Food Chem , IF:6.306 , 2020 Oct , V327 : P127057 doi: 10.1016/j.foodchem.2020.127057
Combining salicylic acid and trisodium phosphate alleviates chilling injury in bell pepper (Capsicum annuum L.) through enhancing fatty-acid desaturation efficiency and water retention.
College of Food, Shenyang Agricultural University, No.120 Dongling Road, Shenhe District, Shenyang City 110866, People's Republic of China.; College of Food, Shenyang Agricultural University, No.120 Dongling Road, Shenhe District, Shenyang City 110866, People's Republic of China. Electronic address: jsjsyau@syau.edu.cn.
Chilling injury (CI) restricts the quality and shelf life of bell pepper fruits; reducing these CI-induced detrimental effects is therefore of high economic and agricultural relevance. Here, we investigated the effects of trisodium phosphate (TSP), salicylic acid (SA), and TSP + SA treatments on pepper fruits under cold stress at 4 degrees C for 25 d. Combined TSP + SA treatment performed an optimal effect. Specifically, TSP + SA treatment enhanced fatty-acid desaturation efficiency, as indicated by the increased expression of key fatty acid desaturase genes, and higher content of unsaturated fatty acids. Meanwhile, TSP + SA treatment inhibited the CI-induced membrane damage, manifested as lower electrolyte leakage and malondialdehyde content. Furthermore, low field-nuclear magnetic resonance and proline content also revealed that TSP + SA treatment mitigated CI through enhancing water retention in pepper fruits. Collectively, our results may shed new light on optimizing the low-temperature storage conditions of post-harvest peppers.
PMID: 32464461
Mol Ecol Resour , IF:6.286 , 2020 Oct doi: 10.1111/1755-0998.13280
The genome of Draba nivalis shows signatures of adaptation to the extreme environmental stresses of the Arctic.
Natural History Museum, University of Oslo, Oslo, Norway.; CEITEC, Masaryk University, Brno, Czech Republic.; Institute of Plant Sciences, University of Bern, Bern, Switzerland.; Science for Life Laboratory, Department of Ecology, Environment and Plant Science, Stockholm University, Stockholm, Sweden.; Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo, Norway.; Department of Botany, The University of British Columbia, Vancouver, Canada.
The Arctic is one of the most extreme terrestrial environments on the planet. Here we present the first chromosome-scale genome assembly of a plant adapted to the high Arctic, Draba nivalis (Brassicaceae), an attractive model species for studying plant adaptation to the stresses imposed by this harsh environment. We used an iterative scaffolding strategy with data from short-reads, single-molecule long reads, proximity ligation data, and a genetic map to produce a 302 Mb assembly that is highly contiguous with 91.6% assembled into eight chromosomes (the base chromosome number). To identify candidate genes and gene families that may have facilitated adaptation to Arctic environmental stresses, we performed comparative genomic analyses with nine non-Arctic Brassicaceae species. We show that the D. nivalis genome contains expanded suites of genes associated with drought and cold stress (e.g. related to the maintenance of oxidation-reduction homeostasis, meiosis, and signaling pathways). The expansions of gene families associated with these functions appear to be driven in part by the activity of transposable elements. Tests of positive selection identify suites of candidate genes associated with meiosis and photoperiodism, as well as cold, drought, and oxidative stress responses. Our results reveal a multifaceted landscape of stress adaptation in the D. nivalis genome, offering avenues for the continued development of this species as an Arctic model plant.
PMID: 33058468
J Exp Bot , IF:5.908 , 2020 Oct , V71 (19) : P5880-5895 doi: 10.1093/jxb/eraa325
Deletion of maize RDM4 suggests a role in endosperm maturation as well as vegetative and stress-responsive growth.
College of Grassland Science and Technology, China Agricultural University, Beijing, China.; Key Laboratory of Pratacultural Science, Beijing Municipality, Beijing, China.; Department of Agronomy and Horticulture, Center for Plant Science Innovation, Beadle Center for Biotechnology, University of Nebraska, Lincoln, NE, USA.; Bond Life Sciences Center, Division of Biological Sciences, Interdisciplinary Plant Group, University of Missouri, Columbia, MO, USA.; Proteomics and Metabolomics Core facility, University of Nebraska-Lincoln, Lincoln, NE, USA.; School of Biological Sciences, Center for Plant Science Innovation, Beadle Center for Biotechnology, University of Nebraska, Lincoln, NE, USA.
