scholarly journals Restriction of Host Range by the sym2 Allele of Afghan Pea Is Nonspecific for the Type of Modification at the Reducing Terminus of Nodulation Signals

1998 ◽  
Vol 11 (5) ◽  
pp. 418-422 ◽  
Author(s):  
Alexandra O. Ovtsyna ◽  
Rene Geurts ◽  
Ton Bisseling ◽  
Ben J. J. Lugtenberg ◽  
Igor A. Tikhonovich ◽  
...  
Keyword(s):  
Host Range ◽  
Bradyrhizobium Japonicum ◽  
Rhizobium Leguminosarum ◽  
Reducing Sugar ◽  
Introgression Lines ◽  
Fixed Nitrogen ◽  
Normal Frequency

Rhizobium leguminosarum bv. viciae strains producing lipo-chitin oligosaccharides (LCOs) that are O-acetylated at the reducing terminus are required for nodulation of wild pea cultivars originating from Afghanistan that possess the recessive sym2A allele. The O-acetylation of the reducing sugar of LCOs is mediated by the bacterial nodX gene, which presumably encodes an acetyltransferase. We found that for nodulation on Afghan pea cultivars and sym2A introgression lines the nodX gene can be functionally replaced by the nodZ gene of Bradyrhizobium japonicum, which encodes a fucosyltransferase that fucosylates the reducing terminus of LCOs. The structure of the nodules, which were induced with normal frequency, was typical for effective pea nodules, and they fixed nitrogen with the same efficiency as nodules induced by nodX-carrying strains.

Pathways for phosphatidylcholine biosynthesis in bacteria

Microbiology ◽  
2003 ◽  
Vol 149 (12) ◽  
pp. 3461-3471 ◽  
Author(s):  
Fernando Martínez-Morales ◽  
Max Schobert ◽  
Isabel M. López-Lara ◽  
Otto Geiger
Keyword(s):  
Borrelia Burgdorferi ◽  
Legionella Pneumophila ◽  
Bradyrhizobium Japonicum ◽  
Sinorhizobium Meliloti ◽  
Rhizobium Leguminosarum ◽  
Brucella Melitensis ◽  
Membrane Lipid ◽  
Mesorhizobium Loti ◽  
Methylation Pathway ◽  
Phosphatidylcholine Biosynthesis

Phosphatidylcholine (PC) is the major membrane-forming phospholipid in eukaryotes with important structural and signalling functions. Although many prokaryotes lack PC, it can be found in significant amounts in membranes of rather diverse bacteria. Two pathways for PC biosynthesis are known in bacteria, the methylation pathway and the phosphatidylcholine synthase (PCS) pathway. In the methylation pathway, phosphatidylethanolamine is methylated three times to yield PC, in reactions catalysed by one or several phospholipid N-methyltransferases (PMTs). In the PCS pathway, choline is condensed directly with CDP-diacylglyceride to form PC in a reaction catalysed by PCS. Using cell-free extracts, it was demonstrated that Sinorhizobium meliloti, Agrobacterium tumefaciens, Rhizobium leguminosarum, Bradyrhizobium japonicum, Mesorhizobium loti and Legionella pneumophila have both PMT and PCS activities. In addition, Rhodobacter sphaeroides has PMT activity and Brucella melitensis, Pseudomonas aeruginosa and Borrelia burgdorferi have PCS activities. Genes from M. loti and L. pneumophila encoding a Pmt or a Pcs activity and the genes from P. aeruginosa and Borrelia burgdorferi responsible for Pcs activity have been identified. Based on these functional assignments and on genomic data, one might predict that if bacteria contain PC as a membrane lipid, they usually possess both bacterial pathways for PC biosynthesis. However, important pathogens such as Brucella melitensis, P. aeruginosa and Borrelia burgdorferi seem to be exceptional as they possess only the PCS pathway for PC formation.

scholarly journals A locus encoding host range is linked to the common nodulation genes of Bradyrhizobium japonicum.

1987 ◽  
Vol 169 (6) ◽  
pp. 2631-2638 ◽  
Author(s):  
A J Nieuwkoop ◽  
Z Banfalvi ◽  
N Deshmane ◽  
D Gerhold ◽  
M G Schell ◽  
...  
Keyword(s):  
Host Range ◽  
Bradyrhizobium Japonicum ◽  
Nodulation Genes ◽  
The Common

scholarly journals A Rhizobium leguminosarum Biovar trifolii Locus Not Localized on the Sym Plasmid Hinders Effective Nodulation on Plants of the Pea Cross-Inoculation Group

1997 ◽  
Vol 10 (7) ◽  
pp. 938-941 ◽  
Author(s):  
Henk P. Roest ◽  
Ine H. M. Mulders ◽  
Herman P. Spaink ◽  
Carel A. Wijffelman ◽  
Ben J. J. Lugtenberg
Keyword(s):  
Rhizobium Leguminosarum ◽  
Outer Membrane Proteins ◽  
Extracellular Polysaccharides ◽  
Fixed Nitrogen ◽  
Significant Similarity ◽  
Sym Plasmid ◽  
Flanking Regions ◽  
Rhizobium Leguminosarum Biovar Trifolii ◽  
Inoculation Group

Introduction of the Sym plasmid pRL1JI into the cured Rhizobium leguminosarum bv. trifolii strain RCR5 resulted in a strain, designated RBL5523, that was expected to nodulate plants of the pea cross-inoculation group. However, effective nodulation occurred only on Vicia sativa plants, not on V. hirsuta or Pisum sativum. After random Tn5 mutagenesis, a derivative of RBL5523 was isolated that effectively nodulated and fixed nitrogen on P. sativum and V. hirsuta. Characterization of the mutant, RBL5787, indicated the cell surface components, extracellular polysaccharides, lipopolysaccharides, and outer membrane proteins, as well as the pattern of Nod metabolites, were indistinguishable from those of the parental strain. To obtain an indication of the function of the mutated locus, the flanking regions were sequenced and used to perform searches in protein and nonredundant nucleotide databases. No significant similarity or homology with any known sequence was detected.

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