Prog Lipid Res , IF:15.083 , 2020 Nov , V80 : P101063 doi: 10.1016/j.plipres.2020.101063
The dynamics and role of sphingolipids in eukaryotic organisms upon thermal adaptation.
Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA; Departamento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, SP, Brazil.; Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA.; Departamento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, SP, Brazil.; Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA; Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, New York, USA; Veterans Administration Medical Center, Northport, New York, USA. Electronic address: maurizio.delpoeta@stonybrook.edu.
All living beings have an optimal temperature for growth and survival. With the advancement of global warming, the search for understanding adaptive processes to climate changes has gained prominence. In this context, all living beings monitor the external temperature and develop adaptive responses to thermal variations. These responses ultimately change the functioning of the cell and affect the most diverse structures and processes. One of the first structures to detect thermal variations is the plasma membrane, whose constitution allows triggering of intracellular signals that assist in the response to temperature stress. Although studies on this topic have been conducted, the underlying mechanisms of recognizing thermal changes and modifying cellular functioning to adapt to this condition are not fully understood. Recently, many reports have indicated the participation of sphingolipids (SLs), major components of the plasma membrane, in the regulation of the thermal stress response. SLs can structurally reinforce the membrane or/and send signals intracellularly to control numerous cellular processes, such as apoptosis, cytoskeleton polarization, cell cycle arresting and fungal virulence. In this review, we discuss how SLs synthesis changes during both heat and cold stresses, focusing on fungi, plants, animals and human cells. The role of lysophospholipids is also discussed.
PMID: 32888959
New Phytol , IF:8.512 , 2020 Nov doi: 10.1111/nph.17062
Differential nucleosome occupancy modulates alternative splicing in Arabidopsis thaliana.
School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, UK.; School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7XH, UK.; Cardiff School of Biosciences, Cardiff University, Cardiff, CF10 3AX, UK.; Computational Sciences, The James Hutton Institute, Dundee, DD2 5DA, UK.; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences - BOKU, Muthgasse 18, 1190, Vienna, Austria.; Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, 80523-1878, USA.; Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY, 14853-2703, USA.
Alternative splicing (AS) is a major gene regulatory mechanism in plants. Recent evidence supports co-transcriptional splicing in plants, hence the chromatin state can impact AS. However, how dynamic changes in the chromatin state such as nucleosome occupancy influence the cold-induced AS remains poorly understood. Here, we generated transcriptome (RNA-Seq) and nucleosome positioning (MNase-Seq) data for Arabidopsis thaliana to understand how nucleosome positioning modulates cold-induced AS. Our results show that characteristic nucleosome occupancy levels are strongly associated with the type and abundance of various AS events under normal and cold temperature conditions in Arabidopsis. Intriguingly, exitrons, alternatively spliced internal regions of protein-coding exons, exhibit distinctive nucleosome positioning pattern compared to other alternatively spliced regions. Likewise, nucleosome patterns differ between exitrons and retained introns pointing to their distinct regulation. Collectively, our data show that characteristic changes in nucleosome positioning modulate AS in plants in response to cold.
PMID: 33135169
New Phytol , IF:8.512 , 2020 Nov doi: 10.1111/nph.17063
The JA-responsive MYC2-BADH-like transcriptional regulatory module in Poncirus trifoliata contributes to cold tolerance by modulation of glycine betaine biosynthesis.
Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Glycine betaine (GB) is known to accumulate in plants exposed to cold, but the underlying molecular mechanisms and associated regulatory network remain unclear. Here, we demonstrated that PtrMYC2 of Poncirus trifoliata integrates the JA signal to modulate cold-induced GB accumulation by directly regulating PtrBADH-l, a betaine aldehyde dehydrogenase (BADH)-like gene. PtrBADH-l was identified based on transcriptome and expression analysis in P. trifoliata. Overexpression and VIGS (virus-induced gene silencing)-mediated knockdown showed that PtrBADH-l plays a positive role in cold tolerance and GB synthesis. Yeast one-hybrid library screening using PtrBADH-l promoter as baits unraveled PtrMYC2 as an interacting candidate. PtrMYC2 was confirmed to directly bind to two G-box cis-acting elements within PtrBADH-l promoter and acts as a transcriptional activator. In addition, PtrMYC2 functions positively in cold tolerance through modulation of GB synthesis by regulating PtrBADH-l expression. Interestingly, we found that GB accumulation under cold stress was JA-dependent and that PtrMYC2 orchestrates JA-mediated PtrBADH-l upregulation and GB accumulation. This study sheds new light on the roles of MYC2 homologue in modulating GB synthesis. In particular, we propose a transcriptional regulatory module PtrMYC2-PtrBADH-l to advance the understanding of molecular mechanisms underlying the GB accumulation under cold stress.
PMID: 33131086
Plant Cell Environ , IF:6.362 , 2020 Nov doi: 10.1111/pce.13938
Phosphatase OsPP2C27 directly dephosphorylates OsMAPK3 and OsbHLH002 to negatively regulate cold tolerance in rice.
The Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.; University of the Chinese Academy of Sciences, Beijing, China.
Improving chilling tolerance is a major target of rice breeding. The OsMAPK3-OsbHLH002-OsTPP1 signalling pathway enhances chilling tolerance in rice: the kinase is activated by cold stress, and subsequently the transcription factor is phosphorylated by the activated kinase, triggering the expression of cold response genes. However, it is largely unknown how this pathway is suppressed in time to avoid it being in a continuously activated state. We found that a novel type 2C protein phosphatase, OsPP2C27, functions as a negative regulator of the OsMAPK3-OsbHLH002-OsTPP1 pathway. A dynamic change in OsMAPK3 activity was found during cold treatment. We show that OsPP2C27 interacts physically with and dephosphorylates OsMAPK3 in vitro and in vivo. Interestingly, OsPP2C27 can also directly dephosphorylate OsbHLH002, the target of OsMAPK3. After cold treatment, survival rates were higher in OsPP2C27-RNAi lines and a T-DNA insertion mutant, and lower in OsPP2C27-overexpression lines, compared to wild type. Moreover, expression of the OsTPP1 and OsDREBs were increased in OsPP2C27-RNAi lines and decreased in OsPP2C27-overexpression lines. These results indicate that cold-induced OsPP2C27 negatively regulates the OsMAPK3-OsbHLH002-OsTPP1 signalling pathway by directly dephosphorylating both phospho-OsMAPK3 and phospho-OsbHLH002, preventing the sustained activation of a positive pathway for cold stress and maintaining normal growth under chilling conditions.
PMID: 33150964
Plant Cell Environ , IF:6.362 , 2020 Nov , V43 (11) : P2712-2726 doi: 10.1111/pce.13868
The HY5 and MYB15 transcription factors positively regulate cold tolerance in tomato via the CBF pathway.
Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou, China.; Department of Horticulture, College of Forestry, Henan University of Science and Technology, Luoyang, China.; Key Laboratory of Plant Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou, China.; Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, China.
