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.

Effects of early-life exposure to allergens and bacteria on recurrent wheeze and atopy in urban children

“…Prevotellaceae and Rikenellaceae; Table E7). Blattabacteria , known endosymbionts of cockroaches, 19 were highly positively correlated with Bla g 1 levels, indicating that some of these bacterial constituents of house dust may originate from the enteric contents of cockroaches. None of the 82 taxa of interest were associated with Fel d 1 allergen levels.…”

Comparison of the Genome Sequences of “Candidatus Portiera aleyrodidarum” Primary Endosymbionts of the Whitefly Bemisia tabaci B and Q Biotypes

“…The "Ca. Portiera" genome assembly is a 351-kb circular molecule that is highly AT biased (73%) and larger than those of other previously reported insect primary endosymbionts such as Tremblaya from mealybugs with a 139-kb genome size (8), Hodgkinia from cicadas with a 144-kb genome size (9), and Carsonella from psyllids with a 160-kb genome size (10) but smaller than those of other primary endosymbionts such as Buchnera from aphids with a 640-kb genome size (11), Blattabacterium from cockroaches with a 630-kb genome size (12), and Wigglesworthia from tsetse flies with a 698-kb genome size (13). The median sequence coverages are 223-and 185-fold for the "Ca.…”

Transovarial Transmission of Rickettsia spp. and Organ-Specific Infection of the Whitefly Bemisia tabaci

“…Only endosymbionts from the blattabacteria that coevolved with termites and cockroaches were reported from the fat body, but no specific functional role for these endosymbionts has been assigned (19,50,52). In whiteflies, vitellogenin and possibly other important proteins are produced in the fat body, and thus, the presence of Rickettsia might indicate a role in these processes.…”