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

2016 ◽  
Vol 113 (40) ◽  
pp. E5982-E5991 ◽  
Author(s):  
Marina Eremina ◽  
Simon J. Unterholzner ◽  
Ajith I. Rathnayake ◽  
Marcos Castellanos ◽  
Mamoona Khan ◽  
...  
Keyword(s):  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Stress Responses ◽  
Constitutive Expression ◽  
Freezing Stress ◽  
Dependent Manner ◽  
Freezing Resistance ◽  
Basal Resistance ◽  
Helix Loop Helix ◽  
Before And After

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.

scholarly journals iTRAQ-Based Comparative Proteomic Analysis of the Roots of TWO Winter Turnip Rapes (Brassica rapa L.) with Different Freezing-Tolerance

2018 ◽  
Vol 19 (12) ◽  
pp. 4077 ◽  
Author(s):  
Xiucun Zeng ◽  
Yaozhao Xu ◽  
Jinjin Jiang ◽  
Fenqin Zhang ◽  
Li Ma ◽  
...  
Keyword(s):  
Cold Acclimation ◽  
Linolenic Acid ◽  
Brassica Rapa ◽  
Freezing Tolerance ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Carbon Fixation ◽  
Freezing Stress ◽  
Turnip Rape ◽  
Mannose Metabolism

The freezing tolerance of roots is crucial for winter turnip rape (Brassica rapa L.) survival in the winter in Northwest China. Cold acclimation (CA) can alleviate the root damage caused by freezing stress. To acknowledge the molecular mechanisms of freezing tolerance in winter turnip rape, two Brassica rapa genotypes, freezing stressed after the induction of cold acclimation, were used to compare the proteomic profiles of roots by isobaric tags for relative and absolute quantification (iTRAQ). Under freezing stress (−4 °C) for 8 h, 139 and 96 differentially abundant proteins (DAPs) were identified in the roots of “Longyou7” (freezing-tolerant) and “Tianyou4” (freezing-sensitive), respectively. Among these DAPs, 91 and 48 proteins were up- and down-accumulated in “Longyou7”, respectively, and 46 and 50 proteins were up- and down-accumulated in “Tianyou4”, respectively. Under freezing stress, 174 DAPs of two varieties were identified, including 9 proteins related to ribosome, 19 DAPs related to the biosynthesis of secondary metabolites (e.g., phenylpropanoid and the lignin pathway), and 22 down-accumulated DAPs enriched in oxidative phosphorylation, the pentose phosphate pathway, fructose and mannose metabolism, alpha-linolenic acid metabolism, carbon fixation in photosynthetic organisms, ascorbate and aldarate metabolism. The expressional pattern of the genes encoding the 15 significant DAPs were consistent with the iTRAQ data. This work indicates that protein biosynthesis, lignin synthesis, the reduction of energy consumption and a higher linolenic acid content contribute to the freezing tolerance of winter turnip rape. Functional analyses of these DAPs would be helpful in dissecting the molecular mechanisms of the stress responses in B. rapa.

scholarly journals Genome-Wide Analysis of the NAC Transcription Factor Gene Family Reveals Differential Expression Patterns and Cold-Stress Responses in the Woody Plant Prunus mume

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 494 ◽  
Author(s):  
Xiaokang Zhuo ◽  
Tangchun Zheng ◽  
Zhiyong Zhang ◽  
Yichi Zhang ◽  
Liangbao Jiang ◽  
...  
Keyword(s):  
Cold Stress ◽  
Gene Family ◽  
Cold Tolerance ◽  
Stress Responses ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Freezing Stress ◽  
Prunus Mume ◽  
Flower Bud ◽  
Freezing Resistance

NAC transcription factors (TFs) participate in multiple biological processes, including biotic and abiotic stress responses, signal transduction and development. Cold stress can adversely impact plant growth and development, thereby limiting agricultural productivity. Prunus mume, an excellent horticultural crop, is widely cultivated in Asian countries. Its flower can tolerate freezing-stress in the early spring. To investigate the putative NAC genes responsible for cold-stress, we identified and analyzed 113 high-confidence PmNAC genes and characterized them by bioinformatics tools and expression profiles. These PmNACs were clustered into 14 sub-families and distributed on eight chromosomes and scaffolds, with the highest number located on chromosome 3. Duplicated events resulted in a large gene family; 15 and 8 pairs of PmNACs were the result of tandem and segmental duplicates, respectively. Moreover, three membrane-bound proteins (PmNAC59/66/73) and three miRNA-targeted genes (PmNAC40/41/83) were identified. Most PmNAC genes presented tissue-specific and time-specific expression patterns. Sixteen PmNACs (PmNAC11/19/20/23/41/48/58/74/75/76/78/79/85/86/103/111) exhibited down-regulation during flower bud opening and are, therefore, putative candidates for dormancy and cold-tolerance. Seventeen genes (PmNAC11/12/17/21/29/42/30/48/59/66/73/75/85/86/93/99/111) were highly expressed in stem during winter and are putative candidates for freezing resistance. The cold-stress response pattern of 15 putative PmNACs was observed under 4 °C at different treatment times. The expression of 10 genes (PmNAC11/20/23/40/42/48/57/60/66/86) was upregulated, while 5 genes (PmNAC59/61/82/85/107) were significantly inhibited. The putative candidates, thus identified, have the potential for breeding the cold-tolerant horticultural plants. This study increases our understanding of functions of the NAC gene family in cold tolerance, thereby potentially intensifying the molecular breeding programs of woody plants.

