Nanoparticle-Mediated Delivery towards Advancing Plant Genetic Engineering

Abstract

Genetic engineering of plants has enhanced crop productivity in the face of climate change and a growing global population by conferring desirable genetic traits to agricultural crops. Efficient genetic transformation in plants remains a challenge due to the cell wall, a barrier to exogenous biomolecule delivery. Conventional delivery methods are inefficient, damaging to tissue, or are only effective in a limited number of plant species. Nanoparticles are promising materials for biomolecule delivery, owing to their ability to traverse plant cell walls without external force and highly tunable physicochemical properties for diverse cargo conjugation and broad host range applicability. With the advent of engineered nuclease biotechnologies, we discuss the potential of nanoparticles as an optimal platform to deliver biomolecules to plants for genetic engineering.

Keywords: biomolecule delivery; gene editing; nanoparticle; plants.

Figure 1.

(A) NPs commonly used for biomolecule delivery in both animal and plant systems cover five major categories: bio-inspired, carbon-based, silicon-based, polymeric, and metallic/magnetic. We provide a visual comparison of delivery of various genetic cargo [DNA, RNA, proteins (site-specific recombinases or nucleases), and ribonucleoprotein (RNP)] with each of the five NP types across animal and plant systems. It is evident that NP-mediated delivery has been utilized with a greater variety of genetic cargo in animals than in plants. (b) NP-mediated cargo delivery is conducted via several means. Physical methods include creating transient pores in the cell membrane with electric fields, sound waves, or light, magnetofection, microinjection, and biolistic particle delivery. Nonphysical methods include the use of cationic carriers, incubation, and infiltration. ^a[64], ^b[86], ^c[87], ^d[88], ^e[89], ^f[68], ^g[90], ^h[91], ⁱ[45], ^j[92], ^k[58], ^l[93], ^m[94], ⁿ[95], ^o[96], ^p[97], ^q[98], ^r[99], ^s[81], ^t[100], ^u[63], ^v[101], ^w[102], ^x[54].

Figure 2.

Genetically Modified Organism (GMO) Cultivation and Regulatory Attitudes Worldwide. Despite a long, expensive regulatory pipeline, the US is a leader for GMO cultivation worldwide, followed by Brazil and Argentina, with Argentina being the first to directly address modern genome editing techniques in GMO legislation. European and Australian regulatory attitudes are strict but have recently evolved as of January 2018, suggesting that regulations for genome-edited plants will soon be relaxed in these regions. Nuclease-based edits without transgene integration escape regulation, even in countries with large agricultural GMO industries and complex regulatory systems. Globally, GMO regulation and commercial use is heterogenous and uncertain due to economic, ecological, and sociopolitical complexities. This map is a simplification of the convoluted global landscape regarding genetically engineered crops. ‘Restrictive to GMOs’ indicates a complete or partial ban on GMOs and GMO-derived products for commercial or research purposes. ^a[75], ^b[79], ^c[80], ^d[103], ^e[104], ^f[105], ^g[106], ^h[132], ⁱ[133].