Refreshing perspectives in a warming world: understanding the cold adaptation strategies of plants – an introduction to a Virtual Issue

Short abstract

This Commentary introduces the Virtual Issue ‘Plant cold hardiness’ that includes the following papers: Campos‐Arguedas et al. (2026), Chamberlain & Wolkovich (2021), Chang et al. (2021), Charra‐Vaskou et al. (2026), Charrier et al. (2015, 2026), Dahro et al. (2022), D'Andrea et al. (2019), Ding et al. (2019), Grossman (2023), Ingram et al. (2025), Kirchhof et al. (2025), Kovaleski (2024), Larter et al. (2026), Mayer & Charron (2021), Mayr et al. (2020), Ming et al. (2021), Shikata et al. (2026), Vitasse et al. (2025), Wang et al. (2025). Access the Virtual Issue at www.newphytologist.com/virtualissues.

Low temperature is a major environmental constraint limiting plant survival. The adaptation of plants to low temperatures in relation to their morphology, productivity and geographical distribution has been well‐studied, and we have gained many insights, from the physics of ice nucleation to species distribution, including the molecular drivers of cold acclimation (Raunkiaer, 1904; Charrier et al., 2023). Nevertheless, global change is jeopardizing the ability of plants to withstand low temperatures, and this poses new challenges for understanding plant cold adaptation and for developing strategies to maintain ecosystem function and agricultural productivity.

During the 13^th International Plant Cold Hardiness Seminar (IPCHS) in Clermont‐Ferrand (France), our scientific community brought together recent advances on low‐temperature adaptation in plants during eight sessions: (1) temperature sensing, signal transduction and cascade signaling pathway; (2) cold acclimation and deacclimation in a warming world: genetic and physiological approaches; (3) ice nucleation and propagation; (4) freezing behaviors (extracellular freezing vs supercooling); (5) late and early frost: changing plant phenology; (6) the migration of cold distribution edges in a warming climate; (7) living in the plant edge: psychrophilic microbes; and (8) hot and cold: insights of multistress. This Virtual Issue compiles some of the key results published in New Phytologist that were presented at the conference, along with other recent papers on the topic. These results reflect the wide array of structural, phenological, biochemical and molecular strategies that plants have evolved to survive at subzero temperatures.

Frost and drought resistance are two important factors in determining species distribution at range margins (Baranger et al., 2024). Larter et al. (2026) compiled a substantial global database on drought and frost resistance to study the evolutionary trade‐offs associated with these resistances. Their analysis revealed a weak trade‐off, with only a few species (e.g. junipers) being resistant to both stress factors. These resistant species are often distributed at high elevations and have evergreen leaf phenology (Chang et al., 2021). These species are also usually resistant to summer embolism but less so to winter embolism; thus, they can recover from nearly total loss of hydraulic conductivity (Mayr et al., 2020). Furthermore, lower statured tree saplings and shrubs, typically protected by midwinter snow cover, are anticipated to face harsher conditions as the snow‐free period extends due to climate change. Charra‐Vaskou et al. (2026) quantified the resistance and recovery (i.e. the two components of the resilience) of the hydraulic system and living cells in a wide range of woody species from various functional groups. By monitoring stem diameter during winter, they developed resilience indexes that were used to predict growth and survival rates under reduced snow conditions at high elevations. These studies emphasize that cold adaptation should be considered together with drought resistance and hydraulic resilience, particularly under future climate scenarios.

In the last decades, another emerging risk is related to late spring frost events, which occur when spring phenology advances faster than late spring freezes due to warming (Chamberlain & Wolkovich, 2021; Kirchhof et al., 2025). Late spring frosts notably affect beech trees, potentially impacting their health and carbon status (D'Andrea et al., 2019). By coupling phenological models, high‐resolution climate and tree‐ring data, Vitasse et al. (2025) identified damaging late spring frosts on tree rings chronology by comparing frost‐sensitive beech with cold‐hardy evergreen Norway spruce. The tree‐ring approach thus defines bioindicators of past late spring frost events, offering an alternative to climatic and phenological records.

