New Phytol , IF:8.512 , 2019 Mar , V221 (4) : P1998-2012 doi: 10.1111/nph.15532
Whirly1 enhances tolerance to chilling stress in tomato via protection of photosystem II and regulation of starch degradation.
State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China.; Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
In plants, the chilling response involves decreased photosynthetic capacity and increased starch accumulation in chloroplasts. However, the mechanisms that modulate these processes remain unclear. We found that the SlWHY1 gene is significantly induced by chilling stress (4 degrees C) in tomato. Three SlWHY1 overexpression (OE) lines grew better than the wild type (WT) under chilling stress; the OE plants retained intact photosynthetic grana lamellae and showed enhanced hydrolysis of starch. By contrast, RNAi lines that inhibited SlWHY1 were more affected than the corresponding WT cultivar. Their grana lamellae were damaged and starch content increased. The psbA gene encodes the key photosystem II (PSII) protein D1. We show that SlWHY1 binds to the upstream region (A/GTTACCCT/A) of SlpsbA and enhances the de novo synthesis of D1 in chloroplasts. Additionally, SlWHY1 regulates the expression of the starch-degrading enzyme alpha-amylase (SlAMY3-L) and the starch synthesis-related enzyme isoamylase gene (SlISA2) in the nucleus, thus modulating the starch content in chloroplasts. We demonstrate that SlWHY1 enhances the resistance of tomato to chilling stress by maintaining the function of PSII and degrading starch. Thus, overexpression of WHY1 may be an effective strategy for enhancing resistance to chilling stress of chilling-sensitive crops in agricultural production.
PMID: 30307037
Plant Cell Environ , IF:6.362 , 2019 Mar , V42 (3) : P854-873 doi: 10.1111/pce.13502
Molecular signatures associated with increased freezing tolerance due to low temperature memory in Arabidopsis.
Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.; Department of Chemistry and Bioscience, Aalborg University, Aalborg East, Denmark.
Alternating temperatures require fast and coordinated adaptation responses of plants. Cold acclimation has been extensively investigated and results in increased freezing tolerance in Arabidopsis thaliana. Here, we show that the two Arabidopsis accessions, Col-0 and N14, which differ in their freezing tolerance, showed memory of cold acclimation, that is, cold priming. Freezing tolerance was higher in plants exposed to cold priming at 4 degrees C, a lag phase at 20 degrees C, and a second triggering cold stress (4 degrees C) than in plants that were only cold primed. To our knowledge, this is the first report on cold memory improving plant freezing tolerance. The triggering response was distinguishable from the priming response at the levels of gene expression (RNA-Seq), lipid (ultraperformance liquid chromatography-mass spectrometry), and metabolite composition (gas chromatography-mass spectrometry). Transcriptomic responses pointed to induced lipid, secondary metabolism, and stress in Col-0 and growth-related functions in N14. Specific accumulation of lipids included arabidopsides with possible functions as signalling molecules or precursors of jasmonic acid. Whereas cold-induced metabolites such as raffinose and its precursors were maintained in N14 during the lag phase, they were strongly accumulated in Col-0 after the cold trigger. This indicates genetic differences in the transcriptomic and metabolic patterns during cold memory.
PMID: 30548618
Plant Cell Environ , IF:6.362 , 2019 Mar , V42 (3) : P846-853 doi: 10.1111/pce.13408
Cold stress signalling in female reproductive tissues.
Biotechnology of Horticultural Crops, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.
Cold stress is a significant threat for plant productivity and impacts on plant distribution and crop production, particularly so when it occurs during the growth phase. A developmental stage at risk is that of flowering, since a single stress event during sensitive stages, such as the full-bloom stage of fruit trees can be fatal for reproductive success. Although pollen development and fertilization are widely viewed as the most critical reproductive phases, the development and function of female reproductive tissues, which in Angiosperms are embedded in the gynoecium, are also affected by cold stress. Today however, we have essentially no understanding of the cold stress response pathways that act during floral organogenesis. In this review, we briefly summarize our current knowledge of cold stress signalling modules active in vegetative tissues that may provide a framework of general principles also transferable to female reproductive tissues. We then align these signalling cascades with those that govern gynoecium development to identify factors that may act in both processes and could thereby contribute to cold stress responses in female reproductive tissues.
