Transgenic crops: end of an era

The era of genetically modified crops may be over.

Two and half decades after herbicide-resistant canola came onto the market, scientists have now adopted newer techniques to design crops. That’s because the new technologies are more efficient and partly because the strict regulations on GM crops have become a barrier to innovation.

“Transgenic was a new tool about 30 or 40 years ago,” said Ron DePauw, science adviser with Secan and a former Agriculture Canada wheat breeder in Swift Current, Sask. “It (the science) has moved from transgenic to cisgenic, which gene editing is.”

Related story: Scientist warns against completely abandoning genetic modification

The beginning of the gene editing era and the demise of transgenic crops may have officially occurred in the middle of May.

On May 14, the United States Department of Agriculture announced its final rule to modernize biotechnology regulations for plant breeding.

The USDA says this will bring its “plant biotechnology regulations into the 21st century by removing duplicative and antiquated processes.”

The new regulations are 189 pages long. But one key change relates to gene editing, a technology in which scientists can precisely insert genes or delete genes from a plant’s DNA.

Cisgenic or epigenetic?

Cisgenesis:

The term cisgenesis derives from “same” and “beginning.” Cisgenics is the genetic modification of a recipient plant, using a natural gene from a crossable plant in the same family.

Gene editing a crop could be described as a form of cisgenics. Genes are deleted from the plant or added from the same family of plants to design a crop with a superior trait – like frost tolerance.

Cisgenic is different from transgenic, where genes are transferred to a plant from a different organism.

Epigenesis:
Epigenetics is the study of biological mechanisms that switch genes on and off. More accurately, to silence or express a gene.

In simple terms, the USDA will now treat gene editing the same as conventional plant breeding.

“Essentially what they’re saying… if you could have got there (a crop trait) with conventional breeding, you’ll receive the same level of oversight as conventional breeding,” said Ian Affleck, vice-president of plant biotechnology with CropLife Canada.

“If you’re upping disease resistance in a plant from 10 percent to 40 percent using the genes that are in the plant with gene editing, you could have gotten there with conventional breeding. It just might have taken you a long, long time.”

For now, the Canadian government doesn’t have a clear position on gene editing and new plant breeding methods.

Groups like CropLife have been lobbying the government to adopt a policy that aligns with the U.S. so Canadian farmers and life science companies are on equal footing.

Genetically modified crops will be treated differently than gene-edited crops in the U.S.

Comprehensive regulations and oversight will still apply because GM crops are typically transgenic. That’s where DNA from another species, perhaps a bacteria, is used to achieve a crop trait, such as herbicide tolerance.

The Arctic Apple, the non-browning apple, is an example of epigenetics and transgenics. Scientists used a transgene and RNA interference to silence genes related to an enzyme called PPO. The Arctic Apple only has a small amount of PPO, so it doesn’t oxidize and brown. Environmental conditions also turn genes on and off. For instance, hot and dry weather might silence certain genes in a plant.
Source: staff research

The USDA announcement will encourage crop science companies to dedicate more resources to gene editing and other technologies.

“Plant breeders will certainly gravitate towards gene editing because of a more clear, predictable and efficient regulatory pathway. Also, because the cost of that technology is much more affordable,” said Affleck, who explained the USDA has been working on this regulatory update since Barack Obama was president.

The USDA decision is relatively new but the transition away from genetically modified technology is not.

Since about 2015, plant breeders have focused more attention on technologies like CRISPR-Cas9, a gene-editing tool developed by scientists at the University of California, Berkeley.

Plant scientists also know much more about the DNA of major crops because the genomes of wheat, canola, corn and other crops have been sequenced.

Researchers can use that knowledge to identify useful genes in a crop, such as wheat, from cultivars around the globe and then employ gene-editing tools to design a new and improved variety — maybe a wheat that uses nitrogen more efficiently.

“Breeders are always looking for new tools to make improvements in the performance of crops. As a (new) tool gets better and better, you stop using the older one (transgenics),” said DePauw, who developed AAC Brandon, the most popular spring wheat in Canada, using conventional plant breeding.

