Shallow water seeding cultivation enhances cold tolerance in tobacco seedlings.

Cold stress can impact plant biology at both the molecular and morphological levels. We cultivated two different types of tobacco seedlings using distinct seeding methods, observing significant differences in their cold tolerance at 4 °C. After 12 h cold stress, shallow water seeding cultivation treatment demonstrates a relatively good growth state with slight wilting of the leaves. Tobacco grown using the float system exhibited short, thick roots, while those cultivated through shallow water seeding had elongated roots with more tips and forks. After cold stress, the shallow water seeding cultivation treatment demonstrated higher antioxidant enzyme activity, and lower malondialdehyde (MDA) content.Transcriptome analysis was performed on the leaves of these tobacco seedlings at three stages of cold treatment (before cold stress, after cold stress, and after 3 days of recovery). Upon analyzing the raw data, we found that the shallow water seeding cultivation treatment was associated with significant functional enrichment of nicotinamide adenine dinucleotide (NAD) biosynthesis and NAD metabolism before cold stress, enrichment of functions related to the maintenance of cellular structure after cold stress, and substantial functional enrichment related to photosynthesis during the recovery period. Weighted gene co-expression network analysis (WGCNA) was conducted, identifying several hub genes that may contribute to the differences in cold tolerance between the two tobacco seedlings. Hub genes related to energy conversion were predominantly identified in shallow water seeding cultivation treatment during our analysis, surpassing findings in other areas. These include the AS gene, which controls the synthesis of NAD precursors, the PED1 gene, closely associated with fatty acid ß-oxidation, and the RROP1 gene, related to ATP production.Overall, our study provides a valuable theoretical basis for exploring improved methods of cultivating tobacco seedlings. Through transcriptome sequencing technology, we have elucidated the differences in gene expression in different tobacco seedlings at three time points, identifying key genes affecting cold tolerance in tobacco and providing possibilities for future gene editing.

Unraveling the intricacies of cold-inducible RNA-binding protein: A comprehensive review.

Cold-inducible RNA-binding protein (CIRP) is a versatile RNA-binding protein, pivotal in modulating cellular responses to diverse stress stimuli including cold shock, ultraviolet radiation, hypoxia, and infections, with a principal emphasis on cold stress. The temperature range of 32-34 °C is most suitable for CIRP expression. The human CIRP is an 18-21 kDa polypeptide containing 172 amino acids coded by a gene located on chromosome 19p13.3. CIRP has an RNA-recognition motif (RRM) and an arginine-rich motif (RGG), both of which have roles in coordinating numerous cellular activities. CIRP itself also undergoes conformational changes in response to diverse environmental stress. Transcription factors such as hypoxia-inducible factor 1 alpha and nuclear factor-kappa B have been implicated in coordinating CIRP transcription in response to specific stimuli. The potential of CIRP to relocate from the nucleus to the cytoplasm upon exposure to different stimuli enhances its varied functional roles across different cellular compartments. The different functions include decreasing nutritional demand, apoptosis suppression, modulation of translation, and preservation of cytoskeletal integrity at lower temperatures. This review explores the diverse functions and regulatory mechanisms of CIRP, shedding light on its involvement in various cellular processes and its implications for human health and disease.

Cell attachment defines sensitivity to cold stress via the Hippo pathway.

Although cells are frequently maintained at cold temperatures during experiments, the effects of cold stress on cell viability and subsequent cellular conditions remain elusive. In this study, we investigated the effects of cold stress on cancer cells under various culture conditions. We showed that cold stress induces ferroptosis, a form of cell death characterized by lipid peroxidation, in sensitive cancer cell lines. High cell density and serum starvation activate the Hippo pathway and suppress cold-induced cell death. Genetic deletion of Hippo pathway components enhances cold stress susceptibility. Furthermore, the cell attachment status influences the response to cold stress, with suspended cells showing greater resistance and faster recovery than attached cells. This study highlights the importance of cellular conditions and the Hippo pathway in the handling and storage of cancer cells at cold temperatures, thereby offering insights into experimental and clinical contexts.

Effects of chronic intermittent cold stress on anxiety-depression-like behaviors in adolescent rats.

