Oral RNAi toxicity assay suggests clathrin heavy chain as a promising molecular target for controlling the 28‐spotted potato ladybird, Henosepilachna vigintioctopunctata

Abstract

BACKGROUND Use of RNA interference (RNAi) technology in effective pest management has been explored for decades. Henosepilachna vigintioctopunctata is a major solanaceous crop pest in Asia. In this study, the effects of the RNAi‐mediated silencing of clathrin heavy chain in H. vigintioctopunctata were investigated. RESULTS Feeding either the in vitro‐synthesized or the bacterially expressed double‐stranded RNAs (dsRNAs) significantly impaired the normal physiology of H. vigintioctopunctata instars and adults. However, the bacterially expressed dsHvChc caused higher mortality than the in vitro‐synthesized ones in the larvae and adults. Moreover, on evaluating the potential risk of dsHvChc on Propylea japonica, significant transcriptional effects of dsHvChc1 were observed, while the organismal level effects were not significant. On the contrary, dsHvChc2 did not affect P. japonica at either level. A similar test revealed significant transcriptional effects of dsPjChc1 on H. vigintioctopunctata, while staying ineffective at the organismal levels. Conversely, dsPjChc2 did not affect H. vigintioctopunctata at either level. Importantly, no effect of dsPjChc1 exposure on H. vigintioctopunctata suggested that other factors besides the 21‐nucleotide (nt) matches between sequences were responsible. Finally, ingestion of dsHvmChc1 derived from H. vigintioctomaculata, containing 265‐nt matches with dsHvChc1, caused 100% mortality in H. vigintioctopunctata. CONCLUSIONS We conclude that (i) species with numerous 21‐nt matches in homologous genes are more likely to be susceptible to dsRNA; (ii) dsRNA can be safely designed to avoid negative effects on non‐target organisms at both transcriptional and organismal levels; (iii) HvChc can be used as an efficient RNAi target gene to effectively manage H. vigintioctopunctata. © 2021 Society of Chemical Industry.

Tyrosine hydroxylase involved in cuticle tanning and reproduction in the 28‐spotted potato ladybeetle, Henosepilachna vigintioctopunctata

“…[22][23][24][25] Our recent study demonstrated that NTOs with numerous 21-nt matches in homologous genes are more likely to be susceptible to dsRNAs; dsRNAs can be safely designed to avoid the negative effect on NTOs at both the transcriptional and organismal levels. 17 In the present study, Harmonia axyridis fourth instar larvae were exposed to 2000 ng dsRNA, which was ten times higher than the dsHvTH dose for Henosepilachna vigintioctopunctata fourth instar larvae. At that level of exposure, dsHvTH and dsHaTH did not affect Harmonia axyridis at the organismal level.…”

“…15,16 Recently, RNAimediated pest control has been proven to be an effective technology for controlling Henosepilachna vigintioctopunctata infestation. [17][18][19][20][21][22] The development and metamorphosis of Henosepilachna vigintioctopunctata includes a larva to pupal transition and then pupal to adult molting. In this larval-pupal-adult transition, the formation, pigmentation, and hardening of the cuticle are critical for Henosepilachna vigintioctopunctata survival and reproduction.…”

“…The coleopteran pest, 28‐spotted potato ladybird, Henosepilachna vigintioctopunctata (Fabricius), is considered the most harmful pest of solanaceous crops in Asia 15,16 . Recently, RNAi‐mediated pest control has been proven to be an effective technology for controlling Henosepilachna vigintioctopunctata infestation 17–22 . The development and metamorphosis of Henosepilachna vigintioctopunctata includes a larva to pupal transition and then pupal to adult molting.…”

Molecular basis for the pheromone-mediated feeding preference of early-instar Mythimna separata larvae

“…Each dsRNA of the MsGOBP1, MsGOBP2, MsPR1, MsOR2 and MsOR3 genes (dsGOPB1, dsGOBP2, dsPR1, dsOR2 and dsOR3) was synthesized using the T7 RiboMAX Express RNAi system (Promega, America). The newly-hatched M. separata larvae were continuously fed with artificial diet containing dsRNA (1 μg dsRNA/1 g artificial diet) for 72 h to suppress the expression of MsGOBP1, MsGOBP2, MsPR1 and MsOR3 genes in larval antennae (59)(60)(61). The interference efficiency of each gene was evaluated by real time qPCR (RT-qPCR).…”

Multiple dsRNases Involved in Exogenous dsRNA Degradation of Fall Armyworm Spodoptera frugiperda

“…More recently, the use of the sprayable double-strand RNA-based biopesticide technology was proven to be effective strategy for controlling Colorado potato beetle Leptinotarsa decemlineata by GreenLight Biosciences ( Rodrigues et al, 2021 ). Not all insects, viz., Lepidopteran and Hemipteran orders, however, show sensitivity to RNAi ( Terenius et al, 2011 ) compared to the Coleopteran order ( Wang et al, 2013 ; Guo et al, 2021 ). Furthermore, to induce systemic RNAi in these highly susceptible insects, a particularly intriguing aspect of RNAi is that the dsRNA is not only capable of entering gut cells but can spread to other tissues as well ( Joga et al, 2016 ).…”