Knockdown of AisHSP19.6 by RNA Interference Increases Susceptibility to Three Insecticides in Agrotis ipsilon

Area of Science:

• Molecular Biology
• Entomology
• Toxicology

Background:

• Heat shock proteins (HSPs) are vital for insect defense against environmental stressors like insecticides.
• The role of HSPs in protecting the agricultural pest Agrotis ipsilon from specific insecticides is not well understood.

Purpose of the Study:

• To identify and characterize a small heat shock protein (sHSP) in Agrotis ipsilon.
• To investigate the function of AisHSP19.6 in response to insecticide-induced oxidative stress and its impact on insecticide susceptibility.

Main Methods:

• Identification and gene expression analysis of AisHSP19.6 in Agrotis ipsilon larvae.
• Exposure of larvae to insecticides (phoxim, lambda-cyhalothrin, chlorantraniliprole) and hydrogen peroxide to assess AisHSP19.6 transcription.
• RNA interference (RNAi) to silence AisHSP19.6 expression.
• Assessment of larval mortality rates post-insecticide exposure in silenced and control larvae.

Main Results:

• A novel sHSP gene, AisHSP19.6, was identified in Agrotis ipsilon, with peak expression in the larval midgut during the sixth instar.
• Insecticide exposure (phoxim, lambda-cyhalothrin, chlorantraniliprole) and H2O2 injection significantly upregulated AisHSP19.6 transcription.
• AisHSP19.6 conferred protection against oxidative stress but did not metabolize the tested insecticides.
• RNAi-mediated silencing of AisHSP19.6 resulted in significantly increased mortality in larvae exposed to phoxim, lambda-cyhalothrin, and chlorantraniliprole.

Conclusions:

• AisHSP19.6 plays a crucial role in protecting Agrotis ipsilon larvae from oxidative stress induced by common insecticides.
• The findings highlight the involvement of sHSPs in insecticide susceptibility in this pest.
• AisHSP19.6 represents a potential target for developing RNAi-based pest management strategies against Agrotis ipsilon.