The induction of C-repeat binding factors (CBFs) is crucial for plant survival at low temperatures. Therefore, understanding the mechanisms that regulate CBF transcription is vital for the future development of crops with increased cold tolerance. Here, we provide evidence for the existence of a LONG HYPOCOTYL 5 (HY5)-MYB15-CBFs transcriptional cascade that plays a crucial role in the cold response in tomato. The exposure of tomato plants to cold (4 degrees C) increased the levels of HY5, MYB15 and CBFs transcripts. Moreover, mutations in HY5 or MYB15 decreased the levels of CBF transcripts. In contrast, overexpression of HY5 or MYB15 increased CBF transcript abundance. Crucially, the HY5 transcription factor activated the expression of MYB15 by directly binding to the promoter region, while both HY5 and MYB15 activated the expression of CBF1, CBF2 and CBF3. Taken together, these data show that HY5 can directly regulate CBF transcript levels, and also influence CBF expression indirectly via MYB15. The coordinated action of HY5 and MYB15 allows precise regulation of CBF expression and subsequent cold tolerance. These findings provide an improved understanding of the molecular mechanisms affording transcriptional regulation of CBFs, which can be exploited in the future to enhance cold tolerance in crops.
PMID: 32799321
Plant Cell Environ , IF:6.362 , 2020 Nov doi: 10.1111/pce.13953
Cell wall modification by the xyloglucan endotransglucosylase/hydrolase XTH19 influences freezing tolerance after cold and sub-zero acclimation.
Max-Planck-Institut fur Molekulare Pflanzenphysiologie, Potsdam, Germany.; La Trobe Institute for Agriculture and Food, La Trobe University, Bundoora, VIC 3086, Australia and Sino-Australian Plant Cell Wall Research Centre, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China.; USDA and Department of Crop Science, North Carolina State University, Raleigh, NC, USA.; Graduate School of Life Sciences, Tohoku University, Aoba-Ku, Sendai, Japan.
Freezing triggers extracellular ice formation leading to cell dehydration and deformation during a freeze-thaw cycle. Many plant species increase their freezing tolerance during exposure to low, non-freezing temperatures, a process termed cold acclimation. In addition, exposure to mild freezing temperatures after cold acclimation evokes a further increase in freezing tolerance (sub-zero acclimation). Previous transcriptome and proteome analyses indicate that cell wall remodeling may be particularly important for sub-zero acclimation. In the present study, we used a combination of immunohistochemical, chemical and spectroscopic analyses to characterize the cell walls of Arabidopsis thaliana and characterized a mutant in the XTH19 gene, encoding a xyloglucan endotransglucosylase/hydrolase (XTH). The mutant showed reduced freezing tolerance after both cold and sub-zero acclimation, compared to the Col-0 wild type, which was associated with differences in cell wall composition and structure. Most strikingly, immunohistochemistry in combination with 3D reconstruction of centers of rosette indicated that epitopes of the xyloglucan-specific antibody LM25 were highly abundant in the vasculature of Col-0 plants after sub-zero acclimation but absent in the XTH19 mutant. Taken together, our data shed new light on the potential roles of cell wall remodeling for the increased freezing tolerance observed after low temperature acclimation. This article is protected by copyright. All rights reserved.
PMID: 33190295
Plant Cell Environ , IF:6.362 , 2020 Nov doi: 10.1111/pce.13941
Naturally occurring circadian rhythm variation associated with clock gene loci in Swedish Arabidopsis accessions.
Earlham Institute, Norwich Research Park, Norwich, UK.; Institute of Integrative Biology, University of Liverpool, Liverpool, UK.; John Innes Centre, Norwich Research Park, Norwich, UK.
Circadian clocks have evolved to resonate with external day and night cycles. However, these entrainment signals are not consistent everywhere and vary with latitude, climate and seasonality. This leads to divergent selection for clocks which are locally adapted. To investigate the genetic basis for this circadian variation, we used a Delayed Fluorescence imaging assay to screen 191 naturally occurring Swedish Arabidopsis accessions for their circadian phenotypes. We demonstrate that period length co-varies with both geography and population sub-structure. Several candidate loci linked to period, phase and Relative Amplitude Error (RAE) were revealed by genome-wide association mapping and candidate genes were investigated using TDNA mutants. We show that natural variation in a single non-synonymous substitution within COR28 is associated with a long-period and late-flowering phenotype similar to that seen in TDNA knock-out mutants. COR28 is a known coordinator of flowering time, freezing tolerance and the circadian clock; all of which may form selective pressure gradients across Sweden. We demonstrate the effect of the COR28-58S SNP in increasing period length through a co-segregation analysis. Finally, we show that period phenotypic tails remain diverged under lower temperatures and follow a distinctive 'arrow-shaped' trend indicative of selection for a cold-biased temperature compensation response. This article is protected by copyright. All rights reserved.
PMID: 33179278
Plant J , IF:6.141 , 2020 Nov , V104 (4) : P1038-1053 doi: 10.1111/tpj.14979
COLD REGULATED 27 and 28 are targets of CONSTITUTIVELY PHOTOMORPHOGENIC 1 and negatively affect phytochrome B signalling.
Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany.; Institute of Synthetic Biology and CEPLAS, Heinrich Heine University Dusseldorf, Dusseldorf, 40225, Germany.; Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, 79104, Germany.; Institute for Plant Sciences, University of Cologne, Cologne, 50674, Germany.; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, 79104, Germany.
Phytochromes are red/far-red light receptors in plants involved in the regulation of growth and development. Phytochromes can sense the light environment and contribute to measuring day length; thereby, they allow plants to respond and adapt to changes in the ambient environment. Two well-characterized signalling pathways act downstream of phytochromes and link light perception to the regulation of gene expression. The CONSTITUTIVELY PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA-105 (COP1/SPA) E3 ubiquitin ligase complex and the PHYTOCHROME INTERACTING FACTORs (PIFs) are key components of these pathways and repress light responses in the dark. In light-grown seedlings, phytochromes inhibit COP1/SPA and PIF activity and thereby promote light signalling. In a yeast-two-hybrid screen for proteins binding to light-activated phytochromes, we identified COLD-REGULATED GENE 27 (COR27). COR27 and its homologue COR28 bind to phyA and phyB, the two primary phytochromes in seed plants. COR27 and COR28 have been described previously with regard to a function in the regulation of freezing tolerance, flowering and the circadian clock. Here, we show that COR27 and COR28 repress early seedling development in blue, far-red and in particular red light. COR27 and COR28 contain a conserved Val-Pro (VP)-peptide motif, which mediates binding to the COP1/SPA complex. COR27 and COR28 are targeted for degradation by COP1/SPA and mutant versions with a VP to AA amino acid substitution in the VP-peptide motif are stabilized. Overall, our data suggest that COR27 and COR28 accumulate in light but act as negative regulators of light signalling during early seedling development, thereby preventing an exaggerated response to light.
PMID: 32890447
Int J Mol Sci , IF:4.556 , 2020 Nov , V21 (22) doi: 10.3390/ijms21228753
Fusion of Mitochondria to 3-D Networks, Autophagy and Increased Organelle Contacts are Important Subcellular Hallmarks during Cold Stress in Plants.
