The unfulfilled potential of nanocarriers for RNA delivery in antiviral crop protection.

Gene silencing mediated by double-stranded RNA (dsRNA) is a promising strategy for crop protection. However, unlike applications targeting fungi or insects, effective antiviral use of exogenous dsRNA requires delivery into the plant cytoplasm, where viruses replicate. Limited cellular uptake and rapid instability on leaf surfaces have driven the development of diverse nanocarrier platforms, including layered double hydroxides, carbon nanotubes, mesoporous silica nanoparticles, chitosan complexes, lipid-based particles and bacterially encapsulated dsRNA. Although these systems often enhance dsRNA stability and apoplastic accumulation, robust symplastic delivery remains poorly characterized. Here we critically examine the gap between experimental success and agronomic performance of nanocarrier-enabled dsRNA delivery systems. Comparative analyses suggest that carrier dose, size, ζ-potential and organic phase affinity influence systemic translocation within the plant, providing a framework for rational carrier design. Defining such principles will be essential for translating RNA-based antiviral strategies into reliable field applications.