Fussy fruit could head to market faster
The ground-cherry might look at first like a purely ornamental plant. A member of the genus Physalis, it bears papery, heart-shaped husks that resemble Chinese lanterns. Within each ground-cherry casing is a small, tart, edible fruit, similar in appearance to a cherry tomato, that is sometimes sold at farmers markets.
The fruit might be more common in supermarkets were it not so difficult to grow in large quantities. Ground-cherry bushes sprawl untidily and can drop their fruits early, and the plants possess other undesirable traits. Diminishing these traits through selective breeding would take years.
Recently, however, a team of researchers reported that, by removing certain portions of the plant’s DNA using common geneediting techniques, they’ve produced a ground-cherry with a larger fruit and a more ordered bush, greatly speeding the process of domestication. Their work, which appeared in the journal Nature Plants, is part of a scientific initiative called the Physalis Improvement Project.
Ground-cherries are related to tomatoes, which have a well-studied genome. Joyce Van Eck, a plant geneticist at Cornell University and an author of the paper, and her colleagues had already discovered that, using CRISPR, a gene-editing technique, they could alter a tomato gene and produce plants that produced flowers more quickly.
The scientists wondered whether the ground-cherry could be similarly altered. They examined the ground-cherry genome for analogues of known tomato genes, and found one: an analogue of a gene called “SELF-PRUNING,” or SP, that in tomatoes controls the shape of the plant.
Using CRISPR, the team removed a small portion of SP from the ground-cherry genome. The resulting plants arranged themselves into more compact bushes. The team performed similar experiments with genes that influence flower number and fruit size.
“Sure enough, when we got those fruit off, they were larger than the parent ground-cherry,” Van Eck said. “Close to 25 percent more weight in the fruit.”
Heartened by these successes, the researchers are working to see whether they can control the shape of ground-cherry bushes with more precision. They are also keen to find a solution to the problem of fruit dropping off the bush.