How a wild grapevine gene helps plants survive freezing stress
image: A proposed working model illustrating the regulatory network of VaWRKY65 in cold tolerance. VaWRKY65 is induced by cold stress, which subsequently activates VaBAM3 and VaPOD36 transcription via interacting with the W-box in their promoters to improve plant starch degradation and ROS scavenging captivity, leading to increased plant cold tolerance. Image link: https://academic.oup.com/view-large/figure/507964438/uhae367f11.tif?login=false
Credit: Horticulture Research
Cold temperatures pose one of the most damaging environmental stresses to grapevine, leading to growth inhibition and yield loss. Conventional breeding for cold resistance is limited by long life cycles and complex genetics, particularly in Vitis vinifera cultivars that are sensitive to freezing. Wild species such as Vitis amurensis, which can survive −40°C winters, offer valuable genetic resources for improving cold tolerance. However, the molecular basis of their superior resilience remains unclear. Soluble sugars and antioxidant enzymes are known to protect plant cells from stress, yet the transcriptional coordination between these two protective systems is poorly understood. Due to these challenges, deeper research on transcriptional regulation of cold response in grapevine is urgently needed.
Researchers from the Wuhan Botanical Garden, Chinese Academy of Sciences, in collaboration with the Turpan Institute of Agricultural Sciences and North Carolina State University, published (DOI: 10.1093/hr/uhae367) new findings on April 1, 2025, in Horticulture Research. The study reveals that the transcription factor VaWRKY65 enhances grapevine cold tolerance by regulating two crucial processes: starch degradation and ROS detoxification. By activating VaBAM3 and VaPOD36, VaWRKY65 simultaneously boosts soluble sugar levels and antioxidant capacity, offering a unified mechanism for cold stress resistance in grapevine.
Through yeast one-hybrid screening, VaWRKY65 was identified as a cold-induced regulator that binds to W-box motifs in the promoters of VaBAM3 and VaPOD36. Overexpression experiments in Arabidopsis thaliana and grapevine roots demonstrated that plants expressing VaWRKY65 or VaBAM3 showed improved freezing tolerance, reduced cellular damage, and elevated levels of soluble sugars. Conversely, VaWRKY65-silenced and CRISPR/Cas9 knockout plants exhibited impaired sugar metabolism, higher ROS accumulation, and increased membrane damage.
Transcriptome analysis revealed that VaWRKY65 overexpression reprogrammed over 2,000 genes, enriching pathways related to starch and sucrose metabolism, flavonoid biosynthesis, and oxidative stress responses. Among them, VaPOD36, encoding a peroxidase enzyme, was directly activated by VaWRKY65, significantly increasing peroxidase activity and reducing ROS accumulation during cold exposure. Microscopic assays confirmed lower hydrogen peroxide and superoxide levels in VaWRKY65-overexpressing lines. Together, these results demonstrate that VaWRKY65 functions as a central regulator that couples carbohydrate metabolism with antioxidant defense to achieve comprehensive cold tolerance.
“Cold stress disrupts both energy metabolism and redox balance in plants,” said Professor Haiping Xin, senior author of the study. “Our research shows that Vitis amurensis has evolved an efficient strategy to overcome these challenges through VaWRKY65, which integrates sugar signaling and ROS detoxification into a single regulatory pathway. This dual control enables the plant to maintain both metabolic activity and cellular integrity under freezing conditions. The discovery provides valuable genetic targets for improving cold resistance in grapevine and other perennial crops.”
The identification of VaWRKY65 as a dual-function regulator opens new possibilities for breeding and engineering cold-tolerant grapevine cultivars. By simultaneously promoting energy balance and antioxidant protection, this gene offers a promising tool for maintaining productivity in regions facing increasing climate variability. Beyond grapevine, the VaWRKY65–VaBAM3–VaPOD36 regulatory module may serve as a universal model for enhancing cold resilience in other horticultural and fruit crops. Future work will explore upstream regulators of VaWRKY65 and evaluate its role in field-grown vines, contributing to sustainable viticulture under extreme temperature stress.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae367
Funding information
This work was supported by the Project funded by the China Postdoctoral Science Foundation (No. 2023 M733717) and the Natural Science Foundation of China (Nos 32302517 and 32025032).
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, 2024. 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.