title: Phylogenetic multilocus sequence analysis of native rhizobia nodulating faba bean (Vicia faba L.) in Egypt.
abstract: The taxonomic diversity of forty-two Rhizobium strains, isolated from nodules of faba bean grown in Egypt, was studied using 16S rRNA sequencing, multilocus sequence analyses (MLSA) of three chromosomal housekeeping loci and one nodulation gene (nodA). Based on the 16S rRNA gene sequences, most of the strains were related to Rhizobium leguminosarum, Rhizobium etli, and Rhizobium radiobacter (syn. Agrobacterium tumefaciens). A maximum likelihood (ML) tree built from the concatenated sequences of housekeeping proteins encoded by glnA, gyrB and recA, revealed the existence of three distinct genospecies (I, II and III) affiliated to the defined species within the genus Rhizobium/Agrobacterium. Seventeen strains in genospecies I could be classified as R. leguminosarum sv. viciae. Whereas, a single strain of genospecies II was linked to R. etli. Interestingly, twenty-four strains of genospecies III were identified as A. tumefaciens. Strains of R. etli and A. tumefaciens have been shown to harbor the nodA gene and formed effective symbioses with faba bean plants in Leonard jar assemblies. In the nodA tree, strains belonging to the putative genospecies were closely related to each other and were clustered tightly to R. leguminosarum sv. viciae, supporting the hypothesis that symbiotic and core genome of the species have different evolutionary histories and indicative of horizontal gene transfer among these rhizobia.
authors.affiliation: National Gene Bank and Genetic Resources, Agricultural Research Center, Giza, Egypt. Electronic address: samehheikal@hotmail.com.
authors.forename: Sameh H
authors.initials: SH
authors.lastname: Youseif
authors.affiliation: National Gene Bank and Genetic Resources, Agricultural Research Center, Giza, Egypt.
authors.forename: Fayrouz H
authors.initials: FH
authors.lastname: Abd El-Megeed
authors.affiliation: Agricultural Genetic Engineering Research Institute, Agricultural Research Center, Giza, Egypt.
authors.forename: Amr
authors.initials: A
authors.lastname: Ageez
authors.affiliation: Centre for Crop Nitrogen Fixation, University of Nottingham, Nottingham, UK.
authors.forename: Edward C
authors.initials: EC
authors.lastname: Cocking
authors.affiliation: National Gene Bank and Genetic Resources, Agricultural Research Center, Giza, Egypt.
authors.forename: Saleh A
authors.initials: SA
authors.lastname: Saleh
mesh_terms: D000217:Acyltransferases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004534:Egypt; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D012231:Rhizobium / Q000145:classification* / Q000235:genetics*; D053204:Root Nodules, Plant / Q000382:microbiology*; D013559:Symbiosis; D031307:Vicia faba / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D000217:Acyltransferases
keywords: Agrobacterium tumefaciens; Egypt; Faba bean; Multilocus sequence analysis; Rhizobium etli; Rhizobium leguminosarum; nodA