BioCNTs Mediated Delivery of Systemically Mobile Small RNAs via Leaf Spray to Control Both Tomato DNA and RNA Viruses

Tomato viral diseases severely restrict the safe and efficient tomato production, and current control methods are lacking. Therefore, the development of green and efficacious biopesticides is imperative. The initiation of RNA interference (RNAi) by topically applied double-stranded RNA (dsRNA) or short hairpin RNA (shRNA) has potential applications in crop protection. However, the instability and limited mobility of exogenous naked RNAi molecules severely limit their practical large-scale application. Here, a robust method combining dsRNA and shRNA-mediated silencing technology with single-walled carbon nanotubes (SWCNTs)-based nanocarriers (BioCNTs) is developed to prevent tomato mosaic virus, tomato spotted wilt virus, and tomato yellow leaf curl virus through exogenous spraying. This method is nontoxic to tomato plants and enables effective delivery of dsRNA or shRNA for long-term silencing. By integrating shRNAs and tRNA-like structure (TLS) with BioCNTs, we developed a highly effective biopesticide with systemic mobility. After 14 days of spraying, the control efficacy remained high in the upper unsprayed leaves. These findings indicate that BioCNTs-mediated dsRNA/shRNA has strong inhibitory effects, and TLS enables systematic movement of shRNA in plants, maintaining long-term virus silencing efficacy. Therefore, the simple and low-cost BioCNTs-TLS system holds significant potential as an effective, green, and sustainable tool for controlling plant viral diseases.