Cold Response Research Articles

Transcriptome response of diatom Skeletonema marinoi to lower temperature

Temperature is an important environmental factor for phytoplankton. Phytoplankton growth, metabolism, biodiversity, productivity, and distribution are influenced by temperature-driven nutrient stratification and mixing, as well as species’ optimal growth temperatures. There have been a number of studies focused on physiological and biochemical mechanisms of environmental–biological interactions in diatoms, yet the underlying transcriptional regulators remain limited. Here, we performed an RNA-seq-based gene expression analysis to explore the Skeletonema marinoi (isolated from Jiaozhou Bay of Qingdao, 36.13°N, 120.16°E on July 5th, 2013) cellular responses induced by low temperature (12 °C). Digital gene expression profiling of S. marinoi generated 20,319 unigenes, of which 573 differentially expressed genes appeared in the low-temperature treatment group. According to GO and KEGG enrichment analysis, different genes were involved in ten metabolic and biosynthesis pathways: ribosome, lipid, porphyrin, and chlorophyll metabolism showed strong transcriptional cold tolerances. The regulation of genes related to translation processes (e.g., pentatricopeptide repeat), fatty acid metabolism (e.g., acyl-CoA synthetase), and photosynthesis (e.g., porphyrin enzymes) provides new molecular-level insight into cold stress responses in eukaryotic marine phytoplankton. Our study suggests that this Skeletonema species could be a potential candidate for understanding the fate of thermo-sensitive diatom communities and oceanic ecosystems facing climate change.

VvJAZ13 Positively Regulates Cold Tolerance in Arabidopsis and Grape.

Cold stress adversely impacts grape growth, development, and yield. Therefore, improving the cold tolerance of grape is an urgent task of grape breeding. The Jasmonic acid (JA) pathway responsive gene JAZ plays a key role in plant response to cold stress. However, the role of JAZ in response to low temperatures in grape is unclear. In this study, VvJAZ13 was cloned from the 'Pinot Noir' (Vitis vinefera cv. 'Pinot Noir') grape, and the potential interacting protein of VvJAZ13 was screened by yeast two-hybrid (Y2H). The function of VvJAZ13 under low temperature stress was verified by genetic transformation. Subcellular localization showed that the gene was mainly expressed in cytoplasm and the nucleus. Y2H indicated that VvF-box, VvTIFY5A, VvTIFY9, Vvbch1, and VvAGD13 may be potential interacting proteins of VvJAZ13. The results of transient transformation of grape leaves showed that VvJAZ13 improved photosynthetic capacity and reduced cell damage by increasing maximum photosynthetic efficiency of photosystem II (Fv/Fm), reducing relative electrolyte leakage (REL) and malondialdehyde (MDA), and increasing proline content in overexpressed lines (OEs), which played an active role in cold resistance. Through the overexpression of VvJAZ13 in Arabidopsis thaliana and grape calli, the results showed that compared with wild type (WT), transgenic lines had higher antioxidant enzyme activity and proline content, lower REL, MDA, and hydrogen peroxide (H2O2) content, and an improved ability of scavenging reactive oxygen species. In addition, the expression levels of CBF1-2 and ICE1 genes related to cold response were up-regulated in transgenic lines. To sum up, VvJAZ13 is actively involved in the cold tolerance of Arabidopsis and grape, and has the potential to be a candidate gene for improving plant cold tolerance.

