Nanocarrier-Assisted Foliar Applications in RNAi-Based Plant Protection Systems

Abstract

RNA interference (RNAi) is a highly effective gene-silencing mechanism that provides sequence-specific protection in plants against viruses, fungal pathogens, and insect pests. Based on this natural defense system, spray-induced gene silencing (SIGS) utilizes the exogenous application of nucleic acid molecules onto plant surfaces to suppress pathogen-derived genes. As this approach does not require the development of transgenic plants, it has emerged as a promising and environmentally friendly strategy for sustainable crop protection. Despite its considerable potential, the practical implementation of SIGS in agriculture remains challenging. The effectiveness of double-stranded RNA (dsRNA) is often constrained by environmental and physicochemical factors, including rainfall, ultraviolet radiation, temperature fluctuations, enzymatic degradation, and limited retention on leaf surfaces, all of which reduce RNA stability and biological efficacy under field conditions. These limitations represent major barriers to the successful application of RNA-based gene-silencing technologies in crop protection. In recent years, nanoparticle-based delivery systems have gained considerable attention as potential tools to address these challenges by enhancing dsRNA stability, prolonging its persistence on leaf surfaces, and improving its biological activity following application. Nevertheless, the successful implementation of RNA-based crop protection strategies requires a comprehensive understanding of the interactions among nanocarriers, dsRNA molecules, plant surfaces, and environmental factors, together with careful evaluation of their biosafety and agricultural applicability.