How peaches fight the cold: A CO₂-triggered self-defense mechanism uncovered

Chilling injury (CI) is a major challenge limiting the shelf life and market value of peaches during cold storage. This study reveals that elevated carbon dioxide (CO₂) can activate the peach’s own genetic defense system to resist cold-induced damage. Researchers identified the ethylene response factor PpERF17 as a key transcription factor that promotes the biosynthesis of jasmonic acid (JA) and γ-aminobutyric acid (GABA), two metabolites critical for cold tolerance. The team further discovered that PpMYC2.1, a master regulator in JA signaling, amplifies this defense loop. Together, these findings provide a natural, chemical-free strategy to reduce fruit spoilage and extend postharvest storage life.

Low-temperature storage is essential for prolonging the freshness of fruits such as peaches, yet it often causes chilling injury characterized by internal browning and tissue breakdown. Traditional methods—like controlled atmosphere or chemical treatments—can delay these effects but are costly or leave residues. Previous research has shown that jasmonic acid (JA) and γ-aminobutyric acid (GABA) play protective roles against cold stress, but their regulatory mechanisms remain poorly understood. Moreover, how elevated carbon dioxide (CO₂) conditions affect transcriptional networks in fruits has not been fully explored. Due to these challenges, it is necessary to investigate how CO₂-responsive genes coordinate JA and GABA biosynthesis to enhance cold tolerance in peach fruit.

Researchers from Zhejiang University and collaborators at the University of Nottingham have reported a breakthrough study published (DOI: 10.1093/hr/uhaf014) on January 15, 2025, in Horticulture Research. The team discovered that elevated CO₂ alone—not low oxygen—is sufficient to prevent chilling injury in peach fruit. The study identifies the CO₂-induced transcription factor PpERF17 as a key activator of the JA and GABA biosynthetic pathways, and demonstrates that it interacts with another regulator, PpMYC2.1, forming a positive feedback loop that strengthens fruit cold resistance.

The researchers treated ‘Zhonghuashoutao’ peach fruit under various controlled atmospheres and found that 10% CO₂ significantly reduced internal browning after cold storage. Elevated CO₂ triggered the expression of PpERF17, which directly bound to and activated the promoters of Pp13S-LOX, PpAOS, PpOPR3, and PpGAD, leading to higher accumulation of JA and GABA. Transient overexpression of PpERF17 in peach and stable transformation in tobacco both enhanced cold tolerance, decreased hydrogen peroxide and malondialdehyde levels, and increased JA and GABA content. Further assays revealed that PpMYC2.1 activates the same target genes and also induces PpERF17, creating two interconnected positive feedback loops—PpMYC2.1–JA and PpMYC2.1–PpERF17–JA. Application of methyl jasmonate (MeJA) further validated that JA accumulation upregulates both PpERF17 and PpMYC2.1, confirming a self-reinforcing defense circuit. The proposed model shows that CO₂ sensing triggers this molecular cascade, culminating in synergistic activation of JA and GABA biosynthesis to alleviate chilling injury and maintain fruit quality.

“Our findings reveal that a simple change in the storage atmosphere can activate a natural defense network within the fruit itself,” said Prof. Changjie Xu, corresponding author of the study. “The CO₂-induced transcription factor PpERF17 acts as a molecular switch that boosts the biosynthesis of JA and GABA, two critical protectants against cold stress. This not only provides new insights into postharvest physiology but also offers an environmentally friendly approach to fruit preservation without chemical additives.”

This discovery presents a sustainable strategy for the postharvest storage of peaches and potentially other fruits sensitive to cold injury. By leveraging natural CO₂ regulation, fruit producers can reduce losses, minimize chemical treatments, and extend storage life while maintaining flavor and quality. Moreover, understanding the PpERF17–PpMYC2.1–JA/GABA feedback loops opens avenues for genetic or biotechnological approaches to enhance chilling tolerance across horticultural species. Future research will focus on identifying upstream CO₂ sensors such as MPK4 and exploring whether similar pathways operate in apples, grapes, and other perishable fruits.

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References

DOI

10.1093/hr/uhaf014

Original Source URL

https://doi.org/10.1093/hr/uhaf014

Funding information

This work was supported by the National Key Research and Development Program of China (2022YFD2100103), Ningbo Key Research and Development Program (2022Z179), Zhejiang Provincial Cooperative Extension Project of Agricultural Key Technology (2022XTTGGP01), and the 111 Project (B17039).

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.