Analysis of Frankia evolutionary radiation using glnII sequences.
Using a glnII (encoding glutamine synthetase II) PCR selective screening, a Frankia ACN14a gene library clone was isolated. A derived glnII-hybridising 2.7-kb HindIII subclone was characterised. Identities of 95% and 93% were observed, respectively, with the corresponding Frankia CpI1 glnI and glnII regions. A variable segment of the glnII region was selected, PCR amplified from various Frankia genomes, sequenced, and used to investigate phylogenetic relationships within the genus. glnII phylogenetic inferences are well-resolved and allowed us to deduce evolutionary trends among Frankia. Frankia radiation seems to begin with a diversification according to the ability or not to infect actinorhizal plants. The infective strains are divided into two clusters matching plant-colonising specificities.
Cournoyer
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B
Laboratoire d'Ecologie Microbienne des Sols, UMR CNRS 5557, Université Claude-Bernard Lyon, Villeurbanne, France. cournoye@biomserv.univ-lyon1.fr
Lavire
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C
D000192:Actinomycetales / Q000145:classification* / Q000201:enzymology / Q000235:genetics*; D019143:Evolution, Molecular; D015723:Gene Library; D016680:Genome, Bacterial; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping
C083818:glutamine synthetase 2; D005974:Glutamate-Ammonia Ligase