Cold Resistance Of Plants Research Articles

Functional Activity of the Photosynthetic Apparatus in Tobacco and Arabidopsis Plants Exposed to Chilling Temperatures

Photosynthetic activities of a chilling-sensitive species, Nicotiana tabacum L. (cv. Samsun), and a chilling-resistant plant, Arabidopsis thaliana Heynh. (L) (ecotype Columbia), were examined in young seedlings exposed to low temperatures. Functional parameters were determined after 1- to 6-day exposure of tobacco and arabidopsis plants at 8 and 2°C, respectively. In tobacco leaves sampled by the end of the experiment, the chlorophyll content decreased by 30%, the ratio of variable to maximum Chl a fluorescence (Fv/Fm) decreased by 5%, and the rate of net (apparent) photosynthesis diminished almost twofold. The concentration of soluble sugars in tobacco leaves increased by 30% approaching 130 mg/g dry wt. In arabidopsis, unlike tobacco, the content and proportions of photosynthetic pigments, as well as the Fv/Fm ratio changed insignificantly upon cooling, whereas net photosynthetic rates decreased to a lesser extent (by a factor of 1.6). The content of sugars in arabidopsis leaves increased fourfold by the end of the low-temperature treatment and reached 90 mg/g dry wt. Thus, the photosynthetic apparatus in chill-sensitive and cold-resistant plants responded differently to chilling temperatures. The data provide evidence that the photosynthetic apparatus in arabidopsis is well preserved upon chilling and can function effectively at cold-hardening temperatures. The thylakoid processes and the reactions of photosynthetic carbon metabolism in leaves of heat-loving tobacco plants are more sensitive to chilling temperatures and undergo changes in a more or less coordinated manner, helping chloroplasts to avoid the excessive generation of reactive oxygen species.

Purification efficiency of zeolite and two planted grasses on sewage and relationship with carbon-nitrogen-phosphorus ratios in simulated constructed wetland system.

For achieving the economical and efficient configuration of constructed wetlands (CWs), a simulated device of vertical flow CWs was used to investigate the effects of different volume ratios of substrates to two cold-resistant plants on pollutant concentrations as well as their ratios in effluent under different inflow domestic sewage concentrations. The average removal rates (ARRs) of ammonia nitrogen, total nitrogen (TN) and total phosphorus were 82.7%, 84.9% and 80.6% respectively in the treatments with zeolite but no plants, which increased by 22.6%, 20.8% and 14.9% compared with those without zeolite and plants. However, in the treatments with zeolite and planted grasses, the ARRs of the three pollutants were over 90%, and those of chemical oxygen demand were lower. The removal rates of ammonia nitrogen, TN and total phosphorus had negative correlations with C:N and N:P ratios and positive correlations with the C:P ratios. Increasing the ratio of zeolite to soil from 1:1 to 2:1 had no significant effects in the removal efficiency. It was suggested that planting Lolium perenne or Poa annua on the substrate with a zeolite to soil volume ratio of 1:1 could be considered as the optimum combination to purify the domestic sewage in north rural areas of China.

Trichostatin A and 5-Aza-2′-Deoxycytidine influence the expression of cold-induced genes in Arabidopsis

ABSTRACTThe expression of cold-induced genes is critical for plants to survive under freezing stress. However, the underlying mechanisms for the decision of when, where, and which genes to express are unclear when a plant meets a sudden temperature drop. Previous studies have demonstrated epigenetics to play a central role in the regulation of gene expression in plant responses to environmental stress. DNA methylation and histone deacetylation are the two most important epigenetic modifications. This study was conducted to investigate the effects of inhibiting DNA methylation and histone deacetylation on gene expression, and to explore the potential role of epigenetics in plant responses to cold stress. The results revealed that histone deacetylase inhibitors (trichostatin A) and DNA methylation inhibitors (5-Aza-2′-deoxycytosine) treatment enhanced cold tolerance. DNA microarray analysis and the gene ontology method revealed 76 cold-induced differently expressed genes in Arabidopsis thaliana seedlings that were treated to 0°C for 24 h following Trichostatin A and 5-Aza-2′-Deoxycytidine. Furthermore, analyses of metabolic pathways and transcription factors of 3305 differentially expressed genes were performed. Each four metabolic pathways were significantly affected (p < 0.01) by Trichostatin A and 5-Aza-2′-Deoxycytidine. Finally, 10 genes were randomly selected and verified via qPCR analysis. Our study indicated that Trichostatin A and 5-Aza-2′-Deoxycytidine can improve the plant cold resistance and influence the expression of the cold-induced gene in A. thaliana. This result will advance our understanding of plant freezing responses and may provide a helpful strategy for cold tolerance improvement in crops.

