Gene-edited CRISPR mushroom escapes US regulation

The US Department of Agriculture (USDA) will not regulate a mushroom genetically modified with the gene-editing tool CRISPR–Cas9.

The long-awaited decision means that the mushroom can be cultivated and sold without passing through the agency's regulatory process — making it the first CRISPR-edited organism to receive a green light from the US government.

“The research community will be very happy with the news,” says Caixia Gao, a plant biologist at the Chinese Academy of Sciences’s Institute of Genetics and Developmental Biology in Beijing, who was not involved in developing the mushroom. “I am confident we'll see more gene-edited crops falling outside of regulatory authority.”

Yinong Yang, a plant pathologist at Pennsylvania State University (Penn State) in University Park, engineered the common white button (Agaricus bisporus) mushroom to resist browning. The effect is achieved by targeting the family of genes that encodes polyphenol oxidase (PPO) — an enzyme that causes browning. By deleting just a handful of base pairs in the mushroom’s genome, Yang knocked out one of six PPO genes — reducing the enzyme’s activity by 30%...