Opaque kernels in maize may result from mutations in many genes, such as OPAQUE-2. In this study, a maize null mutant of RNA-DIRECTED DNA METHYLATION 4 (RDM4) showed an opaque kernel phenotype, as well as plant developmental delay, male sterility, and altered response to cold stress. We found that in opaque kernels, all zein proteins were reduced and amino acid content was changed, including increased lysine. Transcriptomic and proteomic analysis confirmed the zein reduction and proteomic rebalancing of non-zein proteins, which was quantitatively and qualitatively different from opaque-2. Global transcriptional changes were found in endosperm and leaf, including many transcription factors and tissue-specific expressed genes. Furthermore, of the more than 8000 significantly differentially expressed genes in wild type in response to cold, a significant proportion (25.9% in moderate cold stress and 40.8% in near freezing stress) were not differentially expressed in response to cold in rdm4, suggesting RDM4 may participate in regulation of abiotic stress tolerance. This initial characterization of maize RDM4 provides a basis for further investigating its function in endosperm and leaf, and as a regulator of normal and stress-responsive development.
PMID: 32667993
Int J Mol Sci , IF:4.556 , 2020 Oct , V21 (21) doi: 10.3390/ijms21217939
The Grapevine Calmodulin-Like Protein Gene CML21 Is Regulated by Alternative Splicing and Involved in Abiotic Stress Response.
Laboratory of Biotechnology, Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far Eastern Branch of the Russian Academy of Sciences, 690022 Vladivostok, Russia.
Calmodulin-like proteins (CMLs) represent a large family of plant calcium sensor proteins involved in the regulation of plant responses to environmental cues and developmental processes. In the present work, we identified four alternatively spliced mRNA forms of the grapevine CML21 gene that encoded proteins with distinct N-terminal regions. We studied the transcript abundance of CML21v1, CML21v2, CML21v3, and CML21v4 in wild-growing grapevine Vitis amurensis Rupr. in response to desiccation, heat, cold, high salinity, and high mannitol stress using quantitative real-time RT-PCR. The levels of all four splice variants of VaCML21 were highly induced in response to cold stress. In addition, VaCML21v1 and VaCML21v2 forms were highly modulated by all other abiotic stress treatments. Constitutive expression of VaCML21v2 and VaCML21v4 improved biomass accumulation of V. amurensis callus cell cultures under prolonged low temperature stress. Heterologous expression of the grapevine CML21v2 and VaCML21v4 splice variants in Arabidopsis improved survival rates of the transgenic plants after freezing. The VaCML21v2 overexpression enhanced activation of the cold stress-responsive marker genes AtDREB1A and AtDREB2A, while VaCML21v4 overexpression-AtCOR47, AtRD29A, AtRD29B, and AtKIN1 genes after freezing stress in the transgenic Arabidopsis. The results indicate that the grapevine CML21 gene acts as a positive regulator in the plant response to cold stress. The detected variety of CML21 transcripts and their distinct transcriptional responses suggested that this expansion of mRNA variants could contribute to the diversity of grapevine adaptive reactions.
PMID: 33114685
Int J Mol Sci , IF:4.556 , 2020 Oct , V21 (19) doi: 10.3390/ijms21197322
Identification of the Cytosolic Glucose-6-Phosphate Dehydrogenase Gene from Strawberry Involved in Cold Stress Response.
College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China.; Institute of Pomology and Olericulture, Sichuan Agricultural University, Chengdu 611130, China.; Mianyang Academy of Agricultural Sciences, Mianyang 621000, China.
Glucose-6-phosphate dehydrogenase (G6PDH) plays an important role in plant stress responses. Here, five FaG6PDH sequences were obtained in strawberry, designated as FaG6PDH-CY, FaG6PDH-P1, FaG6PDH-P1.1, FaG6PDH-P2 and FaG6PDH-P0, which were divided into cytosolic (CY) and plastidic (P) isoforms based on the bioinformatic analysis. The respective FaG6PDH genes had distinct expression patterns in all tissues and at different stages of fruit development. Notably, FaG6PDH-CY was the most highly expressed gene among five FaG6PDH members, indicating it encoded the major G6PDH isoform throughout the plant. FaG6PDH positively regulated cold tolerance in strawberry. Inhibition of its activity gave rise to greater cold-induced injury in plant. The FaG6PDH-CY transcript had a significant increase under cold stress, similar to the G6PDH enzyme activity, suggesting a principal participant in response to cold stress. Further study showed that the low-temperature responsiveness (LTR) element in FaG6PDH-CY promoter can promote the gene expression when plant encountered cold stimuli. Besides, FaG6PDH-CY was involved in regulating cold-induced activation of antioxidant enzyme genes (FaSOD, FaCAT, FaAPX and FaGR) and RBOH-dependent ROS generation. The elevated FaG6PDH-CY enhanced ROS-scavenging capability of antioxidant enzymes to suppress ROS excessive accumulation and relieved the oxidative damage, eventually improving the strawberry resistance to cold stress.