Gene Regulation and Signal Transduction in the ICE-CBF-COR Signaling Pathway during Cold Stress in Plants.

Low temperature is an abiotic stress that adversely affects the growth and production of plants. Resistance and adaptation of plants to cold stress is dependent upon the activation of molecular networks and pathways involved in signal transduction and the regulation of cold-stress related genes. Because it has numerous and complex genes, regulation factors, and pathways, research on the ICE-CBF-COR signaling pathway is the most studied and detailed, which is thought to be rather important for cold resistance of plants. In this review, we focus on the function of each member, interrelation among members, and the influence of manipulators and repressors in the ICE-CBF-COR pathway. In addition, regulation and signal transduction concerning plant hormones, circadian clock, and light are discussed. The studies presented provide a detailed picture of the ICE-CBF-COR pathway.

Perspective Research Progress in Cold Responses of Capsella bursa-pastoris

Plants respond to cold stress by modulating biochemical pathways and array of molecular events. Plant morphology is also affected by the onset of cold conditions culminating at repression in growth as well as yield reduction. As a preventive measure, cascades of complex signal transduction pathways are employed that permit plants to endure freezing or chilling periods. The signaling pathways and related events are regulated by the plant hormonal activity. Recent investigations have provided a prospective understanding about plant response to cold stress by means of developmental pathways e.g., moderate growth involved in cold tolerance. Cold acclimation assays and bioinformatics analyses have revealed the role of potential transcription factors and expression of genes like CBF, COR in response to low temperature stress. Capsella bursa-pastoris is a considerable model plant system for evolutionary and developmental studies. On different occasions it has been proved that C. bursa-pastoris is more capable of tolerating cold than A. thaliana. But, the mechanism for enhanced low or freezing temperature tolerance is still not clear and demands intensive research. Additionally, identification and validation of cold responsive genes in this candidate plant species is imperative for plant stress physiology and molecular breeding studies to improve cold tolerance in crops. We have analyzed the role of different genes and hormones in regulating plant cold resistance with special reference to C. bursa-pastoris. Review of collected data displays potential ability of Capsella as model plant for improvement in cold stress regulation. Information is summarized on cold stress signaling by hormonal control which highlights the substantial achievements and designate gaps that still happen in our understanding.

Activities of antioxidant enzymes of Arabidopsis thaliana plants during cold hardening to hypothermia

Changes in activities of the enzymes performing direct antioxidant functions were studied in 7–8-week-old plants Arabidopsis thaliana Heinh (L.) of Columbia (Col-0) ecotype. It was found that 5-day cold hardening at 2°C increased plant cold resistance to the subsequent stronger cooling. Under these conditions, the marked changes occurred in activities of superoxide dismutase and III type (guaiacol) peroxidses but not in that of catalase. The total peroxidase activity exceeded the catalase activity before cold hardening. Therefore, peroxidases are able to decompose more H2O2 than catalases and appear to make the dominant contribution to the protection from the cold damage.

Brassinosteroids participate in the control of basal and acquired freezing tolerance of plants

Brassinosteroids (BRs) are growth-promoting plant hormones that play a role in abiotic stress responses, but molecular modes that enable this activity remain largely unknown. Here we show that BRs participate in the regulation of freezing tolerance. BR signaling-defective mutants of Arabidopsis thaliana were hypersensitive to freezing before and after cold acclimation. The constitutive activation of BR signaling, in contrast, enhanced freezing resistance. Evidence is provided that the BR-controlled basic helix-loop-helix transcription factor CESTA (CES) can contribute to the constitutive expression of the C-REPEAT/DEHYDRATION-RESPONSIVE ELEMENT BINDING FACTOR (CBF) transcriptional regulators that control cold responsive (COR) gene expression. In addition, CBF-independent classes of BR-regulated COR genes are identified that are regulated in a BR- and CES-dependent manner during cold acclimation. A model is presented in which BRs govern different cold-responsive transcriptional cascades through the posttranslational modification of CES and redundantly acting factors. This contributes to the basal resistance against freezing stress, but also to the further improvement of this resistance through cold acclimation.