Phylogenomic profiles of whole-genome duplications in Poaceae and landscape of differential duplicate retention and losses among major Poaceae lineages

Poaceae members shared a whole-genome duplication called rho. However, little is known about the evolutionary pattern of the rho-derived duplicates among Poaceae lineages and implications in adaptive evolution. Here we present phylogenomic/phylotranscriptomic analyses of 363 grasses covering all 12 subfamilies and report nine previously unknown whole-genome duplications. Furthermore, duplications from a single whole-genome duplication were mapped to multiple nodes on the species phylogeny; a whole-genome duplication was likely shared by woody bamboos with possible gene flow from herbaceous bamboos; and recent paralogues of a tetraploid Oryza are implicated in tolerance of seawater submergence. Moreover, rho duplicates showing differential retention among subfamilies include those with functions in environmental adaptations or morphogenesis, including ACOT for aquatic environments (Oryzoideae), CK2β for cold responses (Pooideae), SPIRAL1 for rapid cell elongation (Bambusoideae), and PAI1 for drought/cold responses (Panicoideae). This study presents a Poaceae whole-genome duplication profile with evidence for multiple evolutionary mechanisms that contribute to gene retention and losses.

Integrated transcriptomic and metabolomic data reveal the cold stress responses molecular mechanisms of two coconut varieties.

Among tropical fruit trees, coconut holds significant edible and economic importance. The natural growth of coconuts faces a challenge in the form of low temperatures, which is a crucial factor among adverse environmental stresses impacting their geographical distribution. Hence, it is essential to enhance our comprehension of the molecular mechanisms through which cold stress influences various coconut varieties. We employed analyses of leaf growth morphology and physiological traits to examine how coconuts respond to low temperatures over 2-hour, 8-hour, 2-day, and 7-day intervals. Additionally, we performed transcriptome and metabolome analyses to identify the molecular and physiological shifts in two coconut varieties displaying distinct sensitivities to the cold stress. As the length of cold stress extended, there was a prominent escalation within the soluble protein (SP), proline (Pro) concentrations, the activity of peroxidase (POD) and superoxide dismutase (SOD) in the leaves. Contrariwise, the activity of glutathione peroxidase (GSH) underwent a substantial reduction during this period. The widespread analysis of metabolome and transcriptome disclosed a nexus of genes and metabolites intricately cold stress were chiefly involved in pathways centered around amino acid, flavonoid, carbohydrate and lipid metabolism. We perceived several stress-responsive metabolites, such as flavonoids, carbohydrates, lipids, and amino acids, which unveiled considerably, lower in the genotype subtle to cold stress. Furthermore, we uncovered pivotal genes in the amino acid biosynthesis, antioxidant system and flavonoid biosynthesis pathway that presented down-regulation in coconut varieties sensitive to cold stress. This study broadly enriches our contemporary perception of the molecular machinery that contributes to altering levels of cold stress tolerance amid coconut genotypes. It also unlocks several unique prospects for exploration in the areas of breeding or engineering, aiming to identifying tolerant and/or sensitive coconut varieties encompassing multi-omics layers in response to cold stress conditions.

Cold stress induces rapid gene-specific changes in the levels of H3K4me3 and H3K27me3 in Arabidopsis thaliana.

When exposed to low temperatures, plants undergo a drastic reprogramming of their transcriptome in order to adapt to their new environmental conditions, which primes them for potential freezing temperatures. While the involvement of transcription factors in this process, termed cold acclimation, has been deeply investigated, the potential contribution of chromatin regulation remains largely unclear. A large proportion of cold-inducible genes carries the repressive mark histone 3 lysine 27 trimethylation (H3K27me3), which has been hypothesized as maintaining them in a silenced state in the absence of stress, but which would need to be removed or counteracted upon stress perception. However, the fate of H3K27me3 during cold exposure has not been studied genome-wide. In this study, we offer an epigenome profiling of H3K27me3 and its antagonistic active mark H3K4me3 during short-term cold exposure. Both chromatin marks undergo rapid redistribution upon cold exposure, however, the gene sets undergoing H3K4me3 or H3K27me3 differential methylation are distinct, refuting the simplistic idea that gene activation relies on a switch from an H3K27me3 repressed chromatin to an active form enriched in H3K4me3. Coupling the ChIP-seq experiments with transcriptome profiling reveals that differential histone methylation only weakly correlates with changes in expression. Interestingly, only a subset of cold-regulated genes lose H3K27me3 during their induction, indicating that H3K27me3 is not an obstacle to transcriptional activation. In the H3K27me3 methyltransferase curly leaf (clf) mutant, many cold regulated genes display reduced H3K27me3 levels but their transcriptional activity is not altered prior or during a cold exposure, suggesting that H3K27me3 may serve a more intricate role in the cold response than simply repressing the cold-inducible genes in naïve conditions.