PMID: 30043473
Plant Cell Environ , IF:6.362 , 2019 Mar , V42 (3) : P832-845 doi: 10.1111/pce.13387
A novel MYB transcription factor regulates ascorbic acid synthesis and affects cold tolerance.
College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Dehydroascorbate reductase (DHAR) plays an important role in stress responses, but the transcriptional regulation of DHAR in response to abiotic stress is still poorly understood. In this study, we isolated a novel R2R3-type MYB transcription factor from Pyrus betulaefolia by yeast one-hybrid screening, designated as PbrMYB5. PbrMYB5 was localized in the nucleus and could bind specifically to the promoter of PbrDHAR2. PbrMYB5 was greatly induced by cold and salt but slightly by dehydration. Overexpression of PbrMYB5 in tobacco conferred enhanced tolerance to chilling stresses, whereas down-regulation of PbrMYB5 in P. betulaefolia by virus-induced gene silencing resulted in elevated chilling sensitivity. Transgenic tobacco exhibited higher expression levels of NtDHAR2 and accumulated larger amount of ascorbic acid (AsA) than the wild-type plants. Virus-induced gene silencing of PbrMYB5 in P. betulaefolia down-regulated PbrDHAR2 abundance and decreased AsA level, accompanied by an increased sensitivity to the chilling stress. Taken together, these results demonstrated that PbrMYB5 was an activator of AsA biosynthesis and may play a positive role in chilling tolerance, at least in part, due to the modulation of AsA synthesis by regulating the PbrDHAR2 expression.
PMID: 29929211
Int J Mol Sci , IF:4.556 , 2019 Mar , V20 (5) doi: 10.3390/ijms20051130
On a Cold Night: Transcriptomics of Grapevine Flower Unveils Signal Transduction and Impacted Metabolism.
Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. me.sawicki@laposte.net.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. marine.rondeau@univ-reims.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. barbara.courteaux@univ-reims.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. clarisse.rabenoelina@univ-reims.fr.; Luxembourg Institute of Science and Technology (LIST), Environmental Research and Innovation (ERIN) Department, 41 rue du Brill, L- 4422 Belvaux, Luxembourg. gea.guerriero@list.lu.; Institute of Vine and Wine Sciences, UMR 1287 Ecophysiology and Grape Functional Genomics, University of Bordeaux, INRA 210 Chemin de Leysotte - CS 50008, 33882 Villenave d'Ornon CEDEX, France. eric.gomes@inra.fr.; Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Universite Paris-Sud, Universite Evry, Universite Paris-Saclay, Batiment 630, 91405 Orsay, France. ludivine.soubigou-taconnat@inra.fr.; Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Universite Paris-Sud, Universite Evry, Universite Paris-Saclay, Batiment 630, 91405 Orsay, France. sandrine.balzergue@inra.fr.; Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cite, Batiment 630, 91405, Orsay, France. sandrine.balzergue@inra.fr.; IRHS, INRA, AGROCAMPUS-Ouest, Universite d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071 Beaucouze CEDEX, France. sandrine.balzergue@inra.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. christophe.clement@univ-reims.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. ea.barka@univ-reims.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. nathalie.vaillant-gaveau@univ-reims.fr.; Unite de Recherche Resistance Induite et Bioprotection des Plantes-EA 4707, Universite de Reims Champagne-Ardenne, UFR Sciences Exactes et Naturelles, SFR Condorcet FR CNRS 3417, Moulin de la Housse-Batiment 18, BP 1039, 51687 REIMS Cedex 2, France. cedric.jacquard@univ-reims.fr.
