As global climate change intensifies, drought events are becoming more frequent and severe, posing a major threat to agricultural productivity and ornamental plant cultivation. Water deficiency disrupts cellular homeostasis, damages membranes, and triggers excessive accumulation of reactive oxygen species (ROS), ultimately impairing plant growth and survival. While physiological responses to drought have been widely studied, the regulatory networks that coordinate gene expression during water stress remain incompletely understood, particularly in woody ornamental species. MicroRNAs have emerged as key regulators of plant stress responses, yet their roles in drought adaptation are still underexplored in many crops. Based on these challenges, there is a critical need to investigate microRNA-mediated regulatory mechanisms that govern drought responses at the molecular level.
Researchers from Henan University of Science and Technology and collaborating institutions report new insights into drought-response regulation in tree peony in a study published (DOI: 10.1093/hr/uhaf252) in Horticulture Research in 2025. Using multi-omics approaches combined with genetic and physiological analyses, the team identified a drought-responsive regulatory module centered on the microRNA PomiR172d and its target gene PoARR. Their work reveals how this module influences ROS metabolism and determines plant sensitivity or tolerance to water stress.
The researchers subjected tree peony plants to progressive drought and rehydration treatments and monitored changes in phenotype, membrane integrity, stomatal behavior, and water potential. Drought stress caused pronounced leaf wilting, reduced stomatal opening, increased membrane permeability, and a sharp decline in leaf water potential, confirming severe physiological damage under water deficit.
To uncover the underlying regulatory mechanisms, the team conducted integrated transcriptome, microRNA, and degradome sequencing. They identified 883 drought-responsive microRNAs and constructed regulatory networks linking microRNAs, target genes, and transcription factors. Among these, the PomiR172d–PoARR module stood out due to its consistent response to drought and rehydration. Expression analyses revealed a strong negative correlation: drought stress suppressed PomiR172d while inducing PoARR.
Functional validation showed that overexpression of PomiR172d increased drought sensitivity, leading to faster water loss, reduced biomass, and elevated oxidative damage. In contrast, overexpression of PoARR enhanced drought tolerance by maintaining membrane stability and activating antioxidant enzymes such as superoxide dismutase, peroxidase, and catalase. These effects reduced ROS accumulation and improved plant recovery after rehydration. Together, the results demonstrate that PomiR172d acts as a molecular brake on drought tolerance by repressing PoARR, which positively regulates oxidative stress defenses.
“This study highlights how a single microRNA can reshape a plant’s drought response by targeting oxidative stress pathways,” said the senior authors of the study. “By integrating multi-omics data with functional experiments, we were able to move beyond correlation and demonstrate a direct regulatory mechanism. The PomiR172d–PoARR module provides a clear example of how microRNAs fine-tune stress tolerance, offering valuable molecular targets for future breeding and biotechnological strategies aimed at improving drought resilience.”
The discovery of the PomiR172d–PoARR regulatory module has important implications for both basic plant biology and applied crop improvement. By revealing how microRNAs control ROS homeostasis under drought stress, the study provides new molecular targets for breeding drought-resistant varieties of tree peony and potentially other crops. Manipulating similar microRNA–gene modules could enhance stress tolerance without compromising growth or ornamental quality. More broadly, this work demonstrates the power of multi-omics approaches to uncover hidden regulatory layers in plant stress responses, supporting future efforts to develop resilient plants adapted to increasingly water-limited environments.
###
References
DOI
10.1093/hr/uhaf252
Original Source URL
https://doi.org/10.1093/hr/uhaf252
Funding information
This research was funded by the National Natural Science Foundation of China (Grant number 32573070) and the Funded Project of Henan Province Traditional Chinese Medicine Industry Technology System (grant number 2024–23).
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.