Stress, which triggers numerous physiological and behavioral responses in the organism, is a significant risk factor that contributes to the development of psychiatric disorders such as depression and anxiety. This study aimed to investigate the inflammation, oxidative stress status, anxiety, and depression-like behaviors of adolescent rodents exposed to chronic intermittent cold stress. Adolescent male rats were subjected to a modified chronic intermittent cold stress model (21 days, 1 hour/day, 4 °C). Depression-like behaviors were evaluated using the sucrose preference and forced swimming tests, while anxiety-like behaviors were assessed using the open field, elevated plus maze, and light-dark box tests. We measured levels of cortisol, tumor necrosis factor-α, interleukin-1ß, brain-derived natriuretic factor, reactive oxygen species, malondialdehyde, total oxidants and antioxidants, and other chemicals in the prefrontal cortex, thalamus, striatum, and hippocampus brain regions of rats using ELISA and colorimetric methods. Data were analyzed using Student's t-test and Pearson correlation analysis. After the cold stress treatment, both anxiety and depression-like behaviors increased remarkably in the subjects. Our study revealed significant changes in various brain regions among the stress-exposed subjects. Cold stress resulted in decreased BDNF levels in the prefrontal cortex and striatum (p < 0.05), increased cortisol levels in the prefrontal cortex (p < 0.05), increased IL-1ß levels in the hippocampus and thalamus (p < 0.05), increased protein carbonyl levels in the striatum (p < 0.05), and decreased TAS in the prefrontal cortex and thalamus (p < 0.05). Adolescent rats exposed to cold exhibit both anxiety- and depression-like behaviors. This study observed an increase in inflammation in various brain regions, yet the responses to stress varied. Our findings suggest that adolescence is a period of heightened sensitivity to stress, which can lead to dramatic consequences.

Metabolic changes in tomato plants caused by psychrotolerant Antarctic endophytic bacteria might be implicated in cold stress mitigation.

Climate change is responsible for mild winters and warm springs that can induce premature plant development, increasing the risk of exposure to cold stress with a severe reduction in plant growth. Tomato plants are sensitive to cold stress and beneficial microorganisms can increase their tolerance. However, scarce information is available on mechanisms stimulated by bacterial endophytes in tomato plants against cold stress. This study aimed to clarify metabolic changes stimulated by psychrotolerant endophytic bacteria in tomato plants exposed to cold stress and annotate compounds possibly associated with cold stress mitigation. Tomato seeds were inoculated with two bacterial endophytes isolated from Antarctic Colobanthus quitensis plants (Ewingella sp. S1.OA.A_B6 and Pseudomonas sp. S2.OTC.A_B10) or with Paraburkholderia phytofirmans PsJN, while mock-inoculated seeds were used as control. The metabolic composition of tomato plants was analyzed immediately after cold stress exposure (4°C for seven days) or after two and four days of recovery at 25°C. Under cold stress, the content of malondialdehyde, phenylalanine, ferulic acid, and p-coumaric acid was lower in bacterium-inoculated compared to mock-inoculated plants, indicating a reduction of lipid peroxidation and the stimulation of phenolic compound metabolism. The content of two phenolic compounds, five putative phenylalanine-derived dipeptides, and three further phenylalanine-derived compounds was higher in bacterium-inoculated compared to mock-inoculated samples under cold stress. Thus, psychrotolerant endophytic bacteria can reprogram polyphenol metabolism and stimulate the accumulation of secondary metabolites, like 4-hydroxybenzoic and salicylic acid, which are presumably involved in cold stress mitigation, and phenylalanine-derived dipeptides possibly involved in plant stress responses.

SlNAC3 suppresses cold tolerance in tomatoes by enhancing ethylene biosynthesis.