Department of Biosciences, Faculty of Natural Sciences, University of Salzburg, Hellbrunnerstrasse 34, A-5020 Salzburg, Austria.; Ultrastructural Research, Department Biology I, Faculty of Biology, Ludwig-Maximilians-University, Grosshadernerstrasse 2-4, Planegg-Martinsried, D-82152 Munich, Germany.; Department of Botany, Functional Plant Biology, Faculty of Biology, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria.
Low temperature stress has a severe impact on the distribution, physiology, and survival of plants in their natural habitats. While numerous studies have focused on the physiological and molecular adjustments to low temperatures, this study provides evidence that cold induced physiological responses coincide with distinct ultrastructural alterations. Three plants from different evolutionary levels and habitats were investigated: The freshwater alga Micrasterias denticulata, the aquatic plant Lemna sp., and the nival plant Ranunculus glacialis. Ultrastructural alterations during low temperature stress were determined by the employment of 2-D transmission electron microscopy and 3-D reconstructions from focused ion beam-scanning electron microscopic series. With decreasing temperatures, increasing numbers of organelle contacts and particularly the fusion of mitochondria to 3-dimensional networks were observed. We assume that the increase or at least maintenance of respiration during low temperature stress is likely to be based on these mitochondrial interconnections. Moreover, it is shown that autophagy and degeneration processes accompany freezing stress in Lemna and R. glacialis. This might be an essential mechanism to recycle damaged cytoplasmic constituents to maintain the cellular metabolism during freezing stress.
PMID: 33228190
Int J Mol Sci , IF:4.556 , 2020 Nov , V21 (22) doi: 10.3390/ijms21228631
Large-Scale Phosphoproteomic Study of Arabidopsis Membrane Proteins Reveals Early Signaling Events in Response to Cold.
United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan.; Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei 184-8588, Japan.; Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, 3-1-1 Koyadai, Tsukuba 305-0074, Japan.; Department of Biochemistry, Iwate Medical University, Yahaba 028-3694, Japan.; Department of Plant-Bioscience, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.
Cold stress is one of the major factors limiting global crop production. For survival at low temperatures, plants need to sense temperature changes in the surrounding environment. How plants sense and respond to the earliest drop in temperature is still not clearly understood. The plasma membrane and its adjacent extracellular and cytoplasmic sites are the first checkpoints for sensing temperature changes and the subsequent events, such as signal generation and solute transport. To understand how plants respond to early cold exposure, we used a mass spectrometry-based phosphoproteomic method to study the temporal changes in protein phosphorylation events in Arabidopsis membranes during 5 to 60 min of cold exposure. The results revealed that brief cold exposures led to rapid phosphorylation changes in the proteins involved in cellular ion homeostasis, solute and protein transport, cytoskeleton organization, vesical trafficking, protein modification, and signal transduction processes. The phosphorylation motif and kinase-substrate network analysis also revealed that multiple protein kinases, including RLKs, MAPKs, CDPKs, and their substrates, could be involved in early cold signaling. Taken together, our results provide a first look at the cold-responsive phosphoproteome changes of Arabidopsis membrane proteins that can be a significant resource to understand how plants respond to an early temperature drop.
PMID: 33207747
Int J Mol Sci , IF:4.556 , 2020 Nov , V21 (22) doi: 10.3390/ijms21228441
Aux/IAA14 Regulates microRNA-Mediated Cold Stress Response in Arabidopsis Roots.
Department of Plant Bio Sciences, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China.; Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; United Graduate School of Agricultural Sciences, Iwate University, Morioka 020-8550, Japan.; Agri-Innovation Center, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.
The phytohormone auxin and microRNA-mediated regulation of gene expressions are key regulators of plant growth and development at both optimal and under low-temperature stress conditions. However, the mechanistic link between microRNA and auxin in regulating plant cold stress response remains elusive. To better understand the role of microRNA (miR) in the crosstalk between auxin and cold stress responses, we took advantage of the mutants of Arabidopsis thaliana with altered response to auxin transport and signal. Screening of the mutants for root growth recovery after cold stress at 4 degrees C revealed that the auxin signaling mutant, solitary root 1 (slr1; mutation in Aux/IAA14), shows a hypersensitive response to cold stress. Genome-wide expression analysis of miRs in the wild-type and slr1 mutant roots using next-generation sequencing revealed 180 known and 71 novel cold-responsive microRNAs. Cold stress also increased the abundance of 26-31 nt small RNA population in slr1 compared with wild type. Comparative analysis of microRNA expression shows significant differential expression of 13 known and 7 novel miRs in slr1 at 4 degrees C compared with wild type. Target gene expression analysis of the members from one potential candidate miR, miR169, revealed the possible involvement of miR169/NF-YA module in the Aux/IAA14-mediated cold stress response. Taken together, these results indicate that SLR/IAA14, a transcriptional repressor of auxin signaling, plays a crucial role in integrating miRs in auxin and cold responses.
PMID: 33182739
Theor Appl Genet , IF:4.439 , 2020 Nov doi: 10.1007/s00122-020-03725-7
Snow mold of winter cereals: a complex disease and a challenge for resistance breeding.
Laboratory of Plant Infectious Diseases, FRC Kazan Scientific Center of RAS, Ul. Lobachevskogo 2/31, Kazan, 420111, Tatarstan, Russian Federation.; KWS SAAT SE & Co. KGaA, Grimsehlstr. 31, 37555, Einbeck, Germany.; State Plant Breeding Institute, University of Hohenheim, Fruwirthstr. 21, 70599, Stuttgart, Germany. miedaner@uni-hohenheim.de.
KEY MESSAGE: Snow mold resistance is a complex quantitative trait highly affected by environmental conditions during winter that must be addressed by resistance breeding. Snow mold resistance in winter cereals is an important trait for many countries in the Northern Hemisphere. The disease is caused by at least four complexes of soilborne fungi and oomycetes of which Microdochium nivale and M. majus are among the most common pathogens. They have a broad host range covering all winter and spring cereals and can basically affect all plant growth stages and organs. Their attack leads to a low germination rate, and/or pre- and post-emergence death of seedlings after winter and, depending on largely unknown environmental conditions, also to foot rot, leaf blight, and head blight. Resistance in winter wheat and triticale is governed by a multitude of quantitative trait loci (QTL) with mainly additive effects highly affected by genotype x environment interaction. Snow mold resistance interacts with winter hardiness in a complex way leading to a co-localization of resistance QTLs with QTLs/genes for freezing tolerance. In practical breeding, a multistep procedure is necessary with (1) freezing tolerance tests, (2) climate chamber tests for snow mold resistance, and (3) field tests in locations with and without regularly occurring snow cover. In the future, resistance sources should be genetically characterized also in rye by QTL mapping or genome-wide association studies. The development of genomic selection procedures should be prioritized in breeding research.
PMID: 33221940
Front Plant Sci , IF:4.402 , 2020 , V11 : P583666 doi: 10.3389/fpls.2020.583666
Modes of Brassinosteroid Activity in Cold Stress Tolerance.
Biotechnology of Horticultural Crops, School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.