PMID: 33023038
Int J Mol Sci , IF:4.556 , 2020 Oct , V21 (20) doi: 10.3390/ijms21207616
Varying Atmospheric CO2 Mediates the Cold-Induced CBF-Dependent Signaling Pathway and Freezing Tolerance in Arabidopsis.
Adaptive Cropping Systems Laboratory, Agricultural Research Service, USDA, Building 001, 10300 Baltimore Ave., Beltsville, MD 20705, USA.; Dale Bumpers National Rice Research Center, Agricultural Research Service, USDA, Building 001, 10300 Baltimore Ave., Beltsville, MD 20705, USA.; Soybean Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Building 006, 10300 Baltimore Ave., Beltsville, MD 20705, USA.
Changes in the stomatal aperture in response to CO2 levels allow plants to manage water usage, optimize CO2 uptake and adjust to environmental stimuli. The current study reports that sub-ambient CO2 up-regulated the low temperature induction of the C-repeat Binding Factor (CBF)-dependent cold signaling pathway in Arabidopsis (Arabidopsis thaliana) and the opposite occurred in response to supra-ambient CO2. Accordingly, cold induction of various downstream cold-responsive genes was modified by CO2 treatments and expression changes were either partially or fully CBF-dependent. Changes in electrolyte leakage during freezing tests were correlated with CO2's effects on CBF expression. Cold treatments were also performed on Arabidopsis mutants with altered stomatal responses to CO2, i.e., high leaf temperature 1-2 (ht1-2, CO2 hypersensitive) and beta-carbonic anhydrase 1 and 4 (ca1ca4, CO2 insensitive). The cold-induced expression of CBF and downstream CBF target genes plus freezing tolerance of ht1-2 was consistently less than that for Col-0, suggesting that HT1 is a positive modulator of cold signaling. The ca1ca4 mutant had diminished CBF expression during cold treatment but the downstream expression of cold-responsive genes was either similar to or greater than that of Col-0. This finding suggested that betaCA1/4 modulates the expression of certain cold-responsive genes in a CBF-independent manner. Stomatal conductance measurements demonstrated that low temperatures overrode low CO2-induced stomatal opening and this process was delayed in the cold tolerant mutant, ca1ca4, compared to the cold sensitive mutant, ht1-2. The similar stomatal responses were evident from freezing tolerant line, Ox-CBF, overexpression of CBF3, compared to wild-type ecotype Ws-2. Together, these results indicate that CO2 signaling in stomata and CBF-mediated cold signaling work coordinately in Arabidopsis to manage abiotic stress.
PMID: 33076265
Int J Mol Sci , IF:4.556 , 2020 Oct , V21 (20) doi: 10.3390/ijms21207557
Decreased R:FR Ratio in Incident White Light Affects the Composition of Barley Leaf Lipidome and Freezing Tolerance in a Temperature-Dependent Manner.
Biological Research Centre, Institute of Plant Biology, H-6701 Szeged, Hungary.; Department of Plant Biology, University of Szeged, 6720 Szeged, Hungary.; Centre for Agricultural Research, Agricultural Institute, 2462 Martonvasar, Hungary.; Festetics Doctoral School, Georgikon Campus, Szent Istvan University, H-2100 Godollo, Hungary.; Department of Plant-Bioscience, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.; CREA Research Centre for Genomics and Bioinformatics, Fiorenzuola d'Arda, 29017 San Protaso, Italy.
In cereals, C-repeat binding factor genes have been defined as key components of the light quality-dependent regulation of frost tolerance by integrating phytochrome-mediated light and temperature signals. This study elucidates the differences in the lipid composition of barley leaves illuminated with white light or white light supplemented with far-red light at 5 or 15 degrees C. According to LC-MS analysis, far-red light supplementation increased the amount of monogalactosyldiacylglycerol species 36:6, 36:5, and 36:4 after 1 day at 5 degrees C, and 10 days at 15 degrees C resulted in a perturbed content of 38:6 species. Changes were observed in the levels of phosphatidylethanolamine, and phosphatidylserine under white light supplemented with far-red light illumination at 15 degrees C, whereas robust changes were observed in the amount of several phosphatidylserine species at 5 degrees C. At 15 degrees C, the amount of some phosphatidylglycerol species increased as a result of white light supplemented with far-red light illumination after 1 day. The ceramide (42:2)-3 content increased regardless of the temperature. The double-bond index of phosphatidylglycerol, phosphatidylserine, phosphatidylcholine ceramide together with total double-bond index changed when the plant was grown at 15 degrees C as a function of white light supplemented with far-red light. white light supplemented with far-red light increased the monogalactosyldiacylglycerol/diacylglycerol ratio as well. The gene expression changes are well correlated with the alterations in the lipidome.
PMID: 33066276
Plant Genome , IF:3.847 , 2020 Oct : 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 Oct , V157 : P38-46 doi: 10.1016/j.plaphy.2020.09.040
Effect of excessive nitrogen on levels of amino acids and sugars, and differential response to post-harvest cold storage in potato (Solanum tuberosum L.) tubers.
Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China; Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, Wuhan, Hubei, 430070, China.; Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, Wuhan, Hubei, 430070, China.; Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China.; Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China; Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, Wuhan, Hubei, 430070, China. Electronic address: zzq@mail.hzau.edu.cn.
Nitrogen (N) is an important nutrient for increased potato tuber yield. However, excessive N can decrease tuber quality. Furthermore, the impact of optimal and higher N levels of potato tuber metabolic profile at harvest and cold storage remains unclear. This study aimed to investigate the metabolic profiling of free amino acids and sugars in potato tubers affected by different nitrogen levels (optimal, ON; and excessive, EN) at harvest (AH) and cold storage (CS) (~4 degrees C, 4 weeks) through untargeted GC-TOF-MS, and targeted UHPLC-QqQ-MS. Carbohydrate content and vacuolar invertase activity (IV) were determined. Principal component analysis of metabolite data indicated a distinct separation between ON and EN treatments at harvest and cold storage. Multivariate data analysis revealed that sucrose, reducing sugars, and free asparagine were the most altered metabolites (VIP > 1 and P < 0.05), which were involved in starch and sucrose metabolism, and alanine, aspartate and glutamate metabolism. At harvest, the absolute contents of various free amino acids including asparagine were higher (by 1.3-1.5 fold) in the EN treatment than ON treatment, and this difference was maintained at 4-week cold storage. Under the EN treatment, tuber maturity was reduced, and sucrose accumulation was increased at harvest, while IV was increased after cold storage, reducing sugar also accumulated. These results highlighted the negative effects of EN on free amino acid and sugars metabolism in the post-harvest tubers and provided useful information for understanding the underpinning physiological mechanisms.
PMID: 33069979
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 Oct , V40 (10) : P1327-1342 doi: 10.1093/treephys/tpaa070
Explaining the exceptional 4270 m high elevation limit of an evergreen oak in the south-eastern Himalayas.
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Kunming, Yunnan 650204, PR China.; Institute of Botany, University of Basel, Schonbeinstrasse 6, Basel 4056, Switzerland.
Unlike the well-understood alpine treeline, the upper range limits of tree taxa that do not reach the alpine treeline are largely unexplained. In this study, we explored the causes of the exceptionally high elevation (4270 m) occurrence of broad-leaved evergreen oaks (Quercus pannosa) in the south-eastern Himalayas. We assessed the course of freezing resistance of buds and leaves from winter to summer at the upper elevational limit of this oak species. Linked to leaf phenology, we analyzed freezing resistance and assessed minimum crown temperature for the past 65 years. We also examined potential carbon limitation at the range limit of this species. Last season buds and leaves operated at a safety margin of 5.5 and 11 K in mid-winter. Once fully dehardened early in July, last season foliage is damaged at -5.9 and new foliage at -4.6 degrees C. Bud break is timed for late June to early July when low temperature extremes historically were never below -3.0 degrees C. The monsoon regime ensures a long remaining season (149 days), thus compensating for the late onset of shoot growth. Compared with a site at 3450 m, specific leaf area is reduced, foliar non-structural carbohydrate concentrations are similar and the delta13C signal is higher, jointly suggesting that carbon limitation is unlikely at the range limit of this species. We also show that these oaks enter the growing season with fully intact (not embolized) xylem. We conclude that the interaction between phenology and freezing tolerance results in safe flushing, while still facilitating shoot maturation before winter. These factors jointly determine the upper range limit of this oak species. Our study illuminates an exceptional case of broad-leaved evergreen tree performance near the treeline, and by exploring a suite of traits, we can underpin the central role of flushing phenology in such a stressful environment.