Low temperature stress poses a significant challenge to the productivity of horticultural crops. The dynamic expression of cold-responsive genes plays a crucial role in plant cold tolerance. While NAC transcription factors have been extensively studied in plant growth and development, their involvement in regulating plant cold tolerance remains poorly understood. In this study, we focused on the identification and characterisation of SlNAC3 as the most rapid and robust responsive gene in tomato under low temperature conditions. Manipulating SlNAC3 through overexpression or silencing resulted in reduced or enhanced cold tolerance, respectively. Surprisingly, we discovered a negative correlation between the expression of CBF and cold tolerance in the SlNAC3 transgenic lines. These findings suggest that SlNAC3 regulates tomato cold tolerance likely through a CBF-independent pathway. Furthermore, we conducted additional investigations to identify the molecular mechanisms underlying SINAC3-mediated cold tolerance in tomatoes. Our results revealed that SlNAC3 controls the transcription of ethylene biosynthetic genes, thereby bursting ethylene release in response to cold stress. Indeed, the silencing of these genes led to an augmentation in cold tolerance. This discovery provides valuable insights into the regulatory pathways involved in ethylene-mediated cold tolerance in tomatoes, offering potential strategies for developing innovative approaches to enhance cold stress resilience in this economically important crop species.

A C2H2-type zinc finger protein ZAT12 of Poncirus trifoliata acts downstream of CBF1 to regulate cold tolerance.

The Cys2/His2 (C2H2)-type zinc finger family has been reported to regulate multiple aspects of plant development and abiotic stress response. However, the role of C2H2-type zinc finger proteins in cold tolerance remains largely unclear. Through RNA-sequence analysis, a cold-responsive zinc finger protein, named as PtrZAT12, was identified and isolated from trifoliate orange (Poncirus trifoliata L. Raf.), a cold-hardy plant closely related to citrus. Furthermore, we found that PtrZAT12 was markedly induced by various abiotic stresses, especially cold stress. PtrZAT12 is a nuclear protein, and physiological analysis suggests that overexpression of PtrZAT12 conferred enhanced cold tolerance in transgenic tobacco (Nicotiana tabacum) plants, while knockdown of PtrZAT12 by virus-induced gene silencing (VIGS) increased the cold sensitivity of trifoliate orange and repressed expression of genes involved in stress tolerance. The promoter of PtrZAT12 harbors a DRE/CRT cis-acting element, which was verified to be specifically bound by PtrCBF1 (Poncirus trifoliata C-repeat BINDING FACTOR1). VIGS-mediated silencing of PtrCBF1 reduced the relative expression levels of PtrZAT12 and decreased the cold resistance of trifoliate orange. Based on these results, we propose that PtrZAT12 is a direct target of CBF1 and plays a positive role in modulation of cold stress tolerance. The knowledge gains new insight into a regulatory module composed of CBF1-ZAT12 in response to cold stress and advances our understanding of cold stress response in plants.

Molecular Mechanisms of Lipid-Based Metabolic Adaptation Strategies in Response to Cold.

Temperature changes and periods of detrimental cold occur frequently for many organisms in their natural habitats. Homeothermic animals have evolved metabolic adaptation strategies to increase mitochondrial-based energy expenditure and heat production, largely relying on fat as a fuel source. Alternatively, certain species are able to repress their metabolism during cold periods and enter a state of decreased physiological activity known as torpor. By contrast, poikilotherms, which are unable to maintain their internal temperature, predominantly increase membrane fluidity to diminish cold-related damage from low-temperature stress. However, alterations of molecular pathways and the regulation of lipid-metabolic reprogramming during cold exposure are poorly understood. Here, we review organismal responses that adjust fat metabolism during detrimental cold stress. Cold-related changes in membranes are detected by membrane-bound sensors, which signal to downstream transcriptional effectors, including nuclear hormone receptors of the PPAR (peroxisome proliferator-activated receptor) subfamily. PPARs control lipid metabolic processes, such as fatty acid desaturation, lipid catabolism and mitochondrial-based thermogenesis. Elucidating the underlying molecular mechanisms of cold adaptation may improve beneficial therapeutic cold treatments and could have important implications for medical applications of hypothermia in humans. This includes treatment strategies for hemorrhagic shock, stroke, obesity and cancer.

How Cold Shock Affects Ploidy Level and Early Ontogenetic Development of the Sterlet, A. ruthenus L.

