Knock out one gene in a Chinese cabbage and its leaves start to smell of popcorn.
That is the result reported by the cabbage research group at the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Sciences (CAAS) in Beijing. The institute says its scientists have, for the first time, created a popcorn-scented Chinese cabbage from scratch. The paper appeared online in the journal Horticulture Research on 15 October and the institute announced it the next day; China Science Daily (中国科学报) ran the story in its 2 November print edition.
The vegetable is dabaicai (大白菜), known in English as Chinese or napa cabbage. The institute describes it as central to farming and food across East Asia and as the core ingredient of fermented dishes such as paocai (泡菜) pickles.
The smell comes from 2-acetyl-1-pyrroline, or 2-AP, the volatile compound that gives crops a popcorn-like aroma and the scent of fragrant rice. A gene called BADH2 acts as a brake on how much 2-AP a plant makes. When the gene stops working, 2-AP builds up. According to the institute, that loss of function is the direct cause of fragrance in rice, sorghum, oilseed rape, tomato and cauliflower.
The co-corresponding authors are associate researcher Li Guoliang and researcher Zhang Shujiang of the institute and Professor Zhao Jianjun of Hebei Agricultural University.
Not yet a variety
The institute calls the plants new germplasm, meaning breeding material, and frames them as groundwork for future varieties.
In China, gene-edited crops must undergo a safety assessment before they can be grown commercially. Under 2022 agriculture ministry guidelines, plants without foreign genes must complete trials before developers can apply for a safety certificate. Additional food-safety data or field trials may be required if the changes introduce potential risks. Plants containing foreign genes follow the rules for genetically modified crops.
Further rules introduced in April 2023 require checks for unintended genetic changes and leftover genetic material used during editing, along with assessments of key components in crops developed for improved quality.
The institute has not said whether its cabbage lines contain foreign genes or have entered the approval process.
The cabbage follows two popcorn-scented tomato studies by Chinese-led teams reported earlier this year. A team at Xianghu Laboratory in Hangzhou and partners including the University of Adelaide reported a gene-edited tomato with the same popcorn aroma, and a team led by Professor Luo Jie of Hainan University and the Yazhou Bay National Laboratory published related work in Plant Communications.
For now, the popcorn smell belongs to three edited lines of cabbage.
China plants about 23 million mu, or roughly 1.5 million hectares, of Chinese cabbage each year, according to the institute.
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