On a cold December day in Norwich, England, Cathie Martin met me at a laboratory inside the John Innes Centre, where she works.
A plant biologist, Professor Martin has spent almost two decades studying tomatoes, and I had travelled to see her because of a particular one she created — a lustrous, dark purple variety that is unusually high in antioxidants, with twice the amount found in blueberries.
At 66, Martin has silver-white hair, a strong chin, and sharp eyes that give her a slightly elfin look. She has long been interested in how plants produce beneficial nutrients.
The purple tomato is the first she designed to have more anthocyanin, a naturally occurring anti-inflammatory compound.
“All higher plants have a mechanism for making anthocyanins,” Martin explained when we met. “A tomato plant makes them as well, in the leaves. We just put in a switch that turns on anthocyanin production in the fruit.”
Martin noted that, while there are other tomato varieties that look purple, they have anthocyanins only in the skin, so the health benefits are slight.
“People say, ‘oh, there are purple tomatoes already’, but they don’t have these kind of levels,” she said.
The difference is significant. When cancer-prone mice were given Martin’s purple tomatoes as part of their diet, they lived 30% longer than mice fed the same quantity of ordinary tomatoes. They were also less susceptible to inflammatory bowel disease.
After the publication of Martin’s first paper showing the anti-cancer benefit of her tomatoes, in the academic journal Nature Biotechnology in 2008, newspapers and television stations began calling.
“The coverage,” she recalled. “Days and days and days and days of it.”
She considered making the tomato available in shops or offering it online as a juice. However, because the plant contained a pair of genes from a snapdragon — that’s what spurs the tomatoes to produce more anthocyanin — it would be classified as a genetically modified organism (GMO).
That designation brings with it a host of obligations, not just in Britain but many other countries.
In 2018, the Irish Government announced the prohibition/restriction of the commercial cultivation of genetically modified crops.
Then minister for climate action and environment Denis Naughten said that it was a very significant development and that it was critically important that “Ireland takes whatever steps are necessary to maintain our GMO cultivation-free status, which is a key element of our international reputation as a green, sustainable food producer”.
In the US, Prof Martin had envisioned making the juice on a small scale, but just to go through the Food and Drug Administration (FDA) approval process would cost $1m (€850,000). Adding US Department of Agriculture (USDA) approval could push that amount even higher. (Tomato juice is known as a “GM product” and is regulated by the FDA. However, because a tomato has seeds that can germinate, it is also regulated by the USDA.)
“I thought, 'this is ridiculous',” Martin told me.
She eventually did put together the required documentation, but the process, and subsequent revisions, took almost six years.
“Our 'business model’ is that we have this tiny company which has no employees,” Martin said with a laugh.
“Of course, the FDA is used to the bigger organisations [global agricultural conglomerates such as DowDuPont or Syngenta] so this is where you get a bit of a problem.
“When they say, ‘oh, we want a bit more data on this’, it’s easy for a corporation. For me — it’s me that has to do it. And I can’t just throw money at it.”
Martin admitted that, as an academic, she hadn’t been as focused on getting the tomato to market as she might have been. (Her colleague Jonathan Jones, a plant biologist, eventually stepped in to assist.)
However, the process has also been slow because the purple tomato, if approved, would be one of only a very few GMO fruits or vegetables sold directly to consumers. The others include Rainbow papayas, which were modified to resist ringspot virus; a variety of sweetcorn; some russet potatoes; and Arctic apples, which were developed in Canada and resist browning.
It also might be the first genetically modified anything that people actually want.
Since their introduction in the mid-1990s, GMOs have remained wildly unpopular with consumers, who see them as dubious tools of Big Ag, with potentially sinister impacts on both people and the environment.
The purple tomato could perhaps change that. Unlike commercial GMO crops — such as soy and canola — Martin’s tomato wasn’t designed for profit and would be grown in small batches rather than on millions of acres: essentially the opposite of industrial agriculture.
The additional genes it contains (from the snapdragon, itself a relative of the tomato plant) act only to boost production of anthocyanin, a nutrient that tomatoes already make.
More importantly, the fruit’s anti-inflammatory and anti-cancer properties, which seem considerable, are things that many of us actively want. Nonetheless, the future of the purple tomato is far from certain.
“There’s just so much baggage around anything genetically modified,” Martin said. “I’m not trying to make money. I’m worried about people’s health. But in people’s minds it’s all Dr Frankenstein and trying to rule the world.”
In the three decades since GMO crops were introduced, only a tiny number have been developed and approved for sale, almost all of them products made by large agrochemical companies such as Monsanto.
However, within those categories, GMOs have taken over much of the market. Roughly 94% of soybeans grown in the US are genetically modified, as is more than 90% of all corn, rapeseed (canola), and sugarbeet, together covering roughly 170m acres of cropland.
