China fast-tracks edited wheat genome as part of food security drive

The genome edit – which gives wheat resistance to a common fungal infection called powdery mildew and can be applied to different varieties – is the result of work by scientists at the Chinese Academy of Sciences and Suzhou-based biotechnology company Qi Biodesign.

The science behind the genome edit was published in the peer-reviewed journal Nature in 2022, and was the result of eight years of work by researchers at the academy’s Institute of Genetic and Developmental Biology.

Kevin Zhao, a co-founder of Qi Biodesign, said the firm had been working with regulators for the past two years to collect data and perform the safety checks needed to obtain a safety approval.

It was special to get this approval in such a “short time frame”, he said.

This is the first genome edit for wheat to be approved by the Chinese government, and it shows that the country “is very interested in pursuing more effective means to breed better crops in the future for food security purposes”, Zhao said.

“Now that we have this edit approved by the ministry [of agriculture], we can put this edit in many different wheat varieties grown all over China and see how this edit performs across different varieties.”

The first-time safety certificate issuance for the wheat edit was announced alongside eight other genome edits or genetically modified organisms (GMOs) in a post by the Ministry of Agriculture on Wednesday.

The licence for the wheat edit covers the entirety of China, and is valid through May 2029, when it will be up for further renewal.

“Plant diseases cause losses of 11-30 per cent in crop production per year worldwide, threatening global food security. Molecular breeding is an effective and sustainable strategy to improve plant disease resistance,” the researchers wrote in their paper.

Powdery mildew is one of the top three diseases that impact wheat yield in China, Zhao said.

Genome editing differs from the creation of GMOs, which involves altering the genetic material of plants by inserting foreign DNA.

“It’s because of that difference that governments around the world are much more positive [about genome editing],” as the process resembles the natural mutation process that plants go through due to UV radiation from the sun, Zhao said.

The adoption of genetically modified crops worldwide has met some resistance due to concerns over safety, including in the Philippines.

Last month a court there revoked a permit that was granted in 2021 for golden rice, which had been modified to contain a precursor of vitamin A using DNA from daffodils and bacteria, due concerns there was no scientific consensus about its safety.

Genome editing, performed using tools such as CRISPR/Cas9, involves making precise changes within an organism’s own genetic material to achieve the desired mutations without inserting foreign material.

After the edits are made, the editing material is degraded or released from the cell.

Disrupting the function of susceptibility (S) genes – genes that pathogens use to infect plants – is one strategy to create disease-resistant plants. Powdery mildew can be disrupted by editing the mildew resistance locus O (MLO).

However, S genes are “implicated in many essential biological functions” and deleting them can lead to undesirable growth penalties such as smaller crop height and yield “limiting its widespread use in agriculture”, according to the paper.

However, the team was able to create the MLO edit that allowed wheat to retain “crop growth and yields while conferring robust powdery mildew resistance,” even when grown in a field, the paper said.

“We edited four different sites in wheat and together these four edits resulted in disease resistance,” Zhao said.

“The fourth edit that we performed was one that helped maintain or even enhance yields in some wheat varieties” based on results from preliminary experiments, he said.

The government’s approval allows the team to seek partnerships with companies and breeders who own wheat varieties in order to insert the edit and see how it performs growing in fields and to test its commercial application.

Zhao said his firm is seeking out companies with the “most commercially useful” wheat varieties to partner with first. The edit could also be added to other crops that are vulnerable to powdery mildew such as strawberries, tomatoes and cucumber, he said.

China has been a “fairly conservative country” when it comes to agricultural biotechnology, with the first GMO approvals for corn and soybeans only occurring a few years ago. The first guidelines for submitting genome edits for approval were only released in 2022, Zhao said.

“Traditionally speaking whether that be GMO or genome editing, most countries around the world have really focused on the feed crops – those being maze and soy – and they don’t really touch the food crops,” due to concerns the edits could be found to be unsafe after approval, Zhao said.

This approval is a “huge step forward for China,” and Zhao said he hoped it would pave the way for future approvals for wheat and other crops.

The company is now also seeking approval for the edit in other countries that have guidelines in place for genome-edited crops, Zhao said.

Source: SCMP