Two MYB Switches Found Steering Floral Scent in Primula forbesii

Researchers have mapped the full complement of R2R3-MYB transcription factor genes in the fragrant flowering plant Primula forbesii and identified two members of the family, PfMYB31 and PfMYB88, as positive regulators of floral scent biosynthesis. The study, published in BMC Plant Biology, combined a genome-wide survey of the gene family with transcriptomic screening and functional validation, and it reports that silencing either gene in the plant reduced a distinct class of scent compounds.

The survey identified a total of 109 R2R3-MYB genes in the P. forbesii genome, distributed unevenly across nine chromosomes. To organize the family, the authors used two complementary phylogenetic analyses: one tree built from a set containing both R2R3-MYB and R3-MYB proteins, and a second, R2R3-specific tree that classified the 109 PfR2R3-MYB proteins into 27 subgroups. Analysis of gene duplication showed that segmental duplication was the predominant duplication type, and all calculable Ka/Ks ratios were below 1, a pattern consistent with purifying selection. Promoter analysis revealed numerous cis-acting elements associated with hormone signaling, stress responses, and secondary metabolism.

To narrow the large family down to likely scent regulators, the team integrated transcriptomic data, a gene co-expression network, and gene expression patterns. This combined approach singled out PfMYB31 and PfMYB88 as key candidate regulators of floral volatile production. The proteins encoded by the two genes were both found to localize to the nucleus, as expected for transcription factors.

Functional tests using virus-induced gene silencing supported distinct roles for the two candidates. Silencing PfMYB31 decreased phenylpropanoid-derived floral volatiles and lowered the transcript abundance of associated biosynthetic genes, whereas silencing PfMYB88 decreased terpene-derived volatiles and the transcripts of genes in that pathway. In other words, each transcription factor was linked to a different branch of scent metabolism, with PfMYB31 tied to the phenylpropanoid-derived volatiles and PfMYB88 to terpene-derived volatiles.

The authors conclude that the results support distinct positive regulatory roles for PfMYB31 and PfMYB88 in floral scent metabolism and provide candidate loci for further mechanistic and germplasm-based studies in Primula. Because floral scent contributes substantially to the ornamental value of flowering plants and plays important roles in plant-environment interactions, the findings offer a starting point for future work on how scent traits are controlled in this genus. The study is an open-access research article published on 29 October 2026, and the published version notes that the early-release record is subject to further edits before the final Version of Record.

Subject of Research: Genome-wide identification of R2R3-MYB regulators of floral scent biosynthesis in Primula forbesii

Article Title: Genome-wide analysis of the R2R3-MYB family identifies PfMYB31 and PfMYB88 as positive regulators of floral scent biosynthesis in Primula forbesii

Article References: Yang, H., Luo, Y., Deng, W., Liao, J., Lv, Z., Li, W., Pan, Y., Jiang, B., & Jia, Y. (2026). Genome-wide analysis of the R2R3-MYB family identifies PfMYB31 and PfMYB88 as positive regulators of floral scent biosynthesis in Primula forbesii. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10278-2

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10278-2

Keywords: Primula forbesii, R2R3-MYB, floral scent, transcription factors, PfMYB31, PfMYB88, VIGS, phenylpropanoid volatiles, terpene volatiles, gene family analysis, BMC Plant Biology, Genome-wide