Genetic and Epigenetic Factors Influence Radish Root Skin and Flesh Colors

Jenn Hoskins
17th May, 2024

Genetic and Epigenetic Factors Influence Radish Root Skin and Flesh Colors

Image Source: Natural Science News, 2024

Key Findings

  • The study by the Beijing Academy of Agriculture and Forestry Science explored the genetic mechanisms behind color variation in radish taproots
  • Researchers identified three key RsMYB transcription factors—RsMYB1, RsMYB2, and RsMYB3—as main regulators of anthocyanin accumulation in radish taproots
  • These RsMYB genes evolved to perform different roles in various radish subspecies, influencing red flesh and skin colors in different radish varieties
Radish taproots exhibit a remarkable diversity of colors due to the accumulation of anthocyanins, a type of pigment known for its antioxidant properties and health benefits[2]. Understanding the genetic mechanisms behind this color variation is crucial for breeding programs aimed at enhancing these beneficial traits. A recent study conducted by the Beijing Academy of Agriculture and Forestry Science provides significant insights into this area[1]. The study identified three key R2R3-MYB transcription factors—RsMYB1, RsMYB2, and RsMYB3—as the main regulators of anthocyanin accumulation in radish taproots. These transcription factors are proteins that bind to specific DNA sequences to control the expression of genes involved in anthocyanin biosynthesis. The researchers used bulked segregant analysis, a method that helps identify genetic differences associated with specific traits, to pinpoint these genes in two different radish populations. They introduced the RsMYB1-RsF3'H-RsMYB1Met genetic model to explain the complex and variable genetic regulation of taproot color in the Xinlimei radish variety. The study found that these three RsMYB genes underwent functional divergence during radish domestication, meaning they evolved to perform different roles in different subspecies and cultivated types. RsMYB1 was found to regulate the red flesh of Xinlimei radish, while RsMYB2 and RsMYB3 were responsible for the red skin in East Asian big long radish (R. sativus var. hortensis) and European small radish (R. sativus var. sativus), respectively. Furthermore, the researchers identified specific haplotypes—variations of these genes—that are primarily responsible for the regulation of anthocyanin synthesis: RsMYB1-H1, RsMYB2-H10, and RsMYB3-H6. These findings align with earlier studies that have shown the role of MYB transcription factors in anthocyanin biosynthesis in other plants. For example, a study on apples demonstrated that a rearrangement in the upstream regulatory region of the MYB10 gene led to increased anthocyanin levels throughout the plant, resulting in red foliage and red fruit flesh[3]. Similarly, research on carrots identified the DcMYB11c gene as a crucial regulator of anthocyanin biosynthesis, with its overexpression leading to a deep purple phenotype[4]. These studies collectively highlight the conserved nature of MYB transcription factors in regulating anthocyanin accumulation across different plant species. The current study also explored the expression patterns of these RsMYB transcription factors in radish lines with different taproot colors. By analyzing a natural population of 56 germplasms, the researchers were able to correlate specific RsMYB haplotypes with anthocyanin accumulation. This correlation provides a potential strategy for early prediction of color variations in radish breeding programs, which could be highly beneficial for developing new varieties with enhanced nutritional and aesthetic qualities. In summary, this study from the Beijing Academy of Agriculture and Forestry Science sheds light on the genetic mechanisms regulating anthocyanin synthesis in radish taproots. By identifying key RsMYB transcription factors and their functional divergence during domestication, the research offers valuable insights for breeding programs aimed at enhancing anthocyanin content. These findings not only contribute to our understanding of plant genetics but also have practical implications for improving the nutritional value and market appeal of radish varieties.

VegetablesGeneticsPlant Science

References

Main Study

1) Sequence and epigenetic variations of R2R3-MYB transcription factors determine the diversity of taproot skin and flesh colors in different cultivated types of radish (Raphanus sativus L.).

Published 16th May, 2024

Journal: TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik

Issue: Vol 137, Issue 6, May 2024

Related Studies

2) Anthocyanins: From the Field to the Antioxidants in the Body.

https://doi.org/10.3390/antiox9090819

3) Multiple repeats of a promoter segment causes transcription factor autoregulation in red apples.

https://doi.org/10.1105/tpc.108.059329

4) A MYB activator, DcMYB11c, regulates carrot anthocyanins accumulation in petiole but not taproot.

https://doi.org/10.1111/pce.14653


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