Abstract:

Alpha proteobacteria of the genus Wolbachia are a widespread group of maternally inherited endosymbionts of arthropod and nematode hosts. Wolbachia infection induces a range of host phenotypes, including cytoplasmic incompatibility, male killing, feminization and thelytoky induction. Heterogony (cyclical parthenogenesis) is a remarkable characteristic of oak gall wasps, Cynipini, which is the largest tribe in Cynipidae. A few species of Cynipini are exceptionally,which are univoltine and exhibit thelytokous parthenogenesis, probably due to deletion of the arrhenotokous generation from their heterogonic ancestor species with Wolbachia infection. In this study, the presence of Wolbachia was detected using polymerase chain reaction (PCR) primers for the wsp genes in a thelytokous species (Dryocosmus kuriphilus) of the Cynipini. The wsp characteristic 617 bp product was obtained after amplification of extracts from Zhuzhou population. The sequence clearly conformed to Wolbachia group A and was nearly identical to that of Plagiotrochus quercusilicis. The possible implications of Wolbachia infection in the gallwasp are discussed.

Key words: Wolbachia, wsp gene, sequence analysis, thelytoky, Dryocosmus kuriphilus