title: Narrow-host-range bacteriophages that infect Rhizobium etli associate with distinct genomic types.
abstract: In this work, we isolated and characterized 14 bacteriophages that infect Rhizobium etli. They were obtained from rhizosphere soil of bean plants from agricultural lands in Mexico using an enrichment method. The host range of these phages was narrow but variable within a collection of 48 R. etli strains. We obtained the complete genome sequence of nine phages. Four phages were resistant to several restriction enzymes and in vivo cloning, probably due to nucleotide modifications. The genome size of the sequenced phages varied from 43 kb to 115 kb, with a median size of ≈ 45 to 50 kb. A large proportion of open reading frames of these phage genomes (65 to 70%) consisted of hypothetical and orphan genes. The remainder encoded proteins needed for phage morphogenesis and DNA synthesis and processing, among other functions, and a minor percentage represented genes of bacterial origin. We classified these phages into four genomic types on the basis of their genomic similarity, gene content, and host range. Since there are no reports of similar sequences, we propose that these bacteriophages correspond to novel species.
authors.affiliation: Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, UNAM, Cuernavaca, Morelos, México.
authors.forename: Rosa Isela
authors.initials: RI
authors.lastname: Santamaría
authors.forename: Patricia
authors.initials: P
authors.lastname: Bustos
authors.forename: Omar
authors.initials: O
authors.lastname: Sepúlveda-Robles
authors.forename: Luis
authors.initials: L
authors.lastname: Lozano
authors.forename: César
authors.initials: C
authors.lastname: Rodríguez
authors.forename: José Luis
authors.initials: JL
authors.lastname: Fernández
authors.forename: Soledad
authors.initials: S
authors.lastname: Juárez
authors.forename: Luis
authors.initials: L
authors.lastname: Kameyama
authors.forename: Gabriel
authors.initials: G
authors.lastname: Guarneros
authors.forename: Guillermo
authors.initials: G
authors.lastname: Dávila
authors.forename: Víctor
authors.initials: V
authors.lastname: González
mesh_terms: D001435:Bacteriophages / Q000235:genetics* / Q000302:isolation & purification*; D016679:Genome, Viral; D058507:Host Specificity; D008800:Mexico; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D042163:Rhizobium etli / Q000821:virology*; D058441:Rhizosphere; D012988:Soil Microbiology