Healing response of cold recycled asphalt mixtures with electric arc furnace slag under microwave heating and re-compaction

The objective of the present paper is the assessment of the healing efficiency of a thermomechanical treatment (microwave heating and re-compaction) on cold recycled asphalt mixtures. The asphalt mixture specimens were fabricated with different electric arc furnace slag (EAFS) contents to improve the mixtures' microwave susceptibility. The healing response was then assessed in terms of recovery of their initial indirect tensile strength. Furthermore, statistical analysis was conducted by means of a three-way analysis of variance to determine the influence of temperature, re-compaction energy, and EAFS content on the healing capability of the mixtures. Although re-compaction and heating in the ranges studied do not themselves cause healing, the combination of both produced excellent healing performance. The optimal content of EAFS was established at 5% of EAFS over the weight of the asphalt mixture.

Cold-stress induced metabolomic and transcriptomic changes in leaves of three mango varieties with different cold tolerance

BackgroundMango (Mangifera indica L.) is grown in Hainan, Guangdong, Yunnan, Sichuan, and Fujian provinces and Guanxi autonomous region of China. However, trees growing in these areas suffer severe cold stress during winter, which affects the yield. To this regard, data on global metabolome and transcriptome profiles of leaves are limited. Here, we used combined metabolome and transcriptome analyses of leaves of three mango cultivars with different cold stress tolerance, i.e. Jinhuang (J)—tolerant, Tainung (T) and Guiremang No. 82 (G)—susceptible, after 24 (LF), 48 (MF) and 72 (HF) hours of cold.ResultsA total of 1,323 metabolites belonging to 12 compound classes were detected. Of these, amino acids and derivatives, nucleotides and derivatives, and lipids accumulated in higher quantities after cold stress exposure in the three cultivars. Notably, Jinhuang leaves showed increasing accumulation trends of flavonoids, terpenoids, lignans and coumarins, and alkaloids with exposure time. Among the phytohormones, jasmonic acid and abscisic acid levels decreased, while N6-isopentenyladenine increased with cold stress time. Transcriptome analysis led to the identification of 22,526 differentially expressed genes. Many genes enriched in photosynthesis, antenna proteins, flavonoid, terpenoid (di- and sesquiterpenoids) and alkaloid biosynthesis pathways were upregulated in Jihuang leaves. Moreover, expression changes related to phytohormones, MAPK (including calcium and H2O2), and the ICE-CBF-COR signalling cascade indicate involvement of these pathways in cold stress responses.ConclusionCold stress tolerance in mango leaves is associated with regulation of primary and secondary metabolite biosynthesis pathways. Jasmonic acid, abscisic acid, and cytokinins are potential regulators of cold stress responses in mango leaves.

Comparative physiology and transcriptome response patterns in cold-tolerant and cold-sensitive varieties of Solanum melongena