Preliminary study on cold-resistance of Euonymus radicans ‘Emorald & Gold’

A comparative observation was carried out on the changes of anatomical structure and starch content in the leaves of Euonymus radicans ‘Emorald Gold’ during overwintering and cold acclimation, and the photosynthesis-light response curves from the leaves of unacclimated and acclimated seedlings as well as the leaf photosynthetic rate of acclimated and unacclimated seedlings treated at the low temperature stress were studied comparatively. The results showed that the appearance of vacuole division during overwintering and cold acclimation were highly correlated to the development of plant cold-resistance. So were the starch accumulation before the acclimation, the starch degradation after the acclimation and starch accumulation again after de-acclimation. Compared with unacclimated seedlings, the leaf photosynthetic rate and photosynthetic light compensation point of acclimated seedlings decreased, photosynthetic light saturation point increased slightly. The leaf photosynthetic rate of acclimated seedlings still maintained at a higher level after low temperature stress for 72 h , but that of unacclimated seedlings became negentropy, indicating that cold acclimation raised the stability of photosynthesis of seedlings under low temperature stress. And the relation between the above-mentioned adaptive changes and plant cold-resistance was also discussed.

Transcriptome sequencing and de novo analysis of Rosa multiflora under cold stress

Rose is one of most popular ornamental plants in the world. The plant is of high economical value and great cultural importance. Low temperature exerts strong influence on the cultivation and commercial value of rose. The negative impacts could be genetically reduced through elucidating the mechanisms underlying plant cold tolerance. The Illumina Hiseq™ 2000 RNA-seq is a promising approach in gene expression analysis at the transcriptome level. With the transcriptome and DEG analysis, we investigated the gene expression profiles in response to cold stress of Rosa multiflora. The results shed light on the underlying molecular mechanisms of plant cold resistance. In the study, clean data that were generated from three samples of Rosa multiflora under different cold stress (i.e., CK, CT1 and CT2). A total of 61,864 unigenes with an average length of 1216 bp were obtained by assembling the data. A total of 42,553 complete and 1246 partial coding sequences (CDSs) were determined by protein database alignments and ESTScan prediction, respectively. Subsequently, we obtained functional annotations by aligning all unigenes with public protein databases (i.e., NR, Swiss-Prot, KEGG and COG). DEG analysis was performed to assess the changes in gene expression in cold condition (4 and 25 °C) using the FPKM method. The results indicated that there were 4966 up-regulated genes and 4592 down-regulated genes between CK and CT1, and 7915 up-regulated genes and 10,912 down-regulated genes between CK and CT2. We then performed GO enrichment and metabolic pathway enrichment analyses. A series of candidate genes that are involved in cold responsive pathways and a number of transcription factors were selected and discussed. We selected 15 up-regulated and five down-regulated unigenes in Rosa multiflora were quantified using qRT-PCR. The study provides a comprehensive overview of transcriptome response and gene expression profiling of Rosa multiflora in response to cold stress. The large number of transcriptomic sequences obtained in the study provides sufficient resources for molecular markers and gene cloning. The study facilities the understanding of the underlying mechanisms of cold resistance in Rosa multiflora.

Dynamic transcriptome analysis reveals AP2/ERF transcription factors responsible for cold stress in rapeseed (Brassica napusL.).

The APETALA2/ethylene response factor (AP2/ERF) transcription factor (TF) superfamily plays an important regulatory role in signal transduction of the plant responses to various stresses including low temperature. Significant progress has been made in understanding the mechanism of cold resistance in Brassica napus, an important oilseed crop. However, comprehensive studies on the induction and activity of these TFs under low temperature have been lacking. In this study, 132 AP2/ERF genes were identified by transcriptome sequencing of rapeseed leaves exposed to 0, 2, 6, 12, and 24h of low (4°C) temperature stress. The genes were classified into 4 subfamilies (AP2, DREB, ERF, and RAV) and 13 subgroups, among which the DREB subfamily and ERF subfamily contained 114 genes, no genes were assigned to soloist or DREB A3 subgroups. One hundred and eighteen genes were located on chromosomes A1 to C9. GO functional analysis and promoter sequence analysis revealed that these genes are involved in many molecular pathways that may enhance cold resistance in plants, such as the low-temperature responsiveness, methyl jasmonate, abscisic acid, and ethylene-responsiveness pathways. Their expression patterns revealed dynamic control at different times following initiation of cold stress; the RAV and DREB subfamilies were expressed at the early stage of cold stress, whereas the AP2 subfamily was expressed later. Quantitative PCR analyses of 13 cold-induced AP2/ERF TFs confirmed the accuracy of above results. This study is the first dynamic analysis of the AP2/ERF TFs responsible for cold stress in rapeseed. These findings will serve as a reference for future functional research on transcription in rapeseed.

