How roses adjust their scent and hue in salty soils？
image: Major metabolites in the rose petals during flower development. Bud, the petals are covered by sepals; early opening, time before bloom; full opening, bloom time; falling, the petals begin to fall. Dots with different colors show major metabolites in the petals at each developmental stage.
Credit: Horticulture Research
Saline–alkali stress disrupts the delicate chemistry of rose petals, reshaping both their color and aroma profiles. This study reveals that two key compounds—proanthocyanidins and sesquiterpenoids—undergo opposing changes when roses face salt–alkali conditions. At the heart of this shift is MYB5, a transcription factor that activates the color-related ANR gene and represses the aroma-related TPS31 gene. Under stress, this control loosens, reducing color intensity while amplifying aroma compounds. These findings highlight how environmental cues can flip a metabolic switch, offering new insights into how plants adapt—and how breeders might optimize floral traits for tough soils.
As global salinization and alkalinization of soils intensify, plants are increasingly forced to adapt to these harsh environments. One critical survival mechanism involves tweaking secondary metabolism—especially the production of compounds like flavonoids and terpenoids, which contribute to pigmentation, fragrance, and stress defense. While many crops have been studied for their metabolic plasticity under stress, little is known about how perennial ornamental species like roses respond. Furthermore, understanding how one regulator could coordinate multiple pathways has remained elusive. Due to these challenges, investigating how rose petals reprogram their metabolic networks under saline–alkali conditions has become a pressing scientific question.
A team of researchers from Qingdao Agricultural University and partner institutions has uncovered how Rosa rugosa adjusts its floral chemistry in response to saline–alkali stress. Their findings (DOI: 10.1093/hr/uhae243), published on August 30, 2024, in Horticulture Research, show that the transcription factor MYB5 orchestrates a dual genetic cascade—boosting pigment-related genes while dampening scent-producing ones. By integrating metabolomic and transcriptomic approaches, the team uncovered a stress-responsive mechanism that shifts the metabolic balance of rose petals. The work opens new avenues for breeding and biotechnological applications in ornamental plants.
To explore how salt–alkali stress influences petal chemistry, the researchers exposed Rosa rugosa plants to saline–alkaline solutions and conducted multi-omics analyses. They found dramatic shifts in 196 metabolites and 1,363 genes. Flavonoids and terpenoids—the key players behind petal color and scent—showed the most notable changes. Crucially, the transcription factor MYB5 was identified as a metabolic gatekeeper, activating ANR (linked to proanthocyanidins) and repressing TPS31 (associated with sesquiterpenoids).
In follow-up experiments using genetically modified tobacco, the researchers confirmed TPS31's role in terpenoid accumulation. MYB5 was shown to bind directly to the promoters of ANR and TPS31, but its regulatory power weakened under stress. As MYB5 levels dropped, ANR expression decreased, reducing pigment compounds, while TPS31 expression rose, enhancing aroma-related sesquiterpenoids. This stress-induced shift in gene regulation rewired the rose's metabolic output—tilting the balance toward scent over color.
“Our study reveals a surprisingly elegant mechanism by which rose petals fine-tune their metabolic responses to environmental stress,” said Prof. Guohua Chai, corresponding author of the study. “MYB5 doesn't just flip one switch—it simultaneously coordinates two distinct metabolic pathways. This dual control model helps explain how plants can redirect energy under stress, and it gives us valuable genetic tools to improve floral traits in future cultivars.”
This research lays a foundation for both practical and scientific advances. By targeting MYB5, ANR, or TPS31, breeders could engineer roses with enhanced resilience and tailored combinations of color and scent. These findings also have potential beyond ornamentals—industrial biosynthesis platforms could exploit these regulatory circuits to produce valuable plant-derived compounds. More broadly, the study offers a blueprint for how transcription factors mediate complex metabolic shifts in response to stress, providing insights for crop improvement in saline-affected regions.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae243
Funding information
Financial support was obtained from the Key R & D Program of Shandong Province (2023LZGVC012), the Dongying Social Science Project (DYSK-2024-272 to YC), Qingdao People’s Livelihood Science and Technology Project (22-1-3-13-zyyd-nsh), Science & Technology Specific Projects in Agricultural High-tech Industrial Demonstration Area of the Yellow River Delta (2022SZX39), and the Taishan Scholar Program of Shandong (tsqn202103092).
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.