Aug 2026· Plant physiology and biochemistry : PPB· Vol 238, pp.
111665
· 0 citations· 80 references
Medicine
TL;DR
This study deepens the mechanistic understanding of cold tolerance in melon seedlings, confirms that flavonoids and GSH metabolites act as core components facilitating plant stress adaptation, and supplies valuable genetic and metabolic resources to accelerate the breeding of cold-tolerant melon varieties.
Abstract
Early-spring cultivation enables melons to be marketed ahead of the regular season, yet cold stress during this critical growth stage severely suppresses seedling growth and development, ultimately causing substantial yield losses. To date, the physiological shifts, molecular regulatory cascades and metabolic reprogramming triggered by cold stress in melon seedlings have not been fully characterized. In this work, we combined physiological assays, transcriptome, and metabolome profiling to dissect cold-responsive regulatory networks at the seedling stage using two melon inbred lines with divergent cold tolerance: NM3 (cold-tolerant, Netted muskmelon) and M40-1 (cold-sensitive, Hami melon). Our phenotypic and physiological data revealed that cold treatment drastically retarded seedling growth and triggered leaf wilting, alongside elevated reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations in both inbred lines. Relative to cold-sensitive M40-1, NM3 maintained superior growth performance, accompanied by greater accumulation of sensitive and stronger antioxidant enzymatic activities. Transcriptome comparison uncovered sets of differentially expressed genes (DEGs) enriched in phenylalanine metabolism, flavone/flavonol/isoflavonoid biosynthesis, glutathione (GSH) metabolism and fatty acid metabolic pathways. Metabolite quantification further indicated that flavonoids, soluble sugars, lipids and terpenoids accumulated to markedly higher abundances in NM3 after 6 h of cold treatment. Weighted gene co-expression network analysis (WGCNA) integrating transcriptomic and metabolomic datasets pinpointed hub genes and signature metabolites tightly linked to cold tolerance, such as MELO3C017481 (encoding xyloglucan endotransglucosylase-hydrolase 23, XTH23) and MELO3C021100 (encoding heat shock protein 70, HSP70), as well as numerous transcription factors (TFs) and functional genes participating in sugar and flavonoid metabolism. Integrated transcriptomic and metabolomic profiling further verified that genes and metabolites governing flavonoid synthesis and GSH metabolism serve as central modulators of melon cold tolerance. We also found that cold stress robustly activated GSH-related gene expression, and exogenous GSH supplementation effectively relieved cold-induced seedlings injury. Collectively, this study deepens our mechanistic understanding of cold tolerance in melon seedlings, confirms that flavonoids and GSH metabolites act as core components facilitating plant stress adaptation, and supplies valuable genetic and metabolic resources to accelerate the breeding of cold-tolerant melon varieties.
Cold stress is a major environmental constraint limiting wheat productivity worldwide. Although numerous cold-responsive pathways have been identified, the molecular basis of differential cold tolerance among genetically related wheat lines remains poorly understood. In this study, two wheat sibling lines derived from a single progeny plant of the same parental cross, Luyan951 (cold-tolerant) and Luyan955 (cold-sensitive), were employed to investigate the regulatory mechanisms of cold adaptation through integrated physiological, transcriptomic, and metabolomic analyses.
Physiological assays revealed that Luyan951 exhibited markedly enhanced cold tolerance, with a survival rate of 52.67% following cold treatment compared with 20.67% in Luyan955. This enhanced tolerance was accompanied by 1.90–2.41-fold greater increases in antioxidant enzyme activities (SOD, CAT, and POD) and 1.84–4.50-fold greater accumulation of proline and soluble sugars relative to Luyan955, along with substantially lower MDA accumulation. Transcriptomic and metabolomic analyses identified phenylpropanoid biosynthesis and jasmonic acid (JA) signaling as key pathways associated with cold adaptation. Compared with Luyan955, cultivar Luyan951 exhibited stronger activation of these pathways under cold stress. Key genes involved in phenylpropanoid biosynthesis (
CAD
, and
4CL
) and JA signaling (
JAZ
,
MYC2
) were significantly upregulated in Luyan951, as confirmed by qRT-PCR. Bioinformatic analyses further suggested that AP2/ERF transcription factors may act as upstream regulators of these pathways. Furthermore, subcellular localization and transcriptional activation experiments confirmed the nuclear localization and transactivation function of three AP2/ERF genes (
TraesCS5D02G318400
,
TraesCS6A02G381000
,
TraesCS6D02G366100
).
