Low Cold Resistance Research Articles

CsGAT1 modulates GABA metabolism and positively regulates cold resistance in tea plants

Tea plants (Camellia sinensis) are perennial woody economic crops that are often exposed to a range of abiotic stresses, especially low temperatures, during development. γ-Aminobutyric acid (GABA) is a nonprotein amino acid widely distributed in plants that is involved in the low-temperature response of plants. Here, we found that CsGAT1 was upregulated in tea leaves subjected to low-temperature stress according to transcriptomic data. Heterologous expression of CsGAT1 in a yeast mutant revealed that it specifically transports GABA. Subcellular localization assays revealed that CsGAT1 was located on the plasma membrane. The organizational localization experiments revealed that the expression level of CsGAT1 was relatively high in the old leaves and roots and relatively low in the flowers. Testing of different cold-tolerant tea germplasm resources revealed that cultivars with relatively low cold resistance presented relatively low CsGAT1 expression and GABA levels. In addition, Arabidopsis plants overexpressing CsGAT1 presented high levels of GABA accumulation and significant low-temperature resistance. In summary, we believe that CsGAT1 regulates the ability of tea plants to resist low-temperature stress by changing the concentration of GABA inside and outside the cell. This study provides a theoretical basis for breeding new tea cultivars with strong resistance to low-temperature stress during production.

Studies of the molecular mechanisms of grape (<i>Vitis vinifera</i> L.) resistance to low-temperature stress

Abiotic stressors are the main factors limiting the expansion of territories occupied by grape plantations. Industrial viticulture is concentrated in the south of Russia and is limited by climatic factors that do not allow large-scale production in other regions of the country.The present review considers the molecular mechanisms of resistance to low-temperature stress and discusses the role of the main genes determining the ability of plants to survive and acclimatize during a critical temperature drop.One of the most studied ways of responding to cold stress is the interaction of genes in the ICE-CBF-COR cascade, however, a more accurate understanding of the genes responsible for resistance to abiotic environments specifically in grapes requires additional studies. A series of studies of functions of transcription factors and related genes of response to low-temperature stress in various species (Arabidopsis, tea, orange, blueberry, and grape) have identified four main regulons: 1) CBF/DREB, 2) NAC/ZF-HD, 3) AREB/ABF, and 4) MYC/MYB. Studies have demonstrated the function of the HOS1 gene, which negatively regulates the work of ICE1 (a key resistance factor). The review considers candidate genes in various species of annual plants: ICE1, HOS1, SIZ1, MPK3, MPK6, in families of genes: CBF, COR, RD 29A, LTI78, ERD, LEA; DREB1, ADREB1B; WRKY10, and in perennial crops: ICE1, CBF1, HSP70, SUS1, GST, DHN1, BMY5, BHLH102, GR-RBP3, ICE1, GOLS1, GOLS3; CBF; COR27, RD29B, NCED1, ERF105, ZAT10, SAP15, WRKY3, and LEA.Until recently, interspecific hybridization was the leading method for obtaining cold-resistant grape varieties. The main donor of resistance is V. аmurensis Rupr. Recently, the research focused on the genetic basis of grape resistance to low temperatures is actively developing. For instance, a comparative analysis of the transcriptomes of two species contrasting in this trait, i.e. V. amurensis, resistant to low temperatures, and V. vinifera L. with low cold resistance, made it possible to identify three additional candidate genes with an increased expression in response to exposure to low temperatures, namely CBF3, ERF105 and ZAT10. At the same time, the practical application of modern accelerated breeding methods requires the identification of all additional key genes responsible for resistance to low-temperature stress. The components from the cascade of sequentially expressing ICE–CBF–COR genes (ICE1, ICE2, CBF1, CBF2, CBF3, and HOS1) have been selected as candidate genes.

Diversity Patterns of Bermuda Grass along Latitudinal Gradients at Different Temperatures in Southeastern China.

Cynodon dactylon (L.) Pers. (common Bermuda grass) has a limited capacity to grow at low temperatures, which limits its geographical range. Exploring its evolutionary relationship across different environmental gradients is necessary to understand the effects of temperature change on the genetics of common Bermuda grass. In this study, high-throughput transcriptome sequencing was performed on 137 samples of C. dactylon from 16 latitudinal gradients to explore the differential molecular markers and analyze genetic diversity and structure along latitudinal gradients at different temperatures. We primarily sampled more high-quality single nucleotide polymorphisms (SNPs) from populations at lower and middle latitudes. Greater intraspecific genetic variation at each level of temperature treatment could be due to factors such as wind pollination and asexual breeding. Populations of C. dactylon at high latitudes differed from populations at middle and low latitudes, which was supported by a principal component analysis (PCA) and genetic structure analysis, performed at different temperatures. We observed more genetic variation for low-latitude populations at 5 °C, according to an analysis of three phylogenetic trees at different temperature levels, suggesting that low temperatures affected samples with low cold resistance. Based on the results of phylogenetic analysis, we found that samples from high latitudes evolved earlier than most samples at low latitudes. The results provide a comprehensive understanding of the evolutionary phenomenon of landscape genetics, laying the groundwork for future structural and comparative genomic studies of C. dactylon.