Low temperature is a critical environmental factor limiting plant productivity, especially in northern vineyards. To clarify the impact of this stress on grapevine flower, we used the Vitis array based on Roche-NimbleGen technology to investigate the gene expression of flowers submitted to a cold night. Our objectives were to identify modifications in the transcript levels after stress and during recovery. Consequently, our results confirmed some mechanisms known in grapes or other plants in response to cold stress, notably, (1) the pivotal role of calcium/calmodulin-mediated signaling; (2) the over-expression of sugar transporters and some genes involved in plant defense (especially in carbon metabolism), and (3) the down-regulation of genes encoding galactinol synthase (GOLS), pectate lyases, or polygalacturonases. We also identified some mechanisms not yet known to be involved in the response to cold stress, i.e., (1) the up-regulation of genes encoding G-type lectin S-receptor-like serine threonine-protein kinase, pathogen recognition receptor (PRR5), or heat-shock factors among others; (2) the down-regulation of Myeloblastosis (MYB)-related transcription factors and the Constans-like zinc finger family; and (3) the down-regulation of some genes encoding Pathogen-Related (PR)-proteins. Taken together, our results revealed interesting features and potentially valuable traits associated with stress responses in the grapevine flower. From a long-term perspective, our study provides useful starting points for future investigation.
PMID: 30841651
Int J Mol Sci , IF:4.556 , 2019 Mar , V20 (5) doi: 10.3390/ijms20051071
Transcriptome Analysis Reveals Key Cold-Stress-Responsive Genes in Winter Rapeseed (Brassica rapa L.).
College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. 18189560623@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. 18189560623@163.com.; Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108, USA. jeffcoulter@umn.edu.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. liulj198910@163.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. 18894310220@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. 18894310220@163.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. changy157@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. changy157@163.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. vampirepyy@126.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. vampirepyy@126.com.; College of Agronomy and Biotechnology, Hexi University, Zhangye 734000, China. xiucunzeng@126.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. xuyaozhao@126.com.; Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108, USA. xuyaozhao@126.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. wujuny@gsau.edu.cn.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. wujuny@gsau.edu.cn.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. ffyv@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. ffyv@163.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. bj741912523@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. bj741912523@163.com.; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. 18293121851@163.com.; Gansu Provincial Key Laboratory of Aridland Crop Science, Lanzhou 730070, China. 18293121851@163.com.
Low ambient air temperature limits the growth and selection of crops in cold regions, and cold tolerance is a survival strategy for overwintering plants in cold winters. Studies of differences in transcriptional levels of winter rapeseed (Brassica rapa L.) under cold stress can improve our understanding of transcript-mediated cold stress responses. In this study, two winter rapeseed varieties, Longyou-7 (cold-tolerant) and Lenox (cold-sensitive), were used to reveal morphological, physiological, and transcriptome levels after 24 h of cold stress, and 24 h at room temperature, to identify the mechanism of tolerance to cold stress. Compared to Lenox, Longyou-7 has a shorter growth period and greater belowground mass, and exhibits stronger physiological activity after cold stress. Subsequently, more complete genomic annotation was obtained by sequencing. A total of 10,251 and 10,972 differentially expressed genes (DEG) were identified in Longyou-7 and Lenox, respectively. Six terms closely related to cold stress were found by the Gene Ontology (GO) function annotation. Some of these terms had greater upregulated expression in Longyou-7, and the expression of these genes was verified by qRT-PCR. Most of these DEGs are involved in phenylpropanoid biosynthesis, plant hormone signal transduction, ribosome biogenesis, MAPK signaling pathway, basal transcription factors, and photosynthesis. Analysis of the genes involved in the peroxisome pathway revealed that Longyou-7 and Lenox may have different metabolic patterns. Some transcription factors may play an important role in winter rapeseed tolerance to cold stress, and Longyou-7 is slightly slower than Lenox. Our results provide a transcriptome database and candidate genes for further study of winter rapeseed cold stress.
