Akademicka st., 20-033 Lublin, Poland.
Sylwia
S
Wdowiak-Wróbel
Department of Genetics and Microbiology, University of Maria Curie-Skłodowska, 19 Akademicka st., 20-033 Lublin, Poland.
Michał
M
Kalita
Department of Botany, Warsaw University of Life Sciences-SGGW, 159 Nowoursynowska st., 02-766 Warsaw, Poland.
Barbara
B
Łotocka
Department of Genetics and Microbiology, University of Maria Curie-Skłodowska, 19 Akademicka st., 20-033 Lublin, Poland.
Magdalena
M
Wójcik
D000217:Acyltransferases / Q000235:genetics; D027883:Astragalus Plant / Q000382:microbiology* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000235:genetics; D005798:Genes, Bacterial; D056426:Genetic Loci; D059128:Mesorhizobium / Q000235:genetics* / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics; D009586:Nitrogen Fixation; D010802:Phylogeny; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism; D053204:Root Nodules, Plant / Q000382:microbiology* / Q000648:ultrastructure; D017422:Sequence Analysis, DNA; D013559:Symbiosis
D001426:Bacterial Proteins; D000217:Acyltransferases; C060770:NodA protein, Rhizobiales; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales