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

Area of Science:

• Entomology
• Molecular Biology
• Pest Management

Background:

• The fall webworm (Hyphantria cunea) is an invasive forest pest causing significant ecological and economic damage globally.
• Current management relies heavily on chemical pesticides, leading to resistance, environmental harm, and health risks.
• RNA interference (RNAi) presents a promising, eco-friendly alternative, but effective targets and delivery methods are needed.

Purpose of the Study:

• To identify effective RNAi targets for Hyphantria cunea control.
• To develop a practical, bacteria-mediated RNAi application method for this pest.
• To elucidate the molecular mechanisms underlying RNAi-induced mortality in H. cunea.

Main Methods:

• Screening of 23 candidate genes to identify effective RNAi targets using double-stranded RNA (dsRNA) injection.
• Development of bacterially expressed dsRNA targeting identified genes using the L4440 expression vector and E. coli HT115.
• Oral administration of bacterially expressed dsRNA to H. cunea larvae.
• Transcriptome sequencing (RNA-seq) to analyze gene expression changes and metabolic pathway disruptions.

Main Results:

• Two highly effective RNAi targets, vATPase A and Rop, were identified, significantly reducing larval growth and increasing mortality.
• Bacterially expressed dsRNA targeting vATPase A and Rop, when orally administered, caused high mortality and developmental abnormalities.
• RNA-seq revealed significant disruptions in metabolic pathways, particularly insect cuticle metabolism, and identified specific gene expression changes related to oocyte maturation and olfaction.

Conclusions:

• vATPase A and Rop are validated as potent RNAi targets for controlling Hyphantria cunea.
• Bacteria-mediated oral delivery of dsRNA offers a viable and scalable method for managing this invasive pest.
• This study represents a significant advancement in applying RNAi technology for practical pest control, offering an environmentally sound alternative to chemical pesticides.