Generation of aphid-resistant wheat through plant-mediated RNA interference

Aphids (Aphididae) are major agricultural pests that cause substantial economic losses through direct feeding damages and efficient transmission of plant viruses. Current control strategies heavily rely on chemical insecticides, which pose environmental risks and can lead to resistance, underscoring the urgent need for sustainable and targeted alternatives. In this study, we explored plant-mediated RNA interference (RNAi) as a sustainable strategy for aphid control by targeting two distinct genetic elements: the endosymbiotic bacterial gene Smrrl from Buchnera aphidicola, which is essential for aphid survival, nutrient provision, and stress tolerance, and SmDSR32, a novel aphid gene encoding a salivary peptide that is crucial for successful feeding.
Initial in vitro double-stranded RNA (dsRNA) feeding assays confirmed that silencing these two genes significantly increased aphid mortality, demonstrating their importance as RNAi targets. Transgenic wheat lines expressing dsRNA targeting either Smrrl or SmDSR32 were generated. Aphids feeding on these transgenic plants exhibited significantly reduced expression of the target genes, confirming successful uptake and RNAi silencing. This gene suppression led to severe physiological impairments, manifesting as significantly increased mortality, reduced fecundity, and overall decline in population growth over time. Detailed electrical penetration graph (EPG) recordings further revealed profound alterations in feeding behavior, including prolonged periods of stylet pathway activity and significantly shortened sustained ingestion phases. Notably, the silencing effects were not limited to the exposed generation. Offspring of aphids reared on RNAi plants also exhibited sustained fitness deficits, demonstrating that the RNAi-mediated suppression was both persistent and transgenerational. This prolonged impact highlights the robustness of this approach and its potential to provide sustainable control in agricultural settings.
In conclusion, our findings identify two promising RNAi targets, and provide a comprehensive proof-of-concept for using host-induced gene silencing (HIGS) to disrupt critical biological functions in aphids. This strategy offers a novel, effective, and environmentally sustainable approach for managing Sitobion miscanthi in wheat.