GENETIC SOURCES AND NEW GENPLASMA - THE BASIS OF INTRODUCED MAIZE MATERIAL

The efficiency of selection work depends on the availability of the source maize material with genetic diversity, high combination ability and a set of economically valuable traits. Modern maize hybrids are created using only a small portion of gene plasma. Only 5-8% of the species maize diversity is used in the modern breeding process. Of great importance for successful breeding research and effective selection is the introduced material, especially from different parts of the globe. Each form, line, variety or hybrid is characterized by a set of many features and properties. The most important of them change more under the influence of adaptation, when grown in new conditions. Scientists of the Department of genetics, breeding and seed production named after prof. M.O. Zelensky NULES of Ukraine have been working together with the Department of Crop Production of the University of Aleppo (Syrian Arab Republic) for more than 20 years to expand the gene pool, developed a scheme, methods of approaches to the introduced forms for their analysis, testing, selection, followed by the creation of both source material and the creation of high-yielding hybrids in Ukraine and Syria. The article presents materials that highlight the importance of different approaches to the selection of source material, genetic sources, as well as the importance of the new gene plasma in the creation of self-pollinating lines, its preservation and subsequent use in breeding programs. The results of many years of research and reports of their results provide an opportunity to summarize the indicators of the migration effect from one area to another. It is established that the use maize samples of Syrian origin begins with overcoming the low cold resistance and slowed down the initial growth of maize. That is why the original forms of Syrian selection when grown in the conditions of "VP ADS NULES of Ukraine" (Pshenichne village, Vasylkiv district, Kyiv region) have a long growing season and late emergence of panicles. This shortcoming can be eliminated only by selection. The authors have developed proposals for a joint research program, test methods, recommended scheme of work with the original material of Syrian and Ukrainian maize selection. Key words: maize, source material, introduction, cell and genetic engineering, genetic diversity, genetic resources, sources of traits, collections, adaptation.

Physiological and Biochemical Characteristics Related to Cold Resistance in Sugarcane

In order to screen the cold tolerant sugarcane varieties, in Ziyuan County, one of the coldest counties having longest duration for frost and snow, in Guangxi province we comprehensively evaluated 21 sugarcane varieties using subordinate function method combined with correlation analyses based on six physiological and biochemical indexes relevant to cold tolerance under natural conditions. It was found that different sugarcane varieties had different responses to the long duration of continuous cold stress, which were dull for soluble protein, proline and malondialdehyde contents. Based on the analysis by subordinate function method, we divided the tested varieties into three groups of cold tolerance. The group I had four varieties with high cold tolerance, the group II had ten varieties with moderate cold tolerance, and the group III had seven varieties with low cold resistance. It is feasible to evaluate the cold resistance at processing maturing stage by using subordinate function method with multiple physiological and biochemical indexes, which can reveal the differences of cold hardiness in different sugarcane varieties, and provide good references for commercial sugarcane production.