At the same time, resistance to GMO foods has only become more entrenched. The market for products certified to be non-GMO has increased more than 70-fold since 2010, from roughly €350m that year to €26bn by 2018.
There are now more than 55,000 products carrying the “Non-GMO Project Verified” label on their packaging.
For many of us, the rejection of GMOs is instinctive. Our distrust might also stem from the way GMOs were introduced.
When the agribusiness giant Monsanto released its first GMO crop in 1996 — a herbicide-resistant soybean — the company was in need of cash.
By adding a gene from a bacterium, it hoped to create crops that were resistant to glyphosate, the active ingredient in its trademark herbicide, RoundUp, enabling farmers to spray weeds liberally without also killing the soy plant — something that wasn’t possible with traditional herbicides. Commercially, the idea succeeded.
By 2003, RoundUp Ready corn and soy seeds dominated the market, and Monsanto had become the largest producer of genetically engineered seeds, responsible for more than 90% of GMO crops planted globally.
However, the company’s rollout also alarmed and antagonised farmers, who were required to sign restrictive contracts to use the patented seeds and whom Monsanto aggressively prosecuted.
At one point, the company had a 75-person team dedicated solely to investigating farmers suspected of saving seed — a traditional practice in which seeds from one year’s crop are saved for planting the following year — and prosecuting them on charges of intellectual property infringement.
Environmental groups were also concerned because of the skyrocketing use of RoundUp and the abrupt decline in agricultural diversity.
“It was kind of a perfect storm,” says Mark Lynas, an environmental writer and activist who protested against GMOs for over a decade.
“You had this company that had made Agent Orange [the defoliant herbicide which is estimated to have sickened or disabled millions who came in contact with it when it was used by the US military during the Vietnam War] and PCBs [an environmental toxin that the US EPA banned in 1979] that was now using GMOs to intensify the worst forms of monoculture farming. I just remember feeling like we had to stop this thing.”
Once public sentiment was set, it proved hard to shift, even when more beneficial products began to emerge.
One of these, Golden Rice, was made in 1999 by two university researchers hoping to combat vitamin A deficiency, a simple but devastating ailment that causes blindness in millions of people in Africa and Asia every year and can also be fatal.
However, the project foundered after protests by anti-GMO activists in Europe and the US, which in turn alarmed governments and populations in developing countries.
Lynas, who publicly disavowed his opposition to GMOs in 2013, says:
In recent years, many environmental groups have also quietly walked back their opposition as evidence has mounted that existing GMOs are both safe to eat and not inherently bad for the environment.
The introduction of Bt corn, which contains a gene from Bacillus thuringiensis, a naturally insect-resistant bacterium that organic farmers routinely spray on crops, dropped the crop’s insecticide use by 35%.
A pest-resistant Bt eggplant has become popular in Bangladesh, where farmers have also embraced flood-tolerant “scuba rice,” engineered to survive being submerged for up to 14 days rather than just three.
Each year, Bangladesh and India lose roughly 4m tons of rice to flooding — enough to feed 30m people — and waste a corresponding volume of pesticides and herbicides, which then enter the groundwater.
However, in most of the rest of the world, such benefits can seem remote compared with what we think of as “eating naturally”. That’s especially true because, for many of us, GMOs and the harms of industrial agriculture (monocultures, overuse of pesticides and herbicides) remain inextricably linked.
“Because of the way that GMOs were introduced to the public — as a corporate product, focused on profit — the whole technology got tarred,” Lynas says. “In people’s minds, it’s ‘genetic engineering equals monoculture equals the broken food system’. But it doesn’t have to be that way.”
Plant geneticists tend not to be overly concerned about the risks of GMOs, as long as the modifications are made with some care. As a 2016 report by the US National Academy of Sciences found, GMOs were generally safe, although it allowed that minor impacts were theoretically possible.
Fred Gould, a professor of agriculture who was chairman of the committee that prepared the 600-page report, noted that genetic changes that alter a metabolic pathway — the cellular process that transforms biochemical elements into a particular nutrient or compound, like the anthocyanins in Martin’s tomato — were especially important to study because they could cause cascading effects.
However, to me, Gould emphasised that many genetic modifications to food are trivial and extremely unlikely to have any measurable effect on people.
“We’ve been changing all these things already with conventional breeding, and so far we’re doing all right,” Gould said. “Making the same change with genetic engineering — there’s really no difference.”
Almost everything we grow and eat today has had its DNA altered extensively. For millenniums, farmers, discovering that one version of a plant — usually a random genetic mutant — was hardier, or sweeter, or had smaller seeds, would cross it with another that, say, produced more fruit, in the hopes of getting both benefits.