Cold stress is a significant environmental factor that negatively affects plant growth and development in particular when it occurs during the growth phase. Plants have evolved means to protect themselves from damage caused by chilling or freezing temperatures and some plant species, in particular those from temperate geographical zones, can increase their basal level of freezing tolerance in a process termed cold acclimation. Cold acclimation improves plant survival, but also represses growth, since it inhibits activity of the growth-promoting hormones gibberellins (GAs). In addition to GAs, the steroid hormones brassinosteroids (BRs) also take part in growth promotion and cold stress signaling; however, in contrast to Gas, BRs can improve cold stress tolerance with fewer trade-offs in terms of growth and yields. Here we summarize our current understanding of the roles of BRs in cold stress responses with a focus on freezing tolerance and cold acclimation pathways.
PMID: 33240301
Plant Cell Physiol , IF:4.062 , 2020 Nov doi: 10.1093/pcp/pcaa139
EARLY RESPONSE TO DEHYDRATION 7 Remodels Cell Membrane Lipid Composition During Cold Stress in Arabidopsis.
Molecular Plant Biology Unit, Department of Biochemistry, University of Turku, Turku, Finland.; Section Plant Cell Biology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, Science Park 904, Amsterdam, Netherlands.; Department of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.; Department of Molecular Pharmacology and Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywod, IL, USA.
Plants adjust to unfavorable conditions by altering physiological activities such as gene expression. Although previous studies have identified multiple stress-induced genes, the function of many genes during the stress responses remains unclear. Expression of ERD7 (Early Response to Dehydration 7) is induced in response to dehydration. Here, we show that ERD7 plays essential roles in both plant stress responses and development. In Arabidopsis, ERD7 protein accumulated under various stress conditions including exposure to low temperature. A triple mutant of Arabidopsis lacking ERD7 and two closely-related homologs had an embryonic lethal phenotype, whereas a mutant lacking the two homologs and one ERD7 allele had relatively round leaves, indicating that the ERD7 gene family has essential roles in development. Moreover, the importance of the ERD7 family in stress responses was evidenced by the susceptibility of the mutant lines to cold stress. ERD7 protein was found to bind to several, but not all, negatively charged phospholipids, and was associated with membranes. Lipid components and cold-induced reduction of PIP2 in the mutant line were altered relative to wild type. Furthermore, membranes from the mutant line had reduced fluidity. Taken together, ERD7 and its homologs are important for plant stress responses and development and associated with modification of membrane lipid composition.
PMID: 33165601
Ann Bot , IF:4.005 , 2020 Nov doi: 10.1093/aob/mcaa197
Dynamic modeling of cold hardiness in tea buds by imitating past temperature memory.
National Agriculture and Food Research Organization (NARO), Institute of Agro-Environmental Sciences, Kannondai, Tsukuba, Ibaraki, Japan.; Kyushu University, Faculty of Agriculture, Fukuoka, Japan.; Kyushu University, Graduate School of Bioresource and Bioenvironmental Sciences, Fukuoka, Japan.; Kochi University, Faculty of Agriculture and Marine Science, Kochi, Japan.
BACKGROUND AND AIMS: Most perennial plants memorize cold stress for a certain period and retrieve the memories for cold acclimation and deacclimation, which leads to seasonal changes in cold hardiness. Therefore, a model for evaluating cold stress memories is required for predicting cold hardiness and for future frost risk assessments under warming climates. In this study, we develop a new dynamic model of cold hardiness by introducing a function imitating past temperature memory in the processes of cold acclimation and deacclimation. METHODS: We formulated the past temperature memory for plants using thermal time weighted by a forgetting function, and thereby proposed the dynamic model of cold hardiness. We used the buds of tea plants (Camellia sinensis (L.) O. Kuntze) from two cultivars, Yabukita and Yutakamidori, to calibrate and validate this model based on 10 years of observed cold hardiness data. KEY RESULTS: The model captured more than 90% of the observed variations in cold hardiness and predicted accurate values for both cultivars, with root mean square errors of ~1.0 degrees C. The optimized forgetting function indicated that the tea buds memorized both short-term (recent days) and long-term (previous months) temperatures. The memories can drive short-term processes such as increasing/decreasing the content of carbohydrates, proteins, and antioxidants in the buds, as well as long-term processes such as determining the bud phenological stage, both of which vary with cold hardiness. CONCLUSIONS: The use of a forgetting function is an effective means of understanding temperature memories in plants and will aid in developing reliable predictions of cold hardiness for various plant species under global climate warming.
PMID: 33247901
Plant Genome , IF:3.847 , 2020 Nov , V13 (3) : Pe20057 doi: 10.1002/tpg2.20057
Global insights into duplicated gene expression and alternative splicing in polyploid Brassica napus under heat, cold, and drought stress.
Department of Botany, University of British Columbia, 6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada.
Polyploidy has been a prevalent process during plant evolution and it has made a major impact on the structure and evolution of plant genomes. Many important crop plants are polyploid. There is considerable interest in expression patterns of duplicated genes in polyploids. Alternative splicing (AS) is a fundamental aspect of gene expression that produces multiple final transcript types from a single type of mRNAs. The effects of abiotic stress conditions on AS in polyploids has received little attention. We conducted a global transcriptome analysis of Brassica napus, an allotetraploid derived from B. rapa (AT ) and B. oleracea (CT ), by RNA-Seq of plants subjected to cold, heat, and drought stress treatments. Analyses of 27,360 pairs of duplicated genes revealed overall AT subgenome biases in gene expression and CT subgenome biases in the extent of alternative splicing under all three stress treatments. More genes increased in expression than decreased in response to the stresses. Negative correlations were found between expression levels and AS frequency for each type of AS. Cold stress produced the greatest changes in gene expression and AS. Cold-induced AS changes were more likely to be shared with those generated by drought than by heat stress. We used homeologs of FLC and CCA1 as case studies to show the dynamics of how duplicates in a polyploid respond to cold stress. Our results suggest that divergence in gene expression and AS patterns between duplicated genes may increase the flexibility of polyploids when responding to abiotic stressors.
PMID: 33043636
Plant Physiol Biochem , IF:3.72 , 2020 Nov , V156 : P578-590 doi: 10.1016/j.plaphy.2020.10.008
Treatment with spermidine alleviates the effects of concomitantly applied cold stress by modulating Ca(2+), pH and ROS homeostasis, actin filament organization and cell wall deposition in pollen tubes of Camellia sinensis.
Department of Biology, Marmara University, Goztepe Campus, Kadikoy, 34722, Istanbul, Turkey. Electronic address: aslihan.cetinbas@marmara.edu.tr.; Department of Life Sciences, University of Siena, Via Mattioli 4, 53100, Siena, Italy. Electronic address: giampiero.cai@unisi.it.; Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126, Bologna, Italy. Electronic address: stefano.delduca@unibo.it.