PMID: 30832221
Int J Mol Sci , IF:4.556 , 2019 Mar , V20 (6) doi: 10.3390/ijms20061368
Comparative Physiological Analysis Reveals the Role of NR-Derived Nitric Oxide in the Cold Tolerance of Forage Legumes.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China. zpp198904@163.com.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China. shshl1988@126.com.; College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China. zpc365@163.com.; College of Grassland Science, Nanjing Agricultural University, Nanjing 210095, China. zfguo@njau.edu.cn.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Engineering Research Center for Grassland Science, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China. turflab@scau.edu.cn.
The role of nitric oxide (NO) signaling in the cold acclimation of forage legumes was investigated in this study. Medicago sativa subsp. falcata (L.) Arcang. (hereafter M. falcata) is a forage legume with a higher cold tolerance than Medicago truncatula, a model legume. Cold acclimation treatment resulted in increased cold tolerance in both M. falcata and M. truncatula, which was suppressed by pretreatment with tungstate, an inhibitor of nitrate reductase (NR), and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), a scavenger of NO. Likely, NITRATE REDUCTASE 1 (NIA1), but not NIA2 transcript, NR activity, and NO production were increased after cold treatment. Treatments with exogenous NO donors resulted in increased cold tolerance in both species. Superoxide dismutase (SOD), catalase (CAT), and ascorbate-peroxidase (APX) activities and Cu,Zn-SOD2, Cu,Zn-SOD3, cytosolic APX1 (cAPX1), cAPX3 and chloroplastic APX1 (cpAPX1) transcript levels were induced in both species after cold treatment, which was suppressed by tungstate and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Treatment with exogenous NO resulted in enhanced activities of SOD, CAT, and APX. Moreover, higher levels of NIA1 transcript, NR activity, NO production, and antioxidant enzyme activities and transcripts were observed in M. falcata as compared with M. truncatula after cold treatment. The results suggest that NR-derived NO production and upregulated antioxidant defense are involved in cold acclimation in both species, while the higher levels of NO production and its derived antioxidant enzymes are associated with the higher cold tolerance in M. falcata as compared with M. truncatula.
PMID: 30893759
Int J Food Microbiol , IF:4.187 , 2019 Mar , V293 : P137-145 doi: 10.1016/j.ijfoodmicro.2019.01.005
High voltage atmospheric cold air plasma control of bacterial biofilms on fresh produce.
Plasma Research Group, School of Food Science and Environmental Health, Technological University Dublin, Dublin 1, Ireland.; Biofilm Research Group, School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, Belfast BT97BL, UK.; Plasma Research Group, School of Food Science and Environmental Health, Technological University Dublin, Dublin 1, Ireland. Electronic address: paula.bourke@dit.ie.
Atmospheric cold plasma (ACP) offers great potential for decontamination of food borne pathogens. This study examined the antimicrobial efficacy of ACP against a range of pathogens of concern to fresh produce comparing planktonic cultures, monoculture biofilms (Escherichia coli, Salmonella enterica, Listeria monocytogenes, Pseudomonas fluorescens) and mixed culture biofilms (Listeria monocytogenes and Pseudomonas fluorescens). Biotic and abiotic surfaces commonly occurring in the fresh food industry were investigated. Microorganisms showed varying susceptibility to ACP treatment depending on target and process factors. Bacterial biofilm populations treated with high voltage (80kV) ACP were reduced significantly (p<0.05) in both mono- and mixed species biofilms after 60s of treatment and yielded non-detectable levels after extending treatment time to 120s. However, an extended time was required to reduce the challenge mixed culture biofilm of L. monocytogenes and P. fluorescens inoculated on lettuce, which was dependent on biofilm formation conditions and substrate. Contained treatment for 120s reduced L. monocytogenes and P. fluorescens inoculated as mixed cultures on lettuce (p<0.05) by 2.2 and 4.2 Log10 CFU/ml respectively. When biofilms were grown at 4 degrees C on lettuce, there was an increased resistance to ACP treatment by comparison with biofilm grown at temperature abuse conditions of 15 degrees C. Similarly, L. monocytogenes and P. fluorescens exposed to cold stress (4 degrees C) for 1h demonstrated increased tolerance to ACP treatment compared to non-stressed cells. These finding demonstrates that bacterial form, mono versus mixed challenges as well as environmental stress conditions play an important role in ACP inactivation efficacy.