BackgroundClimate change has led to severe cold events, adversely impacting global crop production. Eggplant (Solanum melongena L.), a significant economic crop, is highly susceptible to cold damage, affecting both yield and quality. Unraveling the molecular mechanisms governing cold resistance, including the identification of key genes and comprehensive transcriptional regulatory pathways, is crucial for developing new varieties with enhanced tolerance.ResultsIn this study, we conducted a comparative analysis of leaf physiological indices and transcriptome sequencing results. The orthogonal partial least squares discriminant analysis (OPLS-DA) highlighted peroxidase (POD) activity and soluble protein as crucial physiological indicators for both varieties. RNA-seq data analysis revealed that a total of 7024 and 6209 differentially expressed genes (DEGs) were identified from variety “A” and variety “B”, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment of DEGs demonstrated that the significant roles of starch and sucrose metabolism, glutathione metabolism, terpenoid synthesis, and energy metabolism (sucrose and starch metabolism) were the key pathways in eggplant. Weighted gene co-expression network analysis (WGCNA) shown that the enrichment of numerous cold-responsive genes, pathways, and soluble proteins in the MEgrep60 modules. Core hub genes identified in the co-expression network included POD, membrane transporter-related gene MDR1, abscisic acid-related genes, growth factor enrichment gene DELLA, core components of the biological clock PRR7, and five transcription factors. Among these, the core transcription factor MYB demonstrated co-expression with signal transduction, plant hormone, biosynthesis, and metabolism-related genes, suggesting a pivotal role in the cold response network.ConclusionThis study integrates physiological indicators and transcriptomics to unveil the molecular mechanisms responsible for the differences in cold tolerance between the eggplant cold-tolerant variety “A” and the cold-sensitive variety “B”. These mechanisms include modulation of reactive oxygen species (ROS), elevation in osmotic carbohydrate and free proline content, and the expression of terpenoid synthesis genes. This comprehensive understanding contributes valuable insights into the molecular underpinnings of cold stress tolerance, ultimately aiding in the improvement of crop cold tolerance.

Comparative transcriptomic analysis of the brain-liver Axis reveals molecular mechanisms underlying acute cold stress response in Gynogenetic Mrigal carp

In this study, we produced a population of gynogenetic mrigal carp (Cirrhinus mrigala, GMCJ) through artificial gynogenesis using UV-inactivated white crucian carp spermatozoa. The GMCJ exhibited a faster growth rate and strong resistance to low temperatures, surviving natural winter conditions with temperatures below 10 °C. To gain a deeper insight into GMCJ's molecular response to acute cold stress (a decrease in water temperature from 26 °C to 14 °C within 1 h at a rate of 0.2 °C/min), we conducted a comparative analysis of the histology and transcriptomics of the brain-liver axis. Transmission electron microscopy of the heart tissues revealed that acute cold stress result in widened myofilament spacing, along with enlarged, deformed mitochondria that developed vacuoles and ruptured. We identified differentially expressed genes (DEGs) in the brain (2463 upregulated and 3288 downregulated genes) and liver (1210 upregulated and 1224 downregulated genes). Analysis of the DEGs' correlations indicated that major pathways involved in immunity, disease, metabolism, and growth were active and interconnected. KEGG functional analysis showed that the most enriched pathways in the brain-liver axis involved the regulation of the glucagon pathway, PI3K-Akt signaling pathway, and herpes simplex infection. Numerous genes associated with the nervous-endocrine system were activated, suggesting a coordinated response of the brain-liver axis to acute stress. These findings enhance our understanding of how farmed, particularly gynogenetic fish respond to acute cold stress.

Physiological and transcriptomic comparisons shed light on the cold stress response mechanisms of Dendrobium spp.

