title: Core and symbiotic genes reveal nine Mesorhizobium genospecies and three symbiotic lineages among the rhizobia nodulating Cicer canariense in its natural habitat (La Palma, Canary Islands).
abstract: Cicer canariense is a threatened perennial wild chickpea endemic to the Canary Islands. In this study, rhizobia that nodulate this species in its natural habitats on La Palma (Canary Islands) were characterised. The genetic diversity and phylogeny were estimated by RAPD profiles, 16S-RFLP analysis and sequencing of the rrs, recA, glnII and nodC genes. 16S-RFLP grouped the isolates within the Mesorhizobium genus and distinguished nine different ribotypes. Four branches included minority ribotypes (3-5 isolates), whereas another five contained the predominant ribotypes that clustered with reference strains of M. tianshanense/M. gobiense/M. metallidurans, M. caraganae, M. opportunistum, M. ciceri and M. tamadayense. The sequences confirmed the RFLP groupings but resolved additional internal divergence within the M. caraganae group and outlined several potential novel species. The RAPD profiles showed a high diversity at the infraspecific level, except in the M. ciceri group. The nodC phylogeny resolved three symbiotic lineages. A small group of isolates had sequences identical to those of symbiovar ciceri and were only detected in M. ciceri isolates. Another group of sequences represented a novel symbiotic lineage that was associated with two particular chromosomal backgrounds. However, nodC sequences closely related to symbiovar loti predominated in most isolates, and they were detected in several chromosomal backgrounds corresponding to up to nine Mesorhizobium lineages. The results indicated that C. canariense is a promiscuous legume that can be nodulated by several rhizobial species and symbiotypes, which means it will be important to determine the combination of core and symbiotic genes that produce the most effective symbiosis.
authors.affiliation: Departamento de Microbiología y Biología Celular, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Armas-Capote
authors.affiliation: Departamento de Microbiología y Biología Celular, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Pérez-Yépez
authors.affiliation: Departamento de Microbiología y Genética, Universidad de Salamanca, 37007 Salamanca, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Martínez-Hidalgo
authors.affiliation: Departamento de Biología Vegetal (Botánica), Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Garzón-Machado
authors.affiliation: Departamento de Biología Vegetal (Botánica), Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain.
authors.forename: Marcelino
authors.initials: M
authors.lastname: Del Arco-Aguilar
authors.affiliation: Departamento de Microbiología y Genética, Universidad de Salamanca, 37007 Salamanca, Spain.
authors.forename: Encarna
authors.initials: E
authors.lastname: Velázquez
authors.affiliation: Departamento de Microbiología y Biología Celular, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain. Electronic address: mileonba@ull.es.
authors.forename: Milagros
authors.initials: M
authors.lastname: León-Barrios
mesh_terms: D058448:Biota; D029863:Cicer / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D020459:Genes, rRNA; D059128:Mesorhizobium / Q000145:classification* / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D019105:Random Amplified Polymorphic DNA Technique; D021521:Ribotyping; D053204:Root Nodules, Plant / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013030:Spain
chemical_list: D004269:DNA, Bacterial
keywords: Cicer canariense; Core-gene phylogeny; Mesorhizobium; Novel symbiotypes; Symbiotic-gene phylogeny; Wild chickpea