The aim of the current study was to examine the effect of spermidine treatment concomitant with cold stress on the elongation of Camellia sinensis pollen tube. When exogenous spermidine (0.05 mM) was applied concomitantly with cold stress, pollen germination rate and pollen tube length were significantly increased in comparison with cold stressed pollen tubes. In addition, spermidine treatment concomitantly with cold stress reduced pollen tube abnormalities induced by cold stress. Besides, cold-induced disorganizations of actin filaments were ameliorated after spermidine treatment along with cold stress because anisotropy levels of actin filaments in shank and apex of pollen tubes decreased. Changes in cold-induced callose distribution in the pollen tube cell wall were partially recovered after spermidine/cold stress treatment. Other cold-induced effects (decrease in Ca(2+) content, reduction of pH gradient, accumulation of ROS) were reverted to adequate levels after spermidine treatment in conjunction with cold stress, indicating that pollen tubes are able to cope with stress. Thus, spermidine treatment reorganized the growth pattern of pollen tubes by modulating Ca(2+) and ROS homeostasis, actin cytoskeleton organization, and cell wall deposition in Camellia sinensis pollen tubes under cold stress.
PMID: 33065378
Tree Physiol , IF:3.655 , 2020 Nov doi: 10.1093/treephys/tpaa147
Genome-wide analysis of long noncoding RNAs affecting floral bud dormancy in pears in response to cold stress.
College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R. China.; Economic Crop Station, Agricultural and Rural Bureau of Yongtai County, Fuzhou 350700, P.R. China.; Lianjiang State-owned Forest Farm in Fujian Province, Fuzhou 350500, P.R. China.
The versatile role of long noncoding RNAs (lncRNAs) in plant growth and development has been established, but a systematic identification and analysis of lncRNAs in the pear has not been reported. Bud dormancy is a crucial and complicated protective mechanism for plants in winter. The roles of lncRNAs in the dormancy process remain largely unclear. In this study, we induced pear floral buds to enter into different dormant statuses by simulating four different chilling accumulation conditions. Then, a time series of RNA-seq analysis was performed and we identified 7,594 lncRNAs in Pyrus pyrifolia 'Huanghua' that have not been identified. The sequence and expression of the lncRNAs were confirmed by PCR analysis. In total, 6,253 lncRNAs were predicted to target protein-coding genes including 692 cis-regulated pairs (596 lncRNAs) and 13,158 trans-regulated pairs (6,181 lncRNAs). GO analysis revealed that most of lncRNAs target genes were involved in catalytic activity, metabolic processes and cellular processes. In the trend analysis, 124 long-term cold response lncRNAs and 80 short-term cold response lncRNAs were predicted. Regarding the lncRNA-miRNA regulatory networks, 59 lncRNAs were identified as potential precursors for miRNA members of 20 families, 586 lncRNAs were targets of 261 pear miRNAs and 53 lncRNAs were endogenous target mimics (eTMs) for 26 miRNAs. In addition, three cold response lncRNAs, two miRNAs and their target genes were selected for expression confirmed. The trend of their expression was consistent with the predicted relationships among them and suggesting possible roles of lncRNAs in ABA metabolic pathway. Our findings not only suggest the potential roles of lncRNAs in regulating the dormancy of pear floral buds but also provide new insights into the lncRNA-miRNA-mRNA regulatory network in plants.
PMID: 33147633
BMC Plant Biol , IF:3.497 , 2020 Nov , V20 (1) : P518 doi: 10.1186/s12870-020-02726-4
Comparative transcriptome analysis reveals evolutionary divergence and shared network of cold and salt stress response in diploid D-genome cotton.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 40070, China.; School of Biological, Physical, Mathematics and Actuarial sciences (SBPMAS), Main campus, Jaramogi Oginga Odinga University of Science and Technology (JOOUST), P.O Box 210-40601, Bondo, Kenya.; Economic Crops Research Institute of Xinjiang Academy of Agricultural Science, Urumqi, Xinjiang province, China.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China. wangkunbo@caas.cn.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China. liufcri@caas.com.; School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China. liufcri@caas.com.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China. zhouzl@cricaas.com.cn.
BACKGROUND: Wild species of cotton are excellent resistance to abiotic stress. Diploid D-genome cotton showed abundant phenotypic diversity and was the putative donor species of allotetraploid cotton which produce the largest textile natural fiber. RESULTS: A total of 41,053 genes were expressed in all samples by mapping RNA-seq Illumina reads of G. thurberi (D1), G. klotzschianum (D3-k), G. raimondii (D5) and G. trilobum (D8) to reference genome. The numbers of differently expressed genes (DEGs) were significantly higher under cold stress than salt stress. However, 34.1% DEGs under salt stress were overlapped with cold stress in four species. Notably, a potential shared network (cold and salt response, including 16 genes) was mined out by gene co-expression analysis. A total of 47,180-55,548 unique genes were identified in four diploid species by De novo assembly. Furthermore, 163, 344, 330, and 161 positively selected genes (PSGs) were detected in thurberi, G. klotzschianum, G. raimondii and G. trilobum by evolutionary analysis, respectively, and 9.5-17% PSGs of four species were DEGs in corresponding species under cold or salt stress. What's more, most of PSGs were enriched GO term related to response to stimulation. G. klotzschianum showed the best tolerance under both cold and salt stress. Interestingly, we found that a RALF-like protein coding gene not only is PSGs of G. klotzschianum, but also belongs to the potential shared network. CONCLUSION: Our study provided new evidence that gene expression variations of evolution by natural selection were essential drivers of the morphological variations related to environmental adaptation during evolution. Additionally, there exist shared regulated networks under cold and salt stress, such as Ca(2+) signal transduction and oxidation-reduction mechanisms. Our work establishes a transcriptomic selection mechanism for altering gene expression of the four diploid D-genome cotton and provides available gene resource underlying multi-abiotic resistant cotton breeding strategy.
PMID: 33183239
BMC Plant Biol , IF:3.497 , 2020 Nov , V20 (1) : P504 doi: 10.1186/s12870-020-02697-6
BrrICE1.1 is associated with putrescine synthesis through regulation of the arginine decarboxylase gene in freezing tolerance of turnip (Brassica rapa var. rapa).
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Science, Kunming, 650204, China.; Plant Germplasm and Genomics Center, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.; Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; Changchun Normal University, Changchun, 130032, China.; College of Landscape and Horticulture, Yunnan Agricultural University, Kunming, 650201, China.; Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Science, Kunming, 650204, China. yangyp@mail.kib.ac.cn.; Plant Germplasm and Genomics Center, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China. yangyp@mail.kib.ac.cn.; Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China. yangyp@mail.kib.ac.cn.
