The transgenic Vip3A poplar plant confers high resistance against Hyphantria cunea Drury.

Poplar is severely damaged by Hyphantria cunea (fall webworm), which significantly reduces tree productivity. However, conventional pest management methods are largely ineffective against fall webworm infestation. In this study, we demonstrated that the Vip3A protein possesses high insecticidal activity against H. cunea by overexpressing a synthetic THI1-Vip3A gene in poplar plants. A dicot codon-optimized Vip3A gene, fused with the THI1 chloroplast signal peptide sequence, was chemically synthesized and introduced into the poplar cv. '741' genome via Agrobacterium-mediated transformation. PCR, RT-PCR, and ELISA analyses confirmed the integration and successful expression of the transgene at both the mRNA and protein levels. The Vip3A protein concentration in chloroplasts was approximately 4.8-fold higher than in the whole leaf extract, indicating that the Vip3A protein was successfully targeted to and accumulated within the chloroplasts by the THI1 signal peptide. Subsequently, four transgenic lines with high Vip3A expression were subjected to H. cunea infestation. Compared to wild-type plants, these four transgenic lines exhibited significantly higher resistance, resulting in pest mortality rates exceeding 95% and significantly reduced leaf damage. Together, these results indicate that Vip3A possesses high insecticidal activity against H. cunea. Therefore, transgenic THI1-Vip3A poplar plants can serve as valuable germplasm for breeding poplar cultivars with high resistance to H. cunea infestation.