title: Blattabacteria, the endosymbionts of cockroaches, have small genome sizes and high genome copy numbers.
abstract: Blattabacteria are intracellular endosymbionts of cockroaches and primitive termites that belong to the class Flavobacteria and live only in specialized cells in the abdominal fat body of their hosts. In the present study we determined genome sizes as well as genome copy numbers for the endosymbionts of three cockroach species, Blattella germanica, Periplaneta americana and Blatta orientalis. The sole presence of blattabacteria in the fat body was demonstrated by rRNA-targeting techniques. The genome sizes of the three blattabacteria were determined by pulsed field gel electrophoresis. The resulting total genome sizes for the three symbionts were all approximately 650 +/- 15 kb. Comparison of the genome sizes with those of free-living Bacteroidetes shows extended reduction, as occurs in other obligatory insect endosymbionts. Genome copy numbers were determined based on cell counts and determination of DNA amounts via quantitative PCR. Values between 10.2 and 18.3 and between 323 and 353 were found for the symbionts of P. americana and B. orientalis respectively. Polyploidy in intracellular bacteria may play a significant role in the genome reduction process.
authors.affiliation: Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, Apartado Postal 2085, 46071 Valencia, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: López-Sánchez
authors.forename: Alexander
authors.initials: A
authors.lastname: Neef
authors.forename: Rafael
authors.initials: R
authors.lastname: Patiño-Navarrete
authors.forename: Lara
authors.initials: L
authors.lastname: Navarro
authors.forename: Ricardo
authors.initials: R
authors.lastname: Jiménez
authors.forename: Amparo
authors.initials: A
authors.lastname: Latorre
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000235:genetics*; D020048:Blattellidae / Q000382:microbiology*; D003058:Cockroaches / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005216:Fat Body / Q000382:microbiology; D016680:Genome, Bacterial; D017403:In Situ Hybridization; D010526:Periplaneta / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial