Mol Plant , IF:12.084 , 2020 Jun , V13 (6) : P894-906 doi: 10.1016/j.molp.2020.04.006
Cold-Induced CBF-PIF3 Interaction Enhances Freezing Tolerance by Stabilizing the phyB Thermosensor in Arabidopsis.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.; MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI 48824, USA.; State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China. Electronic address: yangshuhua@cau.edu.cn.
Growth inhibition and cold-acclimation strategies help plants withstand cold stress, which adversely affects growth and survival. PHYTOCHROME B (phyB) regulates plant growth through perceiving both light and ambient temperature signals. However, the mechanism by which phyB mediates the plant response to cold stress remains elusive. Here, we show that the key transcription factors mediating cold acclimation, C-REPEAT BINDING FACTORs (CBFs), interact with PHYTOCHROME-INTERACTING FACTOR 3 (PIF3) under cold stress, thus attenuating the mutually assured destruction of PIF3-phyB. Cold-stabilized phyB acts downstream of CBFs to positively regulate freezing tolerance by modulating the expression of stress-responsive and growth-related genes. Consistent with this, phyB mutants exhibited a freezing-sensitive phenotype, whereas phyB-overexpression transgenic plants displayed enhanced freezing tolerance. Further analysis showed that the PIF1, PIF4, and PIF5 proteins, all of which negatively regulate plant freezing tolerance, were destabilized by cold stress in a phytochrome-dependent manner. Collectively, our study reveals that CBFs-PIF3-phyB serves as an important regulatory module for modulating plant response to cold stress.
PMID: 32311530
Plant Cell , IF:9.618 , 2020 Jun doi: 10.1105/tpc.20.00471
Comparative profiling examines roles of DNA regulatory sequences and accessible chromatin during cold stress response in grasses.
Michigan State University CITY: East Lansing STATE: Michigan United States Of America [US] kenchanmane@gmail.com.
PMID: 32576648
Ecol Lett , IF:8.665 , 2020 Jun , V23 (6) : P1034-1048 doi: 10.1111/ele.13502
Functional roles of microbial symbionts in plant cold tolerance.
Laboratorio de Biologia Vegetal, Instituto de Ciencias Biologicas, Universidad de Talca, Campus Lircay, Talca, Chile.; NERC British Antarctic Survey, High Cross, Cambridge, UK.; IFEVA, CONICET, Universidad de Buenos Aires, Facultad de Agronomia, Buenos Aires, Argentina.; Grupo de Biodiversidad y Cambio Global (BCG), Departamento de Ciencias Basicas, Universidad del Bio-Bio, Campus Fernando May, Chillan, Chile.; Centro de Estudios Avanzados en Zonas Aridas (CEAZA), Facultad de Ciencias del Mar, Universidad Catolica del Norte, Coquimbo, Chile.; Centro de Investigacion en Estudios Avanzados del Maule (CIEAM), Universidad Catolica del Maule, Campus San Miguel, Talca, Chile.
In this review, we examine the functional roles of microbial symbionts in plant tolerance to cold and freezing stresses. The impacts of symbionts on antioxidant activity, hormonal signaling and host osmotic balance are described, including the effects of the bacterial endosymbionts Burkholderia, Pseudomonas and Azospirillum on photosynthesis and the accumulation of carbohydrates such as trehalose and raffinose that improve cell osmotic regulation and plasma membrane integrity. The influence of root fungal endophytes and arbuscular mycorrhizal fungi on plant physiology at low temperatures, for example their effects on nutrient acquisition and the accumulation of indole-3-acetic acid and antioxidants in tissues, are also reviewed. Meta-analyses are presented showing that aspects of plant performance (shoot biomass, relative water content, sugar and proline concentrations and Fv /Fm ) are enhanced in symbiotic plants at low (-1 to 15 degrees C), but not at high (20-26 degrees C), temperatures. We discuss the implications of microbial symbionts for plant performance at low and sub-zero temperatures in the natural environment and propose future directions for research into the effects of symbionts on the cold and freezing tolerances of plants, concluding that further studies should routinely incorporate symbiotic microbes in their experimental designs.
PMID: 32281227
Plant Biotechnol J , IF:8.154 , 2020 Jun , V18 (6) : P1409-1420 doi: 10.1111/pbi.13306
Increased Rubisco content in maize mitigates chilling stress and speeds recovery.
Boyce Thompson Institute, Ithaca, NY, USA.; Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA.; Research School of Biology, The Australian National University, Canberra, ACT, Australia.
Many C4 plants, including maize, perform poorly under chilling conditions. This phenomenon has been linked in part to decreased Rubisco abundance at lower temperatures. An exception to this is chilling-tolerant Miscanthus, which is able to maintain Rubisco protein content under such conditions. The goal of this study was to investigate whether increasing Rubisco content in maize could improve performance during or following chilling stress. Here, we demonstrate that transgenic lines overexpressing Rubisco large and small subunits and the Rubisco assembly factor RAF1 (RAF1-LSSS), which have increased Rubisco content and growth under control conditions, maintain increased Rubisco content and growth during chilling stress. RAF1-LSSS plants exhibited 12% higher CO2 assimilation relative to nontransgenic controls under control growth conditions, and a 17% differential after 2 weeks of chilling stress, although assimilation rates of all genotypes were ~50% lower in chilling conditions. Chlorophyll fluorescence measurements showed RAF1-LSSS and WT plants had similar rates of photochemical quenching during chilling, suggesting Rubisco may not be the primary limiting factor that leads to poor performance in maize under chilling conditions. In contrast, RAF1-LSSS had improved photochemical quenching before and after chilling stress, suggesting that increased Rubisco may help plants recover faster from chilling conditions. Relatively increased leaf area, dry weight and plant height observed before chilling in RAF1-LSSS were also maintained during chilling. Together, these results demonstrate that an increase in Rubisco content allows maize plants to better cope with chilling stress and also improves their subsequent recovery, yet additional modifications are required to engineer chilling tolerance in maize.
PMID: 31793172
Plant Physiol , IF:6.902 , 2020 Jun doi: 10.1104/pp.20.00591
CYCLIC NUCLEOTIDE-GATED ION CHANNEL 14 and 16 promote tolerance to heat and chilling in rice.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University CITY: Nanjing STATE: Jiangsu China [CN].; Zhejiang University CITY: Hangzhou STATE: Zhejiang China [CN].; Nanjing Agricultural University CITY: Nanjing China [CN].; National Experimental Teaching Center for Plant Production, Nanjing Agricultural University CITY: Nanjing STATE: Jiangsu China [CN].; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University CITY: Nanjing China [CN].; Cornell University CITY: Ithaca STATE: New York POSTAL_CODE: 14853 United States Of America [US] jh299@cornell.edu.
