Function Study Of BdRab40 In 20E And Insulin Signal Pathway Of Bactrocera Dorsalis

Bactrocera dorsalis(Hendel), which has a wide host range, is an important pest of fruits and vegetables and can cause huge economic losses. B.dorsalis female adults reach sexual maturity after eclosion by feeding, and then begin to mate and spawn.Studying the reproduction of B.dorsalis female adults and the function of related genes involved in the reproduction is important for the prevention of B.dorsalis. We first study the important roles of 20 E and Insulin signal pathway in reproduction of B.dorsalis female adults. Then we choose Bd Rab40, a member of Rab gene family and differentially expressed in new emergence and maturity period of B.dorsalis, to study the regulation of 20 E and Insulin on Bd Rab40 and the role of Bd Rab40 in B.dorsalis reproduction of female adults.1 Regulation of 20 E and Insulin on reproduction of B.dorsalis female adultsTo study the role of 20 E and Insulin signal pathway in reproduction of B.dorsalis female adults, we detected the expression patterns of transcription factors in the development period of B.dorsalis female adults and tissues. The expression patterns show that: Ec R, USP, E75, In R, IRS, Akt and Foxo are highly expressed in B.dorsalis female adults sexual maturation period, and mainly in the ovary.To further define the functions of two signaling pathways in B.dorsalis female adults reproduction, we synthetised ds RNA of Ec R, USP, In R and Foxo and did microinjection. The results show that the expression of YP in Ec R and In R RNAi groups significantly reduced. They all had an effect on the total and daily fecundity.Ec R, USP and In R RNAi group were lower than the control group, while Foxo RNAi was higher. Thus, 20 E and Insulin signaling pathway regulate the reproduction of B.dorsalis female adults through affecting the deposition yolk protein and spawing.2 The expression patterns and function of Bd Rab40We obtain Bd Rab40 sequence from B.dorsalis c DNA library. Its open reading frame is highly identical with the other insects Rab40 homology. The spatial andtemporal expression patterns of BdRab40 show that, this gene mainly express in sexually mature female adults, in addition, the relative expression of Bd Rab40 in the ovary is significantly higher than other organizations. After 20 E and Insulin injection,the relative expression of Bd Rab40 increased significantly, and silencing Ec R, USP,In R and Foxo by RNAi all reduced the relative expression level of Bd Rab40. These results suggest that, Bd Rab40 may play an important function in the sexual maturity of B.dorsalis female adults, and is regulated by 20 E and Insulin signal pathway.To further determine the function of Bd Rab40, we synthetised Bd Rab40 ds RNA and did microinjection to silence Bd Rab40, and observed the effect of the RNAi on B.dorsalis female adults sexual maturity. The results show that, the mating rate of all groups with normal male did not change, but the 10-11 d ovary of female adults did not develop or not fully develop compared to the control group, and the total and daily fecundity in 15 d after mating were lower than the control group. Moreover, the hatching rate of all groups also did not change. In addition, the expression of YP also significantly reduced in RNAi group by RT-PCR.All the above results suggest that: 20 E and Insulin signaling pathways are involved in the reproduction of B.dorsalis female adults; Bd Rab40 is regulated by20 E and Insulin, and can affect the deposition yolk protein, the development of ovary and oviposition. It plays an important role in the reproduction of B.dorsalis female adults.