scholarly journals Transcriptional Regulation of the phoPR Operon in Bacillus subtilis

2004 ◽  
Vol 186 (4) ◽  
pp. 1182-1190 ◽  
Author(s):  
Zoltán Prágai ◽  
Nicholas E. E. Allenby ◽  
Nicola O'Connor ◽  
Sarah Dubrac ◽  
Georges Rapoport ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Stress Responses ◽  
Response Regulator ◽  
Constitutive Expression ◽  
Phosphate Starvation ◽  
Pho Regulon ◽  
Dependent Manner ◽  
Low Level

ABSTRACT When Bacillus subtilis is subjected to phosphate starvation, the Pho regulon is activated by the PhoP-PhoR two-component signal transduction system to elicit specific responses to this nutrient limitation. The response regulator, PhoP, and its cognate histidine sensor kinase, PhoR, are encoded by the phoPR operon that is transcribed as a 2.7-kb bicistronic mRNA. The phoPR operon is transcribed from two σA-dependent promoters, P1 and P2. Under conditions where the Pho regulon was not induced (i.e., phosphate-replete conditions or phoR-null mutant), a low level of phoPR transcription was detected only from promoter P1. During phosphate starvation-induced transition from exponential to stationary phase, the expression of the phoPR operon was up-regulated in a phosphorylated PhoP (PhoP∼P)-dependent manner; in addition to P1, the P2 promoter becomes active. In vitro gel shift assays and DNase I footprinting experiments showed that both PhoP and PhoP∼P could bind to the control region of the phoPR operon. The data indicate that while low-level constitutive expression of phoPR is required under phosphate-replete conditions for signal perception and transduction, autoinduction is required to provide sufficient PhoP∼P to induce other members of the Pho regulon. The extent to which promoters P1 and P2 are activated appears to be influenced by the presence of other sigma factors, possibly the result of sigma factor competition. For example, phoPR is hyperinduced in a sigB mutant and, later in stationary phase, in sigH, sigF, and sigE mutants. The data point to a complex regulatory network in which other stress responses and post-exponential-phase processes influence the expression of phoPR and, thereby, the magnitude of the Pho regulon response.

Plasma Membrane Aquaporin Members PIPs Act in Concert to Regulate Cold Acclimation and Freezing Tolerance Responses in Arabidopsis thaliana

2020 ◽  
Vol 61 (4) ◽  
pp. 787-802 ◽  
Author(s):  
Arifa Rahman ◽  
Yukio Kawamura ◽  
Masayoshi Maeshima ◽  
Abidur Rahman ◽  
Matsuo Uemura
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Cell Biology ◽  
Integrated Approach ◽  
Freezing Stress ◽  
Single Mutation ◽  
Plasma Membrane Intrinsic Proteins

Abstract Aquaporins play a major role in plant water uptake at both optimal and environmentally stressed conditions. However, the functional specificity of aquaporins under cold remains obscure. To get a better insight to the role of aquaporins in cold acclimation and freezing tolerance, we took an integrated approach of physiology, transcript profiling and cell biology in Arabidopsis thaliana. Cold acclimation resulted in specific upregulation of PIP1;4 and PIP2;5 aquaporin (plasma membrane intrinsic proteins) expression, and immunoblotting analysis confirmed the increase in amount of PIP2;5 protein and total amount of PIPs during cold acclimation, suggesting that PIP2;5 plays a major role in tackling the cold milieu. Although single mutants of pip1;4 and pip2;5 or their double mutant showed no phenotypic changes in freezing tolerance, they were more sensitive in root elongation and cell survival response under freezing stress conditions compared with the wild type. Consistently, a single mutation in either PIP1;4 or PIP2;5 altered the expression of a number of aquaporins both at the transcriptional and translational levels. Collectively, our results suggest that aquaporin members including PIP1;4 and PIP2;5 function in concert to regulate cold acclimation and freezing tolerance responses.

