title: Diversity of Pseudomonas Genomes, Including Populus-Associated Isolates, as Revealed by Comparative Genome Analysis.
abstract: The Pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. Their diversity influences the phylogenetic diversity and heterogeneity of these communities. On the basis of average amino acid identity, comparative genome analysis of >1,000 Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides (eastern cottonwood) trees resulted in consistent and robust genomic clusters with phylogenetic homogeneity. All Pseudomonas aeruginosa genomes clustered together, and these were clearly distinct from other Pseudomonas species groups on the basis of pangenome and core genome analyses. In contrast, the genomes of Pseudomonas fluorescens were organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. Most of our 21 Populus-associated isolates formed three distinct subgroups within the major P. fluorescens group, supported by pathway profile analysis, while two isolates were more closely related to Pseudomonas chlororaphis and Pseudomonas putida. Genes specific to Populus-associated subgroups were identified. Genes specific to subgroup 1 include several sensory systems that act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor. Genes specific to subgroup 2 contain hypothetical genes, and genes specific to subgroup 3 were annotated with hydrolase activity. This study justifies the need to sequence multiple isolates, especially from P. fluorescens, which displays the most genetic variation, in order to study functional capabilities from a pangenomic perspective. This information will prove useful when choosing Pseudomonas strains for use to promote growth and increase disease resistance in plants.
authors.affiliation: Joint Institute for Computational Sciences, University of Tennessee, Knoxville, Tennessee, USA.
authors.forename: Se-Ran
authors.initials: SR
authors.lastname: Jun
authors.affiliation: Molecular Microbiology and Genomics Consultants, Zotzenheim, Germany.
authors.forename: Trudy M
authors.initials: TM
authors.lastname: Wassenaar
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Intawat
authors.initials: I
authors.lastname: Nookaew
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Loren
authors.initials: L
authors.lastname: Hauser
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Visanu
authors.initials: V
authors.lastname: Wanchai
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Miriam
authors.initials: M
authors.lastname: Land
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Collin M
authors.initials: CM
authors.lastname: Timm
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Tse-Yuan S
authors.initials: TY
authors.lastname: Lu
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Schadt
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Mitchel J
authors.initials: MJ
authors.lastname: Doktycz
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: Dale A
authors.initials: DA
authors.lastname: Pelletier
authors.affiliation: Biosciences Division, Oak Ridge Laboratory, Oak Ridge, Tennessee, USA usserydw@ornl.gov.
authors.forename: David W
authors.identifier: http://orcid.org/0000-0003-3632-5512
authors.initials: DW
authors.lastname: Ussery
mesh_terms: D055028:Comparative Genomic Hybridization; D014644:Genetic Variation; D016680:Genome, Bacterial; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D032107:Populus / Q000382:microbiology*; D011549:Pseudomonas / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000302:isolation & purification; D011551:Pseudomonas fluorescens / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D016958:Pseudomonas putida / Q000235:genetics / Q000302:isolation & purification; D058441:Rhizosphere; D017422:Sequence Analysis, DNA