The objective of the present research was to study the effect of cold shock (3 °C and 6 °C) on fertilized eggs of the sterlet, Acipenser ruthenus L. Cold shock was applied for various durations (30, 60 and 90 min) and the ploidy levels, survival, and genotypes of the treated embryos/larvae were recorded. Analysis of ploidy levels confirmed the presence of diploid, triploid, and mosaic (1n/2n, 2n/3n, and 1n/2n/3n) genotypes in experimental groups, while it was strictly diploid in control groups. Microsatellite genotyping confirmed both the incidence of polyspermy and retention of the 2nd polar body in experimental groups. However, patterns of inheritance in all diploid offspring in experimental and control groups revealed classical Mendelian disomic inheritance. Interestingly, the observed mosaic sterlets had normal morphology and were alive. However, some larvae had abnormal morphology which may be due to haploid syndrome. In all treatment groups (treatments: 3 °C-30 min; 3 °C-60 min; 3 °C-90 min; 6 °C-60 min), where the percentage of polyploid/mosaic larvae were high, the mortality was also high. Whereas, in the control groups (where there were only diploid (2n) larvae), the mortality was relatively low.

Potential roles for pattern molecule of PAMP-triggered immunity in improving crop cold tolerance.

KEY MESSAGE: The application of flagellin 22 (flg22), the most widely studied PAMP, enhance crop cold tolerance. ICE1-CBF pathway and SA signaling is involved in the alleviation of cold injury by flg22 treatment. Pathogen infection cross-activates cold response and increase cold tolerance of host plants. However, it is not possible to use the infection to increase cold tolerance of field plants. Here flagellin 22 (flg22), the most widely studied PAMP (pathogen-associated molecular patterns), was used to mimic the pathogen infection to cross-activate cold response. Flg22 treatment alleviated the injury caused by freezing in Arabidopsis, oilseed and tobacco. In Arabidopsis, flg22 activated the expression of immunity and cold-related genes. Moreover, the flg22 induced alleviation of cold injury was lost in NahG transgenic line (SA-deficient), sid2-2 and npr1-1 mutant plants, and flg22-induced expression of cold tolerance-related genes, which indicating that salicylic acid signaling pathway is required for the alleviation of cold injury by flg22 treatment. In short flg22 application can be used to enhance cold tolerance in field via a salicylic acid-depended pathway.

Recovering body temperature from acute cold stress is associated with delayed proinflammatory cytokine production in vivo.

A poor outcome of whole-body hypothermia often results from a late complication, rather than from acute effects of hypothermia. A low body (cell) temperature or the increase in the concentrations of the stress hormones cortisol, epinephrine, and norepinephrine in response to acute cold stress have been proposed as potent proinflammatory cytokine suppressant. In the current study, we tested the hypothesis that the recovery of body temperature from a whole-body intermittent cold-water immersion (CWI, at 13-14 °C for a total 170 min) is associated with a delayed response of proinflammatory cytokines in young healthy men. Our results revealed a delay in the increase in the proinflammatory interleukin 6 and interleukin 1ß cytokines after the CWI, which paralleled the changes in cortisol, epinephrine, norepinephrine, and body temperature. CWI decreased tumor necrosis factor α (TNF-α) immediately and 1 h after the CWI. Although TNF-α had recovered to the pre-immersion level at 2 h after CWI, its natural circadian cycle kinetics was disrupted until 12 h after the CWI. Furthermore, we showed that CWI strongly modified the white blood cell counts, with changes reaching a peak between 1 and 2 h after the CWI.

Cold stress in the harvest period: effects on tobacco leaf quality and curing characteristics.

BACKGROUND: Weather change in high-altitude areas subjects mature tobacco (Nicotiana tabacum L.) to cold stress, which damages tobacco leaf yield and quality. A brupt diurnal temperature differences (the daily temperature dropping more than 20 °C) along with rainfall in tobacco-growing areas at an altitude above 2450 m, caused cold stress to field-grown tobacco. RESULTS: After the flue-cured tobacco suffered cold stress in the field, the surface color of tobacco leaves changed and obvious large browning areas were appeared, and the curing availability was extremely poor. Further research found the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. We hypothesize that cold stress in high altitude environments destroyed the antioxidant enzyme system of mature flue-cured tobacco. Therefore, the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. CONCLUSION: This study confirmed that cold stress in high-altitude tobacco areas was the main reason for the browning of tobacco leaves during the tobacco curing process. This adverse environment seriously damaged the quality of tobacco leaves, but can be mitigated by pay attention to the weather forecast and pick tobacco leaves in advance.