PMID: 32483630
Biochim Biophys Acta Gene Regul Mech , IF:3.51 , 2020 Oct : P194644 doi: 10.1016/j.bbagrm.2020.194644
Identification of genome-wide targets and DNA recognition sequence of the Arabidopsis HMG-box protein AtHMGB15 during cold stress response.
Division of Plant Biology, Bose Insitute, P1/12 C.I.T Scheme VII M, Kolkata 700054, India.; Academy of Scientific and Innovative Research (AcSIR), CSIR-NBRI Campus, Lucknow, India; Computational Biology Lab, Council of Scientific and Industrial Research - National Botanical Research Institute (CSIR-NBRI), Rana Pratap Marg, Lucknow, Uttar Pradesh 226001, India.; Department of Chemistry, Bose Institute, P1/12 C.I.T Scheme VII M, Kolkata 700054, India.; Division of Plant Biology, Bose Insitute, P1/12 C.I.T Scheme VII M, Kolkata 700054, India. Electronic address: shubho@jcbose.ac.in.
AtHMGB15 belongs to a group of ARID-HMG proteins which are plant specific. The presence of two known DNA binding domains: AT rich interacting domain (ARID) and High Mobility Group (HMG)-box, in one polypeptide, makes this protein intriguing. Although proteins containing individual HMG and ARID domains have been characterized, not much is know about the role of ARID-HMG proteins. Promoter analysis of AtHMGB15 showed the presence of various stress responsive cis regulatory elements along with MADS-box containing transcription factors. Our result shows that the expression of AtHMGB15 increased significantly upon application of cold stress. Using ChIP-chip approach, we have identified 6128 and 4689 significantly enriched loci having AtHMGB15 occupancy under control and cold stressed condition respectively. GO analysis shows genes belonging to abiotic stress response, cold response and root development were AtHMGB15 targets during cold stress. DNA binding and footprinting assays further identified A(A/C)--ATA---(A/T)(A/T) as AtHMGB15 binding motif. The enriched probe distribution in both control and cold condition shows a bias of AtHMGB15 binding towards the transcribed (gene body) region. Further, the expression of cold stress responsive genes decreased in athmgb15 knockout plants compared to wild-type. Taken together, binding enrichment of AtHMGB15 to the promoter and upstream to stress loci suggest an unexplored role of the protein in stress induced transcription regulation.
PMID: 33068782
BMC Plant Biol , IF:3.497 , 2020 Oct , V20 (1) : P471 doi: 10.1186/s12870-020-02683-y
Genome-wide characterization and expression analysis of the heat shock transcription factor family in pumpkin (Cucurbita moschata).
School of Resources and Environmental Sciences, Henan Institute of Science and Technology, Xinxiang, 453003, China.; School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, 453003, Henan, China. jpyuan666@163.com.; Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, 453003, China. jpyuan666@163.com.
BACKGROUND: Crop quality and yield are affected by abiotic and biotic stresses, and heat shock transcription factors (Hsfs) are considered to play important roles in regulating plant tolerance under various stresses. To investigate the response of Cucurbita moschata to abiotic stress, we analyzed the genome of C. moschata. RESULTS: In this research, a total of 36 C. moschata Hsf (CmHsf) members were identified and classified into three subfamilies (I, II, and III) according to their amino acid sequence identity. The Hsfs of the same subfamily usually exhibit a similar gene structure (intron-exon distribution) and conserved domains (DNA-binding and other functional domains). Chromosome localization analysis showed that the 36 CmHsfs were unevenly distributed on 18 of the 21 chromosomes (except for Cm_Chr00, Cm_Chr08 and Cm_Chr20), among which 18 genes formed 9 duplicated gene pairs that have undergone segmental duplication events. The Ka/Ks ratio showed that the duplicated CmHsfs have mainly experienced strong purifying selection. High-level synteny was observed between C. moschata and other Cucurbitaceae species. CONCLUSIONS: The expression profile of CmHsfs in the roots, stems, cotyledons and true leaves revealed that the CmHsfs exhibit tissue specificity. The analysis of cis-acting elements and quantitative real-time polymerase chain reaction (qRT-PCR) revealed that some key CmHsfs were activated by cold stress, heat stress, hormones and salicylic acid. This study lays the foundation for revealing the role of CmHsfs in resistance to various stresses, which is of great significance for the selection of stress-tolerant C. moschata.