scholarly journals Variability in the Speed of Cold Deacclimation among Tuber-bearing Wild Potato Species

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 579f-580 ◽  
Author(s):  
Sandra E Vega ◽  
Jiwan P. Palta ◽  
John B. Bamberg
Keyword(s):  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Frost Tolerance ◽  
Wild Potato ◽  
Wild Potato Species ◽  
Potato Species ◽  
Frost Injury ◽  
The World ◽  
Before And After ◽  
High Degree

Frost injury limits the cultivation of potatoes in many regions around the world. We are currently studying the factors that contribute to frost survival in potato in an attempt to improve its frost tolerance. Wild potato species have been distinguished for their high degree of non-acclimated frost tolerance (growing under normal conditions) and their high cold acclimation capacity (able to increase frost tolerance upon exposure to cold). Cold acclimation can be reversed upon exposure to warm temperatures (deacclimation). The ability to gain freezing tolerance rapidly in response to low temperatures as well as not being able to deacclimate rapidly in response to warm daytime temperatures would be advantageous for a plant against spring or fall freezes. Last year we presented evidence for the variability in the speed of cold acclimation among 7 wild tuber-bearing potato species (S. acaule, S. commersonii, S. megistacrolobum, S. multidissectum, S. polytrichon, S. sanctae-rosae and S. toralapanum). The same set of species was used for the present study to find out if there is also variability for the speed of deacclimation. Relative freezing tolerance of these species was measured before and after cold acclimation as well as after one day of deacclimation (exposure to warm temperatures). Our results suggest that there are differences in the speed of deacclimation among these species. We found that while some species lost near a half of their hardiness, others lost only a third or less of their hardiness after one day of deacclimation.

scholarly journals Transcriptional regulation of bark freezing tolerance in apple (Malus domestica Borkh.)

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Yinghai Liang ◽  
Shanshan Wang ◽  
Chenhui Zhao ◽  
Xinwei Ma ◽  
Yiyong Zhao ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Freezing Tolerance ◽  
Malus Domestica ◽  
Stress Responses ◽  
Expression Profiles ◽  
Cellular Membrane ◽  
Freezing Stress ◽  
Freezing Damage ◽  
Regulatory Pathways ◽  
Freezing Acclimation

AbstractFreezing tolerance is a significant trait in plants that grow in cold environments and survive through the winter. Apple (Malus domestica Borkh.) is a cold-tolerant fruit tree, and the cold tolerance of its bark is important for its survival at low temperatures. However, little is known about the gene activity related to its freezing tolerance. To better understand the gene expression and regulation properties of freezing tolerance in dormant apple trees, we analyzed the transcriptomic divergences in the bark from 1-year-old branches of two apple cultivars, “Golden Delicious” (G) and “Jinhong” (H), which have different levels of cold resistance, under chilling and freezing treatments. “H” can safely overwinter below −30 °C in extremely low-temperature regions, whereas “G” experiences severe freezing damage and death in similar environments. Based on 28 bark transcriptomes (from the epidermis, phloem, and cambium) from 1-year-old branches under seven temperature treatments (from 4 to −29 °C), we identified 4173 and 7734 differentially expressed genes (DEGs) in “G” and “H”, respectively, between the chilling and freezing treatments. A gene coexpression network was constructed according to this expression information using weighted gene correlation network analysis (WGCNA), and seven biologically meaningful coexpression modules were identified from the network. The expression profiles of the genes from these modules suggested the gene regulatory pathways that are responsible for the chilling and freezing stress responses of “G” and/or “H.” Module 7 was probably related to freezing acclimation and freezing damage in “H” at the lower temperatures. This module contained more interconnected hub transcription factors (TFs) and cold-responsive genes (CORs). Modules 6 and 7 contained C-repeat binding factor (CBF) TFs, and many CBF-dependent homologs were identified as hub genes. We also found that some hub TFs had higher intramodular connectivity (KME) and gene significance (GS) than CBFs. Specifically, most hub TFs in modules 6 and 7 were activated at the beginning of the early freezing stress phase and maintained upregulated expression during the whole freezing stress period in “G” and “H”. The upregulation of DEGs related to methionine and carbohydrate biosynthetic processes in “H” under more severe freezing stress supported the maintenance of homeostasis in the cellular membrane. This study improves our understanding of the transcriptional regulation patterns underlying freezing tolerance in the bark of apple branches.

scholarly journals Cold Acclimation Affects Physiological and Biochemical Characteristics of Betula platyphylla S. under Freezing Stress