不同品种小麦叶片对拔节期低温的生理响应及抗寒性评价

Cold injury is one of the main problems in winter wheat production in the Huanghuaihai wheat region.Winter wheat grows rapidly at the jointing stage,and becomes sensitive to the drops in temperatures that frequently occur in spring.Low temperature during the jointing stage restricts the growth of winter wheat and directly affects grain yield.Therefore,correctly evaluating and improving the cold resistance of wheat varieties is very important for grain security.In this study,we evaluated the cold tolerance of 24 wheat varieties grown in the Huanghuaihai region.The wheat plants were grown in pots outdoors,and they were moved into an artificial climate chamber and subjected to a cold treatment at the jointing stage.After the cold treatment,we measured seven physiological indices in leaves; relative electrical conductivity,soluble sugars content,soluble protein content,free proline content,malondialdehyde( MDA) content,superoxide dismutase( SOD)activity,and peroxidase( POD) activity.The results showed that the soluble protein content was lower in low-temperaturetreated plants than in the control plants( P0.01),while the other six indices showed higher values in the low-temperature-treated plants than in the control plants( P0.01).Analysis of variance showed that the values of these seven physiological indices differed significantly among varieties both in low-temperature-treated and control plants( P0.01).Compared with control plants,the low-temperature-treated plants showed a greater range of relative conductivity,soluble sugars content,soluble proline content,MDA content,and POD activity,but lower range of soluble protein content and SOD activity.The relative character value,that is,the proportion of the measured value in low-temperature-treated plants to that in control plants,eliminated the genetic background difference.For each wheat variety,we used the relative character values to calculate the average subordinative function value by the subordinative function method,and we calculated the comprehensive score by the polar ordination method.The average subordinative function values ranged from 0.19 to 0.63 and the comprehensive scores from 1.66 to 4.08.Among the 24 cultivars,Liangxing 619 showed the highest value and score,while Shiyou 20 showed the lowest.Using K-means clustering analysis,the 24 winter wheat cultivars were divided into five groups according to cold resistance; strong,high,medium,low,and weak.The strong cold resistance group contained six varieties; Lingxing 619,Fengdecunmai No.1,B07-4056,Shi H083-363,Shannong 055843,and Lingxing 99.The high cold resistance group contained seven varieties; Su 553,Shannong 509,A-9,Zhongyuan No.6,Xumai 4036,Shunmai1718,and Shimai 19.The medium cold resistance group consisted of five varieties; Yaomai 16,C-44,Shannong 05-066,Jimai 585,and Shi B05-7388.The low cold resistance group contained Yanzhan 4110,B-33,B05-6507,and Shi 4185.Two varieties,Shiyou 20 and Shi 06-6136,were in the weak cold resistance group.Correlation analyses showed that the average subordinative function value and comprehensive score were significantly positively correlated with soluble sugars content and relative proline content( P 0.01),and with relative POD activity( P 0.05).The average subordinative function value and comprehensive score were significantly negatively correlated with relative MDA content( P 0.05).In conclusion,the soluble sugars content,free proline content,POD activity,and MDA content in leaves at the jointing stage can serve as cold-resistance indices.Wheat varieties with higher soluble sugars content,free proline content,and POD activity,but lower MDA content in leaves showed stronger cold resistance.Among the 24 varieties,Liangxing 619 showed the strongest cold resistance at the jointing stage,while Shiyou 20 showed the weakest.

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.

CLASSIFICATION OF GENOTYPES OF EUCALYPTUS GLOBULUS UNDER COLD CONDITIONS USING THEIR FREE AMINO ACIDS CONTENT ON LEAVES AND REGULARIZED DISCRIMINANT ANALYSIS (RDA)

ABSTRACT Eucalyptus globulus is an important forestry species for wood and pulp industry; however, its low cold resistance is a serious disadvantage. In this work, chemometric techniques were applied on the leaves’ free amino acid content of different E. globulus genotypes in order to select cold tolerant genotypes. Pattern recognition methods based on regularized discriminant analysis ( RDA ) were used to classify the genotypes by cold resistance using samples’ foliar damages as reference of cold resistance. Correlation between the amino acids content and cold resistance of genotypes was determined from a partial least squares ( PLS ) model. RDA models showed an excellent classification of genotypes (100% of correctly assigned genotypes in external validation), especially when RDA was reduced to quadratic discriminant analysis ( QDA ). Arg, Tyr and Ala, showed the highest correlations with the foliar damage in the PLS model and they could be responsible to improve cold resistance to the studied genotypes.

Comparison of Vernalization Requirements and Frost Resistance of Winter Rape Lines Derived from Double Haploids

AbstractVernalization requirements and cold resistance of 13 lines of winter rape derived from doubled haploids obtained by androgenesis were investigated. The degree of vernalization requirements was examined in two parallel experiments. In the first experiment seedlings aged 2 weeks were vernalized during 63 and 35 days under controlled conditions, at 5 °C. In the second experiment the natural conditions of vernalization were differentiated by sowing the plants at four different dates in spring: March 15th, April 15th, May 15th, and at the latest date excluding vernalization, June 5th. The lines examined revealed differentiation of vernalization requirements that were similar in both experiments; all the lines required a period of exposure to cold before flowering. Cold resistance of lines was estimated in two successive series at −15 °C and −17 °C. Before testing the plants were kept in natural field conditions from the beginning of September until the middle of November. Testing of cold resistance was preceded by hardening under controlled conditions. Considerable differences in cold resistance was found in the forms investigated.The results obtained do not show any relation between frost resistance and the degree of vernalization requirements, as the line characterized by the strongest winter habit of growth showed low cold resistance, whereas the lines which were closer to spring growth habit showed the highest level of cold resistance; the lines with the least vernalization requirements revealed the highest level of cold resistance. This conclusion can be confirmed by the significance of the correlation coefficients between the various indices defining the frost resistance and the indices of vernalization requirements.