Cloning and characterization of KoOsmotin from mangrove plant Kandelia obovata under cold stress.

BACKGROUND: Low temperature is a major abiotic stress that seriously limits mangrove productivity and distribution. Kandelia obovata is the most cold-resistance specie in mangrove plants, but little is known about the molecular mechanism underlying its resistance to cold. Osmotin is a key protein associated with abiotic and biotic stress response in plants but no information about this gene in K. obovata was reported. RESULTS: In this study, a cDNA sequence encoding osmotin, KoOsmotin (GenBank accession no. KP267758), was cloned from mangrove plant K. obovata. The KoOsmotin protein was composed of 221 amino acids and showed a calculated molecular mass of 24.11 kDa with pI 4.92. The KoOsmotin contained sixteen cysteine residues and an N-terminal signal peptide, which were common signatures to most osmotins and pathogenesis-related 5 proteins. The three-dimensional (3D) model of KoOsmotin, contained one α-helix and eleven ß-strands, was formed by three characteristic domains. Database comparisons of the KoOsmotin showed the closest identity (55.75%) with the osmotin 34 from Theobroma cacao. The phylogenetic tree also revealed that the KoOsmotin was clustered in the branch of osmotin/OLP (osmotin-like protien). The KoOsmotin protein was proved to be localized to both the plasma membrane and cytoplasm by the subcellular localization analysis. Gene expression showed that the KoOsmotin was induced primarily and highly in the leaves of K. obovata, but less abundantly in stems and roots. The overexpressing of KoOsmotin conferred cold tolerance in Escherichia coli cells. CONCLUSION: As we known, this is the first study to explore the osmotin of K. obovata. Our study provided valuable clues for further exploring the function of KoOsmotin response to stress.

Energy response and fatty acid metabolism in Onychostoma macrolepis exposed to low-temperature stress.

Temperature is a key environmental factor, and understanding how its fluctuations affect physiological and metabolic processes is critical for fish. The present study characterizes the energy response and fatty acid metabolism in Onychostoma macrolepis exposed to low temperature (10 °C). The results demonstrated that cold stress remarkably disrupted the energy homeostasis of O. macrolepis, then the AMP-activated protein kinase (AMPK) could strategically mobilize carbohydrates and lipids. In particular, when the O. macrolepis were faced with cold stress, the lipolysis was stimulated along with the enhanced fatty acid ß-oxidation for energy, while the fatty acid synthesis was supressed in the early stage. Additionally, the fatty acid composition analysis suggested that saturated fatty acid (SFA) might accumulate while monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) in storage lipids (mainly containing non-polar lipid, NPL) could be utilized to supply energy during cold acclimation. Altogether, this study may provide some meritorious for understanding the cold-tolerant mechanism of fish in the viewpoint of energy balance combined with fatty acid metabolism, and thus to contribute to this species rearing in fish farms in the future.

Transcriptome sequencing reveals the effects of cadmium toxicity on the cold tolerance of the wolf spider Pirata subpiraticus.

As the predominant predator of pests in rice fields, spiders have been exposed to cadmium (Cd) pollution for a long time. The livability of spiders during the overwintering period is closely related to population growth in spring, but the effects of Cd on spider's survival of cold hardness and the underlining mechanism remain unclear. In the present study, we found that some growth parameters (body length, width, mass and livability) in the wolf spider Pirata subpiraticus were altered distinctively under Cd stress. To investigate the effects of Cd toxicity on the spider at molecular levels, RNA-sequencing was performed on the spiderlings undergoing ambient temperature alterations. Transcriptome data showed that a total of 807 differentially expressed genes (DEGs) were yielded in the comparison. The obtained DEGs were mainly linked with metabolism-related process, including oxidoreductase activity and lipid transport, and 25 DEGs were associated with the reported cryoprotectants, including glycerol, arginine, cysteine, heat shock protein, glucose and mannose. Growth factors (insulin growth factor, platelet-derived growth factor and transforming growth factor) and cytochrome P450 encoding genes were dramatically expressed in the spider. Furthermore, transcriptional factors (TFs) family were characterized according to the transcriptomic profile, and ZBTB TFs were represented the most distinctive alterations in the characterized genes. Collectively, our study illustrated that Cd poses disadvantageous effects on the growth of P. subpiraticus at cold ambient temperature, and the spiders are capable of responding to the adverse Cd stress by expressing the genes involved in the metabolism of energy substances, cryoprotectants and immune-related components.

