From orange to yellow: A genetic discovery in carrot carotenoids

Carrot color is influenced by its carotenoid content, and understanding the genetic mechanisms behind this trait is crucial for breeding more nutritious carrots. Recent research uncovers the role of the gene DcCYP97A3, a cytochrome P450 carotene hydroxylase, which affects carotenoid metabolic flow and taproot color in carrots. This study identifies how variations in the DcCYP97A3 gene lead to the distinct colors found in different carrot varieties, with implications for crop improvement and nutritional enhancement.

Carrots are rich in carotenoids, essential for human health, providing important compounds like vitamin A. The color of carrot taproots varies according to the types and levels of carotenoids, including α-carotene, β-carotene, and lutein. The DcCYP97A3 gene is a key player in this process, as it catalyzes the conversion of α-carotene to lutein, a vital xanthophyll. However, the role of this gene in regulating carotenoid biosynthesis across carrot varieties had remained unclear. Based on these challenges, further research is needed to explore the full molecular mechanisms controlling carotenoid accumulation in carrots.

In a recent study published (DOI: 10.1093/hr/uhaf054) in Horticulture Research on February 18, 2025, researchers from Nanjing Agricultural University have shed light on the gene DcCYP97A3, which controls the carotenoid content and color of carrots. Through genetic editing and overexpression experiments, the study revealed how this gene influences the conversion of α-carotene into lutein, altering the color of carrot taproots from orange to yellow, and impacting the overall carotenoid content.

The research focused on two carrot varieties, Kurodagosun (KRD) (orange) and Yellowstone (YST) (yellow), comparing their carotenoid profiles and expression levels of the DcCYP97A3 gene. It was found that the YST variety had higher levels of DcCYP97A3 transcripts, resulting in a greater accumulation of lutein and reduced α-carotene levels. By overexpressing the DcCYP97A3 gene from YST into the orange KRD carrot, the researchers observed a significant shift in carotenoid content, with lutein content increasing and α-carotene decreasing. This shift was further confirmed by gene editing in YST carrots, which showed a reduction in lutein and β-carotene when DcCYP97A3 was knocked out. These findings underscore the role of DcCYP97A3 in shaping carotenoid diversity in carrots, offering insights into how genetic modifications could enhance the nutritional profile of crops.

Dr. Ai-Sheng Xiong, a senior researcher involved in the study, commented, “Our findings provide a clearer understanding of how specific genes like DcCYP97A3 influence carotenoid content, which is critical not only for the color of carrots but also for their nutritional value. This research could lead to the development of carrot varieties with higher nutritional content, catering to the growing demand for healthy food options.”

The implications of this study are significant for both agriculture and nutrition. By manipulating the DcCYP97A3 gene, it may be possible to breed carrots with optimized carotenoid profiles, making them more beneficial for human health. Moreover, these findings can be applied to other crops where carotenoid accumulation affects color and nutritional quality. The research lays the groundwork for future genetic studies aimed at improving vegetable breeding strategies and increasing the nutritional value of staple crops globally.

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References

DOI

10.1093/hr/uhaf054

Original Source URL

https://doi.org/10.1093/hr/uhaf054

Funding information

The research was supported by National Natural Science Foundation of China (32402551), Natural Science Foundation of Jiangsu Province (BK20241562), and Priority Academic Program Development of Jiangsu Higher Education Institutions Project (PAPD).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.