BACKGROUND: In the agricultural areas of Qinghai-Tibet Plateau, temperature varies widely from day to night during the growing season, which makes the extreme temperature become one of the limiting factors of crop yield. Turnip (Brassica rapa var. rapa) is a traditional crop of Tibet grown in the Tibet Plateau, but its molecular and metabolic mechanisms of freezing tolerance are unclear. RESULTS: Here, based on the changes in transcriptional and metabolic levels of Tibetan turnip under freezing treatment, the expression of the arginine decarboxylase gene BrrADC2.2 exhibited an accumulative pattern in accordance with putrescine content. Moreover, we demonstrated that BrrICE1.1 (Inducer of CBF Expression 1) could directly bind to the BrrADC2.2 promoter, activating BrrADC2.2 to promote the accumulation of putrescine, which was verified by RNAi and overexpression analyses for both BrrADC2.2 and BrrICE1.1 using transgenic hair root. The function of putrescine in turnip was further analyzed by exogenous application putrescine and its inhibitor DL-alpha-(Difluoromethyl) arginine (DFMA) under freezing tolerance. In addition, the BrrICE1.1 was found to be involved in the ICE1-CBF pathway to increase the freezing stress of turnip. CONCLUSIONS: BrrICE1.1 could bind the promoter of BrrADC2.2 or CBFs to participate in freezing tolerance of turnip by transcriptomics and targeted metabolomics analyses. This study revealed the regulatory network of the freezing tolerance process in turnip and increased our understanding of the plateau crops response to extreme environments in Tibet.
PMID: 33148172
Plant Mol Biol , IF:3.302 , 2020 Nov doi: 10.1007/s11103-020-01093-w
Enhanced glutathione content improves lateral root development and grain yield in rice plants.
Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea.; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea.; Institute of Life Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea.; Research Institute for Dok-Do and Ulleung-Do, Kyungpook National University, Daegu, 41566, Republic of Korea. kyslhh1228@hanmail.net.; Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, 41566, Republic of Korea. hsy@knu.ac.kr.; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea. hsy@knu.ac.kr.; Advanced Bio-Resource Research Center, Kyungpook National University, Daegu, 41566, Republic of Korea. hsy@knu.ac.kr.
KEY MESSAGE: Enhanced glutathione content improves lateral root development by positively regulating the transcripts of root development genes responsive to glutathione treatment, thereby increasing the overall productivity of rice plants. Glutathione is primarily known as a cellular antioxidant molecule, but its role in lateral root development in rice plants has not been elucidated. Here, we have investigated its role in lateral root development of rice Oryza sativa L. Exogenous glutathione (GSH) promoted both the number and length of lateral roots in rice, and the GSH biosynthesis inhibitor buthionine sulfoximine (BSO) significantly reduced these parameters, compared to untreated plants. The inhibition by BSO was reversed with exogenous GSH. Transcript profiling by RNA-seq revealed that expression of the transcription factor genes DREB and ERF and the hormone-related genes AOS, LOX, JAZ, and SAUR were significantly downregulated in the BSO-treated plants and, in contrast, upregulated in plants treated with GSH and with GSH and BSO together. We generated OsGS-overexpressing transgenic plants in which the transgene is controlled by the abiotic-stress-inducible OsRab21 promoter to study the effect of endogenously increased GSH levels. In cold stress, transgenic rice plants enhanced stress tolerance and lateral root development by maintaining redox homeostasis and improving upregulating the expression of transcription factors and hormone-related genes involved in lateral root development. We observed improved root growth of OsGS-overexpressing plants in paddy fields compared to the wild-type controls. These traits may have alleviated transplanting stress during early growth in the field and accounted for the increased productivity. These results provide information and perspectives on the role of GSH in gene expression, lateral root development, and grain yield in rice.
PMID: 33206358
Front Genet , IF:3.258 , 2020 , V11 : P609184 doi: 10.3389/fgene.2020.609184
Genome-Wide Characterization of the HSP20 Gene Family Identifies Potential Members Involved in Temperature Stress Response in Apple.
College of Horticulture, Henan Agricultural University, Zhengzhou, China.
Apple (Malus domestica Borkh.), an economically important tree fruit worldwide, frequently suffers from temperature stress during growth and development, which strongly affects the yield and quality. Heat shock protein 20 (HSP20) genes play crucial roles in protecting plants against abiotic stresses. However, they have not been systematically investigated in apple. In this study, we identified 41 HSP20 genes in the apple 'Golden Delicious' genome. These genes were unequally distributed on 15 different chromosomes and were classified into 10 subfamilies based on phylogenetic analysis and predicted subcellular localization. Chromosome mapping and synteny analysis indicated that three pairs of apple HSP20 genes were tandemly duplicated. Sequence analysis revealed that all apple HSP20 proteins reflected high structure conservation and most apple HSP20 genes (92.6%) possessed no introns, or only one intron. Numerous apple HSP20 gene promoter sequences contained stress and hormone response cis-elements. Transcriptome analysis revealed that 35 of 41 apple HSP20 genes were nearly unchanged or downregulated under normal temperature and cold stress, whereas these genes exhibited high-expression levels under heat stress. Subsequent qRT-PCR results showed that 12 of 29 selected apple HSP20 genes were extremely up-regulated (more than 1,000-fold) after 4 h of heat stress. However, the heat-upregulated genes were barely expressed or downregulated in response to cold stress, which indicated their potential function in mediating the response of apple to heat stress. Taken together, these findings lay the foundation to functionally characterize HSP20 genes to unravel their exact role in heat defense response in apple.
PMID: 33240335
BMC Evol Biol , IF:3.058 , 2020 Nov , V20 (1) : P142 doi: 10.1186/s12862-020-01710-8
Evolutionary history of the C-repeat binding factor/dehydration-responsive element-binding 1 (CBF/DREB1) protein family in 43 plant species and characterization of CBF/DREB1 proteins in Solanum tuberosum.
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China.; State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China. Luhaibin011@163.com.; State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China. dongdong-1025@hotmail.com.; College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China. chenpeter2289@nwafu.edu.cn.
BACKGROUND: Plants are easily affected by temperature variations, and high temperature (heat stress) and low temperature (cold stress) will lead to poor plant development and reduce crop yields. Therefore, it is very important to identify resistance genes for improving the ability of plants to resist heat stress or cold stress by using modern biotechnology. Members of the C-repeat binding factor/Dehydration responsive element-binding 1 (CBF/DREB1) protein family are related to the stress resistance of many plant species. These proteins affect the growth and development of plants and play vital roles during environmental stress (cold, heat, drought, salt, etc.). In this study, we identified CBF/DREB1 genes from 43 plant species (including algae, moss, ferns, gymnosperms, angiosperms) by using bioinformatic methods to clarify the characteristics of the CBF/DREB1 protein family members and their functions in potato under heat and cold stresses. RESULTS: In this study, we identified 292 CBF/DREB1 proteins from 43 plant species. However, no CBF/DREB1 protein was found in algae, moss, ferns, or gymnosperms; members of this protein family exist only in angiosperms. Phylogenetic analysis of all the CBF/DREB1 proteins revealed five independent groups. Among them, the genes of group I do not exist in eudicots and are found only in monocots, indicating that these genes have a special effect on monocots. The analysis of motifs, gene duplication events, and the expression data from the PGSC website revealed the gene structures, evolutionary relationships, and expression patterns of the CBF/DREB1 proteins. In addition, analysis of the transcript levels of the 8 CBF/DREB1 genes in potato (Solanum tuberosum) under low-temperature and high-temperature stresses showed that these genes were related to temperature stresses. In particular, the expression levels of StCBF3 and StCBF4 in the leaves, stems, and roots significantly increased under high-temperature conditions, which suggested that StCBF3 and StCBF4 may be closely related to heat tolerance in potato. CONCLUSION: Overall, members of the CBF/DREB1 protein family exist only in angiosperms and plays an important role in the growth and development of plants. In addition, the CBF/DREB1 protein family is related to the heat and cold resistance of potato. Our research revealed the evolution of the CBF/DREB1 family, and is useful for studying the precise functions of the CBF/DREB1 proteins when the plants are developing and are under temperature stress.