Calcium signaling has been postulated to be critical for both heat and chilling tolerance in plants, but its molecular mechanisms are not fully understood. Here, we investigated the function of two closely related cyclic nucleotide-gated ion channel (CNGC) proteins OsCNGC14 and OsCNGC16 in temperature-stress tolerance in rice (Oryza sativa) by examining their loss-of-function mutants generated by genome editing. Under both heat and chilling stress, both the cngc14 and cngc16 mutants displayed reduced survival rates, higher accumulation levels of hydrogen peroxide, and increased cell death. In the cngc16 mutant, the extent to which some genes were induced and repressed in response to heat stress was altered and some HSF (Heat Shock factor) and HSP (Heat Shock Protein) genes were slightly more induced compared to the wild type. Furthermore, the loss of either OsCNGC14 or OsCNGC16 reduced or abolished cytosolic calcium signals induced by either heat or chilling stress. Therefore, OsCNGC14 and OsCNGC16 are required for heat and chilling tolerance and are modulators of calcium signals in response to temperature stress. In addition, the loss of their homologs AtCNGC2 and AtCNGC4 in Arabidopsis also lead to compromised low-temperature tolerance. Thus, this study indicates a critical role of CNGC genes in both chilling and heat tolerance in plants, suggesting a potential overlap in calcium signaling in responses to high- and low-temperature stress.
PMID: 32527735
Plant Cell Environ , IF:6.362 , 2020 Jun , V43 (6) : P1394-1403 doi: 10.1111/pce.13745
Polyploidization-driven differentiation of freezing tolerance in Solidago canadensis.
Weed Research Laboratory, Nanjing Agricultural University, Nanjing, China.; Australian Herbicide Resistance Initiative, School of Agriculture and Environment, University of Western Australia, Perth, Western Australia, Australia.
Solidago canadensis, originating from the temperate region of North America, has expanded southward to subtropical regions through polyploidization. Here we investigated whether freezing tolerance of S. canadensis was weakened during expansion. Measurement of the temperature causing 50% ruptured cells (LT50 ) in 35 S. canadensis populations revealed ploidy-related differentiation in freezing tolerance. Freezing tolerance was found to decrease with increasing ploidy. The polyploid populations of S. canadensis had lower ScICE1 gene expression levels but more ScICE1 gene copies than the diploids. Furthermore, more DNA methylation sites in the ScICE1 gene promoter were detected in the polyploids than in the diploids. The results suggest that promoter methylation represses the expression of multi-copy ScICE1 genes, leading to weaker freezing tolerance in polyploid S. canadensis compared to the diploids. The study provides empirical evidence that DNA methylation regulates expression of the gene copies and supports polyploidization-driven adaptation to new environments.
PMID: 32092164
Plant J , IF:6.141 , 2020 Jun doi: 10.1111/tpj.14899
Factors affecting freezing tolerance: a comparative transcriptomics study between field and artificial cold acclimations in overwintering evergreens.
Department of Horticulture, College of Agriculture and Biotechnology, Physiology and Molecular Biology Laboratory of Ornamental Plants, Zhejiang University, Zhejiang, Hangzhou, 866 Yuhangtang Road, 310058, P. R. China.; Department of Horticulture, Iowa State University, Ames, IA, 50010, United States.
Cold acclimation (CA) is a well-known strategy employed by plants to enhance freezing tolerance in winter. Global warming could disturb CA and increase the potential for winter freeze-injury. Thus, developing robust freezing tolerance through complete CA is essential. To explore the molecular mechanisms of CA in woody perennials, we compared field and artificial CAs. Transcriptomic data showed that photosynthesis/photoprotection, and fatty acid metabolism pathways were specifically enriched in field CA; carbohydrate metabolism, secondary metabolism, and circadian rhythm pathways were commonly enriched in both field and artificial CAs. When compared with plants in vegetative growth in the chamber, we found that the light signals with warm air temperatures in fall might induce the accumulation of leaf abscisic acid (ABA) and jasmonic acid (JA) concentrations, and activate Ca(2+) , ABA, and JA signaling transductions in plants. With the gradual cooling occurrence in winter, more accumulation of anthocyanin, chlorophylls degradation, closure/degradation of photosystem II reaction centers, and substantial accumulation of glucose and fructose contributed to obtaining robust freezing tolerance during field CA. Moreover, we observed that in Rhododendron 'Elsie Lee', ABA and JA decreased in winter, which may be due to the strong requirement of zeaxanthin for rapid thermal dissipation and unsaturated fatty acids for membrane fluidity. Taken together, our results indicate that artificial CA has limitations to understand the field CA, and field light signals (like short photoperiod, light intensity, and/or light quality) before the low temperature in fall might be essential for complete CA.
PMID: 32593208
J Exp Bot , IF:5.908 , 2020 Jun , V71 (12) : P3653-3663 doi: 10.1093/jxb/eraa145
WHIRLY1 maintains leaf photosynthetic capacity in tomato by regulating the expression of RbcS1 under chilling stress.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai' an, Shandong, China.
Rubisco, which consists of eight large subunits (RBCLs) and eight small subunits (RBCSs), is a major photosynthetic enzyme that is sensitive to chilling stress. However, it is largely unclear how plants maintain high Rubisco content under low temperature conditions. Here, we report that tomato WHIRLY1 (SlWHY1) positively regulates the Rubisco level under chilling stress by directly binding to the promoter region of SlRbcS1, resulting in the activation of SlRbcS1 expression. SlRbcS1-overexpressing lines had higher Rubisco contents and were more resistant to chilling stress compared with the wild type. Quantitative real-time PCR analyses showed that, among the five RbcS genes, only SlRbcS1 expression is up-regulated by chilling treatment. These results indicate that SlWHIRLY1 specifically enhances the levels of SlRbcS1 and confers tolerance to chilling stress. The amino acid sequence of SlRBCS1 shows 92.67% identity with those of another two RBCS proteins and three residues are specifically found in SlRBCS1. However, mutation of these residues to alanine in SlRBCS1 does not influence its function during cold adaptation. Thus, we conclude that high levels of Rubisco, but not the specific residues in SlRBCS1, play important roles in tolerance to chilling stress in tomato.
PMID: 32189001
J Integr Plant Biol , IF:4.885 , 2020 Jun , V62 (6) : P737-760 doi: 10.1111/jipb.12852
Coordination of light, circadian clock with temperature: The potential mechanisms regulating chilling tolerance in rice.
Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, School of Agriculture, Hunan Agricultural University, Changsha, 410128, China.; Huazhi Rice Bio-tech Company Ltd., Changsha, 410128, China.
Rice (Oryza sativa L.) is a major staple food crop for over half of the world's population. As a crop species originated from the subtropics, rice production is hampered by chilling stress. The genetic mechanisms of rice responses to chilling stress have attracted much attention, focusing on chilling-related gene mining and functional analyses. Plants have evolved sophisticated regulatory systems to respond to chilling stress in coordination with light signaling pathway and internal circadian clock. However, in rice, information about light-signaling pathways and circadian clock regulation and their roles in chilling tolerance remains elusive. Further investigation into the regulatory network of chilling tolerance in rice is needed, as knowledge of the interaction between temperature, light, and circadian clock dynamics is limited. Here, based on phenotypic analysis of transgenic and mutant rice lines, we delineate the relevant genes with important regulatory roles in chilling tolerance. In addition, we discuss the potential coordination mechanism among temperature, light, and circadian clock in regulating chilling response and tolerance of rice, and provide perspectives for the ongoing chilling signaling network research in rice.
PMID: 31243851
Int J Mol Sci , IF:4.556 , 2020 Jun , V21 (13) doi: 10.3390/ijms21134615
Integrated RNA-Seq Analysis and Meta-QTLs Mapping Provide Insights into Cold Stress Response in Rice Seedling Roots.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Rice (Oryza sativa L.) is a widely cultivated food crop around the world, especially in Asia. However, rice seedlings often suffer from cold stress, which affects their growth and yield. Here, RNA-seq analysis and Meta-QTLs mapping were performed to understand the molecular mechanisms underlying cold tolerance in the roots of 14-day-old seedlings of rice (RPY geng, cold-tolerant genotype). A total of 4779 of the differentially expressed genes (DEGs) were identified, including 2457 up-regulated and 2322 down-regulated DEGs. The GO, COG, KEEG, and Mapman enrichment results of DEGs revealed that DEGs are mainly involved in carbohydrate transport and metabolism, signal transduction mechanisms (plant hormone signal transduction), biosynthesis, transport and catabolism of secondary metabolites (phenylpropanoid biosynthesis), defense mechanisms, and large enzyme families mechanisms. Notably, the AP2/ERF-ERF, NAC, WRKY, MYB, C2H2, and bHLH transcription factors participated in rice's cold-stress response and tolerance. On the other hand, we mapped the identified DEGs to 44 published cold-stress-related genes and 41 cold-tolerant Meta-QTLs regions. Of them, 12 DEGs were the published cold-stress-related genes and 418 DEGs fell into the cold-tolerant Meta-QTLs regions. In this study, the identified DEGs and the putative molecular regulatory network can provide insights for understanding the mechanism of cold stress tolerance in rice. In addition, DEGs in KEGG term-enriched terms or cold-tolerant Meta-QTLs will help to secure key candidate genes for further functional studies on the molecular mechanism of cold stress response in rice.
PMID: 32610550
Aquat Toxicol , IF:4.344 , 2020 Jun , V225 : P105550 doi: 10.1016/j.aquatox.2020.105550
The change of accumulation of heavy metal drive interspecific facilitation under copper and cold stress.
Museum, Hebei University, Baoding, Hebei, China; College of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei, China.; College of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei, China.; College of Chemistry and Environmental Science, Hebei University, Baoding, Hebei, China.; College of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei, China. Electronic address: zhaozhao2005001@163.com.; Hebei Key Laboratory of Marine Biological Resources and Environment, Hebei Ocean and Fisheries Science Reseach Institute, Qinhuangdao, Hebei, China. Electronic address: ywxgh@163.com.
Plant diversity has important functions in ecosystem productivity overyielding and community stability. Little is known about the mechanism causing productivity overyielding and stability under harsh conditions. This study investigated the photosynthetic response and subcellular distribution of uni- and co-cultured duckweeds (Lemna aequinoctialis and Spirodela polyrhiza) under excess copper (1.0 mg/L) and low temperature (5 degrees C) conditions. The results showed that the growth of uni-cultured L. aequinoctialis was not different from that of uni-cultured S. polyrhiza across copper treatments at control temperature (25 degrees C). The growth rate of L. aequinoctialis increased by 55.5 % under excess copper concentration when it coexisted with S. polyrhiza, compared with uni-culture. Subcellular distributions of copper were predominantly distributed in cell walls. S. polyrhiza accumulated more copper in cell walls than L. aequinoctialis under uni-cultured condintion at excess copper concentration. Co-cultured S. polyrhiza increased copper accumulation in cell walls of co-cultured L. aequinoctialis to decrease toxicity at excess copper concentration, compared with L. aequinoctialis. Low temperature increased copper toxicity, with duckweeds having lower growth rate and photosynthetic activities (Fv/Fm). The L. aequinoctialis growth rate in co-culture was higher than in uni-culture under excess copper concentration and low temperature conditions, indicating that S. polyrhiza decreased the copper toxicity for L. aequinoctialis. The photosynthetic activity (Fv/Fm) of co-cultured L. aequinoctialis was higher than that of uni-cultured L. aequinoctialis exposed to excess copper concentration at low temperature. The community that formed by co-culturing S. polyrhiza and L. aequinoctialis produced more biomass by avoiding the toxicity of excess copper through heavy metal compartmentalization and photosynthetic activities.
PMID: 32593114
Sci Rep , IF:3.998 , 2020 Jun , V10 (1) : P10427 doi: 10.1038/s41598-020-63006-7
Resistance of Fritillaria imperialis to freezing stress through gene expression, osmotic adjustment and antioxidants.
Plant Biology Department, Faculty of Science, Behbahan Khatam Alanbia University of Technology, Khuzestan, Iran. hajihashemi@bkatu.ac.ir.; Department of Plant Physiology, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, 94976, Nitra, Slovakia.; Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences, 16500, Prague, Czech Republic.; Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.; Interdepartmental Research Center Nutrafood "Nutraceuticals and Food for Health", University of Pisa, Pisa, Italy.; CIRSEC, Centre for Climatic Change Impact, University of Pisa, Via del Borghetto 80, I-56124, Pisa, Italy.
Plant survival in response to freezing stress depends on the efficient activation of tolerance mechanisms. Fritillaria imperialis exposure to freezing stress enhanced signalling molecules Ca(2+) and H2O2 along with overexpression of Ca(2+) signalling proteins (Ca(2+) dependent protein kinases, CPK), followed by upregulation of NHX1 (Na(+)/H(+) antiporter), LEA (late embryogenesis abundant proteins) and P5CS (1-pyrroline-5-carboxylate synthetase). Overexpression of OsCNGC6 was responsible for high accumulation Ca(2+), Na(+) and K(+). The NHX1 gene product transported Na(+) to vacuoles and increased cytosolic K(+) content to re-establish ionic homeostasis under stress conditions. The reduced water potential of leaves was due to high accumulation of osmolytes and ions. No changes were observed in relative water content of leaves, which might be correlated with overexpression of the LEA gene, which protects against dehydration. High accumulation of H2O2 under freezing stress was responsible for activation of antioxidant systems involving SOD, phenols, anthocyanins, catalase and ascorbate peroxidase. Photosynthesis, suppressed in freezing-stressed plants, returned to normal levels after termination of freezing stress. Taken together, our findings suggest that Fritillaria efficiently tolerated freezing stress through induction of signalling mechanisms and overexpression of cold stress-responsive genes, and prevention of cold-induced water stress, oxidative stress and photosynthetic damage.