“In terms of new (GM) products, I’m doubtful…. I think they (scientists) are going on to the newer ways of doing things.”

GM crops will continue to enter the market because many are already in the development pipeline and companies will want a return on their investment, DePauw said.

Stuart Smyth, University of Saskatchewan industry-funded research chair in agri-food innovation, shared a similar opinion.

GM crops, possibly created six to eight years ago, will flow into the market over the next five years. But by the late 2020s, most products will be gene edited.

“The plant breeders are going to (use) the most efficient technology to develop the traits of interest that farmers or the food industry are demanding,” said Smyth. “There may no longer be (new) GM varieties by the end of the decade.”

Smyth and his U of S colleagues have surveyed Canadian plant breeders to assess their use of gene editing.

He found that public plant breeders stopped working on GM crops years ago because of the regulatory hurdles.

“The cost of regulatory approval and having to get foreign market approvals… it pushed the entire public sector out of being able to use the GM technology.”

It’s not just the cost of food safety assessments and environmental safety assessments for GM crops, it’s the time. It can take years to receive domestic approval and then several more years for market access to key countries like China.

Public plant breeders are experimenting with gene editing because it should be easier to commercialize new varieties.

“This is good news for agriculture because it can potentially translate into more new crop varieties, with lower seed prices,” Smyth wrote April 9 in the Western Producer.

However, it’s unlikely that GM crops are totally dead, Smyth added. There may be cases where a transgenic approach makes more sense than other methods.

While gene editing has promise, it’s not going to transform crop science overnight. In many cases, plant scientists don’t know which genes to remove and which ones to add, to achieve a desired trait.

“Where we still struggle, I think every breeder would say this, is there are a lot of genes,” said Richard Cuthbert, a wheat breeder with Ag Canada in Swift Current. “In bread wheat there’s 120,000 genes, roughly. Which ones do we target for gene editing?… (It) does promise to be a powerful tool, but there still has to be a lot of understanding of those genes and how they work.”

If plant scientists do discard transgenics it won’t be the end of the world, DePauw said.

Like all technology, something new eventually comes along and replaces the old.

“You could think about the loss of the horse-drawn wagon. Some people would have seen it as a loss…. But most people couldn’t even imagine going back to an old tool like that.”

Timeline of Genetically modified crops in Canada

1995: Canada approves genetically modified, herbicide-tolerant canola.

1996: Canada approves GM corn and flax.

1997: Canada approves GM soybeans.

1998: Monsanto sues Saskatchewan farmer Percy Schmeiser for patent infringement for growing Roundup Ready canola without paying a licensing fee.

2000: More than 50 percent of canola acres are Roundup Ready.

2001: Triffid flax, a GM variety, is de-registered.

2004: Supreme Court rules in favour of Monsanto, agreeing with lower courts that Schmeiser violated Monsanto’s patent.

2004: Monsanto abandons Roundup Ready wheat, partly because of pressure from farmers who fear loss of sales in export markets.

2005: Canada approves GM sugar beets.

2009: EU detects Triffid, a Canadian variety of GM flax, in a shipment. Flax exports to Europe dry up and flax prices drop to $6 per bushel.

2013: Forage Genetics registers variety of Roundup Ready alfalfa in Canada. GM alfalfa is later grown in Eastern Canada but not Western Canada.

2014: GM corn and canola represent about 98 percent of acres in Canada and GM soybeans 80 percent of acres.

2016: U.S. National Academies of Sciences releases a comprehensive report on GM crops, concluding that there is no association between eating GM food and disease or chronic health problems.

2018: Hollywood movie about Percy Schmeiser, starring Christopher Walken, is filmed in Winnipeg. Called “Percy,” it has yet to be released.

Sources: The State Of Genetically Modified Crop Regulation In Canada, Stuart Smyth, Canadian Food Inspection Agency and staff research

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