Recent Progress on Nanocarriers for Topical-Mediated RNAi Strategies for Crop Protection—A Review

Abstract

To fulfil the growing needs of the global population, sustainability in food production must be ensured. Insect pests and pathogens are primarily responsible for one-third of food losses and harmful synthetic pesticides have been applied to protect crops from these pests and other pathogens such as viruses and fungi. An alternative pathogen control mechanism that is more “friendly” to the environment can be developed by externally applying double-stranded RNAs (dsRNAs) to suppress gene expression. However, the use of dsRNA sprays in open fields is complicated with respect to variable efficiencies in the dsRNA delivery, and the stability of the dsRNA on and in the plants, and because the mechanisms of gene silencing may differ between plants and between different pathogen targets. Thus, nanocarrier delivery systems have been especially used with the goal of improving the efficacy of dsRNAs. Here, we highlight recent developments in nanoparticle-mediated nanocarriers to deliver dsRNA, including layered double hydroxide, carbon dots, carbon nanotubes, gold nanoparticles, chitosan nanoparticles, silica nanoparticles, liposomes, and cell-penetrating peptides, by review of the literature and patent landscape. The effects of nanoparticle size and surface modification on the dsRNA uptake efficiency in plants are also discussed. Finally, we emphasize the overall limitation of dsRNA sprays, the risks associated, and the potential safety concerns for spraying dsRNAs on crops.

Exogenous Application of dsRNA for Protection against Tomato Leaf Curl New Delhi Virus

“…In this respect, we observed that exogenous dsRNAs persist on zucchini leaves for several days (11 dpi), but, even if the quantity of dsRNA molecules provided to the plants is high, only a small amount move systemically; indeed, this translocation occurs within the plant shortly after treatment and is stably maintained. These findings are in line with those previously reported in N. benthamiana [25], tobacco [42] and cucurbits [43] and prompts the need of developing ad hoc nanocarriers able to facilitate the delivery and increase the stability of dsRNAs in the plant [44] and the dsRNA-delivered siRNA production [45].…”

Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense

“…Therefore, specially designed delivery systems have been especially used with the goal to improve the efficacy of dsRNAs. In particular, recent developments in nanoparticle-mediated carriers for dsRNA delivery include layered double hydroxide, carbon dots, carbon nanotubes, gold nanoparticles, chitosan nanoparticles, silica nanoparticles, liposomes, and cell-penetrating peptides [240].…”

A Direct Comparison of Peptide Drug Delivery Systems Based on the Use of Hybrid Calcium Phosphate/Chitosan Nanoparticles versus Unmixed Calcium Phosphate or Chitosan Nanoparticles In Vitro and In Vivo

“…The veterinary applications of nanocarriers are conceptually similar to drug delivery in humans [7]. Nanocontainers also have great agricultural potential for the delivery of nutrients and various agrochemicals including pesticides, herbicides, plant growth regulators, and foreign DNA or RNA in plants [8][9][10] through leaf cuticular or stomatal pathways using foliar spraying methods [11][12][13][14]. Apart from the general use of nanocarriers in the therapy of some disorders and diagnostics, they can also be used for the treatment of some distinctive organ diseases, e.g., eye diseases.…”