Bursicon receptor gene HLGR2 as a potential RNA interference target for control of the fall webworm Hyphantria cunea

Abstract

BACKGROUND: Insect G protein-coupled receptors (GPCRs) have been identified as a new generation of attractive targets for RNA interference (RNAi)-based pest control. A functional study of the leucine-rich repeat-containing (LGR2) gene in Hyphantria cunea (HLGR2) was performed to examine whether it can be used in the molecular control of this notorious pest.RESULTS: The complementary DNA (cDNA) sequence and deduced amino acids of HLGR2 were obtained and analyzed in the present study. HLGR2 is a typical GPCR and shows high structural and sequence similarity with other insect LGR2 proteins. The spatiotemporal expression profiles of HLGR2 showed that HLGR2 was highly expressed at the egg stage and tissues of head and silk gland. After RNAi of HLGR2, distinct phenotypes were observed when HLGR2 expression was suppressed, indicating that HLGR2 is essential in pupation and eclosion. HLGR2 RNAi led to a low pupation rate (45.00%), body malformation, abnormal wing expansion, failed cuticle melanization (63.33%), and high mortality rate (48.33%). Furthermore, we identified eight genes that are regulated by HLGR2. The expression of these eight genes was induced by the HLGR2 signaling pathway and correlated well with cuticle sclerotization. Unlike LGR2 in other insect species, HLGR2 was found to play a crucial role in the control of H. cunea during ecdysis and postecdysial stages. CONCLUSION: HLGR2 is essential for the growth and development and wing expansion and maturation in H. cunea, suggesting HLGR2 is a promising candidate for application in RNAi-based control of this notorious agriculture-forest pest.

Bacteria‐mediated RNAi for managing fall webworm, Hyphantria cunea: screening target genes and analyzing lethal effect

“…The fall webworm Hyphantria cunea Drury (Lepidoptera: Arctiidae), a polyphagous insect that originally evolved in North America, is a globally important invasive pest feeding on at least 300 different plant species 1,2 . It has caused significant economic and ecological damage since it was first reported in China in 1979 3,4 .…”

“…Yan et al 21 identified two chitin deacetylase 2 ( HcCDA2 ) genes in H. cunea , but injection of up to 10 μg of ds HcCDA2a was required for successful RNAi, as indicated by ecdysis failure and larval death. Sun et al 2 reported another RNAi target gene LGR2 (leucine‐rich repeat‐containing) in H. cunea and injecting ds HLGR2 into the wandering‐stage larvae caused body malformation and abnormal wing expansion. In a previous study, we found that injection of the dsRNA of the chitinase 5 gene ( HcCht5 ) blocked larval molting only at the pre‐molting stage 9 .…”

“…Expression of dsRNA in plants to target critical genes in pests is an excellent approach for agriculture pest management; in particular, this approach to the control of coleopteran pests such as the western corn rootworm is at the forefront of development 22 . But this approach may not work for forestry pest control, and H. cunea feeds on at least 300 different plant species 1,2 . By contrast, dsRNA synthesis in bacteria could be an alternative approach with dual benefits in terms of dsRNA synthesis and practical application.…”

Five Visual and Olfactory Target Genes for RNAi in Agrilus Planipennis

“…Due to the high specificity and efficiency of RNAi, more and more research groups tried to develop new pest control methods based on this technology and the latest research results showed that inhibiting the expression of important genes in the growth and development process of insects could cause growth and development disorders or death of insects. Many relevant target genes were screened, such as the inhibitor of apoptosis (IAP), vacuolar sorting protein SNF7 (SNF7), and snakeskin (SSK) of Anoplophora glabripennis (Dhandapani et al, 2020); the chitinase (Sf-CHI), chitin synthase B (Sf-CHSB), sugar transporter SWEET1 (Sf-ST), and hemolin (Sf-HEM) of Spodoptera frugiperda (Wan et al, 2021); the leucine-rich repeat-containing (LGR2) of Hyphantria cunea (Sun et al, 2021) and so on. All of above is the strong evidence that RNAi can be used as a new method for pest control.…”