However, the initiation of freezing (i.e. ice nucleation) in plants is highly stochastic in relation to internal and external ice‐nucleating agents (Lamacque et al., 2026). To characterize frost hazards fully, Kirchhof et al. (2025) examined freeze thresholds in the literature and found that model‐based studies reported consistently higher (less‐hardy) thresholds than empirical measurements did. This discrepancy may lie in temperature measurement, phenological stage and also the intrinsic ice nucleation activity within plant tissues (Charrier et al., 2015). To understand the limits of supercooling in a liquid under negative pressure (i.e. under tension), Ingram et al. (2025) compared the freezing point of extracted sap to that of stems at different water potentials. They concluded that supercooling under tension is a purely physical phenomenon and that nucleation is initiated at the interface between the liquid sap and xylem tissue in relation to cell wall properties.

To better understand and predict the determinants of frost risk in a changing climate, modeling is a valuable tool. For decades, models have been developed along a continuum between empirical and process‐based models (Charrier et al., 2026). By establishing a link between phenological processes (i.e. endodormacy induction and release, ecodormancy release) and cold acclimation and deacclimation, models can predict frost vulnerability based on meteorological variables and phenological processes (Kovaleski, 2024). Conversely, cold hardiness models can also improve prediction of budbreak and associated frost risks in grapevine (Campos‐Arguedas et al., 2026).

In an unprecedented climate context, improving the accuracy of cold hardiness models requires integrating additional processes into an integrative biology framework (Grossman, 2023; Charrier et al., 2026) to maximize realism and genericity. Articles in this Virtual Issue discuss relevant approaches, such as the accumulation of solutes (e.g. soluble sugars, raffinose, proline and other amino acids), which lower the freezing point (Dahro et al., 2022). This approach is thus compatible with tree weakening via damage accumulation and the stress resistance–growth trade‐off (D'Andrea et al., 2019; Charra‐Vaskou et al., 2026). The cold resistance models do not account for cell wall properties, despite their potential to compensate for mechanical and osmotic strains. Cell walls are highly dynamic structures that continuously remodel in response to developmental and environmental cues (Shikata et al., 2026). Remodeling the composition in polysaccharide (pectins and hemicellulose) strengthens the mechanical resistance to the expansion of extracellular ice. These changes influence ice nucleation, tissue connectivity and freezing tolerance. Cold‐induced changes in cell wall properties are not fully reversible and can create a sort of memory that primes plant tissue for a more efficient response to future stimuli.

This structural memory differs from epigenetic memory, which is modulated by DNA‐methylation and also primes plants for future stress, including cold stress (Mayer & Charron, 2021). We are gaining insight into how the changes in transcriptional responses to environmental stimuli regulate cold tolerance in various plant types such as the grass Brachypodium distachyon (Mayer & Charron, 2021) or the lemon tree Citrus sp. (Wang et al., 2025). This raises the question of how to integrate this developing knowledge into the next generation of models based on the perception of environmental signals and their translation into cold acclimation and deacclimation (Charrier et al., 2026). The molecular cascade associated with cold acclimation can be broken down into several key steps: signal perception, signal transduction by second messengers, transcriptional regulation and functional response (Ding et al., 2019). Recent molecular studies have highlighted the key role of various factors including calcium and phytochromes in perception, phosphorylation cascades, calcium signaling and hormonal signaling in signal transduction and the Inducer of CBF Expression (ICE)‐C‐repeat Binding Factor (CBF)‐Cold Regulated genes (COR) pathway in expression (Ding et al., 2019; Ming et al., 2021; Dahro et al., 2022). Activation of COR genes leads to the production of protective molecules, such as nonstructural (protective proteins, dehydrins or antifreeze proteins, solutes) and structural components (cellulose and pectins in the cell wall). Ultimately, integrating these molecular processes into predictive models represents an important future direction for plant cold biology.

Despite global warming, low temperatures still significantly impact the productivity of agroecosystems. Furthermore, the complexity of the processes involved highlights the need for interdisciplinary research, which is currently in development. We anticipate that the IPCHS in Comodoro Rivadavia, Argentina, in August 2027, will continue to advance this rapidly evolving field by fostering interdisciplinary collaborations across scales, from molecules to ecosystems.

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