Implementing Genome Editing as a New Tool in the Breeder’s Toolbox
Although we have seen an upward trend in plant yields in the past decades, current estimates suggest we will not meet future food, feed, and fuel demands. Therefore, we have a need to develop innovative approaches to accelerate crop improvement and make its outcomes more predictable. Some of the challenges in public and private, big or small breeding programs come from finding and bringing together suitable sources of genetic variation for both qualitative and quantitative traits. In the past, breeders have used “exotic germplasm” (wild relative species that can intercross with cultivated varieties) or mutational breeding. Nowadays, new technologies such as Genome Editing bring a new opportunity to not only generate novel genetic variation but also to deploy it more efficiently.
What is Genome Editing?
Genome editing is a novel form of genetic modification that allows for precise targeted modifications in the genome of a given organism. Previously discovered as a surveillance mechanism to protect bacteria from viral infections, it was recently repurposed to allow targeted modifications in genes responsible for multiple characteristics in plants and animals. Remarkably, the genetic modifications obtained are usually indistinguishable from those generated by conventional mutagenesis, and its use and implementation has been determined by regulatory agencies such as USDA. This technology to “edit” plant and animal cells has proved to be so groundbreaking it was awarded the Nobel Prize in an almost record time to Jennifer Douda and Emmanuel Charpertier, who initially published their findings back in 2012.
Is genome editing useful for Agriculture?
Provided that we know a DNA sequence, we can design a genome editing experiment to produce novel genetic variation that could have a relevant effect on a given trait, with little concern for off-targets or with reduced undesired effects. Take for example tomato fruit size (Figure 1.). Domestication and improvement in tomato come from selection for increased fruit size. We know that cultivated tomatoes have little variation in major genes controlling fruit size. Given this, we previously showed that we can use genome editing to fine-tune fruit size by modifying where, when and how strong a gene responsible for fruit size is expressed. The breadth of variation we generated was so striking that when we showed the fruits to other people, they thought they were from different cultivars! In fact, it was the same cultivar, only carrying a different allele (variant) of the gene that we targeted using genome editing (see picture above for a visual reference).
The potential for this technology is remarkable, and we are only at the beginning of understanding its impact in plant breeding. However, most big and small companies are currently testing this technology in their biotech pipelines. My research group at the University of Maryland is interested in developing new strategies to implement genome editing for breeding and trait development. We are pursuing a research program that aims at establishing collaborations with the Maryland Vegetable Industry to understand their current and future needs, and develop strategies to implement genome editing as another tool in the “breeder’s toolbox”. We believe this technology will bring benefits to local and global plant breeding programs and will speed up the valuable work plant breeders do: FEED THE WORLD!
This article appears in October 2023, Volume 14, Issue 8 of the Vegetable and Fruit News
Vegetable & Fruit News, October 2023, Volume 14, Issue 8
Vegetable and Fruit News is a statewide publication for the commercial vegetable and fruit industries and is published monthly during the growing season (April through October). Subscribers will receive an email with the latest edition.
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