Dendrobium spp. comprise a group of tropical orchids with ornamental and medicinal value. Dendrobium spp. are sensitive to low temperature, and the underlying cold response regulatory mechanisms in this group are unclear. To understand how these plants respond to cold stress, we compared the transcriptomic responses of the cold-tolerant cultivar 'Hongxing' (HX) and the cold-sensitive cultivar 'Sonia Hiasakul' (SH) to cold stress. Chemometric results showed that the physiological response of SH in the later stages of cold stress is similar to that of HX throughout the cold treatment. Orthogonal partial least squares discriminant analysis (OPLS-DA) revealed that soluble protein content and peroxidase activity are key physiological parameters for assessing the cold tolerance of these two Dendrobium spp. cultivars. Additionally, weighted gene co-expression network analysis (WGCNA) results showed that many cold response genes and metabolic pathways significantly associated with the physiological indices were enriched in the 12 detected modules. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analyses of the 105 hub genes showed that Dendrobium spp. adapt to cold stress by regulating signal transduction, phytohormones, transcription factors, protein translation and modification, functional proteins, biosynthesis and metabolism, cell structure, light, and the circadian clock. Hub genes of the cold stress response network included the remorin gene pp34, the abscisic acid signaling pathway-related genes PROTEIN PHOSPATASE 2C (PP2C), SNF1-RELATED PROTEIN KINASE 2 (SnRK2), ABRE-BINDING FACTOR 1 (ABF1) and SKI-INTERACTING PROTEIN 17 (SKIP17), the Ca2+ signaling-related GTP diphosphokinase gene CRSH1, the carbohydrate-related gene STARCH SYNTHASE 2 (SS2), the cell wall biosynthesis gene CINNAMYL ALCOHOL DEHYDROGENASE (CAD7), and the endocytosis-related gene VACUOLAR PROTEIN SORTING-ASSOCIATED PROTEIN 52A (VPS52A). The cold-responsive genes and metabolic pathways of Dendrobium spp. revealed in this study provide important insight to enable the genetic enhancement of cold tolerance in Dendrobium spp., and to facilitate cold tolerance breeding in related plants.

Treatment outcome of coronal pulpotomy and indirect pulp capping in mature permanent molars with symptoms of moderate pulpitis: A randomized clinical trial.

This clinical trial aimed to compare the clinical success of coronal pulpotomy and indirect pulp capping (IPC) in managing symptomatic deep proximal caries in molars with moderate pulpitis over a 12-month period. A total of 108 vital mature permanent molars with moderate pulpitis were randomly allocated to the IPC (n = 54) or coronal pulpotomy group (n = 54). Dycal and Biodentine were used as pulp-capping materials, followed by composite restoration. The absence of periapical infection and asymptomatic teeth that positively responded to the cold pulp sensitivity test (only in IPC) was considered posttreatment success at 12 months. Data from the study were analyzed using the Chi-square test and Kaplan-Meier survival analysis. There was a statistically significant difference between preoperative symptoms and the cold pulp sensibility test response (P = 0.000), indicating an association between symptoms and pulp sensibility. The average remaining dentine thickness (RDT) value was 0.48 ± 0.5 mm, with no statistically significant difference found between the location of caries and RDT (P = 0.084, P > 0.05). Compared to the IPC group, the pulpotomy group had a greater number of patients at 12 months after treatment that required no intervention. The Kaplan-Meier survival analysis revealed that the mean survival duration for pulpotomy was 48 weeks, and for IPC, it was 42.3 ± 2.35 weeks. Coronal pulpotomy with Biodentine proved more effective in reducing symptoms, achieving radiographic success, and ensuring tooth survival compared to IPC with calcium hydroxide.

TaMAPK3 phosphorylates TaCBF and TaICE and plays a negative role in wheat freezing tolerance

Freezing temperature during overwintering often kills plants; plants have thus, developed a defense mechanism called ‘cold acclimation’, in which a number of genes are involved in increasing cell protection and gene expression. Mitogen-activated protein kinase (MAPK) controls proteins' activities by phosphorylation and is involved in numerous metabolic pathways. In this study, we identified the protein interaction between TaMAPK3 and the proteins in the cold response pathway, ICE41, ICE87, and CBFIVd-D9. The subcellular localization and bimolecular fluorescence complement (BiFC) assays revealed that these proteins interact in the nucleus or in the plasma membrane. Furthermore, MAPK3-mediated phosphorylation of ICE41, ICE87, and CBFIVd-D9 was verified using an in vitro phosphorylation assay. TaMAPK3-overexpressing transgenic Brachypodium showed a lower survival rate upon freezing stress and lower proline content during cold acclimation, compared to wild-type plants. Furthermore, cold response gene expression analysis revealed that the expression of these genes was suppressed in the transgenic lines under cold treatment. It was further elucidated that MAPK3 mediates the degradation of ICE and CBF proteins, which implies the negative impact of MAPK3 on the freezing tolerance of plants. This study will help to elucidate the molecular mechanisms of cold tolerance and the activity of MAPK3 in wheat.

