CRISPR-Cas9 is revolutionizing the way we create novel crops, but why should growers care?
By Alex Martin
There are plenty of buzzwords surrounding the seed industry in 2018 — GMOs, gene-editing, organic and, of course, CRISPR. While we know a lot surrounding the debate of GMOs versus organic and whether or not GMOs and gene-editing overlap, one gene-editing technology still seems a mystery.
So, what exactly is CRISPR-Cas9, and why does it matter to the seed industry?
CRISPR is a genome editing system that could benefit the seed industry by allowing breeders to make minor changes into the genomes of existing high performance cultivars that will result in enhanced yield, ability to withstand stresses such as drought, heat and diseases and give crops the nutritional qualities that consumers are looking for.
“From an academic perspective, I like to think of plants as machines,” says Nat Graham, a postdoctoral associate from the Voytas lab at the University of Minnesota. “Everything runs on a code — DNA. What we’re focused on from a genome engineering perspective is how can we manipulate DNA for our gain?”
“With traditional transgenics, you would take a genetic sequence and randomly insert it into the DNA, which can disrupt the sequence,” Graham explains. “If it disrupts, you just keep trying again until it doesn’t cause a problem. If you want to turn a sequence off, you’d need to use mutagenesis. CRISPR-Cas9 is a new tool for genome engineering, and it allows breeders to go through the genome, find a sequence and precisely alter it.”
Graham continues by explaining that currently, CRISPR is used to “turn off,” sequences through mutation. His current research focuses on how to insert new sequences by using CRISPR-Cas9, but he emphasizes that most products that come from CRISPR currently turn off mutations.
CRISPR-Cas9 is a protein found in bacteria that were under attack from bacteriophages. It can recognize sequences of invaders and cut the DNA sequences apart. Researchers discovered that the proteins could be programmed to recognize a new sequence and introduce mutations site-specifically into the DNA sequence.
There are a few different ways that CRISPR works to “turn-off,” sequences. Graham explains that one way is to alter the sequence, thus the gene no longer makes sense. If the gene sequence doesn’t make sense, it wouldn’t make the product anymore.
Another way to “turn-off,” the sequence is by completely removing it, which would make the sequence no longer functional. It would stop making the product, because it would no longer be there.
Finally, you could alter current genes. In this idea, instead of traditional mutagenesis, where a researcher would create a desirable sequence, find the sequence to be changed and replace it with the new, more desirable sequence, a researcher could find a specific base pair in a sequence and alter it completely. Graham likes to use sentences as examples for this idea: if you had the sentence “the cat was fat,” and you wanted to change it to “the rat was fat,” CRISPR would allow a researcher to find the sentence and change the “c” to an “r” to create the desired sentence.
Another example he uses is that CRISPR directly edits gene “text,” while genetic modification is more like inserting a new chapter into a book.
“Traditional breeding takes advantage of natural mutations to find new traits,” Graham says. “The difference is we’re causing mutations to happen in the way we choose. We’re accelerating the natural process.”
“CRISPR is new from an academic perspective — it hit the science journals in 2012,” Graham says. “We’re still learning about it and how to make it better. There’s a lot we still need to learn.”
CRISPR is also beneficial to the seed industry because it won’t be regulated like GMOs. Gijs van Rooijen, chief scientific officer of Genome Alberta, says that CRISPR regulations are similar to traditional genetics across Canada.
“If you’re making minor changes such as deletions or insertions, it isn’t different than anything from traditional breeding,” says van Rooijen.
In Canada, crops are regulated through plants with novel traits (PNT). Regardless of how the plant was created, be it through traditional breeding or gene-editing, the government must ask questions about whether or not the trait is novel and if it would make the plant more ‘weedy’ or difficult to control.
“Whether crops are generated through traditional breeding, GMOs, or gene-editing, they will be looking at the risks associated in relation to human health, animal health and environmental health,” van Rooijen says.
“The government also takes into account trade risks when dealing with a new cultivar,” van Rooijen says. “Right now, if you’re growing a GMO variety, chances are it’s going to cause more issues with your trading partners, particularly in Europe. However, if you’re growing traditional varieties, it’s usually okay trade-wise.”
Currently, one of the only gene-edited varieties starting to be marketed in Canada is from Cibus’s Rapid Trait Development System. Developed in 2015, Cibus has begun trialing a sulfonylura (SU) canola trait, which will be marketed with their Draft herbicide. Together, they can control key weeds such as common buckwheat, common ragweed and redroot pigweed.
“With the advances in CRIPSR and gene-editing technology, the technology and regulations are actually straightforward, so smaller companies are encouraged to begin developing their own products,” van Rooijen says. “CRISPR is actually giving smaller companies the ability to compete with larger companies.”
Van Rooijen says that currently, CRISPR research in crops is focused around developing varieties similar to GMOs. However, in using CRISPR in North America, these crops can be regulated as non-GMO. In particular, research has been focused on herbicide tolerance.
“You can imagine that a lot of companies are beginning to look at traits that focus on higher nutritional quality, such as high-oleic soybeans or high-fibre wheat,” van Rooijen says. “These varieties are likely to be seen in the next couple of years. Since companies can make edits to the existing genome, varieties can be developed much faster, but current research focuses on traits that have already been approved.”
Currently, through traditional breeding, it takes around seven years to create a new desirable variety. With genetic modification, it still takes around 10 to 12 years due to regulatory barriers and high costs. Currently, researchers believe genome editing will only take around three to five years, since gene-editing is more precise than other breeding methods.
However, the best part about CRISPR would be it wouldn’t change the way growers have been farming already.
“Growing gene-edited crops won’t be much different from growing GMO varieties,” van Rooijen says. “By providing the available traits, it means growers can use herbicides only when needed, which is better for the crops and the environment. CRISPR will provide similar benefits that GMOs already bring, however they’ll be regulated differently.”
CRISPR could provide growers with improved disease resistance, drought tolerance and higher yields, while providing consumers with better food quality, nutrition and a longer shelf life.
Van Rooijen also believes CRISPR has the potential to expand grower’s export markets. “Growers have the potential to expand into markets where people are weary of GMOs,” he says.
In addition, since CRISPR crops are easier to create than GMOs, van Rooijen says there’s a possibility that the seeds might be sold at a reduced rate in comparison to other GMO traits.
However, van Rooijen says the biggest benefit CRISPR will have is an environmental impact.
“There’s no question that consumers are concerned about the environmental impact of how we grow our food,” van Rooijen says. “We need to grow more efficient crops. With CRISPR, we can grow the amount of food we need to feed the population, but we also increase our efficiency while reducing stress on the environment.”
“CRISPR and gene-editing technologies are revolutionizing the way novel traits can be created,” says van Rooijen. “The positive effects outweigh the negatives, and we must continue to find the consumer’s support so that we can provide the world with better opportunities for growers, consumers and the environment. It’s almost irresponsible to not take this opportunity.”
We’ve come a long way in agriculture. From crop domestication to cross breeding to plant breeding based on genetic information to GMOs, it seems the natural way to go from here is target breeding. Whatever may happen with these technologies, it seems one thing is for certain: CRISPR and gene-editing are paving the future of agriculture.