Silencing of Two Insulin Receptor Genes Disrupts Nymph-Adult Transition of Alate Brown Citrus Aphid

Abstract

Insulin receptors play key roles in growth, development, and polymorphism in insects. Here, we report two insulin receptor genes (AcInR1 and AcInR2) from the brown citrus aphid, Aphis (Toxoptera) citricidus. Transcriptional analyses showed that AcInR1 increased during the nymph–adult transition in alate aphids, while AcInR2 had the highest expression level in second instar nymphs. AcInR1 is important in aphid development from fourth instar nymphs to adults as verified by dsRNA feeding mediated RNAi. The silencing of AcInR1 or/and AcInR2 produced a variety of phenotypes including adults with normal wings, malformed wings, under-developed wings, and aphids failing to develop beyond the nymphal stages. Silencing of AcInR1 or AcInR2 alone, and co-silencing of both genes, resulted in 73% or 60%, and 87% of aphids with problems in the transition from nymph to normal adult. The co-silencing of AcInR1 and AcInR2 resulted in 62% dead nymphs, but no mortality occurred by silencing of AcInR1 or AcInR2 alone. Phenotypes of adults in the dsInR1 and dsInR2 were similar. The results demonstrate that AcInR1 and AcInR2 are essential for successful nymph–adult transition in alate aphids and show that RNAi methods may be useful for the management of this pest.

Expression profiling of winged‐ and wingless‐destined pea aphid embryos implicates insulin/insulin growth factor signaling in morph differences

“…Because of its effects on the expression of these genes, the IIS pathway is thought of as a phenotypic plasticity pathway, generating bodies that match their environment with respect to size, shape and physiology. Correspondingly, multiple studies have implicated the IIS pathway in the regulation of a wide variety of plasticities (Emlen, Warren, Johns, Dworkin, & Lavine, ; Snell‐Rood & Moczek, ; Tang et al, ; Wheeler, Buck, & Evans, ; Wolschin et al, ; reviewed in Nijhout and McKenna, 2018), including late nymphal stage differences between winged and wingless morphs of two aphid species (Ding et al, ; Guo, Zhang, & Liu, ), and long and short‐winged morphs of the brown planthopper, Nilaparvata lugens (Xu et al, ) and the soapberry bug, Jadera haematoloma (Fawcett et al, ). Interestingly, the latter two studies showed different functional requirements for the two insulin receptors, the paralogs InR1 and InR2.…”

Vitellogenin and its receptor play essential roles in the development and reproduction of the brown citrus aphid, Aphis (Toxoptera) citricidus

“…We also explored the functions of AcVg and AcVgR in an RNAi bioassay using plant-stem-mediated dsRNA feeding, which has been used previously to silence genes encoding chitin synthase and insulin receptors in Aph. citricidus (Shang et al, 2016b;Ding et al, 2017).…”

Genome-wide gene expression profiling of the melon fly, Zeugodacus cucurbitae, during thirteen life stages

“…Transcriptome sequencing is an efficient and low-cost method by which to explore gene expression patterns at multiple developmental stages 6,7 , tissues in insects 8,9 . Many insect transcriptomes have been obtained using next-generation sequencing techniques for functional genomic studies 10,11 . For example, in Ceratitis capitata, a conserved Maleness-on-the-Y gene was isolated to be involved in the male sex determination by RNA-Seq.…”