RNA Interference in Aquatic Beetles as a Powerful Tool for Manipulating Gene Expression at Specific Developmental...

Area of Science:

• Developmental Biology
• Genetics
• Entomology

Background:

• RNA interference (RNAi) is a widely used technique for targeted gene silencing via mRNA degradation.
• RNAi is highly efficient in Coleoptera (beetles), making it suitable for studying diverse species.
• Developing RNAi protocols for novel organisms is crucial for expanding research capabilities.

Purpose of the Study:

• To establish and demonstrate RNA interference (RNAi) methods in the aquatic diving beetle Thermonectus marmoratus.
• To apply RNAi across different developmental stages (embryos and larvae) of T. marmoratus.
• To investigate the roles of specific genes in morphology and behavior using RNAi.

Main Methods:

• Gene sequences were obtained via transcriptome assembly.
• Double-stranded RNA (dsRNA) was synthesized using the pCR4-TOPO plasmid and a common primer.
• dsRNA was injected into T. marmoratus embryos or larvae, with larvae immobilized in agarose for injection.
• RNAi efficacy was assessed by observing phenotypes.

Main Results:

• Successful gene knockdown was achieved for the laccase2 (tanning) and white (eye pigmentation) genes, resulting in observable cuticle and eye lightening.
• Knockdown of a lens protein gene led to optical deficiencies and impaired hunting behavior in larvae.
• Specific phenotypes correlated with targeted gene knockdowns, validating the RNAi approach.

Conclusions:

• RNA interference (RNAi) is a versatile and effective tool for functional gene analysis in Thermonectus marmoratus.
• This study provides a framework for applying RNAi in novel beetle species, even with limited genomic data.
• RNAi facilitates the study of both complex morphological traits and behavioral patterns in insects.