The ABCG23‐4 gene regulates wing polyphenism and dispersal potential in the bird cherry‐oat aphid under high‐density stress

BACKGROUND: Aphids are among the most damaging pests in agriculture. Under environmental stress, aphids can transition from a wingless to a winged morph. Wingless aphids maximize local reproduction, while winged aphids facilitate rapid, long-distance dispersal, increase plant virus transmission, and promote the spread of insecticide resistance genes within populations. However, the mechanisms regulating wing polyphenism in Rhopalosiphum padi, one of the most destructive cereal pests worldwide, remain poorly understood. RESULTS: Crowding stress induced by high-density conditions can trigger the transition of R. padi from wingless to winged. Twenty-six ABCG genes were identified and classified into five subfamilies. Under high-density conditions, a single ABCG transporter gene, ABCG23-4, was upregulated. RNA interference (RNAi)-mediated knockdown of this crowding-responsive target effectively disrupted the wing polyphenism decision. RNAi-mediated knockdown of ABCG23-4, accomplished through either direct application of dsRNA or the use of nanomaterial-based carriers, significantly decreased the proportion of winged offspring during the first 2 days following crowding. Hormone assays further demonstrated that the knockdown of ABCG23-4 led to reductions in both insulin and 20-hydroxyecdysone titers. CONCLUSION: These results identify ABCG23-4 as a critical regulator of density-induced wing polyphenism and a promising RNAi target for limiting dispersal and population growth of R. padi, thereby offering new opportunities for integrating molecular tools into sustainable aphid management strategies.