PMID: 33143637
Plant Foods Hum Nutr , IF:2.901 , 2020 Nov doi: 10.1007/s11130-020-00868-2
Two Oleosins Expressed in the Mesocarp of Native Mexican Avocado, Key Genes in the Oil Content.
Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan, Mexico.; Centro Multidisciplinario de Estudios en Biotecnologia, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan, Mexico.; Instituto de Investigaciones Quimico-Biologicas, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacan, Mexico. rlopez@umich.mx.
Intracellular lipid droplets (LD) provide the oil storage mechanism of plants. They are found within seeds as individual structures, even under conditions of cold stress and dehydration, due to the protein that covers them. This protein, called oleosin, is found exclusively in plants and has been widely studied in seeds. Avocado fruits (Persea americana Mill.) are rich in oil, which is stored in the mesocarp, not in the seeds. The presence of oleosin in the mesocarp tissue of avocadoes has been reported, but its physiological role is still unknown. In this study, we identify two genes that code for oleosin in the mesocarp of the native Mexican avocado. These sequences are very different from those of seed oleosins. Both genes are expressed during fruit ripening, while one, PaOle1, has the highest expression in the green fruit stage. The protein of PaOle1 is stable during the fruit ripening process and covers all the mesocarp LDs. The expression of PaOle1 gene and protein is organ specific to avocado mesocarp. Among avocadoes varieties oleosin abundance is directly related to oil content.
PMID: 33184746
Cell Stress Chaperones , IF:2.892 , 2020 Nov , V25 (6) : P869-886 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 Nov , V9 (11) doi: 10.3390/plants9111617
Characterization and Stress Response of the JmjC Domain-Containing Histone Demethylase Gene Family in the Allotetraploid Cotton Species Gossypium hirsutum.
Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.; Collaborative Innovation Center of Henan Grain Crops, Agronomy College, Henan Agricultural University, Zhengzhou 450002, China.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.
Histone modification is an important epigenetic modification that controls gene transcriptional regulation in eukaryotes. Histone methylation is accomplished by histone methyltransferase and can occur on two amino acid residues, arginine and lysine. JumonjiC (JmjC) domain-containing histone demethylase regulates gene transcription and chromatin structure by changing the methylation state of the lysine residue site and plays an important role in plant growth and development. In this study, we carried out genome-wide identification and comprehensive analysis of JmjC genes in the allotetraploid cotton species Gossypium hirsutum. In total, 50 JmjC genes were identified and in G. hirsutum, and 25 JmjC genes were identified in its two diploid progenitors, G. arboreum and G. raimondii, respectively. Phylogenetic analysis divided these JmjC genes into five subfamilies. A collinearity analysis of the two subgenomes of G. hirsutum and the genomes of G. arboreum and G. raimondii uncovered a one-to-one relationship between homologous genes of the JmjC gene family. Most homologs in the JmjC gene family between A and D subgenomes of G. hirsutum have similar exon-intron structures, which indicated that JmjC family genes were conserved after the polyploidization. All G. hirsutumJmjC genes were found to have a typical JmjC domain, and some genes also possess other special domains important for their function. Analysis of promoter regions revealed that cis-acting elements, such as those related to hormone and abiotic stress response, were enriched in G. hirsutum JmjC genes. According to a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, most G. hirsutumJmjC genes had high abundance expression at developmental stages of fibers, suggesting that they might participate in cotton fiber development. In addition, some G. hirsutumJmjC genes were found to have different degrees of response to cold or osmotic stress, thus indicating their potential role in these types of abiotic stress response. Our results provide useful information for understanding the evolutionary history and biological function of JmjC genes in cotton.
PMID: 33233854
Plants (Basel) , IF:2.762 , 2020 Nov , V9 (11) doi: 10.3390/plants9111510
Differential Expression Profiling Reveals Stress-Induced Cell Fate Divergence in Soybean Microspores.
College of Science and Mathematics, Arkansas State University, Jonesboro, AR 72467-1080, USA.; Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72467-0639, USA.; College of Agriculture, Arkansas State University, Jonesboro, AR 72467-1080, USA.; Agricultural Experiment Station, University of Arkansas System Division of Agriculture, Jonesboro, AR 72467-2340, USA.
Stress-induced microspore embryogenesis is a widely employed method to achieve homozygosity in plant breeding programs. However, the molecular mechanisms that govern gametophyte de- and redifferentiation are understood poorly. In this study, RNA-Seq was used to evaluate global changes across the microspore transcriptome of soybean (Glycine max [L.] Merrill) as a consequence of pretreatment low-temperature stress. Expression analysis revealed more than 20,000 differentially expressed genes between treated and control microspore populations. Functional enrichment illustrated that many of these genes (e.g., those encoding heat shock proteins and cytochrome P450s) were upregulated to maintain cellular homeostasis through the mitigation of oxidative damage. Moreover, transcripts corresponding to saccharide metabolism, vacuolar transport, and other pollen-related developmental processes were drastically downregulated among treated microspores. Temperature stress also triggered cell wall modification and cell proliferation-characteristics that implied putative commitment to an embryonic pathway. These findings collectively demonstrate that pretreatment cold stress induces soybean microspore reprogramming through suppression of the gametophytic program while concomitantly driving sporophytic development.
PMID: 33171842
PLoS One , IF:2.74 , 2020 , V15 (11) : Pe0242139 doi: 10.1371/journal.pone.0242139
Overexpression of MdCPK1a gene, a calcium dependent protein kinase in apple, increase tobacco cold tolerance via scavenging ROS accumulation.
College of Horticulture, Nanjing Agricultural University, Nanjing, China.; Guizhou Fruit Institute, Guizhou Academy of Agricultural Science, Guiyang, China.
Calcium-dependent protein kinases (CDPKs) are important calcium receptors, which play a crucial part in the process of sensing and decoding intracellular calcium signals during plant development and adaptation to various environmental stresses. In this study, a CDPK gene MdCPK1a, was isolated from apple (Malusxdomestica) which contains 1701bp nucleotide and encodes a protein of 566 amino acid residues, and contains the conserved domain of CDPKs. The transient expression and western blot experiment showed that MdCPK1a protein was localized in the nucleus and cell plasma membrane. Ectopic expression of MdCPK1a in Nicotiana benthamiana increased the resistance of the tobacco plants to salt and cold stresses. The mechanism of MdCPK1a regulating cold resistance was further investigated. The overexpressed MdCPK1a tobacco plants had higher survival rates and longer root length than wild type (WT) plants under cold stress, and the electrolyte leakages (EL), the content of malondialdehyde (MDA) and reactive oxygen species (ROS) were lower, and accordingly, antioxidant enzyme activities, such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were higher, suggesting the transgenic plants suffered less chilling injury than WT plants. Moreover, the transcript levels of ROS-scavenging and stress-related genes were higher in the transgenic plants than those in WT plants whether under normal conditions or cold stress. The above results suggest that the improvement of cold tolerance in MdCPK1a-overexpressed plants was due to scavenging ROS accumulation and modulating the expression of stress-related genes.
