Unraveling the mechanism of flower color variation in Brassica napus by integrated metabolome and transcriptome analyses

Front Plant Sci. 2024 Jun 12:15:1419508. doi: 10.3389/fpls.2024.1419508. eCollection 2024.

Abstract

Brassica napus is one of the most important oil crops in the world. Breeding oilseed rape with colorful flowers can greatly enhance the ornamental value of B. napus and thus improve the economic benefits of planting. As water-soluble flavonoid secondary metabolites, anthocyanins are very important for the synthesis and accumulation of pigments in the petals of plants, giving them a wide range of bright colors. Despite the documentation of over 60 distinct flower shades in B. napus, the intricacies underlying flower color variation remain elusive. Particularly, the mechanisms driving color development across varying flower color backgrounds necessitate further comprehensive investigation. This research undertook a comprehensive exploration through the integration of transcriptome and metabolome analyses to pinpoint pivotal genes and metabolites underpinning an array of flower colors, including beige, beige-red, yellow, orange-red, deep orange-red, white, light-purple, and purple. First, we used a two-way BLAST search to find 275 genes in the reference genome of B. napus Darmor v10 that were involved in making anthocyanins. The subsequent scrutiny of RNA-seq outcomes underscored notable upregulation in the structural genes F3H and UGT, alongside the MYB75, GL3, and TTG1 transcriptional regulators within petals, showing anthocyanin accumulation. By synergizing this data with a weighted gene co-expression network analysis, we identified CHS, F3H, MYB75, MYB12, and MYB111 as the key players driving anthocyanin synthesis in beige-red, orange-red, deep orange-red, light-purple, and purple petals. By integrating transcriptome and weighted gene co-expression network analysis findings with anthocyanin metabolism data, it is hypothesized that the upregulation of MYB75, which, in turn, enhances F3H expression, plays a pivotal role in the development of pigmented oilseed rape flowers. These findings help to understand the transcriptional regulation of anthocyanin biosynthesis in B. napus and provide valuable genetic resources for breeding B. napus varieties with novel flower colors.

Keywords: Brassica napus; F3H; RNA-seq; anthocyanins; flower color.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was supported by the earmarked fund for China Agriculture Research System, grant number CARS12; the Key Research and Development Program of Jiangxi Province, grant number: 20223BBF61002; Sichuan rape innovation team project of modern agricultural industry technology system, grant number sccxtd-2023–03; Sichuan Science and Technology Program, grant number 2021YFYZ0018; the Accurate Identification Project of Crop Germplasm from Sichuan Provincial Finance Department, grant number 2021ZYGG001; Independent Innovation Project of SAAS, grant number 2022ZZCX004.