However, the process was slow. Simply changing the colour of a tomato from red to yellow while preserving its other traits could take years of crossbreeding. And tomatoes are one of the easiest cases. Introducing even a minor change to a cherry through crossbreeding, I was told, could take up to 150 years.
To those who worry about GMOs, that slowness is reassuring. Yet the way nature alters things is also profoundly haphazard. Sometimes a plant will acquire one trait at the expense of another. Sometimes it actually becomes worse.
The same is true for agricultural crossbreeding. Not only is there no way to control which genes are kept and which are lost, the process also tends to introduce unwanted changes.
Commercial berry growers spent decades trying to create a domesticated version of the black raspberry through crossbreeding, but never succeeded: The thornless berries either tasted worse or produced almost no fruit, or they developed other problems.
It’s also why meeting the needs of modern agriculture — growing produce that can be shipped long distances and hold up in the shop and at home for more than a few days — can result in tomatoes that taste like cardboard, or strawberries that aren’t as sweet as they used to be.
“With conventional breeding, you’re basically just shuffling the genetic deck,” agricultural executive Tom Adams told me.
“You’re never going to carry over only the gene you want.”
In recent years, genetic engineering tools such as Crispr have offered a way around this imprecision, making it possible to identify which genes control which traits — things such as colour, hardiness, sweetness — and to change only those.
“It’s far more precise,” says Andrew Allan, a plant biologist at the University of Auckland. “Instead of rolling the dice, you’re changing only the thing you want to change. And you can do it in one generation instead of 10 or 20.”
From a regulatory perspective, Allan pointed out, all GMOs are treated the same, regardless of the modification and regardless of the scale. The policy is partly a holdover from the early days of genetic engineering, when less was known about the process and its effects. However, it has persisted, in part, because of powerful anti-GMO campaigning.
Eric Ward, co-chief executive of agricultural technology company AgBiome, described the situation as “stuck in a closed loop”.
He went on: “People think, ‘Well, if you’ve got this really strict regulatory system, then it must be really dangerous'. So it becomes self-reinforcing.”
A few days before travelling to Norwich, I joined Martin at the Royal Society in London for the Future Food conference, a series of talks on genetic engineering in agriculture. There I met Haven Baker, a founder of a company called Pairwise, which was started to create fruits and vegetables that are genetically edited but not GMO.
“I don’t think we can change people’s minds about GMOs,” Baker said. “But gene editing is a clean slate. And maybe then GMOs will be able to follow.”
In his talk, Baker noted that there were hundreds of kinds of berries in the world. However, among those we commonly call berries, we eat just four — strawberries, raspberries, blueberries and blackberries.
There’s a reason the other varieties rarely reach us. Sometimes the fruit rots within days after picking (salmonberries), or the plant puts out fruit for only a few weeks in summer (cloudberries).
Sometimes the plant doesn’t produce much fruit at all or is too thorny or sprawling for the fruit to be picked without a vast amount of labour.
Black raspberries, one fruit that Pairwise hopes to bring to market, used to be widely grown in North America until a virus decimated them. (The red raspberries we eat now originally came from Turkey.)
The revived version, which will be in field trials in 2024, has been engineered to be thornless and seedless, while retaining the fruit’s signature jammy flavour.
More recently, the company began a similar project with vegetables.
Very few of us eat the recommended daily allowance of fruit and vegetables, and teenagers eat even less. In an entire year, the average person consumes just a few heads of broccoli.
“So how do we change that?” Baker asked. “People already know that they’re supposed to be eating vegetables. They just aren’t doing it. But if we can use gene editing to make broccoli slightly less bitter, maybe people — and especially kids — will eat more of it, and therefore be getting more fibre and more vitamins, which might make a difference in their long-term health.”
There are some signs that the future of small-scale, bespoke GMO produce may already have begun.
In late April, Martin told me that the USDA had recently updated its regulations to allow more GMO plants to be grown outside, without a three-year field trial or in tightly contained greenhouses (the exceptions are plants or organisms with the potential to be a pest, pathogen or weed).
In the wake of this change, Martin and Jones are planning to make the purple tomato available first to home gardeners, who could grow it from seed as soon as next spring — well before the commercially grown tomato reaches grocery stores. USDA approval is expected by December.
They’re currently testing six varieties to find the most flavourful.
“When we first developed the purple tomato, it was home gardeners who were most interested in it,” Martin noted. “With home gardening, it’s an opt-in system. It’s up to you whether you want to grow it.”
- Adapted from an article that originally appeared in
- Jennifer Kahn is a contributing writer for the magazine and the narrative-programme lead at the Graduate School of Journalism at the University of California, Berkeley.