title: Draft Genomes, Phylogenetic Reconstruction, and Comparative Genomics of Two Novel Cohabiting Bacterial Symbionts Isolated from Frankliniella occidentalis.
abstract: Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwinia pyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely related to Pantoea ananatis but represented a divergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omnipresent in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea.
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom p.facey@swansea.ac.uk.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Facey
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Méric
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Hitchings
authors.affiliation: Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Penglais, Ceredigion, United Kingdom.
authors.forename: Justin A
authors.initials: JA
authors.lastname: Pachebat
authors.affiliation: Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Penglais, Ceredigion, United Kingdom.
authors.forename: Matt J
authors.initials: MJ
authors.lastname: Hegarty
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Xiaorui
authors.initials: X
authors.lastname: Chen
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Laura V A
authors.initials: LV
authors.lastname: Morgan
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: James E
authors.initials: JE
authors.lastname: Hoeppner
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Miranda M A
authors.initials: MM
authors.lastname: Whitten
authors.affiliation: School of Life Sciences, Keele University, Staffordshire, United Kingdom.
authors.forename: William D J
authors.initials: WD
authors.lastname: Kirk
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Dyson
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom MRC CLIMB Consortium, Institute of Life Science, Swansea University, United Kingdom Department of Zoology, University of Oxford, United Kingdom.
authors.forename: Sam K
authors.initials: SK
authors.lastname: Sheppard
authors.affiliation: Institute of Life Sciences, College of Medicine, Swansea University, United Kingdom.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Del Sol
mesh_terms: D000818:Animals; D058947:Bacterial Secretion Systems / Q000235:genetics; D004885:Erwinia / Q000145:classification; D019143:Evolution, Molecular; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D016680:Genome, Bacterial; D023281:Genomics; D010802:Phylogeny; D013559:Symbiosis; D061149:Thysanoptera / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D058947:Bacterial Secretion Systems; D037521:Virulence Factors
keywords: BFo; Frankliniella; evolution; genome; symbiont; thrips