Abstract: Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) are worldwide pests. A pair of primers was designed based on the reported sequences of conservative regions of heat shock protein 90 gene (hsp90) family in other insects, and the fragments isolated from the two whitefly species were amplified by RT-PCR, and their full-length cDNA sequences were obtained by 3′ and 5′RACE. The full-length cDNA of hsp90 of two whitefly species contained 2 166 and 2 160 bp open reading frame (ORF) encoding 722 and 720 amino acids, respectively. The deduced amino acid sequence of hsp90 of T. vaporariorum was aligned with that of B. tabaci and both displayed a high degree of conservation (92.94％). The five highly conserved amino acid residues that characterize all the members of the HSP90 family and the C-terminal pentapeptide MEEVD were found in the two sequences. A phylogenetic tree was constructed based on all the complete amino acid sequences of HSP90 from Insecta by NJ method with genetic distance of Kimura 2-parameter model, which showed that the hsp90 presented good phylogenetic informativeness at both low and high taxonomic levels in Insecta. The results provide new insights into adaptation mechanisms of T. vaporariorum and B. tabaci to extreme environmental stress. Our data provide further support that the hsp90 sequences with ubiquity and high degree of conservation can provide a useful model for phylogenetic analysis.

Key words: Bemisia tabaci biotype B, Trialeurodes vaporariorum, gene cloning, hsp90, heat shock protein, phylogeny