PMID: 30711711
Biomolecules , IF:4.082 , 2019 Mar , V9 (3) doi: 10.3390/biom9030084
Conserved Glycines Control Disorder and Function in the Cold-Regulated Protein, COR15A.
Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA. oluwakemi@mail.usf.edu.; Department of Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany. wborcher@mail.usf.edu.; Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA. knoxbrown@uni-potsdam.de.; Department of Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany. rindflei@uni-potsdam.de.; Department of Physical Biochemistry, University of Potsdam, 14476 Potsdam, Germany. thalhamm@uni-potsdam.de.; Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL 33620, USA. gdaughdrill@usf.edu.
Cold-regulated (COR) 15A is an intrinsically disordered protein (IDP) from Arabidopsis thaliana important for freezing tolerance. During freezing-induced cellular dehydration, COR15A transitions from a disordered to mostly alpha-helical structure. We tested whether mutations that increase the helicity of COR15A also increase its protective function. Conserved glycine residues were identified and mutated to alanine. Nuclear magnetic resonance (NMR) spectroscopy was used to identify residue-specific changes in helicity for wildtype (WT) COR15A and the mutants. Circular dichroism (CD) spectroscopy was used to monitor the coil(-)helix transition in response to increasing concentrations of trifluoroethanol (TFE) and ethylene glycol. The impact of the COR15A mutants on the stability of model membranes during a freeze(-)thaw cycle was investigated by fluorescence spectroscopy. The results of these experiments showed the mutants had a higher content of alpha-helical structure and the increased alpha-helicity improved membrane stabilization during freezing. Comparison of the TFE- and ethylene glycol-induced coil(-)helix transitions support our conclusion that increasing the transient helicity of COR15A in aqueous solution increases its ability to stabilize membranes during freezing. Altogether, our results suggest the conserved glycine residues are important for maintaining the disordered structure of COR15A but are also compatible with the formation of alpha-helical structure during freezing induced dehydration.
PMID: 30832369
Plant Cell Physiol , IF:4.062 , 2019 Mar , V60 (3) : P702-712 doi: 10.1093/pcp/pcy240
Cold Acclimation of the Thermoacidophilic Red Alga Galdieria sulphuraria: Changes in Gene Expression and Involvement of Horizontally Acquired Genes.
Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Di inverted question mark(1/2)sseldorf, Germany.; Department of Plant Biology, Ecology & Evolution, Oklahoma State University, Stillwater, OK, USA.; Graduate School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju, South Korea.; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
Galdieria sulphuraria is a unicellular red alga that lives in hot, acidic, toxic metal-rich, volcanic environments, where few other organisms survive. Its genome harbors up to 5% of genes that were most likely acquired through horizontal gene transfer. These genes probably contributed to G.sulphuraria's adaptation to its extreme habitats, resulting in today's polyextremophilic traits. Here, we applied RNA-sequencing to obtain insights into the acclimation of a thermophilic organism towards temperatures below its growth optimum and to study how horizontally acquired genes contribute to cold acclimation. A decrease in growth temperature from 42i inverted question mark(1/2)C/46i inverted question mark(1/2)C to 28i inverted question mark(1/2)C resulted in an upregulation of ribosome biosynthesis, while excreted proteins, probably components of the cell wall, were downregulated. Photosynthesis was suppressed at cold temperatures, and transcript abundances indicated that C-metabolism switched from gluconeogenesis to glycogen degradation. Folate cycle and S-adenosylmethionine cycle (one-carbon metabolism) were transcriptionally upregulated, probably to drive the biosynthesis of betaine. All these cold-induced changes in gene expression were reversible upon return to optimal growth temperature. Numerous genes acquired by horizontal gene transfer displayed temperature-dependent expression changes, indicating that these genes contributed to adaptive evolution in G.sulphuraria.
