Standard strategy for developing multicomponent nanopesticides: From gene function analysis to co-delivery nano-platform construction

The continuous screening of high-efficiency RNAi targets is labor-consuming and time-costing, which constrains the fast commercialization of RNA pesticides. Thus, incorporating synergistic active ingredients via co-delivery nano-platform offers a promising solution without the need for high-efficiency RNAi targets. The current study aimed to propose a standard strategy for developing multicomponent nanopesticides. The function analysis revealed that the decapentaplegic-like ( Dpp ) participated in fatty acid biosynthesis and cuticle formation, and its RNAi resulted in molting failure and death in destructive green peach aphids. However, the morality caused by Dpp RNAi could not meet the actual demand, and thus a potential synergistic pesticide spirotetramat (SPI) was introduced to assemble with star ploycation (SPc) and ds Dpp to construct a co-delivery nano-platform. The SPc could assemble with SPI into SPI/SPc complex, and the ds Dpp could be further adhered on the surface of complex through electrostatic interaction, which formed stable spherical particles with nanoscale size (322.95 nm) and positive charge (28.22 mV). Notably, the SPI/SPc/ds Dpp complex displayed better adhesion performance on plant leaves, and thus the plant uptake of SPI/SPc/ds Dpp complex was remarkably improved in vivo and in vitro. Meanwhile, the SPI/SPc/ds Dpp complex exhibited amplified contact area on aphid cuticle, and its translocation was improved across the aphid cuticle/cell membrane. Importantly, the stomach and contact toxicity of SPI/SPc/ds Dpp complex was the strongest with the highest aphid mortalities of 94.5 %–96.6 %. The co-delivery nano-platform improved both initial action time and overall bioactivity, addressing the short life disadvantage of ds Dpp and slow-acting property of SPI. Our work proposed a standard strategy for designing multicomponent nanopesticides, which could facilitate the fast commercialization of RNA pesticides.