Chitosan-protected dsRNA increases efficacy against Helicoverpa armigera without compromising biosafety for...

Area of Science:

• Agricultural Science
• Entomology
• Biotechnology

Background:

• Cotton bollworm (Helicoverpa armigera) is a significant global cotton pest.
• Double-stranded RNA (dsRNA) shows potential as a biopesticide for insect control.
• Field application of RNA interference (RNAi) requires enhanced dsRNA stability and proven biosafety.

Purpose of the Study:

• To develop and evaluate chitosan/TPP/dsRNA nanoparticles for enhanced RNAi delivery against Helicoverpa armigera.
• To assess the efficacy and biosafety of dsRNA-nanoparticle complexes for pest management.

Main Methods:

• Synthesized dsRNA-chitosan/tripolyphosphate (TPP) nanoparticles (150-300 nm) targeting chitin synthase II and cytochrome p450 protein 6b6 genes.
• Assessed larval mortality and knockdown effect in Helicoverpa armigera fed with nanoparticle-encapsulated dsRNA.
• Conducted acute oral toxicity tests on beneficial bee species (Scaptotrigona postica and Bombus terrestris).

Main Results:

• Nanoparticle encapsulation increased dsRNA knockdown effect by 100% and significantly enhanced larval mortality compared to naked dsRNA.
• Effective RNAi was achieved at low nanoparticle doses (0.1-1 μg g⁻¹).
• No significant toxicity or lethality was observed in non-target beneficial bees, Scaptotrigona postica and Bombus terrestris.

Conclusions:

• Chitosan/TPP/dsRNA nanoparticles offer a promising strategy for enhancing RNAi efficacy against Helicoverpa armigera.
• This nanoparticle-based dsRNA delivery system presents an efficient and safe approach for managing lepidopteran pests.
• Further research is needed to optimize these nanoparticles for practical field applications.