PMID: 30590832
Ann Bot , IF:4.005 , 2019 Mar , V123 (4) : P681-689 doi: 10.1093/aob/mcy201
Abscisic acid (ABA) and low temperatures synergistically increase the expression of CBF/DREB1 transcription factors and cold-hardiness in grapevine dormant buds.
Universidad de Chile, Facultad de Ciencias, Laboratorio de Bioquimica Vegetal, Casilla, Santiago, Chile.; Programa Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Universidad de Chile, Santiago, Chile.
BACKGROUND AND AIMS: It has been reported that low temperatures (LTs) and the plant hormone abscisic acid (ABA) induce the expression of CBF/DREB1 transcription factors in vegetative tissues and seedlings of Vitis vinifera and Vitis riparia and that foliar applications of ABA to V. vinifera increase the freezing tolerance or cold-hardiness of dormant buds. However, the combined effect of ABA and LTs on the expression of CBF/DREB1 transcription factors and on the acquisition of freezing tolerance in dormant grapevine buds has not been investigated. The objective of this study was to analyse the combined effect of ABA and LT treatments on the expression of CBF/DREB transcription factors and the acquisition of freezing tolerance. METHODS: In vitro experiments with single-bud cuttings of grapevines were used to analyse the effect of ABA, ABA + LT and LT on the expression of CBF/DREB transcription factors, dehydrin and antioxidant genes, the acquisition of freezing tolerance and the endogenous content of ABA. Gene expression analysis was performed by quantitative real-time PCR and freezing tolerance was determined by measuring the low-temperature exotherm by differential thermal analysis. ABA levels were determined by gas chromatography coupled to an electron capture detector. KEY RESULTS: The LT treatment and exogenous application of ABA to grapevine dormant buds increased the expression of the CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6. The joint application of LT and ABA produced a huge increase in the expression of these transcription factors, which was greater than the sum of the increases produced by them individually, which indicates the existence of a synergistic effect between ABA and LT on the activation of these transcription factors. This synergic effect was also observed on the increase in bud cold-hardiness and on the expression of antioxidant and dehydrin genes. CONCLUSIONS: The synergy between ABA and LT on the expression of CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6 plays a key role in cold acclimatization of grapevine buds. The results highlight the importance of the combination of stimuli in the improvement of genetic and physiological responses and help us to understand the adaption of plants to complex environments.
PMID: 30418484
Sci Rep , IF:3.998 , 2019 Mar , V9 (1) : P4470 doi: 10.1038/s41598-019-41065-9
Integrative comparative analyses of metabolite and transcript profiles uncovers complex regulatory network in tomato (Solanum lycopersicum L.) fruit undergoing chilling injury.
Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China.; Department of Plant Sciences, University of California, Davis, CA, 95616, USA.; Horticulture Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China.; Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China. jinliang4002@126.com.; Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331, Chongqing, China. dengwei1977@cqu.edu.cn.
