BACKGROUND RNA interference (RNAi) has potential application in pest control, and selection of the specific target gene is one of the key steps in RNAi. As an important effector, the zinc finger protein (ZFP) gene has high similarity among aphid species, and may have potential use in an RNAi‐based pest control strategy. This study assessed the control efficiency of an RNAi target, MPZC3H10, a CCCH‐type ZFP gene, against green peach aphid. RESULTS ZC3H10 amino acid sequence similarity is more than 97.71% among the five tested aphid species: Myzus persicae, Aphis citricidus, Acyrthosiphon pisum, Diuraphis noxia and Rhopalosiphum maidis. However, no homologous sequence was found in the transcriptome of their ladybeetle predator, Propylaea japonica. Spatial expression patterns revealed that MPZC3H10 showed high expression in the muscle and fat body of M. persicae. The RNAi bioassay revealed that silencing of MPZC3H10 resulted in high mortality (53.33%) in M. persicae. By contrast, there were no observed negative effects on the growth and development of P. japonica when fed on aphids treated with double‐stranded RNA (dsRNA) or injected with a “high dose” of dsRNA. CONCLUSION Targeting MPZC3H10 showed promising efficiency for green peach aphid control via artificially designed dsRNA, and was safe for the predatory ladybeetle. © 2022 Society of Chemical Industry.

No abstract

Carotenoids are involved in many essential physiological functions and are produced from geranylgeranyl pyrophosphate through synthase, desaturase, and cyclase activities. In the pea aphid (Acyrthosiphon pisum), the duplication of carotenoid biosynthetic genes, including carotenoid synthases/cyclases (ApCscA–C) and desaturases (ApCdeA–D), through horizontal gene transfer from fungi has been detected, and ApCdeB has known dehydrogenation functions. However, whether other genes contribute to aphid carotenoid biosynthesis, and its specific regulatory pathway, remains unclear. In the current study, functional analyses of seven genes were performed using heterologous complementation and RNA interference assays. The bifunctional enzymes ApCscA–C were responsible for the synthase of phytoene, and ApCscC may also have a cyclase activity. ApCdeA, ApCdeC, and ApCdeD had diverse dehydrogenation functions. ApCdeA catalyzed the enzymatic conversion of phytoene to neurosporene (three‐step product), ApCdeC catalyzed the enzymatic conversion of phytoene to ζ‐carotene (two‐step product), and ApCdeD catalyzed the enzymatic conversion of phytoene to lycopene (four‐step product). Silencing of ApCscs reduced the expression levels of ApCdes, and silencing these carotenoid biosynthetic genes reduced the α‐, β‐, and γ‐carotene levels, as well as the total carotenoid level. The results suggest that these genes were activated and led to carotenoid biosynthesis in the pea aphid.