Our findings indicate that the phenylpropanoid biosynthesis pathway plays a significant role in the cold tolerance of wheat, and together with the jasmonic acid signaling pathway, it forms a crucial regulatory network. This network promotes the scavenging of reactive oxygen species, maintains osmotic homeostasis, and stabilizes metabolism under low-temperature stress. Integrated analyses further suggest that this network may be coordinated by upstream ERF transcription factors. These findings provide comprehensive insights into the molecular mechanisms of wheat cold adaptation and offer valuable candidate genes and pathways for the genetic improvement of cold tolerance in wheat.
Wen-Jie Zheng, Peng Li, Xin Sun et al.· Frontiers in Plant Science· 0 citations
Freezing injury during winter is a critical abiotic stress that severely impacts the growth, development and, fruit quality of deciduous fruit trees. Cold tolerance can be induced through seasonal cold acclimation, which involves coordinated adjustments in tissue structure, physiology, and biochemistry driven by natural low-temperature, with distinct strategies across plant species. However, the cold-tolerant mechanisms of pear trees during cold acclimation remain poorly understood. Here, one-year-old branches of 10 pear cultivar germplasms were evaluated for cold tolerance based on the semi-lethal low temperature (LT50), with three biological replicates across two consecutive experimental years (2021-2022). LT50 values varied significantly among these materials, ranging from -42.43 ℃ to -32.59 ℃ and exhibited a highly significant negative correlation with field freezing injury indices (r = 0.86091, p < 0.0001). Subsequently, integrating anatomical structure observation, physiological index determination, metabolomics, and transcriptomics (with three biological replicates, each with three technical replicates for all omics and molecular experiments), we compared the low-temperature stress responses of cold-resistant 'Shanli' and cold-sensitive 'Hanhong', with statistical validation via one-way ANOVA, Duncan's multiple range test, Pearson's correlation analysis, and gray relational analysis. The results demonstrated that with decreasing temperature, the xylem ratio and lignin content in 'Shanli' branches increased markedly compared to 'Hanhong', and overwintering capability was correlated with branch lignin synthesis (r = -0.7783, p < 0.01). Cold acclimation enhanced lignin accumulation in 'Shanli' branches by increasing guaiacyl (G) and syringyl (S) units, associated with increased activities of key enzymes (shikimate hydroxycinnamoyl transferase (HCT), caffeoyl shikimate esterase (CSE), ferulate 5-hydroxylase (F5H), cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD)) and critical intermediate metabolites (phenylalanine, ferulic acid, sinapic acid) in the phenylpropanoid pathway. Transcriptomic analysis identified 75 differentially expressed genes (DEGs) (|log2FoldChange|≥1 and FDR < 0.05) mapped to the phenylpropanoid pathway. Five potential key genes from the HCT, CSE, F5H, CAD and POD gene families, together with their co-expressed genes (such as ERF105-like) were identified as potentially associated with lignin content and composition modulationce in pear branches, providing novel insights into the regulatory network of lignin synthesis under natur under cold stress. Our findings reveal relationships between lignin synthesis pathways and cold toleranal low-temperature stress and candidate genes for cold-resistant pear breeding.
Ying Zhao, Xingkai Yan, Ming Lu et al.· BMC Plant Biology· 0 citations
Seedling cold stress is a major abiotic constraint to rice production, and mining elite cold-tolerant genes from wild rice represents a pivotal strategy to enhance cold tolerance in cultivated rice (Oryza sativa L.). Dongxiang wild rice (DXWR, Oryza rufipogon Griff.) is a valuable genetic resource with robust cold tolerance. However, the underlying molecular regulatory mechanisms remain poorly characterized, and the identification of its elite cold-tolerant genes is still limited. In this study, by integrating high-density gene chip, comparative transcriptomic and functional correlation analyses, we identified OsMYBAS1, an R2R3-MYB transcription factor, as a key regulator conferring cold tolerance of DXWR. The Osmybas1 mutants exhibited drastically reduced survival rate under cold stress, accompanied by excessive reactive oxygen species (ROS) accumulation and significant decreases in antioxidant enzyme activity. Comparative transcriptome analysis of the mutants identified 545 cold-induced differentially expressed genes. Functional enrichment analysis indicated that pathways involved in hormone metabolism and signaling were among the most significantly enriched categories, highlighting their key roles in the cold response. Further detection revealed that endogenous abscisic acid (ABA) and jasmonic acid (JA) levels were markedly down-regulated in Osmybas1 mutants after cold treatment, while exogenous ABA or methyl jasmonate (MeJA) application rescued the cold-sensitive phenotype and reversed the abnormal expression of cold-responsive genes. This study suggested that OsMYBAS1 positively regulated seedling cold tolerance by mediating the coordinated modulation of ABA/JA signaling and ROS homeostasis. These findings elucidated an important molecular mechanism underlying DXWR cold tolerance and provided a novel gene target and theoretical foundation for cold-tolerant rice molecular breeding.
