Science

These super crops can save us from climate disaster

Tonnes of rotting apples and ugly spuds never even make it to supermarket shelves. Tweaking their genes can change that
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Farming has a major food waste problem. Approximately 40 per cent of the food produced globally goes uneaten every year, and much of this wastage occurs even before the food leaves the farm. In fact, it’s estimated that 7.2 per cent of all food harvested in the UK is wasted at the primary production stage as a result of several factors – disease, bad weather, cosmetic imperfections and more.

Of course, food waste occurs further along the supply chain as well. Produce is often damaged during transportation and storage due to improper packaging and poor handling. Plus, not all purchased food is eaten – after all, how many times have we tossed spotty potatoes or bruised apples into the kitchen bin? In all, a whopping 1.3 billion tonnes of food (worth $1 trillion) is wasted every year – yet 811 million people worldwide still go hungry. Food waste is also bad for climate, as rotting food in landfills produces large quantities of the methane; the World Wildlife Fund estimates that putting an end to food waste would result in a decrease by six to eight per cent of all human-generated greenhouse gas emissions.

To this end, scientists are deploying a new weapon in the fight against food waste: gene editing. They hope that the technology can help develop next-generation crops that are more resistant to pests and diseases, sustain less damage during transportation and storage, or have a longer shelf life – essentially quasi-imperishable produce. The technology is lucrative, with estimates suggesting that the global gene-editing market could be worth $8.71 billion by 2026.

Unlike in genetically modified crops – which typically involve the removal of a preferred gene from one species and introducing it into another – gene editing is a small, controlled tweak to the existing DNA of an organism. This can be carried out using several methods, including the CRISPR technique that enables scientists to remove, add, or alter sections of a DNA sequence to obtain desired traits.

“Gene editing allows us to work within the plant or animal’s own family, without the need to introduce outside DNA into the final product,” says Fan-Li Chou, the vice president of Scientific Affairs and Policy at the American Seed Trade Association. “It can reach the same endpoint as more traditional breeding methods – but with greater precision, and in years instead of decades.”

Gene-edited crops are largely still in the works. In the US, Idaho-based potato processor Simplot has acquired a license to harness CRISPR to develop new types of spuds. It currently sells several varieties of bioengineered potatoes under its Innate brand, which are modified using an intragenic technology called RNAi silencing. This effectively “turns down” the volume of genes associated with undesirable traits, such as polyphenol oxidase or PPO, an enzyme responsible for browning and blackspot bruising. “Moving forward, we are working on gene editing to achieve similar benefits. For example, we can use CRISPR technology to deactivate [these genes],” says Doug Cole, director of marketing and Biotech Affairs at Simplot Plant Sciences. The company expects to launch gene-edited potatoes in 2023.

This could help address one of the root problems of potato waste: ugly spuds. “Shoppers aren’t quick to put bruised potatoes in their grocery cart, even if the vegetables are perfectly healthy and taste fine,” says Chou. “And in restaurants, potatoes prepped before the dinner rush often need to be thrown out at the end of the night because of their brown colour”. Overall, a whopping 400 million pounds of potatoes are discarded each year in the US alone.

Beyond potatoes, Yinong Yang, a plant pathologist at Pennsylvania State University, has successfully engineered the white button mushroom to reduce browning and increase its shelf life. To do so, he knocked out one of the mushroom’s six PPO genes using CRISPR, effectively reducing browning activity by 30 per cent. Yang is currently working to improve the mushroom, with the aim of commercialising new varieties in the future.

In Australia, a team of researchers at the Queensland University of Technology is using CRISPR to tweak a genome in the Cavendish banana – which makes up the majority of global banana production – in order to boost its resistance against a deadly fungal disease called Fusarium wilt tropical race 4 (TR4). The disease has already wreaked havoc in the Americas, the Philippines and parts of the Middle East, laying waste to thousands of hectares of crops and disrupting supply chains.

“A huge amount of food is lost both pre- and post-harvest, and this is all part of food waste. I believe that gene editing has the potential to significantly reduce losses of food, much of it through resistance to pests and diseases,” says James Dale, the leader of the university’s Banana Biotechnology Program. It’s estimated that up to 40 per cent of crop yields worldwide are rendered inedible due to such causes. However, Dale says that the bananas are still in development and will not hit supermarket shelves for at least another five years.

In the same vein, researchers at Tuskegee University in Alabama are harnessing CRISPR to make sweet potatoes more resistant to a widely occurring disease called sweet potato feathery mottle virus . According to Marceline Egnin, a professor of plant and soil sciences at Tuskegee University, this is done by editing specific proteins in the sweet potato that enable the virus to establish itself and replicate, thus making the plant less vulnerable to infection.

The technology can also be utilised to edit the genes that make sweet potato sensitive to ethylene, Egnin explains, which causes spoilage, or to improve skin hardiness so as to minimise damage during storage. “Food waste usually occurs post-harvest, so if we can identify the genes that make crops susceptible to post-harvest spoilage and edit them, we will greatly increase the percentage of harvested food that reaches consumers’ tables globally,” she says.

Elsewhere, researchers have discovered that it is possible to use CRISPR to improve the aesthetic quality of produce. For instance, boosting anthocyanin production in fruits such as tomatoes can give them a vibrant hue, making them more appealing to consumers and reducing waste. Additionally, as Cole explains, gene-editing can strengthen cells, making certain foods less prone to being damaged during harvest or transport. “This could benefit the whole supply chain,” he says.

But even as gene-editing technology advances, proponents in this field face a key barrier: consumer perception. Conventional genetically modified (GM) produce has a bad rap, with many consumers harboring concerns around food safety. According to research conducted by Pew, 49 per cent of US consumers believe that GM foods are worse for their health compared with non-GM foods. But Cole is optimistic. “Opinions can be changed through education,” he says. “Once most people understand that gene editing follows some natural processes found in traditional breeding, they are more likely to accept it – especially when it solves major food problems such as waste.

Then there are the regulatory hurdles . In the US, regulators assert that because gene-edited crops do not contain foreign DNA, they are not considered genetically modified and thus are not subject to restrictions. In contrast, the EU has adopted a far tougher approach. In 2018, the European Court of Justice ruled that gene editing counts as genetic engineering, and that any organisms altered using gene-editing techniques are subject to the same regulations as genetically modified organisms. This means that all gene-edited crops face a lengthy risk assessment by the European Food Safety Authority, and must be approved by the majority of EU member nations before they can be grown.

There are signs that the UK could relax its stance after Brexit, as it is no longer bound by EU regulations. Following a public consultation, the UK government is determining whether or not to deregulate gene-edited crops and foods, which would make it easier for scientists to conduct field trials and gain commercial approval. This could pave the way for other countries to follow suit in the future.

“As we talk about innovation in our communications, medicine, transportation and so many other aspects of life, it’s important that we include agriculture as a vital piece of the discussion,” says Chou. “As a society, there is too much at stake for us not to have an open and transparent dialogue about the potential that evolving breeding methods, such as gene editing, have to address society’s most pressing challenges – from hunger to climate change to sustainability.”

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This article was originally published by WIRED UK