Small subunit of a cold-resistant plant, Timothy, does not significantly alter the catalytic properties of Rubisco in transgenic rice.

Effects of overexpression of high activity-type Rubisco small subunit (RbcS) from a cold-resistant plant, timothy (Phleum pratense), on kinetic properties of Rubisco were studied in rice (Oryza sativa). The full-length mRNA sequence of timothy RbcS (PpRbcS1) was determined by 5'RACE and 3'RACE. The coding sequence of PpRbcS1 was fused to the chlorophyll a/b-binding protein promoter and introduced into rice. PpRbcS was highly expressed in leaf blade and accounted for approximately 30 % of total RbcS in homozygous transgenic lines. However, the catalytic turnover rate and K m for CO2 of Rubisco did not significantly change in these transgenic lines compared to non-transgenic rice, suggesting that PpRbcS1 is not effective for improvement of catalytic efficiency of rice Rubisco. The photosynthetic rate and growth were essentially unchanged, whereas the photosynthetic rate at low CO2 condition was marginally increased in transgenic lines. Rubisco content was significantly increased, whereas soluble protein, nitrogen, and chlorophyll contents were unchanged in transgenic lines compared to non-transgenic rice. Because the kinetic properties were similar, observed slight increase in photosynthetic rate at low CO2 is considered to be large due to increase in Rubisco content in transgenic lines. Introduction of foreign RbcS is an effective approach for the improvement of Rubisco kinetics and photosynthesis. However, in this study, it was suggested that RbcS of high activity-type Rubisco, even showing higher amino acid identity with rice RbcS, did not always enhance the catalytic turnover rate of Rubisco in rice. Thus, we should carefully select RbcS to be overexpressed before introduction.

Cloning and transformation of INDUCER of CBF EXPRESSION1 (ICE1) in tomato.

The tomato plant (Solanum lycopersicum Mill.) is sensitive to cold, and low field temperatures can result in shortened growth periods and decreased crop yield. Transcription of CRT/DRE-binding factor (CBF) is regulated by INDUCER of CBF EXPRESSION1 (ICE1). CBF activates many downstream genes that confer cold tolerance on plants. ICE1 has been used in genetic engineering to improve cold-resistance in several plant species. Here, ICE1 in a plant expression vector was used to transform a tissue-cultured rhubarb tomato variety using Agrobacterium tumefaciens. The transgenic and control plants were compared at 4°C for 0, 24, and 72 h. We measured leaf physiological indicators related to cold resistance, including malondialdehyde (MDA) and proline (Pro) contents, and peroxidase (POD) and catalase (CAT) activities. At 72 h, the MDA content in transgenic plants was significantly lower than in control plants, indicating a lower membrane lipid injury. The Pro contents and the CAT and POD activities in the transgenic plants increased significantly compared with those of the control plants. For Pro, the increase continued over the prolonged stress exposure, while CAT and POD activities reached peak levels at 24 h. These results are consistent with the roles of Pro, CAT, and POD in defending the integrity of plant cells. Our study not only improves the cold resistance of tomato, but also provides the foundation for further research on the role of ICE1 as a transcription factor in plant cold resistance.

浮床栽培水芹菜的自然越冬及净水试验

通过水面浮床栽培试验，研究了水芹菜(Oenanthejavanica (Blume) DC)的自然越冬存活率、生物量以及在富营养化水体中对氮、磷的吸收。研究表明，浮床栽培的水芹菜在武汉地区可以自然越冬，存活率为76%，植株的平均鲜量为108.22 g/株，其中水上部分占80.2%，水下部分占19.8%。在元月至4月生长期内，每平方米水面栽培的水芹菜可从水中直接吸收52.23 g的氮和11.51 g的磷。结果表明，水芹是一种适合在低温情况下进行水培的植物，并对富营养化水体有良好的净化效果。 By planting cress (Oenanthejavanica (Blume) DC) with the floating bed on water surface, survey was carried out on its overwintering livability, biomass and capability to absorb nitrogen and phosphorus in the eutrophicated water body. Research showed that the cress was able to live through the winter in Wuhan area with survey rate of about 76%. The individual biomass was as high as 108.22 g/ind., with upper water surface part of 80.2% and under water of 19.8%. From January to April, cress planted on water surface per square could absorb 52.23 g nitrogen and 11.51 g phosphorus. Results suggested that cress is a cold-resistant plant which can be planted on the floating bed. It has a high potential for clearing the eutrophicated water.