PMID: 32591518
Rice (N Y) , IF:3.912 , 2020 Jun , V13 (1) : P43 doi: 10.1186/s12284-020-00401-8
Transcriptome Sequencing and iTRAQ of Different Rice Cultivars Provide Insight into Molecular Mechanisms of Cold-Tolerance Response in Japonica Rice.
Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region, Ministry of Education, Northeast Agriculture University, Harbin, 150030, Heilongjiang, China.; Bei Da Huang Kenfeng Seed Limited Company, Harbin, 150431, Heilongjiang, China.; PlantTech Biotechnology Co., Ltd., Beijing, 100000, China.; Key Laboratory of Germplasm Enhancement, Physiology and Ecology of Food Crops in Cold Region, Ministry of Education, Northeast Agriculture University, Harbin, 150030, Heilongjiang, China. hongweizhao_cool@126.com.
BACKGROUND: Rice (Oryza sativa L.) is one of the most important crops cultivated in both tropical and temperate regions. However, it has a high sensitivity to cold stress and chilling stress limits its nitrogen uptake and metabolism. To identify the genes and pathways involved in cold tolerance, specifically within nitrogen metabolism pathways, we compared gene and protein expression differences between a cold-tolerant cultivar, Dongnong428 (DN), and a cold-sensitive cultivar, Songjing10 (SJ). RESULTS: Using isobaric tags for relative or absolute quantification (iTRAQ) with high-throughput mRNA sequencing (RNA-seq) techniques, we identified 5549 genes and 450 proteins in DN and 6145 genes and 790 proteins in SJ, which were differentially expressed during low water temperature (Tw) treatments. There were 354 transcription factor (TF) genes (212 downregulated, 142 upregulated) and 366 TF genes (220 downregulated, 146 upregulated), including 47 gene families, differentially expressed in DN under control (CKDN) vs. DN under low-Tw (D15DN) and SJ under control (CKSJ) vs. SJ under low-Tw D15SJ, respectively. Genes associated with rice cold-related biosynthesis pathways, particularly the mitogen-activated protein kinase (MAPK) signaling, zeatin biosynthesis, and plant hormone signal transduction pathways, were significantly differentially expressed in both rice cultivars. Differentially expressed proteins (DEPs) associated with rice cold-related biosynthesis pathways, and particularly glutathione metabolism, were significantly differentially expressed in both rice cultivars. Transcriptome and proteome analysis of the nitrogen metabolism pathways showed that major genes and proteins that participated in gamma-aminobutyric acid (GABA) and glutamine synthesis were downregulated under cold stress. CONCLUSION: Cold stress conditions during reproductive growth, resulted in genes and proteins related to cold stress biosynthesis pathways being significantly differentially expressed in DN and SJ. The present study confirmed the known cold stress-associated genes and identified new putative cold-responsive genes. We also found that translational regulation under cold stress plays an important role in cold-tolerant DN. Low-Tw treatments affected N uptake and N metabolism in rice, as well as promoted Glu metabolism and the synthesis of ornithine and proline in cold-sensitive SJ.
PMID: 32572635
Genes (Basel) , IF:3.759 , 2020 Jun , V11 (6) doi: 10.3390/genes11060634
metaRE R Package for Meta-Analysis of Transcriptome Data to Identify the cis-Regulatory Code behind the Transcriptional Reprogramming.
Institute of Cytology and Genetics, Lavrentyeva avenue 10, 630090 Novosibirsk, Russia.; Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands.; Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russia.
At the molecular level, response to an external factor or an internal condition causes reprogramming of temporal and spatial transcription. When an organism undergoes physiological and/or morphological changes, several signaling pathways are activated simultaneously. Examples of such complex reactions are the response to temperature changes, dehydration, various biologically active substances, and others. A significant part of the regulatory ensemble in such complex reactions remains unidentified. We developed metaRE, an R package for the systematic search for cis-regulatory elements enriched in the promoters of the genes significantly changed their transcription in a complex reaction. metaRE mines multiple expression profiling datasets generated to test the same organism's response and identifies simple and composite cis-regulatory elements systematically associated with differential expression of genes. Here, we showed metaRE performance for the identification of low-temperature-responsive cis-regulatory code in Arabidopsis thaliana and Danio rerio. MetaRE identified potential binding sites for known as well as unknown cold response regulators. A notable part of cis-elements was found in both searches discovering great conservation in low-temperature responses between plants and animals.
PMID: 32526881
Plant Physiol Biochem , IF:3.72 , 2020 Jun , V154 : P195-203 doi: 10.1016/j.plaphy.2020.06.005
Characterization of CBL-CIPK signaling complexes and their involvement in cold response in tea plant.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, 310008, China.; National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China.; National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, 310008, China. Electronic address: yjyang@tricaas.com.; National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, 310008, China. Electronic address: xcw75@tricaas.com.
Calcineurin B-like (CBL) proteins, a class of Ca(2+)-binding proteins, play vital roles in calcium signal transduction by interacting specifically with CBL-interacting protein kinases (CIPKs), and these two gene families and their interacting complexes are involved in regulating plant responses to various environmental stimuli. In the present study, eight CBL and 25 CIPK genes were identified in tea plant and divided into four and five subfamilies, respectively. Analysis of the expression of these genes in response to abiotic stresses (mature leaves treated with cold, salinity, and PEG and young shoots treated with cold) revealed that CsCBL1/3/5 and CsCIPK1/4/5/6a/7/8/10b/10c/12/14a/19/23a/24 could be induced by at least two stresses. Under cold stress, CsCBL9 and CsCIPK4/6a/6b/7/11/14b/19/20 were upregulated in both mature leaves and young shoots, CsCBL1/3/5 and CsCIPK1/8/10a/10b/10c/12/14a/23a/24 were induced only in mature leaves, and CsCIPK5/25 were induced only in young shoots. Yeast two-hybrid analysis showed that CsCBL1 could interact with CsCIPK1/10b/12 but not with CsCIPK6a/7/11/14b/20. CsCBL9 was found to interact with CsCIPK1/10b/12/14b but not with CsCIPK6a/7/11/20. These results suggest divergent responses to cold stress regulated by CBL-CIPK complexes between tea plant and Arabidopsis, as well as between mature leaves and young shoots in tea plant. A model of Ca(2+)-CsCBL-CsCIPK module-mediated abiotic stress signaling in tea plant is proposed.
PMID: 32563043
Plant Physiol Biochem , IF:3.72 , 2020 Jun , V151 : P34-46 doi: 10.1016/j.plaphy.2020.03.007
The chilling tolerance divergence 1 protein confers cold stress tolerance in processing tomato.
Key Laboratory of Agricultural Biotechnology, College of Life Science, Shihezi University, Shihezi, 832000, China.; Key Laboratory of Agricultural Biotechnology, College of Life Science, Shihezi University, Shihezi, 832000, China. Electronic address: jianboz9@sina.com.
Tomato (Lycopersicon esculentum Mill [Solanum lycopersicum L.].) is an important food material and cash crop, as well as a model plant for genetic evolution and molecular biology research. However, as a cold-sensitive crop originating from the tropics, the growth and development of tomato is often affected by low temperature stress. Therefore, how processing tomatoes resist this type of stress has important theoretical and practical significance. In this study, the LeCOLD1 gene was cloned from processing tomato. Subcellular localization analysis showed that LeCOLD1 was located in the plasma membrane. Real-time quantitative PCR analysis showed that LeCOLD1 was highly expressed in roots. Drought, salt and low temperatures induced the expression of COLD1. Overexpression and RNA interference vectors of LeCOLD1 were constructed and were transformed into tomato by the Agrobacterium-mediated method, and then obtaining transgenic tomato plants. It was found that LeCOLD1 increased the height of processing tomato plants and increased the length of their roots. In addition, overexpression of LeCOLD1 significantly improved the cold resistance of the plants. Overexpressing LeCOLD1 in tomato plants reduced the damage to the cell membrane, accumulation of ROS and photoinhibition of PSII, and maintained the high activity of antioxidant enzymes and the content of osmotic regulators. Further analysis revealed that during low temperature stress, the cells maintained high levels of antioxidant enzyme activity by regulating the transcription of the genes encoding these enzymes. The results show that overexpressing LeCOLD1 in tomato increases the plants' resistance to low temperatures, and that reducing LeCOLD1 expression makes the plants more sensitive to low temperatures.
PMID: 32193092
Tree Physiol , IF:3.655 , 2020 Jun , V40 (7) : P841-855 doi: 10.1093/treephys/tpaa028
Freezing stress survival mechanisms in Vaccinium macrocarpon Ait. terminal buds.
Department of Horticulture, University of Wisconsin-Madison, 1575 Linden Drive, Madison, WI 53706, USA.; Tree Fruit Research and Extension Center, Washington State University, 1100 N Western Ave, Wenatchee, WA 98801, USA.
Plants' mechanisms for surviving freezing stresses are essential adaptations that allow their existence in environments with extreme winter temperatures. Although it is known that Vaccinium macrocarpon Ait. buds can acclimate in fall and survive very cold temperatures during the winter, the mechanism for survival of these buds is not known. The main objective of this study was to determine which of the two major mechanisms of freezing stress survival, namely, deep supercooling or freeze-induced dehydration, are employed by V. macrocarpon terminal buds. In the present study, no low-temperature exotherms (LTEs) were detected by differential thermal analysis. Furthermore, a gradual reduction of relative liquid water content in the inner portions of buds during magnetic resonance imaging (MRI) scans performed between 0 and -20 degrees C (where no damage was detected in controlled freezing tests (CFT)) indicates these buds may not deep supercool. The higher ice nucleation activity of outer bud scales and the appearance of large voids in this structure in early winter, in conjunction with the MRI observations, are evidence supportive of a freeze-induced dehydration process. In addition, the presence of tissue browning in acclimated buds as a result of freezing stress was only observed in CFT at temperatures below -20 degrees C, and this damage gradually increased as test temperatures decreased and at different rates depending on the bud structure. Ours is the first study to collect multiple lines of evidence to suggest that V. macrocarpon terminal buds survive long periods of freezing stress by freeze-induced dehydration. Our results provide a framework for future studies of cold hardiness dynamics for V. macrocarpon and other woody perennial species and for the screening of breeding populations for freezing stress tolerance traits.
PMID: 32163157
Tree Physiol , IF:3.655 , 2020 Jun doi: 10.1093/treephys/tpaa070
Explaining the exceptional 4,270 m high elevation limit of an evergreen oak in the south-eastern Himalaya.
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 620204, Yunnan, China RP.; Institute of Botany, University of Basel, Schonbeinstrasse 6, 4056, Basel, Switzerland.
Unlike the well understood alpine treeline, the upper range limits of tree taxa that do not reach the alpine treeline are largely unexplained. In this study, we explored the causes of the exceptionally high elevation (4,270 m) occurrence of broad-leaved evergreen oaks (Quercus pannosa) in SE Himalayas. We assessed the course of freezing resistance of buds and leaves from winter to summer at the upper elevational limit of this oak species. Linked to leaf phenology, we analyzed freezing resistance and assessed minimum crown temperature for the past 65 years. We also examined potential carbon limitation at the range limit of this species. Last season buds and leaves operated at a safety margin of 5.5 and 11 K in mid-winter. Once fully dehardened early in July, last season foliage is damaged at -5.9 and new foliage at -4.6 degrees C. Bud break is timed for late June to early July when low temperature extremes historically were never below -3.0 degrees C. The monsoon regime ensures a long remaining season (149 d), thus compensating for the late onset of shoot growth. Compared to a site at 3450 m, specific leaf area (SLA) is reduced, foliar non-structural carbohydrate (NSC) concentrations are similar, and the delta13C signal, is higher, jointly suggesting that carbon limitation is unlikely at the range limit of this species. We also show that these oaks enter the growing season with fully intact (not embolized) xylem. We conclude that the interaction between phenology and freezing tolerance results in safe flushing, while still facilitating shoot maturation before winter. These factors jointly determine the upper range limit of this oak species. Our study illuminates an exceptional case of broad-leafed evergreen tree performance near treeline, and by exploring a suite of traits, we can underpin the central role of flushing phenology in such a stressful environment.
PMID: 32483630
BMC Genomics , IF:3.594 , 2020 Jun , V21 (1) : P425 doi: 10.1186/s12864-020-06841-2
Understanding the early cold response mechanism in IR64 indica rice variety through comparative transcriptome analysis.
Division of Plant Biology, Bose Institute, P1/12 CIT Scheme VII M, Kolkata, 700054, India.; Structural Biology & Bioinformatics Division, CSIR- Indian Institute of Chemical Biology, Kolkata, 700032, India.; Division of Plant Biology, Bose Institute, P1/12 CIT Scheme VII M, Kolkata, 700054, India. shubho@jcbose.ac.in.
