Maize is one of the world’s most important crops, yet it is notoriously fragile when temperatures drop. As a C4 plant, its photosynthetic machinery evolved for warmth, and even a brief cold snap can stunt seedlings and slash yields. Now, a team of researchers at the HUN-REN Centre for Agricultural Research in Martonvásár, Hungary, has uncovered something remarkable: the amount of light a young maize plant receives while it acclimates to cool temperatures determines how it will respond days later to an entirely different threat, salt stress. The finding, published in Plant Cell Reports, reveals that a plant’s environmental history is written into its metabolism in ways that span every organ, from leaf to root.
The experiment was elegantly simple in design. Young maize seedlings of the MV350 hybrid were grown hydroponically under controlled conditions, then exposed to an acclimating temperature of 15 degrees Celsius for three days. Crucially, one group experienced this cool period under normal growth light of 250 micromoles per square metre per second, while a second group was shaded at just 50 micromoles. Afterward, the plants faced either a severe cold challenge at 5 degrees Celsius or a salinity treatment with 0, 50, or 150 millimolar sodium chloride. The researchers then dissected the response at every level: chlorophyll fluorescence to track photosynthetic health, gene expression analysis by RT-qPCR, and an impressive metabolomics arsenal including GCxGC-TOF mass spectrometry for primary metabolites, untargeted LC-MS for conjugated compounds, and targeted profiling of hormones and polyamines.
The physiological measurements told a subtle story. The maximum quantum efficiency of Photosystem II, measured as Fv/Fm, barely declined after salt treatment, indicating that neither acclimation nor salinity inflicted irreversible damage. But the light-adapted quantum yield, Y(II), dropped significantly in plants exposed to 150 millimolar salt, and the decrease was more pronounced in plants that had previously been cold-acclimated. In parallel, the regulated non-photochemical quenching parameter Y(NPQ) rose, especially in cold-treated plants. Together, these signals suggest that moderate cold had sensitised the photosynthetic apparatus to subsequent osmotic stress, activating protective energy-dissipation mechanisms at the cost of photosynthetic efficiency, a classic trade-off seen in stress-primed plants.
The gene expression data revealed three striking patterns. First, the light-signalling genes ZmCOP1 and ZmHY5 were expressed predominantly in leaves and were strongly suppressed by low temperature, confirming that the light-sensing machinery itself responds to cold. Second, stress-responsive genes such as ZmERF33, ZmPMP3-1, and the sugar transporter ZmSWEET1a showed pronounced organ-specific regulation that depended on both temperature and light. Third, the polyamine oxidase gene ZmPAO1 remained comparatively active in stems even as it declined elsewhere, hinting that the stem is not merely a passive conduit but an active participant in coordinating the plant’s systemic stress response, possibly through redox signalling, since polyamine oxidases generate hydrogen peroxide as a by-product.
When salt was applied after cold acclimation, the transcriptional echoes of the earlier treatment were still audible. Most of the tested genes, including ZmPAO1, ZmPMP3-5, ZmZIP1, and ZmPIF1, were reduced under increasing salinity, but the magnitude and pattern of these changes depended on whether the plants had been light- or shade-acclimated. The most dramatic interaction appeared in ZmDREB80, a dehydration-responsive element-binding transcription factor. In shade-acclimated plants exposed to moderate salt, ZmDREB80 expression surged, particularly in stems, while in light-acclimated plants no such increase was detected. This single gene captured the essence of the study: the light conditions during a cold episode three days earlier had selectively reprogrammed how the plant would transcriptionally confront a completely different stressor.
The metabolomics results were equally compelling. Cold acclimation in the light triggered substantial accumulations of soluble sugars and amino acids in leaves, while the same cold period in shade produced far weaker changes. Under severe cold, sugars paradoxically decreased in light-acclimated leaves but increased in stems and roots, most likely reflecting reduced synthesis in the photosynthetic tissue combined with active export of photoassimilates to other organs. Amino acid pools behaved similarly, with root amino acid accumulation in the cold occurring only when acclimation had taken place in the light. The polyamine putrescine and its catabolite 1,3-diaminopropane rose significantly in leaves and stems, but only under light-acclimated conditions, while spermidine and spermine increased in the roots of light-acclimated plants under severe cold.
