Recently, Cucurbitaceae Vegetable Genetics and Breeding Group in the Institute of Vegetables and Flowers (IVF, CAAS) uncovered a new mechanism by which intron variation in the carotenoid cleavage dioxygenase-encoding gene (CsCCD1) regulates carotenoid content in cucumber fruits. They also developed new cultivated cucumber germplasm with high carotenoid content. The research findings were published in《Plant Biotechnology Journal》(IF5 year = 12.1).

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide. Carotenoids, as essential precursors of vitamin A, not only convert into vitamin A in the body but also possess various physiological functions such as antioxidant activity, maintaining visual health, and regulating immunity. Therefore, developing new cucumber varieties with high carotenoid content is of significant importance for improving human dietary nutrition and promoting health. This study map-cloned a key gene CsCCD1, which encodes carotenoid cleavage dioxygenase, regulating the formation of yellow flesh in cucumber. A single nucleotide polymorphism (SNP, A-G) in its intron leads to abnormal transcript splicing, resulting in the loss of a critical protein domain and a significant reduction in enzyme activity. This ultimately causes a substantial accumulation of carotenoids in the fruit, resulting in the yellow flesh. Transient overexpression of CsCCD1 in the yellow-fleshed Xishuangbanna cucumber confirmed its key role in regulating flesh color in both cultivated and semi-wild cucumbers. Additionally, the study developed new cucumber germplasm with high carotenoid content with 6-7 times higher carotenoid levels. These findings provide genetic resources for breeding new cucumber varieties with high carotenoid content.

The research was supported by the State Key Laboratory of Vegetable Biobreeding, the National Key Research and Development Program, the National Natural Science Foundation of China, the Earmarked Fund for Modern Agro-industry Technology Research System, Science and Technology Innovation Program of the Chinese Academy of Agricultural Science.

Link to this paper: https://doi.org/10.1111/jipb.13571

By Shaoyun Dong(dongshaoyun@caas.cn)