The creation of edited plants through tissue culture is often inefficient, time-consuming works for only limited species and genotypes, and causes unintended changes to the genome and epigenome. Now scientists at the University of Minnesota have developed new methods to optimize producing gene-edited plants.
These methods are expected to alleviate a long-standing bottleneck in gene editing and make it easier and faster to develop and test new crop varieties.
Regardless of dramatic advances in scientists’ capacity to edit plant genomes using gene-editing tools, for example, CRISPR and TALENs, specialists were stuck utilizing an old-fashioned approach—tissue culture. It has been being used for decades and is expensive, labor-intensive, and requires exact work in a sterile environment. Scientists used tissue culture to convey genes and gene editing reagents or chemicals that drive the reaction to plants.
Dan Voytas, a professor in Genetics, Cell Biology and Development in the College of Biological Sciences said, “A handful of years ago the National Academy of Sciences convened a meeting of plant scientists, calling on the community to solve the tissue culture bottleneck and help realize the potential of gene editing in plants. We have advanced genome editing technology, but we needed a novel way to deliver gene-editing reagents to plants efficiently. The methods in this paper present a whole new way of doing business.”
Ryan Nasti and Michael Maher developed these new methods that leverage essential plant growth regulators responsible for plant development.
Scientists used growth regulators and gene editing reagents and triggered seedlings to develop new shoots that contain edited genes. They then collected seeds from these gene-edited shoots and continue experiments. No cell cultures needed.
Both approaches vary in the way the growth regulators are applied. The approach developed by Nasti allows small-scale rapid testing—with results in weeks instead of months or years—of different combinations of growth regulators. The approach created by the same basic principles to make the process more accessible by eliminating the need for a sterile lab environment.
Maher said, “With this method, you don’t need sterile technique. You could do this in your garage. This technique opens up the possibility that smaller research groups with fewer resources can gene edit plants and test how well they do.”
Dan Voytas, a professor in Genetics, Cell Biology and Development in the College of Biological Sciences and senior author on the paper, said, “Nasti and Maher have democratized plant gene editing. It will no longer take months in a sterile lab with dozens of people in tissue culture hoods.”
Scientists used a tobacco species as their model, but have already demonstrated the method works in grape, tomato and potato plants. They believe the findings will likely transfer across many species. Plant geneticists and agricultural biotechnologists aim to ensure stable food sources for a growing global population in a warming climate, where pest outbreaks and extreme weather events are commonplace. These new methods will allow them to work more efficiently.
The new methods will:
- Drastically reduce the time needed to edit plant genes from as long as nine months to as short as a few weeks.
- Work in more plant species than was possible using tissue culture, which is limited to specific species and varieties.
- Allow researchers to produce genetically edited plants without the need for a sterile lab, making it a viable approach for small labs and companies to utilize.