Hormone profiling added another layer of complexity. Abscisic acid, the central stress hormone, increased under both acclimating and severe cold, with the parallel rise in its degradation products confirming that the increase came from enhanced biosynthesis rather than slowed breakdown. Interestingly, the light conditions shifted where the abscisic acid accumulated: mainly in leaves and stems of light-acclimated plants, but in roots of shade-acclimated ones. Salicylic acid declined in leaves and roots during cold but rose in the stem under severe cold, while jasmonic acid and its active isoleucine conjugate dropped across all organs under severe cold, an unexpected response given that most studies report jasmonate accumulation during chilling.
Perhaps the most consequential finding emerged from the principal component analysis of primary metabolites in salt-treated plants. In every organ, the light-acclimated, salt-treated group separated clearly from the shade-acclimated and non-acclimated salt-treated groups, which clustered together. The loading vectors pointed to coordinated shifts in TCA-cycle intermediates such as citrate, malate, succinate, and fumarate, in soluble sugars, and in nitrogen-related metabolites including glutamate, asparagine, and citrulline. In leaves, photorespiration and redox compounds like glycine and serine dominated; in stems, phenylalanine and coumaric acid, precursors of the phenylpropanoid pathway, were decisive; in roots, asparagine and succinate pointed to nitrogen storage and respiration. This is the signature of a systemic, pathway-level reorganisation rather than a scatter of isolated metabolite changes.
The phenylpropanoid data reinforced the protective narrative. Chlorogenic acids increased in leaves of salt-treated plants in a concentration-dependent manner, more strongly in light-acclimated plants, consistent with their role as antioxidants and redox buffers. Ferulic acids rose more prominently in the roots of light-acclimated plants under high salinity, suggesting reinforced cell wall cross-linking at the soil-plant interface where ionic stress is first perceived. Feruloyl-putrescine conjugates, which combine polyamine and phenolic chemistry, accumulated almost exclusively in roots, hinting at a specialised strategy for wall reinforcement and ion flux regulation. Meanwhile, salt-induced accumulations of sugars, amino acids, and jasmonate signalling were actually dampened in light-acclimated plants, suggesting a shift toward energy-efficient osmotic regulation and reduced stress perception.
The authors are careful to note the limits of their interpretation. Because salt was applied immediately after the cold acclimation period, the design cannot distinguish a persistent acclimated physiological state from stress memory in the strict mechanistic sense, and the metabolic changes are indicators of altered physiological states rather than direct proof of mechanisms governing membrane stability or ion homeostasis. Still, the implications are significant. This is the first study to systematically map the organ-specific and systemic regulatory network underlying the light-temperature-salt interaction in maize, and it demonstrates that cold acclimation under sufficient light establishes a whole-plant, organ-coordinated state that reshapes subsequent salinity responses. As maize cultivation pushes northward into regions where sudden cold snaps and saline soils increasingly coexist, understanding how a plant’s environmental history primes its metabolism could become a powerful tool for breeders seeking resilient hybrids.
Subject of Research: Light-dependent cold acclimation and its effects on salt stress responses in maize
Article Title: Light-defined cold acclimation reprograms organ-specific metabolic and transcriptional landscapes for salt stress responses in maize
Article References: Benczúr, K., Gholizadeh, F., Pál, M., Janda, T., Hamow, K. Á., Dernovics, M., Nagy, K., Majláth, I., Darko, E., Wu, J., Van Le, N., & Szalai, G. (2026). Light-defined cold acclimation reprograms organ-specific metabolic and transcriptional landscapes for salt stress responses in maize. Plant Cell Reports, 45(10), Article 320. https://doi.org/10.1007/s00299-026-04008-z
Image Credits: AI Generated
DOI: 10.1007/s00299-026-04008-z
Keywords: maize, cold acclimation, salt stress, light signalling, metabolomics, gene expression, abscisic acid, polyamines, phenylpropanoids, photosynthesis, organ-specific response, stress priming
News Source: Alan Morgan. (October 5, 2026). Sunlight During Cold Prepares Maize for Salt Stress, Study Finds. Scienmag.