Reorganization of chloroplast ultrastructure associated with low-temperature hardening of Arabidopsis plants

When following low-temperature acclimation (5 days at 2°C) of cold-resistant plants of Arabidopsis (Arabidopsis thaliana Heynh. (L.), ecotype Columbia) in relation to the changes in chloroplast ultrastructure, we registered the high efficiency of hardening and the ability of hardened plants to lower a threshold of frost damage by about 3°C. During hardening, the area of grana in the chloroplasts more than doubled, with considerably increased numbers of thylakoids per granum and thylakoids per chloroplast. The rate of apparent photosynthesis decreased to lesser extent than the rate of dark respiration, as a result the content of soluble sugars increased fourfold, ensuring an adaptive reorganization of metabolism, which enabled the hardened plants to survive even at below-zero temperatures (up to −7°C). The authors conclude that a considerable increase in the number of thylakoids in the chloroplasts helps maintain photosynthesis at low above-zero temperatures and is a prerequisite for the accumulation of soluble sugars in Arabidopsis leaves.

An Overview of Cold Resistance in Plants

AbstractCold is a typical environmental stress factor that limits the geographical distribution and growth of various plants. It affects crop quality and productivity. In the contemporary years, with the plant cold‐resistant genetic engineering development, great progress was obtained in this field. This paper gave a general statement about the development of plant cold resistantance on the level of unsaturated fatty acids, protective enzymes, functional genes and regulation genes, aiming to provide some useful information and ideas to researchers who work on plant cold breeding and the mechanism of cold resistance. As research continues, we could develop further multiple resistant plant species.

RAN1 is involved in plant cold resistance and development in rice (Oryza sativa).

Of the diverse abiotic stresses, low temperature is one of the major limiting factors that lead to a series of morphological, physiological, biochemical, and molecular changes in plants. Ran, an evolutionarily conserved small G-protein family, has been shown to be essential for the nuclear translocation of proteins. It also mediates the regulation of cell cycle progression in mammalian cells. However, little is known about Ran function in rice (Oryza sativa). We report here that Ran gene OsRAN1 is essential for the molecular improvement of rice for cold tolerance. Ran also affects plant morphogenesis in transgenic Arabidopsis thaliana. OsRAN1 is ubiquitously expressed in rice tissues with the highest expression in the spike. The levels of mRNA encoding OsRAN1 were greatly increased by cold and indoleacetic acid treatment rather than by addition of salt and polyethylene glycol. Further, OsRAN1 overexpression in Arabidopsis increased tiller number, and altered root development. OsRAN1 overexpression in rice improves cold tolerance. The levels of cellular free Pro and sugar levels were highly increased in transgenic plants under cold stress. Under cold stress, OsRAN1 maintained cell division and cell cycle progression, and also promoted the formation of an intact nuclear envelope. The results suggest that OsRAN1 protein plays an important role in the regulation of cellular mitosis and the auxin signalling pathway.

Global Analysis of Transcriptome Responses and Gene Expression Profiles to Cold Stress of Jatropha curcas L.

