Parental RNA interference (pRNAi) in insects: mechanisms, applications, and challenges in pest management.

Parental RNA interference (pRNAi) is a promising gene-silencing mechanism observed in progeny through the introduction of double-stranded RNA (dsRNA) in parental insects. This technique has been studied in multiple insect species, including Diabrotica virgifera virgifera and Tribolium castaneum, where it effectively reduces egg hatch rates and causes developmental abnormalities by targeting essential genes. pRNAi leverages the systemic RNAi pathway, wherein silencing signals initiated in the parent are transmitted to the offspring via maternal or paternal routes. The paper explores key factors influencing pRNAi efficacy, such as dsRNA stability, delivery methods and exposure timing. dsRNA degradation by endogenous dsRNases and the alkaline nature of insect guts are major obstacles. Additionally, maternal pRNAi has been extensively studied, highlighting its ability to suppress target gene expression across generations, whereas paternal pRNAi remains less understood. Applications of pRNAi include targeting genes for reducing reproduction, altering sex ratios and inducing lethality. Despite its potential, challenges like variable effectiveness across species, environmental impacts and limited understanding of molecular mechanisms persist. These findings underscore the scope and limitations of pRNAi as a sustainable pest management strategy.