Flower power: Decoding the cellular basis of floral fragrance
image: Isolation and analysis of single-cell transcriptomes from mei petals. A Petal protoplast extraction at BS and FS. B UMAP visualization of samples at BS and FS. C Correlation analysis of scRNA-seq profiling and bulk RNA-seq at BS (a) and FS (b), respectively.
Credit: Horticulture Research
A recent study has unraveled the intricate cellular blueprint behind the iconic fragrance of Prunus mume flowers. Using state-of-the-art single-cell RNA sequencing, researchers have constructed a high-resolution map of gene expression within petal cells across blooming stages. This atlas not only identifies six key cell types but also pinpoints the genetic pathways responsible for floral scent production. These discoveries mark a significant leap forward in understanding floral scent biosynthesis and could open new doors to cultivating aromatic plant varieties and innovations in the fragrance industry.
Floral fragrances are nature’s allure, enticing pollinators and helping plants adapt to environmental challenges. These scents, primarily generated in petals, consist of complex compounds like terpenoids and benzenoids/phenylpropanoids, which hold immense ornamental and commercial value. However, despite advances in identifying genes tied to volatile production, the cellular landscapes where these scents are made and the dynamic expression of related genes remain elusive. Bridging this knowledge gap requires a detailed exploration of the molecular and cellular organization of flower petals.
In a pioneering effort, researchers at Northwest A&F University have created the first-ever single-cell gene expression map of Prunus mume petals. Published (DOI: 10.1093/hr/uhae189) in Horticulture Research on July 10, 2024, the study harnesses cutting-edge single-cell RNA sequencing to dissect gene activity in petals during budding and full-blooming stages. By identifying six distinct cell types, the research provides an unprecedented look into the molecular pathways driving floral scent biosynthesis and highlights their cellular precision.
This study focused on the petals of Prunus mume ‘Fenhong Zhusha,’ a fragrant cultivar celebrated for its floral aroma. Researchers identified six key cell types, including epidermal and parenchyma cells as well as vascular tissues, each playing specialized roles in scent production. The dynamic fragrance profile peaked at full bloom, with benzyl acetate and eugenol emerging as the dominant volatiles. Integrating single-cell and bulk RNA sequencing data, the team pinpointed 28 genes in the benzenoid/phenylpropanoid pathway, including PmPAL2, PmBAHD3, and PmEGS1, all exhibiting stage-specific expression. Among the standout discoveries, PmBAHD3 was revealed as a multifunctional enzyme synthesizing both benzyl acetate and eugenol. These genes were predominantly active in epidermal and parenchyma cells, as confirmed through in situ hybridization. This cellular atlas not only clarifies the molecular mechanisms behind Prunus mume’s iconic fragrance but also offers fresh perspectives on spatially distinct metabolic processes in woody plant petals, setting the stage for groundbreaking applications.
Dr. Tengxun Zhang, the lead researcher, expressed excitement over the findings: “Our study reveals the cellular complexity of floral scent biosynthesis in Prunus mume. This research not only provides a detailed molecular roadmap but also unlocks new possibilities for advancing ornamental horticulture and the fragrance industry.”
The insights gained from this research have far-reaching applications. By targeting key genes like PmBAHD3 involved in scent biosynthesis, breeders could develop new aromatic cultivars with enhanced fragrance profiles. Additionally, the cellular atlas of Prunus mume serves as a model for studying scent production in other ornamental plants, offering transformative potential for the perfume and flavor industries. This work represents a significant step toward sustainable cultivation and innovation in high-value plants, with implications for both science and industry.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae189
Funding information
The work supported by the National Natural Science Foundation of China (No. 32301659), the Natural Science Basic Research Program of Shaanxi (Program No. 2023-JC-QN-0188), and the Chinese Universities Scientific Fund (No. 2452021098).
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, 2022. 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.