Background Jatropha curcas L., also called the Physic nut, is an oil-rich shrub with multiple uses, including biodiesel production, and is currently exploited as a renewable energy resource in many countries. Nevertheless, because of its origin from the tropical MidAmerican zone, J. curcas confers an inherent but undesirable characteristic (low cold resistance) that may seriously restrict its large-scale popularization. This adaptive flaw can be genetically improved by elucidating the mechanisms underlying plant tolerance to cold temperatures. The newly developed Illumina Hiseq™ 2000 RNA-seq and Digital Gene Expression (DGE) are deep high-throughput approaches for gene expression analysis at the transcriptome level, using which we carefully investigated the gene expression profiles in response to cold stress to gain insight into the molecular mechanisms of cold response in J. curcas.ResultsIn total, 45,251 unigenes were obtained by assembly of clean data generated by RNA-seq analysis of the J. curcas transcriptome. A total of 33,363 and 912 complete or partial coding sequences (CDSs) were determined by protein database alignments and ESTScan prediction, respectively. Among these unigenes, more than 41.52% were involved in approximately 128 known metabolic or signaling pathways, and 4,185 were possibly associated with cold resistance. DGE analysis was used to assess the changes in gene expression when exposed to cold condition (12°C) for 12, 24, and 48 h. The results showed that 3,178 genes were significantly upregulated and 1,244 were downregulated under cold stress. These genes were then functionally annotated based on the transcriptome data from RNA-seq analysis.ConclusionsThis study provides a global view of transcriptome response and gene expression profiling of J. curcas in response to cold stress. The results can help improve our current understanding of the mechanisms underlying plant cold resistance and favor the screening of crucial genes for genetically enhancing cold resistance in J. curcas.

Influence of temperature on micro-environment, plant eco-physiology and nitrogen removal effect in subsurface flow constructed wetland

Six horizontal subsurface-flow constructed wetlands were operated year round at a wastewater treatment plant (WWTP) in Nanjing, China, to investigate the influence of temperature on nitrogen removal, micro-environment and plant eco-physiological characteristics. The data obtained showed that the removal rates of DON, NH4+-N and TN were significantly temperature-dependent. The substrate ureases activity and microbial nitrification intensity dropped as temperature decreased. Urease activity and nitrification intensity in planted wetlands were distinctly higher than that in unplanted wetlands. DO concentration in mid- and upper-layer of the wetlands had greater seasonal variation than that in bottom-layer. The net photosynthetic rate and evaporation rate of reeds were both significantly positively correlated to temperature. Consequently, in order to obtain more consistent year round nutrient removal, it is suggested that some appropriate heat-preservation measures are used to cover the surface of the wetlands, cold resistant plants that are active year round, and enhanced aeration in mid- and upper layer should be adopted.

Porous Silicon Biosensor for the Detection of Transgenic Cotton of Antifeezing Protein

Genetic engineering has been used extensively for improving cold resistance in plants. In this paper, an optical immunoassay was developed by the optic reflectance spectroscopy of the porous silicon biosensor to monitor the success of transgenic frost-resistant cotton. Transgenic cotton extract samples and anti- antifreeze protein (AFP) antibodies were employed as the target and probe, respectively. Porous silicon is functionalized by using oxidation and silanization, then anti- AFP antibodies were immobilized to the porous silicon pore used a crosslink method. The changes of reflectance spectrum before and after antigen-antibody react ion are observed. The results show that transgenic frost-resistant cotton extract samples caused obvious red shift in reflectance spectrum of porous silicon while common cotton was not. Control experiment with negative antibodies shows high specifcity and conventional ELASA and Western experiment were also carried for comparison. Compare to conventional ELASA and Western, porous silicon biosensor is quick and accurate determination for the detection of transgenic cotton of antifeezing protein.

Enhanced tolerance to low temperature in tobacco by over-expression of a new maize protein phosphatase 2C, ZmPP2C2

Low temperature is one of the most common environmental stresses affecting plant growth and agricultural production. Serine/threonine protein phosphatases 2C (PP2Cs) have been suggested to play an important role in stress signaling. To identify potential new member of the PP2C proteins in maize and investigate its functions for stress responses, the ZmPP2C2 gene, encoding a new PP2C protein from maize roots, was cloned by RT-PCR and RACE-PCR. Its constitutive expression in roots, stems and leaves of maize seedlings was detected by RNA gel blot, and its regulation in response to cold stress was also examined. To further evaluate its function in the cold stress response, we over-expressed the ZmPP2C2 gene in tobacco under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter, and assessed a series of physiological changes in wild type and transgenic plants under low temperatures. Compared with wild type tobacco under cold stress, plants that over-expressed ZmPP2C2 displayed higher germination speed and rate, higher antioxidant enzyme (SOD, POD, CAT) activities, with lower cold-induced electrolyte leakage and malondialdehyde (MDA) contents. These results show that over-expression of ZmPP2C2 in tobacco enhanced tolerance to cold stress, suggesting that this new gene, ZmPP2C2, may act as a positive regulator of cold resistance in plants.