BACKGROUND: Cellular reprogramming in response to environmental stress involves alteration of gene expression, changes in the protein and metabolite profile for ensuring better stress management in plants. Similar to other plant species originating in tropical and sub-tropical areas, indica rice is highly sensitive to low temperature that adversely affects its growth and grain productivity. Substantial work has been done to understand cold induced changes in gene expression in rice plants. However, adequate information is not available for early gene expression, especially in indica variety. Therefore, a transcriptome profile was generated for cold shock treated seedlings of IR64 variety to identify early responsive genes. RESULTS: The functional annotation of early DEGs shows enrichment of genes involved in altered membrane rigidity and electrolytic leakage, the onset of calcium signaling, ROS generation and activation of stress responsive transcription factors in IR64. Gene regulatory network suggests that cold shock induced Ca2+ signaling activates DREB/CBF pathway and other groups of transcription factors such as MYB, NAC and ZFP; for activating various cold-responsive genes. The analysis also indicates that cold induced signaling proteins like RLKs, RLCKs, CDPKs and MAPKK and ROS signaling proteins. Further, several late-embryogenesis-abundant (LEA), dehydrins and low temperature-induced-genes were upregulated under early cold shock condition, indicating the onset of water-deficit conditions. Expression profiling in different high yielding cultivars shows high expression of cold-responsive genes in Heera and CB1 indica varieties. These varieties show low levels of cold induced ROS production, electrolytic leakage and high germination rate post-cold stress, compared to IR36 and IR64. Collectively, these results suggest that these varieties may have improved adaptability to cold stress. CONCLUSIONS: The results of this study provide insights about early responsive events in Oryza sativa l.ssp. indica cv IR64 in response to cold stress. Our data shows the onset of cold response is associated with upregulation of stress responsive TFs, hydrophilic proteins and signaling molecules, whereas, the genes coding for cellular biosynthetic enzymes, cell cycle control and growth-related TFs are downregulated. This study reports that the generation of ROS is integral to the early response to trigger the ROS mediated signaling events during later stages.
PMID: 32580699
BMC Plant Biol , IF:3.497 , 2020 Jun , V20 (1) : P298 doi: 10.1186/s12870-020-02511-3
Identification of small RNAs during cold acclimation in Arabidopsis thaliana.
Department of Biology I, Plant Molecular Cell Biology, Ludwig-Maximilians-Universitat Munchen, LMU Biocenter, Grosshaderner Str. 2-4, 82152, Planegg-Martinsried, Germany.; Computational Systems Biology, Technische Universitat Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663, Kaiserslautern, Germany.; Department of Biology I, Plant Molecular Biology, Ludwig-Maximilians-Universitat Munchen, LMU Biocenter, Grosshaderner Str. 2-4, 82152, Planegg-Martinsried, Germany.; Department of Biology I, Plant Molecular Cell Biology, Ludwig-Maximilians-Universitat Munchen, LMU Biocenter, Grosshaderner Str. 2-4, 82152, Planegg-Martinsried, Germany. wolfgang.frank@lmu.de.
BACKGROUND: Cold stress causes dynamic changes in gene expression that are partially caused by small non-coding RNAs since they regulate protein coding transcripts and act in epigenetic gene silencing pathways. Thus, a detailed analysis of transcriptional changes of small RNAs (sRNAs) belonging to all known sRNA classes such as microRNAs (miRNA) and small interfering RNA (siRNAs) in response to cold contributes to an understanding of cold-related transcriptome changes. RESULT: We subjected A. thaliana plants to cold acclimation conditions (4 degrees C) and analyzed the sRNA transcriptomes after 3 h, 6 h and 2 d. We found 93 cold responsive differentially expressed miRNAs and only 14 of these were previously shown to be cold responsive. We performed miRNA target prediction for all differentially expressed miRNAs and a GO analysis revealed the overrepresentation of miRNA-targeted transcripts that code for proteins acting in transcriptional regulation. We also identified a large number of differentially expressed cis- and trans-nat-siRNAs, as well as sRNAs that are derived from long non-coding RNAs. By combining the results of sRNA and mRNA profiling with miRNA target predictions and publicly available information on transcription factors, we reconstructed a cold-specific, miRNA and transcription factor dependent gene regulatory network. We verified the validity of links in the network by testing its ability to predict target gene expression under cold acclimation. CONCLUSION: In A. thaliana, miRNAs and sRNAs derived from cis- and trans-NAT gene pairs and sRNAs derived from lncRNAs play an important role in regulating gene expression in cold acclimation conditions. This study provides a fundamental database to deepen our knowledge and understanding of regulatory networks in cold acclimation.
PMID: 32600430
BMC Plant Biol , IF:3.497 , 2020 Jun , V20 (1) : P259 doi: 10.1186/s12870-020-02474-5
Transcription factor TabHLH49 positively regulates dehydrin WZY2 gene expression and enhances drought stress tolerance in wheat.
College of Life Science/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, China.; College of Nursing, Weinan Vocational&Technical College, Weinan, 714000, China.; School of Agriculture, Yunnan University, Kunming, 650000, China.; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266000, China.; College of Life Science/State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, 712100, China. linszhang@nwsuaf.edu.cn.
BACKGROUND: As functional proteins, dehydrins are found in many maturing seeds and vegetable tissues under adverse environmental conditions. However, the regulation of dehydrin expression remains unclear. RESULTS: In this study, a novel drought stress-related bHLH transcription factor, TabHLH49, was isolated from a wheat cDNA library treated with the drought and cold stress by using yeast one-hybrid system. TabHLH49 protein possesses a typical conserved bHLH domain and is a Myc-type bHLH transcription factor. TabHLH49 was detected in the nucleus of tobacco epidermal cells, and the amino acid sequences at the C-terminus (amino acids 323-362) is necessary for its transactivation activity. Real-time PCR analyses revealed the tissue-specific expression and drought stress-responsive expression of TabHLH49 in wheat. In addition, the verification in Y1H and electrophoretic mobility shift assays illustrated that TabHLH49 protein can bind and interact with the promoter of the wheat WZY2 dehydrin. Furthermore, the dual-luciferase assays showed that TabHLH49 can positively regulate the expression of WZY2 dehydrin. The transient expression and BSMV-mediated gene silencing of TabHLH49 also showed that TabHLH49 positively regulates the expression of WZY2 dehydrin and improves drought stress resistance in wheat. CONCLUSIONS: These results provide direct evidences that TabHLH49 positively regulates expression level of dehydrin WZY2 gene and improves drought tolerance of wheat.
PMID: 32503498
Plant Mol Biol , IF:3.302 , 2020 Jun , V103 (3) : P303-320 doi: 10.1007/s11103-020-00993-1
Characterisation of the ERF102 to ERF105 genes of Arabidopsis thaliana and their role in the response to cold stress.
Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universitat Berlin, Albrecht-Thaer-Weg 6, 14195, Berlin, Germany.; Max-Planck-Institute of Molecular Plant Physiology, 14476, Potsdam, Germany.; Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universitat Berlin, Albrecht-Thaer-Weg 6, 14195, Berlin, Germany. tschmue@zedat.fu-berlin.de.
KEY MESSAGE: The four phylogenetically closely related ERF102 to ERF105 transcription factors of Arabidopsis thaliana are regulated by different stresses and are involved in the response to cold stress. The ETHYLENE RESPONSE FACTOR (ERF) genes of Arabidopsis thaliana form a large family encoding plant-specific transcription factors. Here, we characterise the four phylogenetically closely related ERF102/ERF5, ERF103/ERF6, ERF104 and ERF105 genes. Expression analyses revealed that these four genes are similarly regulated by different hormones and abiotic stresses. Analyses of tissue-specific expression using promoter:GUS reporter lines revealed their predominant expression in root tissues including the root meristem (ERF103), the quiescent center (ERF104) and the root vasculature (all). All GFP-ERF fusion proteins were nuclear-localised. The analysis of insertional mutants, amiRNA lines and 35S:ERF overexpressing transgenic lines indicated that ERF102 to ERF105 have only a limited impact on regulating shoot and root growth. Previous work had shown a role for ERF105 in the cold stress response. Here, measurement of electrolyte leakage to determine leaf freezing tolerance and expression analyses of cold-responsive genes revealed that the combined activity of ERF102 and ERF103 is also required for a full cold acclimation response likely involving the CBF regulon. These results suggest a common function of these ERF genes in the response to cold stress.
PMID: 32185689
Phytochemistry , IF:3.044 , 2020 Jun , V174 : P112346 doi: 10.1016/j.phytochem.2020.112346
Comparative metabolomics analysis of the response to cold stress of resistant and susceptible Tibetan hulless barley (Hordeum distichon).
State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, 850002, China; Agricultural Research Institute, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 850002, China.; State Key Laboratory of Hulless Barley and Yak Germplasm Resources and Genetic Improvement, Lhasa, 850002, China; Agricultural Research Institute, Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, 850002, China. Electronic address: yhjxzls@sina.com.
Plants cultivated on the Qinghai-Tibetan Plateau grow in an extremely cold environment and thus are exposed to cold stress. To assess the metabolic processes during cold exposure of Tibetan hulless barley (Hordeum distichon L.), metabolic analyses were conducted on one tolerant (XiLa) and one sensitive (ZangQing) cultivar exposed to six temperatures (24 degrees C, 12 degrees C, 5 degrees C, 0 degrees C, -5 degrees C, -8 degrees C) for 24 h. In total, 770 metabolites were identified, including amino acids and derivatives, carbohydrates, flavonoids, lipids, nucleotides and derivatives, and phenolamides. In principal component analysis, the samples were clearly grouped according to the cultivar, suggesting that the two cultivars have differential responses to cold stress. In cold-grown plants, eight metabolites, including monoacylglycerol (MAG, 18:2), MAG (18:3), deoxyadenosine, 6-methylmercaptopurine, and coniferin, were significantly altered in XiLa, but not in ZangQing when compared to the levels in control plants, and thus, these compounds can be considered as potential biomarkers of exposure to cold stress in hulless barley. Furthermore, differentially altered metabolites between seedlings exposed to -8 degrees C and those maintained at 24 degrees C were significantly enriched in glutathione metabolism. The findings of this study will be useful for the development of cultivars with cold stress tolerance.
PMID: 32229337
Gene , IF:2.984 , 2020 Jun , V742 : P144602 doi: 10.1016/j.gene.2020.144602
Transcriptomic response to cold of thermophilous medicinal plant Marsdenia tenacissima.
Key Laboratory of Medicinal Plant Biology of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan 650201, China; National & Local Joint Engineering Research Center on Germplasm Utilization & Innovation of Chinese Medicinal Materials in Southwestern China, Kunming, Yunnan 650201, China.; Plant Germplasm and Genomics Center, The Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; School of Information Science and Engineering, Yunnan University, Kunming, Yunnan 650201, China.; College of Plant Protection, Yunnan Agricultural University, Kunming, Yunnan 650201, China.; Plant Germplasm and Genomics Center, The Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China. Electronic address: zhouyanli@mail.kib.ac.cn.
Extracts from Marsdenia tenacissima, involving tenacissoside H, I and G, have been used as remedies of cancer, inflammation and asthma. Low temperature serves as one of the main factors constrain the planting expansion and quality of M. tenacissima, but its functional mechanism has been known scarcely for the lack of genomic information and transcriptional profile. Here we investigated the transcriptomic responses of M. tenacissima under cold stress to gain insight into the molecular mechanism of low temperature sensitivity. Total RNAs were collected from samples obtained at 4-time points (after 0, 3, 6 and 48 h cold treatments with 4 degrees C, respectively), then used for library construction and sequenced on the Illumina Hiseq 4000 platform. Passing quality assessments, 500794 transcripts, and 206137 unigenes were de novo assembly out in Trinity v2.4.0, holding contig N50 of 2566 bp and unigene mean length of 754 bp. 44.20% of assembled unigenes were annotated to the well-known public protein database on a basis of sequence similarity. Using statistical comparison of the fragments per kilo base of transcript per million reads mapped (FPKM) values between conditions, 6082 group-specific differentially expressed genes (DEGs) were identified and considered as cold-responsive genes, which contained copious transcription factors and active secondary metabolism. Among them, 43 unigenes were constantly up-regulated expression along with cold time, which mainly implicated in the biosynthesis of secondary metabolites, carbon metabolism, RNA and DNA metabolism. Conversely, 21 unigenes involved in photosynthesis, cell wall, protein degradation, and transporters were downregulated continually with cold timescale. Experimentally, MtEF1alpha was chosen as the best housekeeping gene. Functional enrichments found that damaging of cold stress on M. tenacissima may be ascribed to inability of photosynthesis, ribsome processing, flavonoid biosynthesis and terpenoids degradation. Correlation analysis between cold induced transcription factors and tenacissoside biosynthesis-related genes indicated that 3beta-HSD significant positively correlated with bHLH51, and 4-MSO with NF-YB, GRAS3, Trihelix, FAR1, MYB60, MYBS1, bZIP43. Further promoter clone found MYB-binding site in the promoter of 4-MSO. In view of the reported cold tolerance of MYB60, it is recommended as a potential candidate suitable for future molecular design of exaptation cultivation with high bioactive constituents.