Tomato fruit are especially susceptible to chilling injury (CI) when continuously exposed to temperatures below 12 degrees C. In this study, integrative comparative analyses of transcriptomics and metabolomics data were performed to uncover the regulatory network in CI tomato fruit. Metabolite profiling analysis found that 7 amino acids, 27 organic acids, 16 of sugars and 22 other compounds had a significantly different content while transcriptomics data showed 1735 differentially expressed genes (DEGs) were down-regulated and 1369 were up-regulated in cold-stored fruit. We found that the contents of citrate, cis-aconitate and succinate were increased, which were consistent with the expression of ATP-citrate synthase (ACS) and isocitrate dehydrogenase (IDH) genes in cold-treated tomato fruit. Cold stress promotes the expression of ACS and IDH which may increase the synthesis of citrate, cis-aconitate and succinate. Alanine and leucine had increased contents, which may result from alanine aminotransferase (ALT) and branched-chain amino acid aminotransferase (BcAT)'s high expression levels, respectively. Overall the transcriptomics and metabolomics data in our study explain the molecular mechanisms of the chilling injury and expands our understanding of the complex regulatory mechanisms of a metabolic network in response to chilling injury in tomato fruit.
PMID: 30872788
Plant Physiol Biochem , IF:3.72 , 2019 Mar , V136 : P188-195 doi: 10.1016/j.plaphy.2019.01.023
Exogenous gamma-aminobutyric acid treatment improves the cold tolerance of zucchini fruit during postharvest storage.
Department of Plant Physiology, Facultad de Ciencias, University of Granada, Fuentenueva s/n, 18071, Granada, Spain. Electronic address: fpalma@ugr.es.; Department of Plant Physiology, Facultad de Ciencias, University of Granada, Fuentenueva s/n, 18071, Granada, Spain; Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, Wageningen, Netherlands.; Department of Plant Physiology, Facultad de Ciencias, University of Granada, Fuentenueva s/n, 18071, Granada, Spain.; Department of Biology and Geology, Agrifood Campus of International Excellence (CeiA3), CIAIMBITAL, University of Almeria, La Canada de San Urbano s/n, 04120, Almeria, Spain.
This work examines the effect of a treatment with 1mM of gamma-aminobutyric acid (GABA) on zucchini fruit during postharvest cold storage. Specifically, the effect of GABA on postharvest quality was measured, as well as its implication in the GABA shunt and other related metabolic pathways. The treatments were performed in Sinatra, a variety of zucchini highly sensitive to low-temperature storage. The application of GABA improved the quality of zucchini fruit stored at 4 degrees C, with a reduction of chilling-injury index, weight loss, and cell death, as well as a lower rate of electrolyte leakage. GABA content was significantly higher in the treated fruit than in the control fruit at all times analyzed. At the end of the storage period, GABA-treated fruit had higher contents of both proline and putrescine. The catabolism of this polyamine was not affected by exogenous GABA. Also, over the long term, the treatment induced the GABA shunt by increasing the activities of the enzymes GABA transaminase (GABA-T) and glutamate decarboxylase (GAD). GABA-treated fruit contained higher levels of fumarate and malate than did non-treated fruit, as well as higher ATP and NADH contents. These results imply that the GABA shunt is involved in providing metabolites to produce energy, reduce power, and help the fruit to cope with cold stress over the long term.
PMID: 30685698
Plant Sci , IF:3.591 , 2019 Mar , V280 : P18-30 doi: 10.1016/j.plantsci.2018.11.008
Microtubule dynamics modulate sensing during cold acclimation in grapevine suspension cells.
Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131, Karlsruhe, Germany; Research Center of Chinese Jujube, Agricultural University of Hebei, Baoding, Hebei, China. Electronic address: wanglxht@163.com.; Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131, Karlsruhe, Germany; Department of Plant Biology, Faculty of Biological Sciences, Tarbiat Modares University, Teheran, Iran.; Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Fritz-Haber-Weg 4, D-76131, Karlsruhe, Germany.