Effect of cold stress on ovarian & uterine microcirculation in rats and the role of endothelin system.

BACKGROUND: Cold, an environmental factor, induces many reproductive diseases. It is known that endothelin (ET) is a potent vasoconstrictor, and cold stress can increase the expression of ET and its receptors. The cold stress rat model was developed to examine two parameters: (1) the effects of cold stress on ovarian and uterine morphology, function, and microvascular circulation and (2) possible mechanisms of ET and its receptors involved in cold stress-induced menstruation disorders. METHODS: The rat cold stress model was prepared with an ice water bath. The estrous cycle was observed by methylene blue and hematoxylin and eosin (H&E) staining. Serum estradiol 2 (E2), testosterone (T), progesterone (P) were detected by radioimmunoassay. Hemorheology indices were measured. The real-time blood flow of auricle and uterine surfaces was measured. Expressions of CD34 and α-SMA in ovarian and uterine tissues were detected by immunohistochemistry. ET-1 contents in serum were tested, and expressions of ET-receptor types A and B (ET-AR and ET-BR) in ovarian tissues were detected via Western blotting. RESULTS: Cold stress extended the estrous cycle, thereby causing reproductive hormone disorder, imbalance of local endothelin/nitric oxide expression, and microcirculation disturbance. Cold-stress led to up-regulation of ET-AR expression and protein and down-regulation of ET-BR expression in rats. CONCLUSIONS: This study suggests that the reason for cold stress-induced dysfunction in reproductive organs may be closely related to the imbalance of ET-1 and its receptor expressions, leading to microvascular circulation disorders in local tissues.

Combined transcriptomic and metabolomic analyses uncover rearranged gene expression and metabolite metabolism in tobacco during cold acclimation.

Cold temperatures often severely restrict the growth, distribution and productivity of plants. The freezing tolerance of plants from temperate climates can be improved by undergoing periods of cold acclimation (CA). Tobacco is an important economic plant and is sensitive to cold stress. However, the dynamic changes and regulatory mechanisms of gene expression and metabolic processes during CA remain largely unknown. In this study, we performed RNA sequencing and metabolomic profiling analyses to identify the genes and metabolites specifically expressed during CA. Our transcriptomic data revealed 6905 differentially expressed genes (DEGs) during CA. Functional annotation and enrichment analyses revealed that the DEGs were involved mainly in signal transduction, carbohydrate metabolism and phenylpropanoid biosynthesis. Moreover, a total of 35 significantly changed metabolites were identified during CA via an LC-MS platform. Many protective metabolites, such as amino acids, carbohydrates, tricarboxylic acid (TCA) cycle intermediates and phenylpropanoid-related substances, were identified during CA. The gene-metabolite network extensively outlined the biological processes associated with the utilization of sugars, activation of amino acid metabolism, TCA cycle and phenylpropanoid biosynthesis in tobacco under CA. The results of our present study provide a comprehensive view of signal transduction and regulation, gene expression and dynamic changes in metabolites during CA.

The ethylene responsive factor CdERF1 from bermudagrass (Cynodon dactylon) positively regulates cold tolerance.

