title: The new species Enterobacter oryziphilus sp. nov. and Enterobacter oryzendophyticus sp. nov. are key inhabitants of the endosphere of rice.
abstract: BACKGROUND
  Six independent Gram-negative, facultatively anaerobic, non-spore-forming, nitrogen-fixing rod-shaped isolates were obtained from the root endosphere of rice grown at the International Rice Research Institute (IRRI) and investigated in a polyphasic taxonomic study.
  
  
  RESULTS
  The strains produced fatty acid patterns typical for members of the family Enterobacteriaceae. Comparative sequence analyses of the 16S rRNA as well as rpoB genes allocated the strains to two well-defined groups within the genus Enterobacter, family Enterobacteriaceae. The analyses indicated Enterobacter radicincitans, Enterobacter arachidis and Enterobacter oryzae to be the closest related species. An RpoB (translated) protein comparison supported the placement in the genus Enterobacter and the relatedness of our isolates to the aforementioned species. Genomic DNA:DNA hybridization analyses and biochemical analyses provided further evidence that the novel strains belong to two new species within the genus Enterobacter. The two species can be differentiated from each other and from existing enteric species by acid production from L-rhamnose and D-melibiose, decarboxylation of ornithine and utilization of D-alanine, D-raffinose L-proline and L-aspartic acid, among other characteristics. Members of both species revealed capacities to colonise rice roots, including plant-growth-promoting capabilities such as an active supply of fixed nitrogen to the plant and solubilisation of inorganic phosphorus, next to traits allowing adaptation to the plant.
  
  
  CONCLUSIONS
  Two novel proposed enterobacterial species, denominated Enterobacter oryziphilus sp. nov. (type strain REICA_142(T)=LMG 26429(T)=NCCB 100393(T)) and Enterobacter oryzendophyticus sp. nov. (type strain REICA_082(T)=LMG 26432(T) =NCCB 100390(T)) were isolated from rice roots. Both species are capable of promoting rice growth by supplying nitrogen and phosphorus.
authors.affiliation: Department of Microbial Ecology, University of Groningen, Centre for Ecological and Evolutionary Studies, Nijenborgh 7, Groningen 9747AG, The Netherlands. phardoim@gmail.com
authors.forename: Pablo Rodrigo
authors.initials: PR
authors.lastname: Hardoim
authors.forename: Rashid
authors.initials: R
authors.lastname: Nazir
authors.forename: Angela
authors.initials: A
authors.lastname: Sessitsch
authors.forename: Dana
authors.initials: D
authors.lastname: Elhottová
authors.forename: Elisa
authors.initials: E
authors.lastname: Korenblum
authors.forename: Leonard Simon
authors.initials: LS
authors.lastname: van Overbeek
authors.forename: Jan Dirk
authors.initials: JD
authors.lastname: van Elsas
mesh_terms: D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000502:physiology; D004755:Enterobacteriaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005227:Fatty Acids / Q000032:analysis; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012275:Oryza / Q000382:microbiology*; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit