title: Chickpea rhizobia symbiosis genes are highly conserved across multiple Mesorhizobium species.
abstract: Chickpea has been considered as a restrictive host for nodulation by rhizobia. However, recent studies have reported that several Mesorhizobium species may effectively nodulate chickpea. With the purpose of investigating the evolutionary relationships between these different species with the ability of nodulating the same host, we analysed 21 Portuguese chickpea rhizobial isolates. Symbiosis genes nifH and nodC were sequenced and used for phylogenetic studies. Symbiotic effectiveness was determined to evaluate its relationship with symbiosis genes. The comparison of 16S rRNA gene-based phylogeny with the phylogenies based on symbiosis genes revealed evidence of lateral transfer of symbiosis genes across different species. Chickpea is confirmed as a nonpromiscuous host. Although chickpea is nodulated by many different species, they share common symbiosis genes, suggesting recognition of only a few Nod factors by chickpea. Our results suggest that sequencing of nifH or nodC genes can be used for rapid detection of chickpea mesorhizobia.
authors.affiliation: Departamento de Biologia, Universidade de Evora, Evora, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Laranjo
authors.forename: Ana
authors.initials: A
authors.lastname: Alexandre
authors.forename: Raúl
authors.initials: R
authors.lastname: Rivas
authors.forename: Encarna
authors.initials: E
authors.lastname: Velázquez
authors.forename: J Peter W
authors.initials: JP
authors.lastname: Young
authors.forename: Solange
authors.initials: S
authors.lastname: Oliveira
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D029863:Cicer / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics; D009586:Nitrogen Fixation; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013559:Symbiosis / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D012336:RNA, Ribosomal, 16S; D010088:Oxidoreductases; C029130:nitrogenase reductase; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales