Over the years, the control and management of crop diseases have been based heavily on the application of a broad diversity of synthetic pesticides, including insecticides, fungicides, and herbicides; in spite of the environmental and health damages caused by the extensive use and exposure of these chemical substances like the resurgence of the pest population, resistance development, non-target organisms, and of course potential health risks to farmers, rural populations, and consumers. Thus, the design of novel, sustainable and eco-friendly solutions for crop improvement and pest control is urgently needed.
Nanoparticle-mediated double-stranded (ds)RNA or small interfering RNA (miRNA/siRNA) delivery systems can protect RNAs against several factors affecting the stability of RNA, such as degradation by UV light, free endonucleases, pH and others. The sprayed dsRNAs can be uptaken into the epidermal cells or may remain on the leaf surface. In the plant, dsRNA molecules can move through vascular bundles to distal parts of the organism and then they can be directly taken up by different target pathogens (insects and pathogenic fungi) and trigger the RNAi response. Alternatively, cellular uptake may imply the penetration of the dsRNAs into the plant cell cytoplasm where the endogenous RNAi machinery can process dsRNAs into active siRNAs. Mature siRNAs also can be distributed throughout plant tissues systemically. Then, mature siRNAs can trigger the degradation of specific transcripts and protect the plant against a viral attack or taken up by other target organisms (insects and pathogenic fungi) and susequently trigger the RNAi response. Also, fungi and insects may incorporate the dsRNAs directly from the plant surface. In addition to nanoparticles, chemical modifications can also stabilize RNA and protect it from pH variations and degradation, especially in insects. Read more in our Review article in Journal of experimental botany (2023).