Abstract: 【Aim】To assess the conditions of gene RNA interference mediated by the nanocarrier-delivery system in the pea aphid (Acyrthosiphon pisum). 【Methods】The cuticle development-related gene chitin synthase 2 (CHS2) gene, the metabolism-related enzyme vacuolar H⁺ATPase AC39 (VhaAC39) gene, the water-specific aquaporin (Wsa) gene and the key enzyme of N6 methyladenosine (m6A) modification methyltransferase-like protein 14 (METTL14) gene of A. pisum were selected. Different concentrations (10-5 000 ng/μL, 5-250 ng/individual) of dsRNAs of the above four genes were injected into the 4th instar nymphs of A. pisum through the nanocarrier-delivery system, and the expression levels of the above four genes at 48 h after injection were determined by qRT-PCR, to screen the optimal concentration of dsRNA. qRT-PCR was used to detect the expression levels of the above four genes at 12, 24, 36, 48, 60 and 72 h after injecting the dsRNAs of the above four genes at the optimal concentration into the 4th instar nymphs of A. pisum through the nanocarrier-delivery system, to screen the optimal time for RNA interference mediated by the nanocarrier-delivery system.【Results】The expression level of CHS2 was significantly decreased by 47.5% at 48 h after injecting 50 ng/μL (25 ng/individual) of dsCHS2 into the 4th instar nymph of A. pisum as compared to that of the control group injected with dsEGFP. The expression levels of METTL14 decreased significantly after injecting 50-500 ng/μL (25-100 ng/individual) of dsMETTL14 into the 4th instar nymphs of A. pisum as compared to that of the control group injected with dsEGFP, exhibiting a dose-dependent effect. The expression level of VhaAC39 decreased significantly by 53.4% at 48 h after injecting 50 ng/μL (25 ng/individual) of dsVhaAC39 into the 4th instar nymph of A. pisum as compared to that of the control group injected with dsEGFP, while the expression level of Wsa showed no significant change at 48 h after dsWsa injection. The expression levels of CHS2, METTL14 and VhaAC39 all decreased most significantly at 48 h after injection of dsRNAs of target genes, while the expression level of Wsa decreased most significantly at 60 h after injection of dsWsa, as compared to those in the control group injected with dsEGFP.【Conclusion】 The optimal concentration of dsRNA in RNA interference mediated by nanocarrier-delivery system is 50 ng/μL (25 ng/individual), and higher RNA interference efficiency appears at 48-60 h after treatment. This study provides new clues for aphid RNA interference with nanocarrier-delivery system.

Key words: Acyrthosiphon pisum, dsRNA, RNA interference, nanocarrier-delivery system, RNA-based pesticides