Effects Of The Extracts From Celtis Kunmingensis And Alnus Nepalensis On Transcriptional Level Of Vitellogenin And Its Receptor In Tomicus Yunnanensis

Tomicus yunnanensis is a pest of a variety of pine trees, and has a serious damage on Yunnan pine. Previous studies in our lab found that extracts from Celtis Kunmingensis and Alnus nepalensis can interfere egg laying of T. yunnanensis. In order to reveal the underlying mechnisms, the effects of extracts from C. Kunmingensis and A. nepalensis on the transcriptional level of vitellogenin(Vg) and its receptor(VgR) in T. yunnanensis were investigated in this study. For faciliating the cloning of Vg and VgR gene sequences, we first sequenced the transcriptome of T. yunnanensis. In total, 28837383 clean reads were obtained, which were assembled into 47408 unigenes. Of them, 17023 were annotated in the Nr database with an E-value < 10-5. Based on the annotation, we identified 4 Vg and VgR genes, respectively. Accoding to Vg and the VgR gene sequences plus with the conservative sequences of them, partial sequences of Vg and VgR were isolated from T. yunnanensis. They were 570 bp and 162 bp, respectively. The deduced amino acid sequence of Vg showed the highest identity(76%) with that of Dendroctonus ponderosae, and had 61% and 60% identity with Pissodes strobi and Anthonomus grandis, respectively. The deduced amino acid sequence of VgR showed the highest identity(88%) with that of D. ponderosae, and had 47% identity with Tribolium castaneum. Phylogenetic trees indicated that Vg and VgR genes of T. yunnanensis gathered with those from other coleopteran insects. The real-time quantitative PCR analysis showed that Vg gene expressed at in different tissues including head, thorax, wing, ovary and other redidues of male T. yunnanensis, but the expression profile was different. VgR gene was specifically expressed in ovarian tissue. There are consistency of Vg and VgR’s expression profiles at different developmental stages. They both had a high transcriptional levle in pupal stage and mature female. Their transcriptional levels were low or extremely weak in other stages. The extracts from C. Kunmingensis and A. nepalensis interference experiment showed that the transcriptional level of Vg gene in T. Yunnanensis decreased compared with the control group after treated by C. Kunmingensis leaf extracts. VgR gene’s transcriptional levle didn’t show obvious change. The transcriptional levles of Vg and VgR both decreased in the A. nepalensis leaf extracts treated group when compared with the control group after 20 days and 40 days, but Vg and VgR’s transcriptional levles were higher than the control group after 60 days, especially for the Vg gene. The results provide the basic data for further clarifying the molecular mechanisms of the non-host smells influencing on egg laying of T. yunnanensis, which is beneficial for designing effective method to control the damage of this pest.