Correction: Cold adaptation and response genes of Antarctic Cryobacterium sp. SO2 from the Fildes Peninsula, King George Island

Correction: Cold adaptation and response genes of Antarctic Cryobacterium sp. SO2 from the Fildes Peninsula, King George Island

Effects of exogenous glycine betaine on growth and development of tomato seedlings under cold stress.

Low temperature is a type of abiotic stress affecting the tomato (Solanum lycopersicum) growth. Understanding the mechanisms and utilization of exogenous substances underlying plant tolerance to cold stress would lay the foundation for improving temperature resilience in this important crop. Our study is aiming to investigate the effect of exogenous glycine betaine (GB) on tomato seedlings to increase tolerance to low temperatures. By treating tomato seedlings with exogenous GB under low temperature stress, we found that 30 mmol/L exogenous GB can significantly improve the cold tolerance of tomato seedlings. Exogenous GB can influence the enzyme activity of antioxidant defense system and ROS levels in tomato leaves. The seedlings with GB treatment presented higher Fv/Fm value and photochemical activity under cold stress compared with the control. Moreover, analysis of high-throughput plant phenotyping of tomato seedlings also supported that exogenous GB can protect the photosynthetic system of tomato seedlings under cold stress. In addition, we proved that exogenous GB significantly increased the content of endogenous abscisic acid (ABA) and decreased endogenous gibberellin (GA) levels, which protected tomatoes from low temperatures. Meanwhile, transcriptional analysis showed that GB regulated the expression of genes involved in antioxidant capacity, calcium signaling, photosynthesis activity, energy metabolism-related and low temperature pathway-related genes in tomato plants. In conclusion, our findings indicated that exogenous GB, as a cryoprotectant, can enhance plant tolerance to low temperature by improving the antioxidant system, photosynthetic system, hormone signaling, and cold response pathway and so on.

Involvement of Escherichia coli YbeX/CorC in ribosomal metabolism.

YbeX of Escherichia coli, a member of the CorC protein family, is encoded in the same operon with ribosome-associated proteins YbeY and YbeZ. Here, we report the involvement of YbeX in ribosomal metabolism. The ΔybeX cells accumulate distinct 16S rRNA degradation intermediates in the 30S particles and the 70S ribosomes. E. coli lacking ybeX has a lengthened lag phase upon outgrowth from the stationary phase. This growth phenotype is heterogeneous at the individual cell level and especially prominent under low extracellular magnesium levels. The ΔybeX strain is sensitive to elevated growth temperatures and to several ribosome-targeting antibiotics that have in common the ability to induce the cold shock response in E. coli. Although generally milder, the phenotypes of the ΔybeX mutant overlap with those caused by ybeY deletion. A genetic screen revealed partial compensation of the ΔybeX growth phenotype by the overexpression of YbeY. These findings indicate an interconnectedness among the ybeZYX operon genes, highlighting their roles in ribosomal assembly and/or degradation.

Genomic responses to climate: Understanding local adaptation in the Andean tree species Nothofagus pumilio and implications for a changing world

