Controlling the development of the dengue vector Aedes aegypti using HR3 RNAi transgenicChlamydomonas

TheAedes aegyptimosquito plays an important role in the spread of diseases, including epidemic ones, such as dengue fever, Zika virus disease, yellow fever, and chikungunya disease. To control the population ofAe.aegypti, we transferred an HR3 RNAi fragment into the microalgaeChlamydomonas, which serves as food forAe.aegyptilarvae. Results showed that the HR3 RNAi transgenic algal strains were lethal toAe.aegypti. The integumentary system of larvae fed with HR3 RNAi transgenic algal strains was severely damaged. Muscles of the larvae were unevenly distributed and disordered, and their midgut showed disintegration of the intestinal cavity. RNA-Seq results demonstrated that on the 4th day of inoculation with the transgenic algae, the abundance of early expressed genes in the 20E signal transduction pathway of larvae fed with the HR3 RNAi transgenic algal strain significantly reduced. These genes include E74, E75, E93, and 20E receptor complex EcR/USP and FTZ-F1 gene regulated by HR3. In later experiments, a scale test of 300Ae.aegyptieggs per group was carried out for 30 days, and the survival rate ofAe.aegyptifed with the HR3 RNAi transgenic strain was only 1.3%. These results indicate that the HR3 RNAi transgenic strain exerts obvious insecticidal effect.