Nanotechnology, a powerful tool for plant science

Kan Wang and Victor Lin
Iowa State Scientists Kan Wang and Victor Lin.

Iowa State scientists are the first to use nanotechnology to penetrate plant cell walls and simultaneously deliver a gene and a chemical that triggers its expression with controlled precision. The research, supported by the Plant Sciences Institute, presents a powerful new tool for targeted delivery into plant cells.

The work is a collaborative effort between the labs of Kan Wang, director of the Center for Plant Transformation and professor of agronomy and genetics, development and cell biology, and Victor Lin, professor of chemistry and senior scientist at the U.S. DOE Ames Laboratory. Wang and Lin with postdoctoral research associates Francois Torney and Brian Trewyn present their methods and results in "Mesoporous Silica Nanoparticles Deliver DNA and Chemicals into Plants," a highlighted article in the May issue of Nature Nanotechnology.

Thus far, there are no other examples of nanotechnology being used in agriculture or plant biology said Lin.

“Other universities may have good materials and research programs, but they may not have the agricultural application or the plant scientists on their campuses as we do here at Iowa State,” he said.

The project started with an ISU proprietary technology developed by Lin's group. It is a porous, silica nanoparticle system with a honeycomb-like structure that can be filled with chemicals or molecules. The system has a unique “capping” strategy that seals chemicals inside. It can be chemically activated to release its cargo, providing total control for timing the delivery.

Even though the Lin group has demonstrated that this system could be engulfed easily by animal cells, animal cells don't have rigid cell walls like plants. To make the system work on plants, they modified the nanoparticle surface with a chemical coating, allowing naked plant cells to absorb the nanoparticles.

In order to deliver into walled plant cells, a common practice in genetic transformation, biologists often use a gene gun. To adapt the system for standard gene gun use, the chemists made another modification to the nanoparticle surface. They synthesized even smaller gold particles to cap the nanoparticles. These "golden gates" prevented leakage of the encapsulated chemical and added weight to the nanoparticles, enabling their delivery into the plant cell.

"With the mesoporous nanoparticles, we can deliver two biogenic species at the same time. We can bring in a gene and induce it in a controlled manner at the same time and at the same location,” said Wang. “This is truly a breakthrough.”

The biologists successfully used the technology to introduce DNA and chemicals to Arabidopsis, tobacco and corn plants. In the future, scientists could use the new technology to deliver imaging agents or other genetic materials, such as RNA and proteins, inside cell walls. This would provide plant biologists with a window into intracellular events and more opportunities to study the gene functions and mechanisms.