Societal Impact StatementForest trees tend to be strongly genetically adapted to their local environments, but climate change will probably subject trees to novel combinations of precipitation, temperature, and photoperiod. Local adaptation was investigated in the ecologically and economically important Patagonian tree species Nothofagus pumilio by characterizing its genetic diversity in relation to the varied environmental conditions across its range. These insights are useful for conservation and management decisions, for example by identifying suitable populations to establish seed source plantations for restoration and characterizing relationships with environmental drivers of selection to better understand how this species will respond to climate change.SummaryNothofagus pumilio is a foundation tree species that inhabits a 2000‐km‐long range in the southern Andes, a region with two perpendicular environmental gradients: temperature and photoperiod (North–South), and precipitation (West–East). We investigated local adaptation patterns by searching for relationships between environmental clines and signatures of adaptation in candidate genes related to stress response, growth, and phenology. Using a paired site sampling design within a landscape genome analysis, we analyzed 493 adult N. pumilio trees in 20 sampling sites across the species' latitudinal range. We screened 47,336 single nucleotide polymorphism (SNP) loci in 1632 contigs (i.e., coding regions along the genome). Population structure and genetic diversity analyses preceded four genome scan analyses using genetic and environmental data. Population structure and genetic diversity are mainly oriented along the latitude axis. Genome scans identified 445 outlier SNPs, which are loci showing signatures of selection. Temperature and photoperiod variables were associated with notably more outliers than precipitation. However, the most frequent biological functions among genes were water deprivation response and cold response, suggesting that stress response is comprised of complex and polygenic traits that are affected by many environmental variables. Our findings suggest that N. pumilio shows signatures of local adaptation to extant climate conditions, including temperature, photoperiod, and precipitation. However, climate change is likely to alter existing relationships among environmental conditions to which this species is currently adapted. These changes may have unpredictable consequences for the species' future survival, adaptation potential, and the people who depend upon these forests.

Full-length transcriptome sequencing provides insights into alternative splicing under cold stress in peanut.

Peanut (Arachis hypogaea L.), also called groundnut is an important oil and cash crop grown widely in the world. The annual global production of groundnuts has increased to approximately 50 million tons, which provides a rich source of vegetable oils and proteins for humans. Low temperature (non-freezing) is one of the major factors restricting peanut growth, yield, and geographic distribution. Since the complexity of cold-resistance trait, the molecular mechanism of cold tolerance and related gene networks were largely unknown in peanut. In this study, comparative transcriptomic analysis of two peanut cultivars (SLH vs. ZH12) with differential cold tolerance under low temperature (10°C) was performed using Oxford Nanopore Technology (ONT) platform. As a result, we identified 8,949 novel gene loci and 95,291 new/novel isoforms compared with the reference database. More differentially expressed genes (DEGs) were discovered in cold-sensitive cultivar (ZH12) than cold-tolerant cultivar (SLH), while more alternative splicing events were found in SLH compared to ZH12. Gene Ontology (GO) analyses of the common DEGs showed that the "response to stress", "chloroplast part", and "transcription factor activity" were the most enriched GO terms, indicating that photosynthesis process and transcription factors play crucial roles in cold stress response in peanut. We also detected a total of 708 differential alternative splicing genes (DASGs) under cold stress compared to normal condition. Intron retention (IR) and exon skipping (ES) were the most prevalent alternative splicing (AS) events. In total, 4,993 transcription factors and 292 splicing factors were detected, many of them had differential expression levels and/or underwent AS events in response to cold stress. Overexpression of two candidate genes (encoding trehalose-6-phosphatephosphatases, AhTPPs) in yeast improves cold tolerance. This study not only provides valuable resources for the study of cold resistance in peanut but also lay a foundation for genetic modification of cold regulators to enhance stress tolerance in crops.

Fat-free mass is associated with exercise pressor responses, but not cold pressor responses, in humans: influence of maximal voluntary contraction.

