Nanoparticle-Shielded dsRNA Delivery for Enhancing RNAi Efficiency in Cotton Spotted Bollworm Earias vittella (Lepidoptera: Nolidae)

Abstract

The spotted bollworm Earias vittella (Lepidoptera: Nolidae) is a polyphagous pest with enormous economic significance, primarily affecting cotton and okra. However, the lack of gene sequence information on this pest has a significant constraint on molecular investigations and the formulation of superior pest management strategies. An RNA-seq-based transcriptome study was conducted to alleviate such limitations, and de novo assembly was performed to obtain transcript sequences of this pest. Reference gene identification across E. vittella developmental stages and RNAi treatments were conducted using its sequence information, which resulted in identifying transcription elongation factor (TEF), V-type proton ATPase (V-ATPase), and Glyceraldehyde -3-phosphate dehydrogenase (GAPDH) as the most suitable reference genes for normalization in RT-qPCR-based gene expression studies. The present study also identified important developmental, RNAi pathway, and RNAi target genes and performed life-stage developmental expression analysis using RT-qPCR to select the optimal targets for RNAi. We found that naked dsRNA degradation in the E. vittella hemolymph is the primary reason for poor RNAi. A total of six genes including Juvenile hormone methyl transferase (JHAMT), Chitin synthase (CHS), Aminopeptidase (AMN), Cadherin (CAD), Alpha-amylase (AMY), and V-type proton ATPase (V-ATPase) were selected and knocked down significantly with three different nanoparticles encapsulated dsRNA conjugates, i.e., Chitosan-dsRNA, carbon quantum dots-dsRNA (CQD-dsRNA), and Lipofectamine-dsRNA conjugate. These results demonstrate that feeding nanoparticle-shielded dsRNA silences target genes and suggests that nanoparticle-based RNAi can efficiently manage this pest.

Insect α-Amylases and Their Application in Pest Management

“…Moreover, the biological synthesis of Bacillus thuringiensis-coated zinc oxide nanoparticles (Bt-ZnO NPs) has demonstrated significant effects on the hatchability, fecundity, and larval and pupal development period of Callosobruchus maculatus [96]. α-amylase can also work as a target gene; it could be knocked down with nanoparticle-encapsulated dsRNA conjugates to manage pests efficiently [97].…”

Development and application of an RNA nanostructure to induce transient RNAi in difficult transgenic plants

“…[ 13 ] NPs have also emerged as promising carriers for dsRNA, as they improve its stability and enhance RNAi efficiency. [ 14–24 ] For example, cationic lipid NPs have been applied to deliver dsRNA and protect plants against fungal diseases, thereby increasing dsRNA stability. [ 21 ] RNA NPs, on the other hand, can be constructed using structural motifs from bottom up, and they can self‐assemble into specific structures with strong stability.…”

Impact of transgenerational host switch on gut bacterial assemblage in generalist pest, Spodoptera littoralis (Lepidoptera: Noctuidae)

“…Such studies will facilitate a deeper understanding of the microbial contribution to host adaptation and also aid in identifying the conserved (core) microbial population in the gut. A profound understanding of the gut bacterial contribution to host adaptation can be used for formulating eco-friendly pest management practices, such as developing biochemical and biopesticides (i.e., RNAi-based products), that eliminate or disrupt insect symbiosis (Qadri et al, 2020 ; Joga et al, 2021 ; Zhang et al, 2022 ; Sandal et al, 2023 ), antimicrobial peptides (Carter et al, 2013 ), introducing a foreign microbe (Moran and Yun, 2015 ), incompatible insect technique (Atyame et al, 2016 ), paratransgenesis (Caragata and Walker, 2012 ), and pheromones alteration (Cardé and Minks, 1995 ). This study tries to elucidate the influence of matching and mismatching plant diets between generations on S. littoralis larval gut bacterial communities.…”