Xinjian Zou, Hong-Guang Xie, Juan Ye et al.· Rice· 0 citations
In natural environments, plants are often exposed to multiple abiotic stresses simultaneously. Their combined effects usually cause more severe damage than a single stress. However, little is known about the coordinated response mechanisms of cool-season turfgrass to combined drought and cold stress. Two accessions of Annual bluegrass (Poa annua L.) with contrasting stress tolerance were used in this study: Huangzhong (HZ, tolerant) and Zhouqu (ZQ, sensitive). Physiological phenotyping, stomatal behavior observation, transcriptomics, and metabolomics were integrated to systematically compare their responses to drought, cold, and combined stress. The aim was to reveal the physiological and molecular regulatory differences between the two accessions and to identify the core pathways underlying combined stress responses. Results showed that combined stress significantly aggravated photosynthetic inhibition and oxidative damage. The sensitive accession ZQ exhibited much greater damage than the tolerant accession HZ. Transcriptomic and metabolomic analyses identified 11,440 and 13,631 differentially expressed genes, as well as 2585 and 2642 differentially accumulated metabolites in HZ and ZQ, respectively, under combined stress. Weighted gene co-expression network analysis (WGCNA) identified a core module (MEred) significantly correlated with photosynthetic efficiency and antioxidant capacity, with HCT and PAL as candidate hub genes. Meanwhile, multi-omics integration revealed that phenylpropanoid biosynthesis was strongly activated only in the tolerant accession HZ, and clustering analysis further demonstrated that the molecular profiles under combined stress closely resembled those under drought stress alone. This study provides new insights into the coordinated regulatory network of cool-season turfgrass in response to multiple abiotic stresses. It also offers potential targets for genetic improvement and functional utilization of stress-tolerance genes.
Juanxia Li, Fu Ran, Chunling Deng et al.· Plant physiology and biochem...· 0 citations
Combined stress more strongly inhibited plant height, stem diameter, fresh weight, net photosynthetic rate, and transpiration rate than single stresses, and insights into alfalfa adaptation to multiple abiotic stresses are provided.
Lihe Su, Yongcheng Chen, Xudong Zhang et al.· Journal of Agricultural and...· 0 citations
Pyrus betulifolia Bunge is a salt‑tolerant rootstock for pear, but its salt‑tolerance mechanisms remain largely unknown. In this study, P. betulifolia seedlings were subjected to graded NaCl stress at concentrations of 0 (CK), 50 (T1), 100 (T2), and 200 (T3) mM. We integrated phenotypic observation, physiological assessment, transcriptomic profiling, and functional gene validation to systematically elucidate its salt tolerance mechanisms. Salt stress inhibited seedling growth and root traits in a concentration-dependent manner, and T3 caused the most severe damage. Osmotic solutes responded differentially: soluble sugars peaked under T2, while proline peaked under T3. Antioxidant enzymes showed tissue-specific biphasic responses and declined after prolonged T3 stress. Meanwhile, chlorophyll and photosynthesis decreased, whereas anthocyanin increased, indicating a metabolic shift from photosynthesis to photoprotection. Transcriptome analysis revealed distinct responses depending on stress intensity: mild stress induced membrane lipid remodeling, moderate stress activated circadian rhythm and hormone signaling, and severe stress enhanced phenylpropanoid biosynthesis and thiamine metabolism. Gene Set Enrichment Analysis (GSEA) further highlighted progressive enrichment of phenylpropanoid biosynthesis, heme binding, and oxidoreductase activity. Weighted Gene Co‑expression Network Analysis (WGCNA) identified a blue module significantly positively correlated with root traits, from which the hub gene PbSTY46 was identified. Functional validation via overexpression, loss‑of‑function mutants, and pharmacological interventions (MeJA/DIECA) confirmed that PbSTY46 acts through JA signaling to enhance antioxidant enzyme activities and thereby confer salt tolerance. Collectively, P. betulifolia adopts a "survival‑first" strategy that coordinates growth arrest, osmotic homeostasis, and ROS scavenging. These findings establish PbSTY46 as a key regulator that links JA signaling to antioxidant defense. Thus, PbSTY46 represents a promising candidate for marker‑assisted breeding of salt‑tolerant pear cultivars.
Ning Yan, Wei-Chi Wang, Aihao Zhao et al.· Plant Science· 0 citations