Cold stress is one of the major environmental factors that limit growth and utilization of bermudagrass [Cynodon dactylon (L.) Pers], a prominent warm-season turfgrass. However, the molecular mechanism of cold response in bermudagrass remains largely unknown. In this study, we characterized a cold-responsive ERF (ethylene responsive factor) transcription factor, CdERF1, from bermudagrass. CdERF1 expression was induced by cold, drought and salinity stresses. The CdERF1 protein was nucleus-localized and encompassed transcriptional activation activity. Transgenic Arabidopsis plants overexpressing CdERF1 showed enhanced cold tolerance, whereas CdERF1-underexpressing bermudagrass plants via virus induced gene silencing (VIGS) method exhibited reduced cold resistance compared with control, respectively. Under cold stress, electrolyte leakage (EL), malondialdehyde (MDA), H2O2 and O2- contents were reduced, while the activities of SOD and POD were elevated in transgenic Arabidopsis. By contrast, these above physiological indicators in CdERF1-underexpressing bermudagrass exhibited the opposite trend. To further explore the possible molecular mechanism of bermudagrass cold stress response, the RNA-Seq analyses were performed. The result indicated that overexpression of CdERF1 activated a subset of stress-related genes in transgenic Arabidopsis, such as CBF2, pEARLI1 (lipid transfer protein), PER71 (peroxidase) and LTP (lipid transfer protein). Interestingly, under-expression of CdERF1 suppressed the transcription of many genes in CdERF1-underexpressing bermudagrass, also including pEARLI1 (lipid transfer protein) and PER70 (peroxidase). All these results revealed that CdERF1 positively regulates plant cold response probably by activating stress-related genes, PODs, CBF2 and LTPs. This study also suggests that CdERF1 may be an ideal candidate in the effort to improve cold tolerance of bermudagrass in the further molecular breeding.

Studies on the cold tolerance of ratoon 'Chaling' common wild rice

BACKGROUND: Rice is the staple food of many people around the world. However, most rice varieties, especially widely grown indica varieties and hybrids, are sensitive to cold stress. In order to provide a basis for the utilization of a common wild rice (CWR, Oryza rufipogon Griff.) named 'Chaling' CWR in cold-tolerant rice breeding and deepen the understanding of rice cold tolerance, the cold tolerance of ratoon 'Chaling' CWR was studied under the stress of the natural low temperature in winter in Changsha, Hunan province, China, especially under the stress of abnormal natural low temperature in Changsha in 2008, taking other ratoon CWR accessions and ratoon cultivated rice phenotypes as control. RESULTS: The results showed that ratoon 'Chaling' CWR can safely overwinter under the natural conditions in Changsha (28° 22' N), Hunan province, China, which is a further and colder northern place than its habitat, even if it suffers a long-term low temperature stress with ice and snow. In 2008, an extremely cold winter appeared in Changsha, i.e., the average daily mean temperature of 22 consecutive days from January 13 to February 3 was - 1.0 °C, and the extreme low temperature was - 4.7 °C. After subjected to this long-term cold stress, the overwinter survival rate of ratoon 'Chaling' CWR was 100%, equals to that of ratoon 'Dongxiang' CWR which is northernmost distribution in the word among wild rice populations, higher than those of ratoon 'Fusui' CWR, ratoon 'Jiangyong' CWR, and ratoon 'Liujiang' CWR (63.55-83.5%) as well as those of ratoon 'Hainan' CWR, ratoon 'Hepu' CWR, and all the ratoon cultivated rice phenotypes including 3 japonica ones, 3 javanica ones, and 5 indica ones (0.0%). CONCLUSIONS: The results indicate that ratoon 'Chaling' CWR possesses strong cold tolerance and certain freezing tolerance.

Reduced oxidative stress increases acute cold stress tolerance in zebrafish.

Cold stress is a major threat to fish in both nature and aquaculture, and can induce oxidative stress in various fish. While the exact role of oxidative stress in cold-caused mortality is still unknown. The purpose of the present study was to evaluate the effects of oxidative stress on cold tolerance in fish and verify whether changing oxidative status could affect cold tolerance. We firstly demonstrated that acute cold exposure induced high oxidative stress in zebrafish liver, which may lead to mortality. Then we performed in vivo and in vitro experiments to determine the effects of the altered oxidative status on cold tolerance in zebrafish and zebrafish liver cell line (ZFL), respectively. In the in vivo study, the zebrafish which were fed with α-lipoic acid or reduced glutathione had lower cold-caused oxidative stress and tissues damage, and showed higher cold tolerance. In the experiment using zebrafish cells, increasing oxidative stress by H2O2 decreased the cellular cold tolerance, and the cold tolerance was partly recovered when oxidative stress was reduced by the addition of Vitamin C (VC). Taken together, we conclude that the reduction of oxidative stress increases cold tolerance in fish.