Harnessing DNA Nanostructures for Precision Gene Silencing in Plants
The ability to manipulate plant genes with precision has enormous implications for agriculture, from creating more resilient crops to enhancing nutritional content. However, delivering biomolecules such as DNA and RNA into plant cells has long been a major challenge due to the presence of a rigid cell wall—a structural barrier that makes it difficult for external genetic material to pass through. Traditional delivery methods, such as bacterial infection (Agrobacterium) and particle bombardment (biolistics), are limited in scope, often leading to tissue damage or inefficiency.
Now, researchers at UC Berkeley’s Landry Lab have introduced a nanotechnology-based approach that bypasses these hurdles. In their study, "DNA Nanostructures Coordinate Gene Silencing in Mature Plants," they explore how engineered DNA nanostructures—designed with specific shapes, sizes, and mechanical properties—can deliver siRNA into plant cells to regulate gene expression.
Breaking Through the Cell Wall: How DNA Nanostructures Work
DNA nanotechnology takes advantage of Watson–Crick base pairing, allowing scientists to assemble DNA strands into custom, pre-designed shapes. These DNA nanostructures, often measuring just a few nanometers in size, have already shown promise in drug delivery and gene therapy in animal systems—but their potential in plants remained largely unexplored.
In this study, researchers tested a variety of DNA nanostructures to determine which characteristics led to the most efficient delivery into plant cells. They found that:
Smaller nanostructures (under 10 nm) had the highest internalization rates, likely due to their ability to pass through the small pores of the plant cell wall.
Stiffer nanostructures were taken up more readily than flexible ones, suggesting that mechanical properties play a role in penetration efficiency.
The shape of the nanostructure influenced delivery success, with compact, 3D structures outperforming elongated, flexible designs.
To confirm whether these nanostructures could successfully deliver functional genetic material, the team loaded them with small interfering RNA (siRNA)—a molecule that can silence specific genes by preventing messenger RNA (mRNA) from being translated into protein.
Silencing Genes with Precision
To test the effectiveness of DNA nanostructures in gene silencing, the researchers introduced siRNA targeting the green fluorescent protein (GFP) gene in transgenic Nicotiana benthamiana plants. If the siRNA successfully silenced GFP expression, the fluorescence would decrease, serving as a measurable indicator of gene silencing success.
Their results showed that:
siRNA-loaded nanostructures significantly reduced GFP fluorescence, proving that gene silencing had occurred.
Gene silencing efficiency depended on the siRNA attachment location on the nanostructure, with certain configurations enhancing silencing effectiveness.
Different nanostructures triggered distinct gene silencing pathways, either by degrading mRNA (leading to direct gene suppression) or blocking translation at the protein synthesis stage.
These findings suggest that DNA nanostructures can be tailored not just for gene delivery, but also for specific gene regulation strategies, making them highly versatile tools for plant bioengineering.
The Future of Plant Genetic Engineering with DNA Nanotechnology
This study marks an important step toward the use of nanotechnology-driven plant bioengineering. By leveraging precisely designed DNA nanostructures, scientists may be able to develop crops with enhanced traits, such as:
Drought and disease resistance, by silencing genes that make plants vulnerable to stress.
Improved nutritional content, by regulating metabolic pathways.
More sustainable agricultural practices, by reducing reliance on chemical treatments and genetic modification techniques that require external mechanical aid.
Unlike conventional genetic engineering approaches, DNA nanostructures offer a non-disruptive, programmable, and highly targeted method for modifying plant gene expression. Because no external force (such as a gene gun or electroporation) is required for delivery, this approach could revolutionize plant biotechnology, making genetic modifications more efficient and less invasive.
As research in DNA nanotechnology and plant bioengineering progresses, these innovations could help address some of the biggest challenges in agriculture—ensuring food security, sustainability, and crop resilience in an ever-changing climate.
References:
H. Zhang,G.S. Demirer,H. Zhang,T. Ye,N.S. Goh,A.J. Aditham,F.J. Cunningham,C. Fan,& M.P. Landry (2019). DNA nanostructures coordinate gene silencing in mature plants. Proc. Natl. Acad. Sci. U.S.A., 116 (15): 7543-7548.