PMID: 33211731
Plant Signal Behav , IF:1.671 , 2020 Nov , V15 (11) : P1814547 doi: 10.1080/15592324.2020.1814547
Overexpression of Arabidopsis ICE1 enhances yield and multiple abiotic stress tolerance in indica rice.
Division of Plant Physiology, ICAR-Indian Agricultural Research Institute , New Delhi, India.; Department of Botany, School of Life Sciences, Bharathidasan University Tiruchirappalli , Tiruchirappalli, India.
ICE1 (Inducer of CBF Expression 1), a MYC-type bHLH transcription factor, is a regulator of cold tolerance in Arabidopsis. Indica rice, which occupies the major rice cultivated area, is highly sensitive to cold stress. Hence in this study, Arabidopsis ICE1 (AtICE1) was overexpressed in indica rice to analyze its role in reproductive stage cold and other abiotic stress tolerance to indica rice. AtICE1 was overexpressed by using stress inducible AtRD29A promoter in mega rice cv. MTU1010. Under cold stress conditions, AtICE1 overexpression lines showed lower accumulation of MDA and H2O2, higher membrane stability, and thus higher seedling survival rate than the WT plants. Expression levels of OsDREB1A, OsMYB3R2, and OsTPP1 were significantly higher in transgenics as compared with WT under cold stress conditions. AtICE1 transgenic rice plants produced 44-60% higher grain yield as compared with WT plants under control conditions in three independent experiments. Of the three AtICE1 overexpression lines, two lines produced significantly higher grain yield as compared with WT plants after recovery from cold, salt and drought stresses. AtICE1 overexpression lines showed significantly higher stomatal density and conductance under non-stress conditions. qRT-PCR analysis showed that expression levels of stomatal pathway genes viz., OsSPCH1, OsSPCH2, OsSCR1, OsSCRM1, OsSCRM2 and OsMUTE were significantly higher in AtICE1 transgenics as compared with WT plants. The components of water use viz., stomatal conductance, photosynthesis, and instantaneous WUE were higher in transgenics as compared with WT plants. The results showed that AtICE1 confers multiple stress tolerance to indica rice, and the role of ICE1 in stress tolerance and stomatal development is conserved across species.
PMID: 32924751
Plant Signal Behav , IF:1.671 , 2020 Nov , V15 (11) : P1807722 doi: 10.1080/15592324.2020.1807722
Polyamine biosynthetic pathways and their relation with the cold tolerance of maize (Zea mays L.) seedlings.
College of Agriculture, Anhui Agricultural University , Hefei, Anhui Province, P.R. China.; Seed Science Center, College of Agriculture and Biotechnology, Zhejiang University , Hangzhou, China.; Department of Agronomy, Faculty of Agriculture, Mansoura University , Mansoura, Egypt.; College of Agricultural Science and Engineering, Hohai University , Nanjing, China.
BACKGROUND: The present study was designed to investigate the inhibition role of two polyamine biosynthesis inhibitors, i.e., D-arginine (D-Arg) and DL-alpha-difluoromethylornithine (DFMO), in polyamine biosynthesis under chilling stress in different tissues of two maize inbred lines - Huang C (chilling-tolerance) and Mo17 (chilling-sensitive). RESULTS: The results showed that exposure to the lower concentration of polyamine biosynthesis inhibitors improved seedlings growth, such as the root length, root and shoot fresh weight, chlorophyll a (chl a). The effectiveness of 10 microM D-Arg treatments was more prominent than those of 10 microM DFMO. However, the higher concentration of inhibitors suppressed seedlings growth, and the exposure to 100 microM DFMO caused stronger decreases in the photosynthetic pigments, such as chlorophyll a (chl a), chlorophyll b (chl b), total chlorophyll and carotenoids, than the other treatments. Meanwhile, the inhibitor treatments caused the lower content of putrescine (Put) in roots, mesocotyls and coleoptiles in both maize inbred lines as compared with untreated plants. However, the lower concentration (10 microM) of polyamine biosynthetic inhibitors improved the Spd content, except 10 microM D-Arg in root of Huang C, and 10 microM DFMO in coleoptiles of both Mo17 and Huang C. The correlation analysis found that Spd was positively significantly correlated with root length and shoot fresh weight of seedling. CONCLUSION: It was showed that the Spd played an important role in seedling growth improvement. At the same concentration of polyamine biosynthetic inhibitors, the Put contents in different tissues of the seedlings treated with DFMO were generally lower than those treated with D-Arg, except for Put contents in root of Mo17 with 10 microM treatment. Moreover, the treatments of 100 microM were more prominent than those of 10 microM treatments. Exposure to 100 microM D-Arg and 100 microM DFMO could each decrease the activities of Arginine decarboxylase (ADC), Ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) in all maize tissues. However, the decrease of the ADC activity was more prominent in 100 microM D-Arg-treated seedlings, while the decrease of SAMDC and ODC activities was prominent in 100 microM DFMO-treated seedlings. Genes involved in polyamine biosynthesis, such as ADC, ODC, SAMDC, and PAO, showed different expression patterns in response to chilling stress and polyamine biosynthesis inhibitors. This study suggested that Put was synthesized via both the ADC and ODC pathways after chilling stress, with the ODC pathway being the major one.
PMID: 32799616
Plant Signal Behav , IF:1.671 , 2020 Nov : P1845048 doi: 10.1080/15592324.2020.1845048
Molecular cloning and functional characterization of GmAAPTs from soybean (Glycine max).
College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University , Nanjing, P.R.China.; Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen) , Nanjing, P.R.China.; College of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University , Nanjing, P.R.China.; Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences , Nanjing, P.R.China.
Aminoalcoholphosphotransferase (AAPT) utilizes diacylglycerols and cytidine diphosphate-choline/ethanolamine as substrates for the synthesis of phosphatidylcholine (PC)/phosphatidylethanolamine (PE). Plant AAPTs involved in phospholipid metabolism mediate diverse physiological processes; however, little is known about their functions in triacylglycerol (TAG) metabolism and seed germination. In the present study, we isolated and characterized two AAPTs, GmAAPT1 and GmAAPT2, from soybean (Glycine max). GmAAPT1 and GmAAPT2 exhibited strong similarity in their amino acid contents and expression patterns, and both were found to localize to the endoplasmic reticulum and Golgi apparatus. In vitro enzymatic analyses showed that GmAAPT1 and GmAAPT2 contributed to PC and PE synthesis and exhibited choline/ethanolamine phosphotransferase-like enzymatic properties. The overexpression of GmAAPT1 and GmAAPT2 in Arabidopsis led to reduced levels of seed TAG and polyunsaturated fatty acids and decreased seed germination under freezing stress. Together, these findings suggest that GmAAPTs mediate TAG metabolism and negatively regulate seed freezing tolerance.
PMID: 33164676