Tea plants (Camellia sinensis) rely on a well-developed root system to absorb water and nutrients. However, drought stress significantly weakens root growth, causes cell damage, and leads to oxidative stress. Plants often respond to drought by accumulating reactive oxygen species (ROS), which can impair root function if not effectively removed. Tea polyphenols, known for their antioxidant properties, are abundant secondary metabolites synthesized through the phenylpropanoid pathway. While previous studies suggested that polyphenols may contribute to stress defense, the molecular mechanism connecting polyphenol accumulation with root drought tolerance remained unclear. Due to these challenges, there is a critical need to investigate how tea polyphenols regulate root stress responses.
Researchers from Hunan Agricultural University reported new findings (DOI: 10.1093/hr/uhaf048) on June 1, 2025, in Horticulture Research, revealing how tea polyphenols enhance root drought tolerance in tea plants. The study shows that tea polyphenols activate the phenylpropanoid metabolic pathway and regulate the transcription factor CsMYB77, which in turn promotes the expression of the peroxidase gene CsPOD44. This regulatory cascade enhances antioxidant activity, protects root cellular structure, and improves drought resilience.
In comparative drought experiments among different tea cultivars, drought-tolerant varieties exhibited a stronger increase in tea polyphenol content, suggesting a positive relationship between polyphenol accumulation and stress resistance. When exogenous tea polyphenols were applied to seedlings under drought conditions, plants displayed longer root systems, greater biomass, and lower electrolyte leakage and malondialdehyde levels, indicating reduced cellular injury. Microscopic and ultrastructural analyses further showed that treated roots retained intact epidermal and cortical cell structures, and developed more robust root hairs.
Metabolomic and transcriptomic profiling revealed a significant enrichment of phenylpropanoid pathway activity under polyphenol treatment. Weighted gene co-expression network analysis highlighted CsMYB77 as a central regulatory transcription factor correlated with peroxidase activity. Functional assays confirmed that overexpression of CsMYB77 in Arabidopsis thaliana improved drought tolerance, while silencing CsMYB77 in tea plants caused reduced polyphenol levels and weakened stress resistance. Further molecular tests, including yeast one-hybrid, luciferase complementation, and EMSA assays, demonstrated that CsMYB77 directly binds to the CsPOD44 promoter, activating its transcription.
“Our research provides strong evidence that tea polyphenols are not just nutritional compounds, but active regulators of stress resilience,” said the study’s lead authors. “By identifying the CsMYB77–CsPOD44 regulatory module, we revealed how tea plants naturally strengthen their root antioxidant defenses when facing drought. This mechanism gives us new clues for breeding and managing drought-resistant tea varieties.”
These findings open new possibilities for improving drought tolerance in tea cultivation. The CsMYB77–CsPOD44 regulatory module offers a promising molecular target for breeding programs focused on climate-resilient tea varieties. The demonstrated effectiveness of exogenous tea polyphenols suggests potential for field-level anti-stress treatments to support tea plant health during drought periods. More broadly, this study contributes to understanding how metabolite-mediated transcriptional pathways enhance root resilience, providing insights that may extend to other perennial crops facing increasingly variable climate conditions.
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References
DOI
10.1093/hr/uhaf048
Original Source URL
https://doi.org/10.1093/hr/uhaf048
Funding information
This study was financially supported by the project of National Natural Science Foundation of China (32372765); the project of National Key Research and Development Plan (2022YFD1600801); the project of National Tea Tree Breeding Joint Research Project (GJCSYZLHGG-12); the project of Major Science and Technology Innovation Projects in Hunan Province (2021NK1020); the project of Chenzhou National Sustainable Development Agenda Innovation Demonstration Zone Construction Project (2022SFQ48); and the project of Special Project for the Construction of Modern Agricultural Industrial Technology Systems in Hunan Province (HARS-10).
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.