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1777
Author(s):  
Faujiah Nurhasanah Ritonga ◽  
Siyu Yan ◽  
Song Chen ◽  
Syamsudin A. Slamet ◽  
Laswi Irmayanti ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Cold Acclimation ◽  
Chlorophyll Content ◽  
Tree Species ◽  
Freezing Stress ◽  
Betula Platyphylla ◽  
Biochemical Characteristics ◽  
Physiological And Biochemical Characteristics ◽  
Before And After ◽  
Physiological And Biochemical

Cold and freezing stress is one of the most harmful environmental stresses, especially in temperate and subtropical areas, that adversely affects plant growth, development, and yield production. Betula platyphylla Sukaczev, also known as white birch, is one of the most valuable, important, and widely distributed tree species in East Asia. This study explored the effects of cold acclimation (CA) in reducing the destructive effect of freezing stress in B. platyphylla seedlings. We measured the physiological and biochemical characteristics of B. platyphylla seedlings, such as chlorophyll content, electrolyte leakage (EL), malondialdehyde (MDA), antioxidant enzymes (such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), and proline content before and after freezing stress to observe the contribution of CA in reducing the detrimental effects of freezing stress. The results showed that CA increased physiological and biochemical characteristics of B. platyphylla seedlings before and after freezing stress, except for chlorophyll content. Antioxidant enzymes were significantly positively correlated with proline, MDA, and EL content, and negatively correlated with chlorophyll content. Moreover, histochemical detection (H2O2 and O2−) and cell death were revealed to be induced by cold stress in B. platyphylla seedlings. Furthermore, it was revealed that increased time and decreased temperature of the CA process significantly influenced the physiological and biochemical parameters. Overall, the CA process significantly reduced the detrimental effects of freezing stress compared to the control treatment in B. platyphylla seedlings. Taken together, these findings provide beneficial information toward understanding the mechanism of CA and freezing stress in B. platyphylla. Furthermore, the substantial activity of physiological and biochemical results could be used as selection criteria for screening time and temperature points of cold/freezing stress in further omics analyses. In addition, the combination of current study results, further omics analyses, and genetic engineering techniques directly contribute to sustainable forest management systems, tree plantations, and conservation of tree species, especially non-cold/non-freezing tolerant tree species.

scholarly journals Physiological and molecular characterisation of lucerne (Medicago sativa L.) germplasm with improved seedling freezing tolerance

2016 ◽  
Vol 67 (6) ◽  
pp. 655 ◽  
Author(s):  
M. Rokebul Anower ◽  
Anne Fennell ◽  
Arvid Boe ◽  
Ivan W. Mott ◽  
Michael D. Peel ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Electrolyte Leakage ◽  
Soluble Sugars ◽  
Survival Rates ◽  
Complex Trait ◽  
Growth Conditions ◽  
Before And After ◽  
Medicago Sativa L

We conducted greenhouse experiments to compare 14 lucerne (alfalfa, Medicago sativa L.) germplasms for their survival following freezing. Some are collections adapted to the Grand River National Grasslands in South Dakota. We hypothesised that these collections might have developed a tolerance to survive the frigid growth conditions common there. Two of these collections, River side (RS) and Foster ranch (FR), showed greater freezing tolerance than the other germplasms tested, based on their consistent survival rates with or without cold acclimation. In multiple freezing studies, RS and FR had average survival rates of 74% and 79%, respectively, in contrast to the commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively). The average temperature at which 50% of ions in plant tissues leak out (LT50) by freezing based on leaf electrolyte leakage was closely correlated with survival rates. Leaf LT50 improved 2–3-fold after 3 days of cold acclimation, based on leaf electrolyte leakage analysis, reaching −18°C, –9.6°C, –8.5°C, and −5°C for RS, FR, Apica, and CUF, respectively. Comparison of total soluble sugars and relative water content in shoots before and after cold acclimation showed that they were not well correlated with freezing tolerance and could not explain the superior responses of RS and FR during cold acclimation. Transcript analysis of cold-responsive MsCBF1, MsCBF2 and CAS15B genes showed that RS, FR, Apica and CUF exhibited distinct patterns of cold induction. Although RS, FR and Apica showed a rapid or greater increase in expression level of one or two of these genes, CUF showed only a moderate induction in MsCBF2 and CAS15B transcripts, suggesting that expression of these genes may be a good molecular marker for freezing tolerance in lucerne. The findings provide evidence that freezing tolerance in lucerne is a complex trait and that a combination of different mechanisms may greatly improve freezing tolerance. RS and FR are potential resources in breeding for improving freezing tolerance in lucerne.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

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