# Nanomaterial-Mediated RNAi Targeting Chitin Metabolism Genes in MEAM1 Cryptic Species of Bemisia tabaci (Hemiptera: Aleyrodidae)

## TL;DR

This study explores using RNA interference with nanomaterials to target chitin metabolism genes in a harmful insect pest, effectively reducing its survival and reproduction.

## Contribution

A novel nanomaterial-based dsRNA delivery system is shown to enhance RNAi effects in whiteflies by targeting chitin metabolism genes.

## Key findings

- Nanomaterial-assisted dsRNA delivery significantly increased nymph mortality and reduced adult emergence in Bemisia tabaci.
- Multi-target dsRNA achieved higher efficacy and earlier gene silencing compared to single-target dsRNA.
- Stage-specific expression patterns of chitin metabolism genes were identified using RT-qPCR.

## Abstract

Chitin metabolism plays a critical role in the growth and development of insects and offers potential targets for RNA interference (RNAi)-based pest management. We identified five functional genes in the chitin metabolic pathway of Bemisia tabaci and analyzed their expression patterns in various developmental stages. Using a nanocarrier-based dsRNA delivery system, we achieved efficient gene silencing of genes in the chitin metabolism pathway, resulting in an increase in nymph mortality and a marked reduction in adult emergence rates. Moreover, nymphs exposed to multi-target dsRNA showed an earlier onset of gene silencing than those treated with single-target dsRNAs.

The whitefly Bemisia tabaci is a globally invasive pest that threatens crop production through feeding and virus transmission. In this study, we identified genes encoding enzymes in the chitin metabolism pathway of B. tabaci—β-N-acetylglucosaminidase (BtNAG), N-acetylglucosamine kinase (BtNAGK), phosphoacetylglucosamine mutase (BtPAGM), UDP-N-acetylglucosamine pyrophosphorylase (BtUAP), and glucosamine-6-phosphate N-acetyltransferase (BtGNA)—using bioinformatic analysis. Quantitative reverse-transcription PCR (RT-qPCR) analyses revealed distinct stage-specific expression patterns for these genes. We used the nanomaterial star polycation (SPc) to deliver gene-specific double-stranded RNA (dsRNA) targeting these genes to fourth instar B. tabaci nymphs, which resulted in significant mortality and developmental defects upon gene silencing. Notably, the fusion dsRNA targeting three genes—BtNAG1, BtNAGK, and BtUAP—achieved approximately 80% nymph mortality, 70% inhibition of adult emergence, and an earlier onset of gene silencing. These findings provide evidence that nanomaterial-assisted delivery of dsRNA can significantly enhance RNAi effects in hemipteran pests and that dsRNA targeting chitin metabolic genes may be an effective strategy for RNAi-based control of B. tabaci.