A striking thing happened in a research greenhouse at Hiroshima University in Japan: red perilla plants turned green. But this wasn't a trick of the light — it was the result of a precise genetic change that also made the plants significantly healthier.
Researchers used a powerful gene-editing tool called CRISPR-Cas9 to modify red perilla, a plant commonly known as "shiso" in Japan. The team disabled a single gene called flavanone 3-hydroxylase, or F3H, which normally helps produce the red pigments in the leaves.
"Plants edited at the F3H gene lost their characteristic red pigmentation and developed green leaves that were virtually indistinguishable in appearance from conventional green perilla varieties," said Hidemasa Bono, a professor at Hiroshima University's Graduate School of Integrated Sciences for Life who led the research.
But the real surprise came from what was happening inside the plants. Chemical analyses revealed that the edited plants produced far less of the red anthocyanin pigments, while accumulating much higher amounts of compounds called flavones — which are linked to various health benefits. In particular, levels of luteolin, a flavone known for its antioxidant and anti-inflammatory properties, increased approximately sixfold.
The findings, published in the journal Frontiers in Plant Science, could point to a new way to develop crops with enhanced nutritional value for both food and medicine.
Perilla belongs to the mint family and is grown across Asia. In Japan, it's used to color and flavor pickled plums. In Korea, it's called "kkaennip" and often wrapped around grilled meat. In Vietnam, it's known as "tía tô" and added to soups and spring rolls. The plant contains more than 400 different bioactive compounds, including substances associated with antioxidant, anti-inflammatory, and antibacterial effects.
One important finding: the researchers were able to create edited plants that no longer contained any foreign DNA from the gene-editing process itself. This means the perilla could potentially be classified as a non-transgenic crop — one developed without inserting genes from other species.
"By modifying a single enzyme gene in red perilla, we have successfully changed the plant's metabolism to increase its health-promoting compounds," Bono said. "Genome editing makes it possible to develop high-performance perilla with enhanced value for food and pharmaceutical applications."
The team now plans to use these newly developed plant lines to study how perilla's many compounds are regulated, and to explore turning them into functional foods enriched with beneficial nutrients.
"We hope to translate these findings into the development of high-value functional foods enriched with beneficial compounds and to explore the use of perilla as a new source of naturally derived pharmaceutical materials," Bono said.