From fragrance wheel to functional genes: a multi-omics investigation into fragrance type formation in ornamental Hedychium flowers

Abstract

Floral scent is a crucial quality trait in ornamental plants, yet research has been hampered by the lack of standardized sensory evaluation and the disconnect between genes, volatile compounds, and human perception. Hedychium is an excellent model for fragrance research due to its diverse fragrance types and rich volatile organic compound (VOC) profiles. This study establishes a sensory-omics framework to connect genetic pathways, VOC chemistry, and fragrance perception in Hedychium flowers. A multidisciplinary approach combined sensory panel analysis (developing a fragrance wheel), VOC profiling (HS–SPME–GC–MS and PTR–ToF–MS), transcriptomics, and functional characterization of key biosynthetic genes in 30 Hedychium accessions representing six fragrance types. Six distinct fragrance types were classified (e.g. strong floral, fruity), linked to specific VOC profiles (e.g. monoterpenoids, esters). PTR–ToF–MS validated rapid detection of key fragrance markers. Supervised partial least squares-discriminant analysis (PLS-DA) modeling of VOC signatures enabled fragrance-type classification and key variable selection. Transcriptomic analysis coupled with weighted gene co-expression network analysis (WGCNA) revealed two key gene modules-MEbrown (terpenoid-associated) and MEyellow (phenylpropanoid-associated)-that underlie fragrance variation. Functional validation through in vitro enzymatic assays and transient overexpression in tobacco leaves confirmed HcTPS1 as a eucalyptol synthase and HmBEAT1 as a benzyl acetate synthase. Collectively, these findings provide a comprehensive framework for Hedychium flowers, thereby elucidating the molecular and chemical basis of their sensory fragrance variation. The study delivers valuable genetic resources and a predictive model that establishes a foundation for the targeted breeding of floral fragrance in ornamental horticulture.

Acknowledgements

We sincerely thank the sensory evaluation volunteers from the Flower Research Center at South China Agricultural University for their valuable contributions to this study. This research was supported by the Provincial Rural Revitalization Strategy of Guangdong Province in 2024 (grant 2024-NPY-00-038), National Natural Science Foundation of China (Grant no. 31770738), and the Key-Areas Research and Development Program of Guangdong Province (grant 2020B020220007).

Author contributions

Y.Z. and Y.F. designed the study. Y.Z., F.W., X.W., M.X., T.G., Q.W., L.W., and Y.Y. performed the research with support from Y.F. Y.Z., F.W., and X.W. analyzed the data. R.Y. and Y.F. contributed key resources. Y.F. and Y.Z. wrote the manuscript with critical input from F.W., X.W., M.X., T.G., Q.W., L.W., Y.Y., and R.Y. All authors read and approved the final manuscript.

Data availability

The nucleotide sequences of HcTPS1 (PX095165) and HmBEAT1 (PX095164) have been deposited in GenBank. The raw transcriptome data have been submitted to the NCBI Sequence Read Archive (SRA) database (PRJNA1303972). All other data are available from the corresponding author on reasonable request.

Conflicts of interest statement

The authors have not declared a conflict of interest.

Supplementary materail

Supplementary material is available at Horticulture Research online.

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