Ground Cherry: CRISPR Used to Make a New, Tasty, Genetically Modified Fruit

Before corn was corn, it was a skinny grass that produced only a single row of kernels on each stalk. Long centuries of breeding turned it into a fast-growing plant with big, sweet, kernel-dense ears. In fact, most of the produce we’re familiar with now took hundreds of generations to become what they are today. But now scientists, armed with powerful CRISPR-Cas9 gene editing technology, are whittling down the domestication process to just a few years. Their first experiment is the ground cherry — a formerly wild, now-delicious fruit that has everything it takes to become the next strawberry.

In a paper published Monday in the journal Nature Plants, a team of researchers outlined how they used CRISPR to make the ground cherry (Physalis pruinosa) more suitable for agriculture. The sweet, tropical-flavored fruit, about the size of a cherry and nestled in a protective papery husk, is known as an “orphan crop” — one with some desirable characteristics but not enough to make farmers want to grow them. In the wild, the ground cherry is, well, wild — it grows all over the place and has small, sparse fruits that fall off the vine when they’re ripe.

But by using CRISPR to edit out its unattractive elements, scientists think it may eventually be found in the produce section of the supermarket.

“With some improvements, maybe it could become a specialty fruit crop in the United States and give farmers another fruit crop to grow that’s not a tree,” Joyce Van Eck, Ph.D., a plant biotechnology expert at the Boyce Thompson Institute and one of the paper’s co-authors, tells Inverse.

In the past, the Van Eck lab has studied how to use gene editing to tweak productivity, fruit size, and other qualities in tomatoes. For their new experiments, the team chose ground cherries because, as part of the Solanaceae family, they’re related to tomatoes (as well as potatoes, tobacco, eggplants, and peppers) — and so their DNA is relatively well-mapped and well understood. Van Eck wondered whether her team’s previous work could be used to fast-track the domestication of the ground cherry.

With colleagues at Cornell University and Cold Spring Harbor Laboratory, Van Eck and her team have discovered that it is indeed possible. By editing genes associated with indeterminate growth and making the plant’s shoots stop growing once they produce flowers, they’ve successfully changed the way the ground cherry grows to make the vines less rambling and wild.

“We have taken something that’s very wild and unmanageable and kind of tamed it, made it more compact, an easier growth habit to deal with,” says Van Eck.

This is a very important trait for farmers, for whom making efficient use of space is crucial. “We’re also getting more flowers and more fruits, so we’ve improved yield in a sense.” They’ve also made the fruits noticeably larger. In the future, they want to target genes associated with sugar content to make the fruit sweeter, something that has already been done in tomato gene editing.

Van Eck doesn’t anticipate that we’ll be buying pints of ground cherries in the grocery store in the next five years, but she’s optimistic it will happen eventually. Once they get the modified ground cherries out of the lab, they’ll need to get them into the hands of farmers, whose feedback on the actual experience of growing the fruits will decide which traits need to be fixed next. Next on the list, says Van Eck, is the plant’s habit of dropping ripe fruit on the ground, which creates both a harvesting challenge and a food safety hazard. Given their successes in shaping the fruit’s other characteristic, it’s hard to imagine this will be a problem.

Ironically, the thing that might be the greatest obstacle to getting ground cherries into your grocery basket might be the genetic tool that makes this research all possible. Since CRISPR is patented by the Broad Institute, any produce created using it can’t be sold unless the scientists behind it pay the hundreds of thousands of dollars for the right to use it.

“As researchers we benefit from the fact that we don’t have to pay up front to use this technology, which is wonderful, it’s such a powerful tool, but once we start talking commercialization, the cost of licensing just about knocked me off my chair,” says Van Eck.

She and her colleagues aren’t deterred, as they could form their own company or partner with an existing company to help bring other modified crops and the newly revamped ground cherry to market — possibly with a more attractive name, too.