title: Presence of Wolbachia in insect eggs containing antimicrobially active anthraquinones.
abstract: Wolbachia are obligatory, cytoplasmatically inherited alpha-proteobacteria, which are common endosymbionts in arthropods where they may cause reproductive abnormalities. Many insects are well known to protect themselves from deleterious microorganisms by antibiotic components. In this study, we addressed the question whether Wolbachia are able to infect insects containing antimicrobial anthraquinones and anthrones, and if so, whether these genotypes of Wolbachia comprise a monophyletic cluster within one of the known supergroups. Leaf beetles of the taxon Galerucini (Galerucinae) are known to contain 1,8-dihydroxylated anthraquinones and anthrones. Also, the scale insect Dactylopius contains an anthraquinone glycoside, carminic acid. Our analyses revealed that a representative of the Galerucini, Galeruca tanaceti and Dactylopius, are indeed infected by endosymbiotic Wolbachia bacteria. Phylogenetic analysis of the wsp and ftsZ genes of these bacteria revealed that strains in G. tanaceti cluster in supergroup A, whereas those present in Dactylopius are distinctive from each other and from those of G. tanaceti. They are clustering in supergroups A and B. Wolbachia strains present in close, but anthraquinone-free relatives of G. tanaceti were shown to belong also to supergroup A. From these results, we can conclude (1) a double infection in Dactylopius, (2) that the presence of antimicrobial compounds such as anthraquinones does not necessarily protect insects from infection by Wolbachia, and (3) that genotypes of Wolbachia-infecting anthraquinone-containing insects most likely do not comprise a unique genotype. These results show that Wolbachia bacteria might be adapted to cope even with conditions usually detrimental to other bacteria and that these adaptations are widespread among Wolbachia supergroups.
authors.affiliation: Freie Universität Berlin, Institute of Biology, Haderslebener Str. 9, Berlin, 12163, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Pankewitz
authors.forename: Anja
authors.initials: A
authors.lastname: Zöllmer
authors.forename: Monika
authors.initials: M
authors.lastname: Hilker
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Gräser
mesh_terms: D000818:Animals; D000880:Anthraquinones / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000032:analysis; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001517:Coleoptera / Q000737:chemistry / Q000382:microbiology / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D006430:Hemiptera / Q000737:chemistry / Q000382:microbiology / Q000502:physiology; D008969:Molecular Sequence Data; D010063:Ovum / Q000737:chemistry / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D020577:Wolbachia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D004269:DNA, Bacterial; C071525:FtsZ protein, Bacteria; D012336:RNA, Ribosomal, 16S; C112171:Wsp protein, Wolbachia