title: Succession of the gut microbiota in the cockroach Blattella germanica.
abstract: The cockroach gut harbors a wide variety of microorganisms that, among other functions, collaborate in digestion and act as a barrier against pathogen colonization. Blattabacterium, a primary endosymbiont, lives in the fat body inside bacteriocytes and plays an important role in nitrogen recycling. Little is known about the mode of acquisition of gut bacteria or their ecological succession throughout the insect life cycle. Here we report on the bacterial taxa isolated from different developmental instars of the cockroach Blattella germanica. The bacterial load in the gut increased two orders of magnitude from the first to the second nymphal stage, coinciding with the incorporation of the majority of bacterial taxa, but remained similar thereafter. Pyrosequencing of the hypervariable regions V1-V3 of the 16S rRNA genes showed that the microbial composition differed significantly between adults and nymphs. Specifically, a succession was observed in which Fusobacterium accumulated with aging, while Bacteroides decreased. Blattabacterium was the only symbiont found in the ootheca, which makes the vertical transmission of gut bacteria an unlikely mode of acquisition. Scanning electron microscopy disclosed a rich bacterial biofilm in third instar nymphs, while filamentous structures were found exclusively in adults.
authors.affiliation: Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.
authors.forename: Purificación
authors.initials: P
authors.lastname: Carrasco
authors.affiliation: Genomics and Health Area, Foundation for the Health and Biomedical of the Community of Valencia, Valencia, Spain.
authors.forename: Ana Elena
authors.initials: AE
authors.lastname: Pérez-Cobas
authors.affiliation: Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.
authors.forename: Claudia
authors.initials: C
authors.lastname: van de Pol
authors.affiliation: Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Baixeras
authors.affiliation: Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.|Genomics and Health Area, Foundation for the Health and Biomedical of the Community of Valencia, Valencia, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: Moya
authors.affiliation: Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain.|Genomics and Health Area, Foundation for the Health and Biomedical of the Community of Valencia, Valencia, Spain.
authors.forename: Amparo
authors.initials: A
authors.lastname: Latorre
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D003058:Cockroaches / Q000382:microbiology*; D005260:Female; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny
keywords: 16S rRNA gene; Blattella germanica; cockroach gut microbiota; ecological succession; endosymbionts