title: Genome sequence of the Drosophila melanogaster male-killing Spiroplasma strain MSRO endosymbiont.
abstract: Spiroplasmas are helical and motile members of a cell wall-less eubacterial group called Mollicutes. Although all spiroplasmas are associated with arthropods, they exhibit great diversity with respect to both their modes of transmission and their effects on their hosts; ranging from horizontally transmitted pathogens and commensals to endosymbionts that are transmitted transovarially (i.e., from mother to offspring). Here we provide the first genome sequence, along with proteomic validation, of an endosymbiotic inherited Spiroplasma bacterium, the Spiroplasma poulsonii MSRO strain harbored by Drosophila melanogaster. Comparison of the genome content of S. poulsonii with that of horizontally transmitted spiroplasmas indicates that S. poulsonii has lost many metabolic pathways and transporters, demonstrating a high level of interdependence with its insect host. Consistent with genome analysis, experimental studies showed that S. poulsonii metabolizes glucose but not trehalose. Notably, trehalose is more abundant than glucose in Drosophila hemolymph, and the inability to metabolize trehalose may prevent S. poulsonii from overproliferating. Our study identifies putative virulence genes, notably, those for a chitinase, the H2O2-producing glycerol-3-phosphate oxidase, and enzymes involved in the synthesis of the eukaryote-toxic lipid cardiolipin. S. poulsonii also expresses on the cell membrane one functional adhesion-related protein and two divergent spiralin proteins that have been implicated in insect cell invasion in other spiroplasmas. These lipoproteins may be involved in the colonization of the Drosophila germ line, ensuring S. poulsonii vertical transmission. The S. poulsonii genome is a valuable resource to explore the mechanisms of male killing and symbiont-mediated protection, two cardinal features of many facultative endosymbionts.
  
  
  OBJECTIVE
  Most insect species, including important disease vectors and crop pests, harbor vertically transmitted endosymbiotic bacteria. These endosymbionts play key roles in their hosts' fitness, including protecting them against natural enemies and manipulating their reproduction in ways that increase the frequency of symbiont infection. Little is known about the molecular mechanisms that underlie these processes. Here, we provide the first genome draft of a vertically transmitted male-killing Spiroplasma bacterium, the S. poulsonii MSRO strain harbored by D. melanogaster. Analysis of the S. poulsonii genome was complemented by proteomics and ex vivo metabolic experiments. Our results indicate that S. poulsonii has reduced metabolic capabilities and expresses divergent membrane lipoproteins and potential virulence factors that likely participate in Spiroplasma-host interactions. This work fills a gap in our knowledge of insect endosymbionts and provides tools with which to decipher the interaction between Spiroplasma bacteria and their well-characterized host D. melanogaster, which is emerging as a model of endosymbiosis.
authors.affiliation: Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Paredes
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Herren
authors.affiliation: Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Fanny
authors.initials: F
authors.lastname: Schüpfer
authors.affiliation: Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.
authors.forename: Ray
authors.initials: R
authors.lastname: Marin
authors.affiliation: Pôle Protéomique, Plateforme Génomique Fonctionnelle de Bordeaux, University of Bordeaux, Bordeaux, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Claverol
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Chih-Horng
authors.identifier: http://orcid.org/0000-0002-2857-0529
authors.initials: CH
authors.lastname: Kuo
authors.affiliation: Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland laure.beven@bordeaux.inra.fr bruno.lemaitre@epfl.ch.
authors.forename: Bruno
authors.initials: B
authors.lastname: Lemaitre
authors.affiliation: INRA, University of Bordeaux, Unité Mixte de Recherche 1332, Villenave d'Ornon, France laure.beven@bordeaux.inra.fr bruno.lemaitre@epfl.ch.
authors.forename: Laure
authors.initials: L
authors.lastname: Béven
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics*; D004331:Drosophila melanogaster / Q000382:microbiology*; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013149:Spiroplasma / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial
references.citation: Genome Res. 2006 Feb;16(2):149-56
references.pmid: 16365377
references.citation: PLoS One. 2012;7(10):e48606
references.pmid: 23119070
references.citation: Mol Microbiol. 1995 Oct;18(2):283-93
references.pmid: 8709847
references.citation: Can J Microbiol. 2006 Sep;52(9):857-67
references.pmid: 17110978
references.citation: Biochim Biophys Acta. 1977 Mar 1;465(2):275-89
references.pmid: 16250340
references.citation: Insect Mol Biol. 1999 Feb;8(1):133-9
references.pmid: 9927182
references.citation: BMC Genomics. 2013;14:20
references.pmid: 23324387
references.citation: Genetica. 2006 May;127(1-3):207-15
references.pmid: 16850225
references.citation: Adv Parasitol. 2009;70:99-121
references.pmid: 19773068
references.citation: Science. 1986 Feb 28;231(4741):990-2
references.pmid: 3945814
references.citation: Annu Rev Microbiol. 1980;34:677-709
references.pmid: 7002035
references.citation: J Proteome Res. 2012 Jan 1;11(1):224-36
references.pmid: 22129229
references.citation: Microbiology. 2005 Aug;151(Pt 8):2793-803
references.pmid: 16079355
references.citation: FEBS Lett. 1997 Jul 14;411(2-3):161-3
references.pmid: 9271197
references.citation: Heredity (Edinb). 2006 Jul;97(1):27-32
references.pmid: 16685282
references.citation: FEMS Microbiol Lett. 2002 Apr 23;210(1):7-17
references.pmid: 12023071
references.citation: Int J Syst Bacteriol. 1999 Apr;49 Pt 2:611-8
references.pmid: 10319483
references.citation: J Bacteriol. 1976 Mar;125(3):946-54
references.pmid: 1254560
references.citation: J Bacteriol. 1999 Dec;181(24):7449-56
references.pmid: 10601200
references.citation: Mol Plant Microbe Interact. 2000 Oct;13(10):1145-55
references.pmid: 11043476
references.citation: Biochem Genet. 1996 Aug;34(7-8):269-86
references.pmid: 8894049
references.citation: PLoS Comput Biol. 2006 Nov 10;2(11):e151
references.pmid: 17096591
references.citation: Mol Ecol. 2009 Mar;18(6):1294-305
references.pmid: 19226322
references.citation: Elife. 2014;3:e02964
references.pmid: 25027439
references.citation: Cell Microbiol. 2014 Jul;16(7):1119-32
references.pmid: 24438161
references.citation: Genome Biol Evol. 2014 Mar;6(3):500-9
references.pmid: 24534435
references.citation: BMC Microbiol. 2012;12:7
references.pmid: 22243650
references.citation: J Bacteriol. 1994 Jan;176(2):388-94
references.pmid: 8288533
references.citation: Trends Microbiol. 2011 Dec;19(12):614-20
references.pmid: 22032828
references.citation: Science. 2010 Jul 9;329(5988):212-5
references.pmid: 20616278
references.citation: Int J Syst Evol Microbiol. 2004 May;54(Pt 3):893-918
references.pmid: 15143041
references.citation: J Bacteriol. 2005 Oct;187(19):6824-31
references.pmid: 16166545
references.citation: Nucleic Acids Res. 1992 Apr 11;20(7):1559-65
references.pmid: 1349741
references.citation: Science. 2005 Jan 21;307(5708):436-8
references.pmid: 15662018
references.citation: Genome Biol Evol. 2013;5(6):1151-64
references.pmid: 23711669
references.citation: Curr Opin Genet Dev. 2004 Dec;14(6):627-33
references.pmid: 15531157
references.citation: FEMS Microbiol Lett. 2005 Aug 1;249(1):131-7
references.pmid: 16000238
references.citation: Nat Rev Microbiol. 2012 Jan;10(1):13-26
references.pmid: 22064560
references.citation: Microbiology. 2004 Sep;150(Pt 9):3035-40
references.pmid: 15347761
references.citation: Genetics. 2006 Sep;174(1):363-76
references.pmid: 16783009
references.citation: PLoS One. 2011;6(7):e21831
references.pmid: 21818272
references.citation: Mol Ecol. 2014 Mar;23(6):1558-70
references.pmid: 24274471
references.citation: Ann Microbiol (Paris). 1984 Jan-Feb;135A(1):73-82
references.pmid: 6201097
references.citation: Science. 1986 Jun 6;232(4755):1253-5
references.pmid: 17810745
references.citation: Appl Environ Microbiol. 2008 Oct;74(19):6053-9
references.pmid: 18708518
references.citation: Parasitology. 2000 May;120 ( Pt 5):439-46
references.pmid: 10840973
references.citation: Biochem Biophys Res Commun. 2014 Apr 18;446(4):927-32
references.pmid: 24650664
references.citation: MBio. 2013;4(2). pii: e00532-12. doi: 10.1128/mBio.00532-12
references.pmid: 23462112
references.citation: Annu Rev Phytopathol. 2003;41:483-500
references.pmid: 12730387
references.citation: PLoS One. 2009;4(5):e5703
references.pmid: 19492088
references.citation: BMC Genomics. 2008;9:195
references.pmid: 18442384
references.citation: Isr J Med Sci. 1987 May;23(5):429-33
references.pmid: 3667220
references.citation: Appl Environ Microbiol. 2010 Jun;76(11):3420-6
references.pmid: 20363791
references.citation: Apoptosis. 2007 May;12(5):877-85
references.pmid: 17294083
references.citation: Genome Biol Evol. 2011;3:195-208
references.pmid: 21266540
references.citation: Res Microbiol. 1997 Feb;148(2):163-75
references.pmid: 9765797
references.citation: Genome Biol Evol. 2013;5(8):1512-23
references.pmid: 23873917
references.citation: Heredity (Edinb). 2014 Apr;112(4):399-408
references.pmid: 24281548
references.citation: Microbiol Mol Biol Rev. 2004 Sep;68(3):560-602, table of contents
references.pmid: 15353570
references.citation: PLoS Biol. 2004 Mar;2(3):E69
references.pmid: 15024419
references.citation: PLoS One. 2010;5(8):e12149
references.pmid: 20730104
references.citation: Genome Res. 2004 Jul;14(7):1394-403
references.pmid: 15231754
references.citation: Genome Announc. 2014 Jan 09;2(1):null
references.pmid: 24407648
references.citation: BMC Biol. 2008;6:27
references.pmid: 18577218
references.citation: BMC Genomics. 2013;14:22
references.pmid: 23324436
references.citation: J Bacteriol. 1996 Dec;178(23):7003-9
references.pmid: 8955327
references.citation: Mol Syst Biol. 2012;8:600
references.pmid: 22864382
references.citation: Cell Microbiol. 2011 Sep;13(9):1385-96
references.pmid: 21740495
references.citation: Microb Comp Genomics. 1999;4(1):29-46
references.pmid: 10518300