Researchers Identify Molecular Brake and Release Mechanism Controlling Sweet Osmanthus Floral Fragrance Production

Scientists reveal how the jasmonic acid signaling pathway regulates linalool production in sweet osmanthus, enabling the engineering of floral fragrances.

By: AXL Media

Published: Apr 30, 2026, 9:46 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Molecular Architecture of Floral Volatiles

The distinctive and globally recognized fragrance of Osmanthus fragrans, commonly known as sweet osmanthus, has long been a subject of horticultural fascination. While the flower is prized for its ornamental beauty and economic value in the food and perfume industries, the underlying biological processes that govern its aromatic output were not fully understood. Researchers from Zhejiang Agriculture and Forestry University and Anhui Agricultural University have now mapped the molecular pathways responsible for these scents. Their findings clarify how plant hormones act as chemical messengers to trigger the synthesis of linalool, a dominant monoterpene that provides the flower with its signature olfactory profile.

Hormonal Control of the Linalool Synthase Gene

The investigation focused on the relationship between jasmonic acid, a vital plant hormone, and the expression of the OfTPS2 gene, which functions as a linalool synthase. By tracking hormone fluctuations across three distinct flowering stages, the research team observed that jasmonic acid levels correlate precisely with the accumulation of linalool. To verify this link, the scientists treated flowers with methyl jasmonate, which resulted in a marked increase in OfTPS2 transcription. This confirmed that the hormone acts as a positive regulator, effectively signaling the plant to begin the intense production of volatile compounds during the peak of its blooming cycle.

Identifying the OfJAZ3 Molecular Brake

At the heart of this scent production is a sophisticated "brake and release" mechanism involving a protein known as OfJAZ3. Under normal conditions, this protein acts as a molecular repressor by binding to the transcription factor OfMYB21. This interaction prevents the transcription factor from activating the OfTPS2 gene, keeping scent production in check. The study utilized dual-luciferase and EMSA assays to demonstrate that OfJAZ3 interferes with the binding process, effectively acting as a physical barrier that keeps the floral fragrance synthesis turned off until the appropriate biological signals are received.