Today’s Brussels sprouts taste better than you might remember from childhood. It’s not that your refined adult palate appreciates them better. Rather a new variety has displaced the original vegetable. You can thank plant breeders for the change. And modern breeders, armed with new gene-editing technology, are looking to replicate Brussels sprouts’ reinvention.
In the late 1990s scientists identified specific chemicals, called glucosinolates, that made Brussels sprouts taste bitter. Plant breeders started growing old seeds, previously discarded for producing paltry harvests, to identify tastier versions with lower levels of these compounds. Then they crossed these delicious but low-yield plants with modern, more prolific individuals until they found a descendant that made plenty of tasty sprouts, transforming the once maligned vegetable from a bitter pill into a popular side dish.
But other veggies haven’t fared as well. That’s because most breeding decisions favor plant traits that matter to vegetable growers, not vegetable eaters. “I’d say disease resistance is probably the major focus these days of most breeding programs because that’s what imperils the ability of the farmer to grow the crop,” says Harry Klee, a professor emeritus of horticulture at the University of Florida, who specializes in tomatoes. “Quality traits are really completely ignored.”
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In addition, breeders who focus on consumer crops must navigate the controversy surrounding genetically modified organisms (GMOs). Although all domesticated species now have different genetics than their ancestors, in agriculture, the term GMO refers to a plant that carries genes imported from a completely different species—and these changes are subject to stricter regulation. But newer techniques are allowing breeders to work within the context of a plant’s own genome, making tweaks that don’t trigger complicated rules.
Flavor is challenging to target because different people have different preferences—plus, even under the best conditions, flavor quality is more complex than something like yield. “We’ve spent a lot of time and money figuring out what flavor is, and most breeding programs don’t have the capacity to measure those things,” Klee says.
But interest in prioritizing flavor is starting to build, thanks in part to new genetic technology such as the gene-snipping technique CRISPR and DNA sequencing that is cheap enough to use liberally. “There’s never been a better time to be a fruit breeder or a vegetable breeder because we have more tools and techniques,” says Susan Brown, an apple breeder at Cornell University.
Some companies are beginning to use those tools to tackle the challenge of developing tastier veggies. One company, Pairwise, is fighting the same compounds that plagued Brussels sprouts: glucosinolates. But this time researchers are modifying salad greens—and they’re armed with the science of gene editing.
Although kale, for instance, is particularly healthy, many prefer eating the less bitter romaine or iceberg lettuce. So Pairwise scientists figured out how to use CRISPR to edit a kalelike mustard green to fit that palate. They wanted to turn off the genes that code for an enzyme called myrosinase, which breaks down the glucosinolates and creates bitterness once the leaf is chewed in a diner’s mouth. The result is a healthy but less bitter green that the company is marketing this year under the brand Conscious Foods.
This is an example of where flavor-minded gene editing can shine, says Tom Adams, co-founder and CEO of Pairwise. “From a gene-editing perspective, I think where taste comes in is that we can remove things that people don’t like,” he says. “It’s a lot more difficult to think about how you can bring in the really complex, great tastes.” To create those more complex tastes, Adams says, traditional breeding is still the best path.
Traditional breeding is the cornerstone of another high-tech flavor effort as well, one that seeks to reverse the ways of thinking that got us to tasteless vegetables in the first place. Instead of growing varieties that can withstand the storage and transportation needs of the agricultural system, a company called Plenty is shrinking the vast distance from the field to the table. Plenty grows its plants in indoor vertical farming facilities closer to consumers, so produce stays fresher, says Nate Storey, the company’s co-founder and chief science officer.
When Plenty decided to start with greens, he says, the team grew thousands of traditionally bred varieties in its facilities. Then the researchers adopted only the ones that resulted in the tastiest crops rather than trying to develop new varieties. “There’s no need to rebuild a wheel,” Storey says of the technique. “We just screen all the wheels that exist and find the ones that work best in our system.”
This method does not always succeed, however. The company couldn’t find a tomato that thrived in its facilities, so it’s working on developing its own variety using a sped-up version of traditional breeding.
Tomatoes are a popular target. A third company is creating more flavorful tomatoes using epigenetics—changing the expression of genes instead of the genes themselves. Whereas Pairwise is snipping out the gene sequences that produce an enzyme that interferes with flavor, Sound Agriculture is programming gene expression. This approach dials down production of undesirable compounds by making their genetic sequences less accessible for transcription.
Understanding how precisely to modify expression to get a desired result is still a work in progress, says Travis Bayer, co-founder and chief technology officer of Sound Agriculture. “The science of epigenetics in plants is really exciting and it’s something that is evolving pretty rapidly,” he says. The company’s first epigenetically grown product, a tomato dubbed Summer Swell, is due to hit shelves this spring. Other projects in the works focus on leafy greens, as well as a handful of fruits, Bayer says.
All these vegetable growers hope that more flavorful products on store shelves will convince people to consume the recommended allowances of fruits and vegetables—and do so better than decades of nutritional guidance have.
“Don’t waste your time talking about trying to educate people to eat better,” says Klee, the tomato breeding researcher. “Just give them products that taste better, that they want to eat.”