As jasmine flowers open, how do their scent compounds and the genes that produce them change? In 2025, Jingping Fang and colleagues studied “Hutou,” a jasmine cultivar with many overlapping layers of petals.
Although this cultivar is popular as an ornamental plant, its scent compounds and the mechanisms that produce them had not been sufficiently studied. By decoding its genetic information and comparing compounds and gene activity across five flowering stages, the researchers sought to connect its fragrance characteristics with their biological origins.
From buds to wilted flowers
The study used Hutou grown in a greenhouse in China. Samples were taken at five stages: closed buds, flowers beginning to open, fully open flowers, flowers beginning to senesce, and wilted flowers, with three biological replicates per stage. This was an analysis of plant samples, not an experiment asking people to evaluate fragrance.
Volatile compounds were captured in the gas phase and separated and analyzed by gas chromatography–mass spectrometry. However, the researchers did not simply collect the air around blooming flowers. Frozen, ground flower samples were placed in containers and extracted at 60°C.
The results therefore compare floral constituents under standardized extraction conditions. They must be distinguished from direct measurements of how much garden flowers emit into the air at a given moment or how strong they smell to people.
912 compounds does not mean 912 different smells
Across samples from all stages, the researchers reported 912 volatile compounds. Terpenes and esters were prominent categories, and the sum of compound amounts derived from instrument signals increased from buds to fully open flowers, then declined toward wilting.
The number 912 refers to compounds assigned by matching analytical information against databases and other resources. It does not mean that people distinguished 912 different odors. Moreover, the amounts were based on comparisons with the signal from a reference compound, not absolute amounts individually verified using a standard for every compound.
The researchers focused on 16 compounds that changed early in flowering and were calculated to account for more than 1% of the total at the beginning of opening or at full bloom. Of these, five were classified as having an odor by consulting a database of chemical properties. High detected abundance and importance to the human nose were not the same thing.
The five candidate compounds
The five included α-farnesene, benzyl alcohol, and three esters. Based on their known odor properties, the authors considered them candidates contributing to floral, fruity, and leafy impressions, among others.
α-Farnesene and the three esters generally increased up to full bloom and then decreased. In contrast, benzyl alcohol was most abundant when flowers began to open. Candidate scent compounds therefore did not all rise and fall at the same time.
However, the researchers did not mix these five compounds to recreate the floral scent or ask people to evaluate how the fragrance changed when individual compounds were omitted. The study did not prove that these five determine the scent; rather, it narrowed down apparently important candidates from changes in abundance and known properties.
The five were selected from the 16 compounds chosen on the basis of abundance in the first place. Other compounds associated with jasmine fragrance, such as benzyl acetate, were also detected. This selection method alone cannot evaluate low-abundance compounds or how people perceive mixtures of multiple compounds.
Investigating the genetic information behind scent production
Another pillar of the study was decoding the Hutou genome, the plant’s full genetic information. The researchers assembled sequences corresponding to 13 chromosomes, capturing end-to-end sequences for 11 of them. Approximately 24,000 protein-coding genes were predicted.
They also measured RNA transcribed from genes at each flowering stage to examine which genes were used extensively and when. RNA provides clues to the processes through which genetic information functions. Rather than merely identifying gene names, the researchers examined whether their activity corresponded in time with changes in compounds.
For example, several genes in the pathway producing sesquiterpenes, a group that includes α-farnesene, were more active from early opening to full bloom. In some cases, increases in gene RNA preceded increases in compound amounts.
For benzyl acetate, methyl benzoate, and other compounds, changes in genes thought to participate in biosynthesis also corresponded with changes in the compounds. The genome showed evidence of expansion of related genes through duplication. The authors suggest that which gene copies are active at which times contributes to differences in compound types and amounts.
These correspondences are important clues for investigating mechanisms. However, simultaneous increases and decreases alone cannot establish that a particular gene caused an increase in a compound.
Candidates for regulating gene activity also emerged
The researchers compared the behavior of many genes together, looking for groups associated with changes in scent compounds. HTWRKY41 and HTWRKY53, which may regulate expression of other genes, and HTHSP90, a member of a family that helps proteins function, emerged as central candidates.
For HTWRKY53, they also performed additional experiments using tobacco cells and leaves. The protein accumulated in the cell nucleus and showed the ability to suppress gene expression in an artificial assay system. This tested a property of the protein, going a step beyond correlation alone.
However, it remains unknown which genes this candidate directly regulates in Hutou flowers or how manipulating it would change actual scent compounds. The authors also identify further experiments to determine its direct target genes as a future task.
A foundation for horticulture and fragrance uses
The authors suggest that combining scent-compound data, changes in gene activity during flowering, and genomic information provides a foundation for considering Hutou breeding and use as a fragrance material. Because known constituents associated with jasmine tea aroma were also found, they discuss the work as a clue for exploring materials for scenting tea.
However, the study did not produce tea and compare its quality, or make trial perfumes and assess preference or longevity. Whether the results for this one cultivar under these sampling and extraction conditions also apply to other jasmines or actual products requires separate testing.
The research was supported by the Natural Science Foundation of Fujian Province and the China Scholarship Council. The authors declared no competing interests.
Summary
During Hutou flowering, the amounts of many volatile compounds changed, and scent-related gene activity also varied over time. Not all abundantly detected compounds were classified as having an odor, and even candidate scent compounds differed in when they increased.
The authors offer a way to understand floral scent not just as a list of compounds, but as biosynthetic machinery that changes as flowers open. Using the new genomic information as a foundation, they linked changes in compounds with gene activity and narrowed down candidates for subsequent direct testing. Establishing this foundation for understanding fragrance characteristics and connecting them to horticulture and material uses is the study’s major achievement.
References
Fang, J., Zhou, L., Chen, Q., et al. (2025). Integrated multi-omics analysis unravels the floral scent characteristics and regulation in “Hutou” multi-petal jasmine. Communications Biology, 8, 256. DOI: 10.1038/s42003-025-07685-w. Full original article. © The Author(s) 2025. The original article is licensed under CC BY-NC-ND 4.0.
