RNA Interference Depletion of the Halloween Gene Disembodied Implies its Potential Application for Management of Planthopper Sogatella furcifera and Laodelphax striatellus

Abstract

Sogatella furcifera and Laodelphax striatellus are economically important rice pests in China by acting as vectors of several rice viruses, sucking the phloem sap and blocking the phloem vessels. Ecdysteroid hormone 20-hydroxyecdysone regulates insect development and reproduction. A cytochrome P450 monooxygenase CYP302A1 (22-hydroxylase), encoded by the Halloween gene disembodied (dib), plays a critical role in ecdysteroidogenesis. The objective of this study is to test whether dib genes are potential targets for RNA interference-based management of S. furcifera and L. striatellus. We cloned and characterized Sfdib and Lsdib. The open reading frame regions of dib genes were generated and used for designing and constructing dsRNA fragments. Experiments were conducted using oral delivery of dsdib to investigate the effectiveness of RNAi in S. furcifera and L. striatellus nymphs. Real-time quantitative reverse transcriptase-PCR analysis demonstrated that continuous ingestion of dsdib at the concentration of 0.01, 0.05 and 0.50 mg/ml diminished Sfdib expression levels by 35.9%, 45.1% and 66.2%, and ecdysone receptor (SfEcR) gene mRNA levels by 34.0%, 36.2% and 58.5% respectively in S. furcifera, and decreased Lsdib expression level by 18.8%, 35.8% and 56.7%, and LsEcR mRNA levels by 25.2%, 46.8% and 68.8% respectively in L. striatellus. The reduction in dib and EcR transcript abundance resulted in observable phenotypes. The development of nymphs was impaired and the survival was negatively affected. Our data will enable the development of new insect control strategies and functional analysis of vital genes in S. furcifera and L. striatellus nymphs.

Instar-dependent systemic RNA interference response in Leptinotarsa decemlineata larvae

“…Similar results have also been documented in Aedes aegypti [51], Sogatella furcifera and Laodelphax striatellus [52]. Moreover, our results showed that ingestion of dsLdSAHase by young L. decemlineata larvae caused higher RNAi efficiency than that by old larvae.…”

Non-Invasive Delivery of dsGST Is Lethal to the Sweet Potato Whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae)

“…4). Similar results were observed in Sogatella furcifera [72], Nilapravata lugens [73], Aedes aegypti [51], etc. However, certain other studies have also observed that increasing dsRNA concentration beyond an optimal dose did not improve extent of gene silencing, although the optimal concentration of dsRNA may vary for the insect species in question, mode of cognate dsRNA delivery, and the developmental stages of insects [15,12] [13,16,48,51,52,57,64,74].…”

RNA Interference in Insect Vectors for Plant Viruses

“…Knockdown of the Halloween gene disembodied ( dib ) in this insect delayed nymphal growth and caused mortality [129], while gene silencing by dsRNA feeding showed that the cytochrome P450 monooxygenase CYP353D1v2 could significantly enhance the sensitivity of L. striatellus to imidacloprid [130]. …”

“…Knockdown of the disembodied ( dib ) gene in this insect delayed nymphal growth and caused high mortality rates [129]. Introduction of dsRNA of the Halloween gene phantom ( phd ) in the diet of second instars successfully knocked down the expression levels of ecdysteroid hormones ecdysone (E) and 20-hydroxyecdysone (20E), and caused mortality, while slowing down ecdysis during the nymphal stages [161].…”