An information system to manage hypothermia in newborn lambs

AbstractManagement information can be used as a substitute for other business resources. Sheep farmers may find such substitution provides a means to maintain incomes as the price of information falls relative to other scarce resources during the severe cost price squeeze they are currently experiencing.To illustrate how management information may be obtained and used, a multivariate regression technique is described. This is applied to data on the physiological responses of newborn lambs to cold exposure. It shows that an increase of one standard deviation in total body insulation provides a significantly greater direct response in cold resistance in lambs bred for high cold resistance (HCR) compared with lambs bred for low cold resistance (LCR). The countervailing correlated drop in peak metabolic response to cold exposure did not show a significant between-line difference. This information suggests that HCR lambs give a metabolically more efficient response to cold exposure than LCR lambs. Subsequent research has provided physiological evidence to corroborate these findings.The cold resistance of lambs has been shown to be related to lamb survival in the field. Information obtained about the response of individuals or groups of lambs to cold exposure by methods such as those described here may suggest more cost-effective steps that managers should take in order to exploit to the full the varying abilities to resist cold. This in turn should improve enterprise gross output by reducing lamb mortality. It should also reduce costs by ensuring that steps to control cold exposure or alleviate its symptoms are provided only when necessary.

Description of the effects of a single gene which inhibits the normal metabolic response of newborn lambs to exogenous noradrenaline

A group of newborn Scottish Blackface lambs previously selected for low cold resistance failed to show the normal metabolic response to subcutaneous injection of exogenous noradrenaline. A subsequent study showed this failure to be due to a single major gene. Further studies on the thermogenic and physiological responses and on the inheritance of the trait, are described here. Two intercross matings between nonresponders produced responder lambs indicating that the gene is not recessive. The increases in metabolic rate and rectal temperature after injection of noradrenaline were much greater in responder than in non-responder lambs (P<0·001), as were the increases in heart rate and respiration rate (P<0·001). Dissected brown adipose tissue from non-responders was apparently normal and indistinguishable from brown adipose tissue from responders. Although there was no apparent effect of the gene on birthweight or survival, survival under normal field conditions may be affected.

Hormonal Regulation of Morphogenesis and Cold-resistance

Seedlings of alfalfa (Medicago saliva L.) cv. Ranger and cv. Hairy Peruvian were grown under conditions of long day and high temperatures or short day and low temperatures. Under long days and high temperatures, both varieties developed an elongated shoot and exhibited relatively low cold-resistance, as measured by the extent of leakage of cellular substances, after being exposed to sub-zero temperature. Under short days and low temperatures, Ranger seedlings developed a rosette growth and exhibited an improved response to sub-zero temperature. In contrast, Hairy Peruvian seedlings developed an elongated shoot and did not acquire cold-resistance. Hairy Peruvian grown in a nutrient solution containing abscisic acid, however, developed a rosette and acquired an improved response to sub-zero temperature, like cv. Ranger under short days and low temperatures. Addition of gibberellic acid to Ranger seedlings grown under these conditions nullified the environmental effects, since they developed an elongated shoot and did not acquire cold-resistance. It is concluded that abscisic acid and gibberellic acid are involved in the interrelationship between morphogenesis and cold-resistance in the seedlings of the two alfalfa cultivars.

Resistance to body cooling in male and female sheep, and the effects of previous exposure to chronic cold, acute cold and repeated short cold shocks

SUMMARYTwenty-eight female and 26 uncastrated male Scottish Blackface sheep were shorn and subjected to two acute cold exposures one week apart. Between exposures and for one week before the first exposure the sheep were kept either at +30°C (thermoneutral), or at +8°C (subcriticai), or at + 30°C with daily short cold shocks. Food intakes were restricted.Females showed significantly greater resistance to body cooling than males during both acute exposures.Both males and females showed acclimatization (increased resistance to body cooling) as a result of the first acute exposure.Exposure to +8°C for one week did not produce significant acclimatization. Exposure to +8°C for two weeks tended, in females only, to increase acclimatization above that resulting from the first acute exposure.Daily short cold shocks reduced cold resistance and inhibited acclimatization in females, but had little effect in males.The male sheep lost significantly more weight during treatment and became thinner than the females. It was suggested that this, and their low cold resistance, might be related to a lesser ability of males to store fat as a subsequent source of energy.