Phylogenetic Analysis of Endosymbionts Associated with Bemisia tabaci (Hemiptera: Aleyrodidae)

Abstract

Endosymbionts include primary endosymbionts and secondary endosymbionts, accreting with insects. Endosymbionts evolve with insects and benefit from each other. A report was given on the difference of endosymbionts found in Bemisia tabaci (Gennadius 1889) and Trialeurodes vaporariorum (Westwood 1856) before. However, the phylogentic analysis of primary and secondary bacterial symbionts associated with the whitefly B tabaci B biotype are poorly known. Here are presented the results of cloning and sequencing 16S rDNA of primary and secondary endosymbionts in B tabaci living for extended periods on different host plants in Beijing. Molecular phylogenetic trees, including about 1 000bp 16S rDNA of primary endosymbionts, and about 1 250bp 16S rDNA of secondary endosymbionts in B tabaci were constructed. The results indicate that primary endosymbionts in B tabaci were Proteobacteria, Gammaproteobacteria, Oceanospirillales, Halomonadaceae, Zymobacter and Candidatus Portiera aleyrodidarum. Secondary endosymbionts in B tabaci were Proteobacteria, Gammaproteobacteria, Enterobacteriales and Enterobacteriaceae. The primary and secondary endosymbionts in B tabaci from different host plants or other countries might belong to different ecological types from one species specifically. B tabaci independently acquired various endosymbionts when living on different host plants, and these endosymbionts played important roles for B tabaci's accomodation in different environments. The phylogentic trees based on 16S rDNA of primary endosymbionts could be explained by geographical origin more reasonably than those of the secondary endosymbionts, and the phylogentic trees based on 16S rDNA of secondary endosymbionts can be explained by varying host resources more reasonably than those of primary endosymbionts. B tabaci may have been introduced to China via the importation of Poinsettia plants.