This study examined the contributions of fat mass (FM) and fat-free mass (FFM) to the magnitude of exercise pressor responses in humans. The cumulative blood pressure responses (blood pressure index; BPI) to handgrip exercise (BPIhg), post-exercise-circulatory-occlusion (BPIpeco), and cold-pressor activation (BPIcpt) were collected from 67 individuals grouped by BMI (27.8 ± 7.3 kg/m2), FFM index (FFMi, 29.1 ± 3.8 kg/m2), and FM index (FMi 12.5 ± 4.8 kg/m2) quartiles. BPI responses to HG were also normalized to the time-tension index of HG, providing a relative index of exercise pressor response magnitude (BPInorm). BPIhg and BPIpeco were significantly elevated in the third FFMi quartile (p ≤ 0.034), while BPInorm significantly decreased in the second and fourth quartiles (p ≤ 0.029). In contrast, no differences in BPIcpt were observed across any FFMi, BMI, or FMi quartiles (p ≥ 0.268). FFM was independently associated with BPIhg, BPI-peco, and BPInorm (all p ≤ 0.049), however, FFM was eliminated as an independent predictor when maximal voluntary contraction (MVC) was included in these regression models (all p ≥ 0.495). Neither FFM nor MVC was associated with BPIcpt (p ≥ 0.229). These findings indicate that exercise pressor responses, but not cold-pressor responses, are significantly associated with FFM in humans, and that this association is driven by FFM related differences in MVC.

Lipid metabolism and MAPK-ICE1 cascade play crucial roles in cold tolerance of banana

Low temperature is a major environmental factor that limits the growth, yield, and geographical distribution of Cavendish and Dajiao bananas (Musa spp.). Dajiao bananas exhibit a significantly higher cold tolerance than the Cavendish cultivar. However, the underlying mechanisms involved in cold tolerance regulation in Dajiao plants have not been determined. In this study, we investigated the mechanisms underlying the differences in cold tolerance at the cellular level between the cold-sensitive Cavendish and cold-tolerant Dajiao banana types through comparative metabolomics and transcriptomics analyses in calli exposed to cold treatment under dark conditions. A higher accumulation of lipids was observed in Dajiao calli cells compared to Cavendish cells under cold stress. After cold treatment, 4,626 and 5,516 differentially expressed genes (DEGs) were identified in Cavendish and Dajiao banana cells, respectively. By integrating the transcriptomic and metabolomic datasets, we discovered that the linoleic acid and α-linoleic acid metabolism and the Abscisic acid (ABA)-independent Mitogen-activated protein kinase (MAPK) cascade-Inducer of CBF expression 1 (ICE1) signal transduction pathway (including Mitogen-activated protein kinase kinase kinase 1 [MEKK1], MAPK5, ICE1, and Cold-regulated 47 [COR47]) played crucial roles in the cold tolerance of Dajiao bananas. Our study provides new insights into cold response regulation and novel cold tolerance mechanisms, providing valuable leads and targets for the genetic improvement of cold tolerance in bananas.

Acyl carrier protein OsMTACP2 confers rice cold tolerance at the booting stage.

Low temperatures occurring at the booting stage in rice (Oryza sativa L.) often result in yield loss by impeding male reproductive development. However, the underlying mechanisms by which rice responds to cold at this stage remain largely unknown. Here, we identified MITOCHONDRIAL ACYL CARRIER PROTEIN 2 (OsMTACP2), the encoded protein of which mediates lipid metabolism involved in the cold response at the booting stage. Loss of OsMTACP2 function compromised cold tolerance, hindering anther cuticle and pollen wall development, resulting in abnormal anther morphology, lower pollen fertility, and seed setting. OsMTACP2 was highly expressed in tapetal cells and microspores during anther development, with the encoded protein localizing to both mitochondria and the cytoplasm. Comparative transcriptomic analysis revealed differential expression of genes related to lipid metabolism between the wild type and the Osmtacp2-1 mutant in response to cold. Through a lipidomic analysis, we demonstrated that wax esters, which are the primary lipid components of the anther cuticle and pollen walls, function as cold-responsive lipids. Their levels increased dramatically in the wild type but not in Osmtacp2-1 when exposed to cold. Additionally, mutants of two cold-induced genes of wax ester biosynthesis, ECERIFERUM1 and WAX CRYSTAL-SPARSE LEAF2, showed decreased cold tolerance. These results suggest that OsMTACP2-mediated wax ester biosynthesis is essential for cold tolerance in rice at the booting stage.