Rewiring dormancy: miR319c unlocks potato sprouting secrets

Potatoes don't sprout by accident—timing is everything. A newly identified microRNA, named stu-miR319c, has been found to play a pivotal role in telling potato tubers when to break dormancy and start growing. Scientists revealed that this microRNA targets key transcription factors and modulates the jasmonic acid (JA) pathway, acting as a genetic switch between dormancy and sprouting. By manipulating its levels, researchers could accelerate or delay sprouting in genetically modified tubers. The discovery sheds light on a finely tuned molecular mechanism behind one of the most critical stages in potato storage and agriculture—and opens the door to smarter control over one of the world’s most essential food crops.

Potato tuber dormancy is a carefully timed biological pause that allows postharvest storage and planting to occur at optimal times. However, premature or delayed sprouting can reduce tuber quality and cause losses during storage. While plant hormones such as abscisic acid (ABA), gibberellins (GA), and jasmonic acid (JA) are known to influence dormancy, the regulatory roles of non-coding RNAs like microRNAs (miRNAs) in this process are far less understood. In many crops, miRNAs have emerged as critical players in developmental control. Due to these gaps in knowledge, uncovering how miRNAs mediate dormancy transitions in potatoes has become an urgent priority for researchers seeking to improve storage and sprouting control.

A research team from Gansu Agricultural University has unveiled new insights into potato dormancy regulation through microRNA activity. Published (DOI: 10.1093/hr/uhae303) in Horticulture Research on October 30, 2024, their study identified stu-miR319c as a key molecule that influences the shift from dormancy to sprouting. By applying genome-wide sequencing and functional assays in transgenic potatoes, the team found that this miRNA regulates the expression of TCP transcription factors and activates the JA signaling pathway. These findings mark a significant step forward in understanding—and ultimately manipulating—tuber dormancy in one of the world's most widely cultivated crops.

The researchers examined potato tubers at three stages—dormant, dormancy-released, and sprouting—stored under different temperatures. High-throughput small RNA sequencing revealed a suite of microRNAs, with stu-miR319c showing consistent upregulation during the transition to sprouting. Functional experiments confirmed that stu-miR319c directly suppresses TCP transcription factors StTCP26 and StTCP27, which are known inhibitors of sprouting. Overexpression of this miRNA led to earlier sprouting, while silencing it extended dormancy. Further probing linked stu-miR319c to the JA pathway—a key hormonal regulator of plant development. Application of methyl jasmonate (MeJA) at optimal concentrations significantly accelerated sprouting in wild-type tubers, and stu-miR319c transgenic lines displayed matching changes in JA levels and expression of JA biosynthesis genes. Interestingly, the influence of miR319c extended beyond timing alone; transgenic plants exhibited altered tuber shape, skin texture, and bud eye distribution—traits with direct relevance to commercial breeding. Together, the data point to a dual-action mechanism where stu-miR319c regulates both gene expression and hormone production to fine-tune the timing and physical traits of potato sprouting. This integrated pathway offers not just a molecular explanation for dormancy release, but a toolkit for improving agricultural outcomes through precision breeding.

“This discovery highlights the sophistication of microRNA-based regulation in crop development,” said Dr. Ning Zhang, the study's senior author. “Stu-miR319c doesn't just flip a switch—it acts as a fine-tuner, integrating environmental and hormonal cues to control when and how tubers sprout. Its stable inheritance and targeted function make it a strong candidate for future breeding strategies.” Zhang emphasized that miR319c's involvement in both transcription factor targeting and jasmonate signaling positions it as a central node in the complex network governing dormancy, with potential applications across diverse crop systems.
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The ability to control tuber dormancy through a single microRNA opens promising avenues for breeding potato varieties with customized storage and sprouting profiles. Farmers could benefit from crops that resist premature sprouting in storage, while processors might select for rapid-sprouting varieties to match planting schedules. Beyond potatoes, this research provides a framework for identifying and harnessing similar miRNA-based controls in other vegetatively propagated crops. Future technologies could combine genetic editing and targeted hormone treatments to optimize dormancy duration in a climate-resilient and supply chain-conscious agricultural landscape—turning molecular insights into tangible solutions for global food systems.

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References

DOI

10.1093/hr/uhae303

Original Source URL

https://doi.org/10.1093/hr/uhae303

Funding information

This research was funded by the Gansu Science and Technology Major Project (No. 22ZD6NA009), National Key Research and Development Program of China (No. 2022YFD1602103), and the Gansu Science and Technology Major Project (No. 23ZDNA006).

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.