Characterization of a Newly Discovered Symbiont of the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae)

Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, “Candidatus Portiera aleyrodidarum,” and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified inB. tabaci . In this study, we report and describe the finding of an additional bacterium in the indigenousB. tabaci cryptic species China 1 (formerly known asB. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA andgltA genes showed that the bacterium belongs to theAlphaproteobacteria subdivision of theProteobacteria and has a close relationship with human pathogens of the genusOrientia . Consequently, we temporarily named itOrientia -like organism (OLO). OLO was found in six of eight wild populations ofB. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescencein situ hybridization (FISH) ofB. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with “Ca . Portiera aleyrodidarum.” The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between “Ca . Portiera aleyrodidarum” and OLO. Based on these results, we propose “Candidatus Hemipteriphilus asiaticus” for the classification of this symbiont fromB. tabaci .