Wild carnation genome reveals routes to restore floral scent
image: Volatilome comparison between D. broteri West and East lineages.
Credit: Horticulture Research
Domestication has given cultivated carnations striking colors, varied forms, and long vase life, but often at the cost of fragrance. By assembling the first high-quality reference genome of the wild carnation Dianthus broteri and comparing it with cultivated carnations, researchers traced genomic and biochemical changes linked to scent loss. The study found that wild plants retain richer scent-related gene functions and emit a complex blend of floral volatiles, while cultivated carnations show genomic patterns consistent with selection away from secondary metabolism. It also identified the terpene synthase gene DbrTPS18 as a strong candidate for explaining scent differences between wild lineages, creating a practical starting point for breeding carnations with renewed fragrance.
Floral scent is more than an ornamental trait: volatile organic compounds (VOCs) help plants attract pollinators, deter enemies, and communicate with their surroundings. Yet carnation breeding has historically favored flower color, shape, productivity, and longevity, leaving many modern varieties only faintly scented. Understanding this loss has been difficult because high-quality genomes are available mainly for cultivated carnations, whereas their fragrant wild relatives remain poorly represented. Without those wild reference genomes, researchers cannot clearly separate domestication-related changes from deeper species differences or identify useful scent-associated variants. Because of these challenges, deeper research is needed into how domestication reshapes fragrance pathways and how wild genetic diversity can support scent restoration.
Published (DOI: 10.1093/hr/uhag130) on April 7, 2026, in Horticulture Research, the study was conducted by researchers at the University of Seville, the University of Salzburg, and the University of Vienna. The team generated an 876-megabase pseudo-chromosome assembly of diploid D. broteri and integrated comparative genomics, floral volatile profiling, gene-expression analysis, and variant association testing. Their goal was to explain why wild carnations can produce strong, terpenoid-rich scents while cultivated Dianthus caryophyllus generally releases a weaker fragrance, and to identify genomic resources that could guide future ornamental breeding.
The new D. broteri genome anchored more than 86% of its sequence to 15 pseudo-chromosomes and contained 43,817 predicted genes. Transposable elements (TEs) occupied 82.42% of the genome, largely because of Gypsy long terminal repeat retrotransposons, while cultivated carnations showed fewer TEs overall but more insertions within or near genes. Gene-family analysis revealed that wild D. broteri retained expansions linked to secondary metabolism and stress responses, whereas cultivated carnations showed contractions in functions associated with volatile biosynthesis. Gas chromatography–mass spectrometry (GC–MS) detected 59 floral VOCs in D. broteri. The strongly scented western lineage produced 52 compounds and was dominated by the sesquiterpenoids (E)-β-caryophyllene and (E)-nerolidol; the eastern lineage emitted only 21 compounds and was nearly scentless. Expression analysis showed stronger activity of upstream mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathway genes in western flowers. Among 39 lineage-specific single-nucleotide polymorphisms (SNPs), 18 occurred in the gene DbrTPS18. Across the full gene, researchers found 24 nonsynonymous substitutions, including 15 near conserved catalytic motifs and three in the predicted N-terminal chloroplast transit peptide. Sixteen variants were significantly associated with major terpene emissions.
The authors said the results suggest that carnation fragrance was not lost through a single genomic switch. Instead, scent differences appear to reflect several interacting layers, including pathway activity, metabolic resource allocation, and variation affecting terpene synthase function and cellular targeting. They said the DbrTPS18 findings are especially promising because the gene is highly expressed in both wild lineages, yet its sequence differs where enzyme performance may be affected. However, the authors emphasized that laboratory validation is still required before these variants can be treated as direct causes of scent intensity or composition.
The reference genome and candidate variants offer breeders a new toolkit for recovering fragrance from wild carnations. D. broteri can now be used as a genomic reservoir for screening scent-related alleles, comparing metabolic pathways, and developing molecular markers for selection. The findings may help breeders combine fragrance with commercially important traits such as flower form, color, and vase life, although such trait combinations will require careful testing across genetic backgrounds. More broadly, the study shows why wild relatives matter in crop and ornamental improvement: traits weakened during domestication may remain accessible in unmanaged populations. Functional studies of DbrTPS18 and related pathway genes could clarify which variants reliably enhance scent and whether they perform consistently in cultivated carnations.
###
References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhag130
Funding information
This work was supported by the Spanish Ministry of Science, Innovation and University for projects (PID2023-147752NB-I00 and PGC2018-098358-B-I00) and PhD funding (PRE2019-088229 for J.P.-A.).
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.