Cold acclimation is of practical relevance, since it can avoid cold-induced damage in various crops. To efficiently activate cold acclimation requires that the chilling stress is perceived and processed efficiently. In the current work, we use a transgenic cell line of V. rupestris expressing a GFP-labelled tubulin to follow the effect of cold acclimation and the relation between microtubules and the expression of the transcription factor Cold Box Factor 4 (CBF4) as molecular readout for adaptive responses to cold stress. We find that chilling induced cold tolerance correlated with increased CBF4 expression. We show that cold acclimation can be achieved through stabilisation of microtubules by taxol, as well as through transient elimination of microtubules by pronamide in the absence of cold stress. Furthermore, results from inhibitor studies indicate that transcriptional activation of CBF4 appears to be under control of calcium influx. We screened a population of the ancestor of V. sylvestris and could identify different clades with strong induction of CBF4, indicative of genetic variation in cold adaptability that can be used for breeding. We summarize our findings into a working model where microtubule dynamics controls the sensitivity of cold induced calcium influx mediating the induction of CBF4 culminating in cold hardening.
PMID: 30823996
J Plant Physiol , IF:3.013 , 2019 Mar , V234-235 : P80-93 doi: 10.1016/j.jplph.2019.01.007
Dynamic changes in the starch-sugar interconversion within plant source and sink tissues promote a better abiotic stress response.
Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA 95616, USA; Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.; Department of Plant Sciences, University of California, One Shield Avenue, Davis, CA 95616, USA. Electronic address: dmbeckles@ucdavis.edu.
Starch is a significant store of sugars, and the starch-sugar interconversion in source and sink tissues plays a profound physiological role in all plants. In this review, we discuss how changes in starch metabolism can facilitate adaptive changes in source-sink carbon allocation for protection against environmental stresses. The stress-related roles of starch are described, and published mechanisms by which starch metabolism responds to short- or long-term water deficit, salinity, or extreme temperatures are discussed. Numerous examples of starch metabolism as a stress response are also provided, focusing on studies where carbohydrates and cognate enzymes were assayed in source, sink, or both. We develop a model that integrates these findings with the theoretical and known roles of sugars and starch in various species, tissues, and developmental stages. In this model, localized starch degradation into sugars is vital to the plant cold stress response, with the sugars produced providing osmoprotection. In contrast, high starch accumulation is prominent under salinity stress, and is associated with higher assimilate allocation from source to sink. Our model explains how starch-sugar interconversion can be a convergent point for regulating carbon use in stress tolerance at the whole-plant level.
PMID: 30685652
Gene , IF:2.984 , 2019 Mar , V689 : P102-113 doi: 10.1016/j.gene.2018.11.092
Transcriptomic and evolutionary analyses of white pear (Pyrus bretschneideri) beta-amylase genes reveals their importance for cold and drought stress responses.
College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: 2016104019@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: 2016104030@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: 2017804152@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: 2017104017@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: Slzhang@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: taost@njau.edu.cn.; College of Horticulture, Nanjing Agricultural University, Nanjing, China, 210095. Electronic address: huangxs@njau.edu.cn.
beta-amylase (BAM) genes play essential roles in plant abiotic stress responses. Although the genome of Chinese white pear (Pyrus bretschneideri) has recently been made available, knowledge regarding the BAM family in pear, including gene function, evolutionary history and patterns of gene expression remains limited. In this study, we identified 17 PbBAMs in the pear genome. Of these, 12 PbBAM members were mapped onto 9 chromosomes and 5 PbBAM genes were located on scaffold contigs. Based on gene structure, protein motif analysis, and the topology of the phylogenetic tree of the PbBAM family, we classified member genes into 4 groups. All PbBAM genes were found to contain typical glycosyl hydrolysis 14 domain motifs. Interfamilial comparisons revealed that the phylogenetic relationships of BAM genes in other Rosaceae species were similar those found in pear. We also found that whole-genome duplication (WGD)/segmental duplication events played critical roles in the expansion of the BAM family. Next, we used transcriptomic data to study gene expression during the response of drought and low temperate responses, and found that genes in Group B were related to drought and cold stress. We identified four PbBAM genes associated with abiotic stress in Pear. Finally, by analyzing co-expression networks and co-regulatory genes, we found that PbBAM1a and PbBAM1b were associated with the pear abiotic stress response.
PMID: 30576803