Nano-enabled RNA interference at the plant-virus interface: antiviral mechanisms, nanocarrier delivery and translational challenges.

Viral diseases remain among the most difficult constraints in horticultural crops because they reduce yield, impair market quality, persist in vegetatively propagated material and are intensified by mixed infections, insect vectors and climate-driven shifts in disease epidemiology. Conventional measures, including resistant cultivars, sanitation, vector management, pesticide use and virus-free planting material, remain essential but often lack the precision and flexibility required for rapidly evolving plant-virus pathosystems. RNA interference (RNAi) provides a sequence-specific antiviral strategy by converting viral or exogenously supplied double-stranded RNA into small interfering RNAs that guide Argonaute/RISC complexes toward complementary viral transcripts. Nevertheless, naked RNA molecules are constrained by poor environmental stability, inconsistent uptake across plant surfaces and tissues, transient persistence, cost barriers and regulatory uncertainty. The central translation gap, however, is not whether SIGS can can function under controlled conditions, but whether laboratory efficacy can be converted into field stable, scalable formulations that retaion RNA on foliage, with UV exposure, rainfall, and nuclease degradation, faciliate entry into relevant tissues, and provide reproducible antiviral activity across crops. Nanotechnology can address these limitations by protecting dsRNA/siRNA cargoes, improving foliar and cellular delivery, enabling controlled release and supporting antiviral activity through immunomodulatory or direct nanoparticle effects. This review synthesizes current knowledge on plant virus infection and movement, host-virus interactions, antiviral RNAi pathways, viral RNAi suppressors, nanocarrier systems for RNA delivery, direct antiviral nanoparticles, postharvest integration, biosafety and regulatory considerations, and emerging opportunities in multi-virus targeting and AI-guided design. Rather than treating all nanocarrier systems as equivalently mature, the review critically compares their evidence base, biological versus formulation-driven limitations, and position along the laboratory-to-field translation pathway. The review proposes a practical translational framework in which nano-enabled RNAi is developed through mechanism-informed target selection, formulation optimization, field validation, monitoring and farmer-ready deployment for sustainable plant virus management.