PMID: 32199947
Cell Stress Chaperones , IF:2.892 , 2020 Jun doi: 10.1007/s12192-020-01115-y
Control of stress-induced apoptosis by freezing tolerance-associated wheat proteins during cryopreservation of rat hepatocytes.
Departement des Sciences biologiques, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-Ville, Montreal, QC, H3C 3P8, Canada.; Departement des Sciences biologiques, Universite du Quebec a Montreal, C.P. 8888, Succ. Centre-Ville, Montreal, QC, H3C 3P8, Canada. averill.diana@uqam.ca.
Cryopreservation is used for long-term storage of cells and tissues. Cryoprotectants such as dimethyl disulfoxide (DMSO) are used to protect cells against freeze-thaw damage. Despite the use of cryoprotectants, hepatocytes are sensitive to stresses imposed by freeze and thaw processes, which cause physical damage, loss of functionality, or cell death. As an alternative, we have developed new technology using several recombinant wheat proteins as cryoprotectants: TaENO (enolase), TaBAS1 (2-Cys peroxiredoxin), and a combination of WCS120 (dehydrin) with TaIRI-2 (inhibitor of ice recrystallization). This study aims to understand the mechanisms by which these plant proteins protect rat hepatocytes against cell death incurred during cryopreservation. Our analysis revealed that for cells cryopreserved with DMSO, cell death occurred by apoptosis and necrosis. Apoptosis was detected by activation of effector caspases-3 and -7, PARP cleavage, and nuclear chromatin condensation. These apoptotic events were inhibited when hepatocytes were cryopreserved with the different plant proteins. Cryopreservation with DMSO activated apoptosis through the mitochondrial pathway: the Bax/Bcl-2 protein ratio increased, mitochondrial membrane potential decreased, and initiator caspase-9 was activated. Furthermore, the endoplasmic reticulum pathway of apoptosis was activated: levels of the chaperone Bip/GRP78 decreased, pro-apoptotic transcription factor CHOP was induced, and initiator caspase-12 was activated. Activation of the mitochondrial and endoplasmic reticulum pathways of apoptosis was attenuated when hepatocytes were cryopreserved with the different recombinant proteins. This study improves understanding of mechanisms of cryoprotection provided by these plant proteins during freezing stress. These proteins are natural products and show promising potential by decreasing cell death during cryopreservation of hepatocytes.
PMID: 32529603
Plants (Basel) , IF:2.762 , 2020 Jun , V9 (6) doi: 10.3390/plants9060720
Maize Tolerance against Drought and Chilling Stresses Varied with Root Morphology and Antioxidative Defense System.
College of Agronomy and Biotechnology, Southwest University/Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing 400716, China.; Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; Department of Agronomy, University of Agriculture, Faisalabad 38040, Pakistan.; Department of Botany, Division of Science and Technology, University of Education, Lahore 54770, Pakistan.
Maize belongs to a tropical environment and is extremely sensitive to drought and chilling stress, particularly at early developmental stages. The present study investigated the individual and combined effects of drought (15% PEG-Solution) and chilling stress (15/12 degrees C) on morpho-physiological growth, osmolyte accumulation, production of reactive oxygen species (ROS), and activities/levels of enzymatic and non-enzymatic antioxidants in two maize hybrids (i.e., "XD889" and "XD319") and two inbred cultivars (i.e., "Yu13" and "Yu37"). Results revealed that individual and combined exposure of drought and chilling stresses hampered the morpho-physiological growth and oxidative status of maize cultivars, nevertheless, the interactive damage caused by drought + chilling was found to be more severe for all the studied traits. Between two individual stress factors, chilling-induced reductions in seedling length and biomass of maize cultivars were more compared with drought stress alone. Greater decrease in root length and biomass under chilling stress ultimately decreased the volume and surface area of the root system, and restricted the shoot growth. All the stress treatments, particularly chilling and drought + chilling, triggered the oxidative stress by higher accumulation of superoxide anion, hydrogen peroxide, hydroxyl ion, and malondialdehyde contents compared with the control. Variations in response of maize cultivars were also apparent against different stress treatments, and XD889 performed comparatively better than the rest of the cultivars. The better growth and greater stress tolerance of this cultivar was attributed to the vigorous root system architecture, as indicated by higher root biomass, root surface area, and root volume under drought and chilling stresses. Moreover, efficient antioxidant defense system in terms of higher total antioxidant capability, superoxide dismutase, peroxidase, catalase, and glutathione reductase activities also contributed in greater stress tolerance of XD889 over other cultivars.
PMID: 32517168
Arch Anim Nutr , IF:1.691 , 2020 Jun , V74 (3) : P206-221 doi: 10.1080/1745039X.2019.1693860
Plant extract supplementation as a strategy for substituting dietary antibiotics in broiler chickens exposed to low ambient temperature.
Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran.; Department of Poultry Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.; Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.; Department of Animal Science, Faculty of Agriculture, University of Zabol, Zabol, Iran.; Department of Animal Sciences, College of Agricultural Sciences and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.
The present study was conducted to investigate the effects of two plant extracts as alternatives to dietary antibiotics in broiler chickens exposed to low ambient temperature. A total of 300 one-day-old male broiler chickens were randomly assigned to four dietary treatments (5 replicate pens; 15 broiler chickens each) which consisted of starter (d 0 to 10), and grower (d 10 to 28) diets. Dietary treatments included a basal diet (negative control, NC) and three similar diets that were either supplemented with 200 mg/kg of Prosopis farcta extract (PFE), Rhus coriaria L. extract (RCE) or an antibiotic premix containing oxytetracycline (positive control, PC). In order to simulate low ambient temperature, room temperature was maintained at 32 degrees C during the first 3 d of the trial and afterwards, the temperature was gradually reduced by approximately 1.5 degrees C each day to 14 degrees C on d 21. PFE and PC treatments exerted a significant effect on body weight gain at d 28. Diet PFE was effective in reducing mortality when compared with diet NC (p < 0.05). Furthermore, diet PFE caused increases in ileal digestibility of gross energy, dry matter and organic matter when compared with diet NC (p < 0.05). Diets PFE and PC decreased coliforms, total aerobic bacteria and total anaerobic bacteria loads in the caeca when compared with diet NC (p < 0.05). Moreover, the addition of PFE to the diet improved villous height in all small intestinal segments as well as villous height:crypt depth ratio in the duodenum when compared with diet NC (p < 0.05). The results indicated that PFE is not only a valid alternative to oxytetracycline under cold stress conditions, with no antibiotic resistance, but also has the potential to increase the resistance of broiler chickens against ascites syndrome. Moreover, the addition of RCE at the concentration of 200 mg/kg to the diet was not sufficient to improve the performance of broiler chickens (similar to diet PC) but maybe more effective at higher concentrations.
PMID: 31852306