PMID: 33054710
Plant Mol Biol , IF:3.302 , 2020 Oct doi: 10.1007/s11103-020-01079-8
A CCR4-associated factor 1, OsCAF1B, confers tolerance of low-temperature stress to rice seedlings.
Department of Life Sciences, National Central University, Jhongli City, Taoyuan County, 320, Taiwan, ROC.; Department of Life Sciences, National Central University, Jhongli City, Taoyuan County, 320, Taiwan, ROC. chungan@cc.ncu.edu.tw.
KEY MESSAGE: Rice is an important crop in the world. However, little is known about rice mRNA deadenylation, which is an important regulation step of gene expression at the post-transcriptional level. The CCR4-NOT1 complex contains two key components, CCR4 and CAF1, which are the main cytoplasmic deadenylases in eukaryotic cells. Expression of OsCAF1B was tightly coupled with low-temperature exposure. In the present study, we investigated the function of OsCAF1B in rice by characterizing the molecular and physiological responses to cold stress in OsCAF1B overexpression lines and dominant-negative mutant lines. Our results demonstrate that OsCAF1B plays an important role in growth and development of rice seedlings at low temperatures. Rice is a tropical and subtropical crop that is sensitive to low temperature, and activates a complex gene regulatory network in response to cold stress. Poly(A) tail shortening, also termed deadenylation, is the rate-limiting step of mRNA degradation in eukaryotic cells. CCR4-associated factor 1 (CAF1) proteins are important enzymes for catalysis of mRNA deadenylation in eukaryotes. In the present study, the role of a rice cold-induced CAF1, OsCAF1B, in adaptation of rice plants to low-temperature stress was investigated. Expression of OsCAF1B was closely linked with low-temperature exposure. The increased survival percentage and reduced electrolyte leakage exhibited by OsCAF1B overexpression transgenic lines subjected to cold stress indicate that OsCAF1B plays a positive role in rice growth under low ambient temperature. The enhancement of cold tolerance by OsCAF1B in transgenic rice seedlings involved OsCAF1B deadenylase gene expression, and was associated with elevated expression of late-response cold-related transcription factor genes. In addition, the expression level of OsCAF1B was higher in a cold-tolerant japonica rice cultivar than in a cold-sensitive indica rice cultivar. The results reveal a hitherto undiscovered function of OsCAF1B deadenylase gene expression, which is required for adaptation to cold stress in rice.
PMID: 33025522
Photosynth Res , IF:3.216 , 2020 Oct doi: 10.1007/s11120-020-00785-0
Photosynthesis on the edge: photoinhibition, desiccation and freezing tolerance of Antarctic bryophytes.
Department of Biology, Universitat de Les Illes Balears / INAGEA, Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain. pereraalicia11@gmail.com.; Department of Biology, Universitat de Les Illes Balears / INAGEA, Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.; Department of Botany, Ecology and Plant Physiology, Universidad de La Laguna (ULL), 38200 La Laguna, Canarias, Spain.
In Antarctica, multiple stresses (low temperatures, drought and excessive irradiance) hamper photosynthesis even in summer. We hypothesize that controlled inactivation of PSII reaction centres, a mechanism widely studied by pioneer work of Fred Chow and co-workers, may effectively guarantee functional photosynthesis under these conditions. Thus, we analysed the energy partitioning through photosystems in response to temperature in 15 bryophyte species presenting different worldwide distributions but all growing in Livingston Island, under controlled and field conditions. We additionally tested their tolerance to desiccation and freezing and compared those with their capability for sexual reproduction in Antarctica (as a proxy to overall fitness). Under field conditions, when irradiance rules air temperature by the warming of shoots (up to 20 degrees C under sunny days), a predominance of sustained photoinhibition beyond dynamic heat dissipation was observed at low temperatures. Antarctic endemic and polar species showed the largest increases of photoinhibition at low temperatures. On the contrary, the variation of thermal dissipation with temperature was not linked to species distribution. Instead, maximum non-photochemical quenching at 20 degrees C was related (strongly and positively) with desiccation tolerance, which also correlated with fertility in Antarctica, but not with freezing tolerance. Although all the analysed species tolerated - 20 degrees C when dry, the tolerance to freezing in hydrated state ranged from the exceptional ability of Schistidium rivulare (that survived for 14 months at - 80 degrees C) to the susceptibility of Bryum pseudotriquetrum (that died after 1 day at - 20 degrees C unless being desiccated before freezing).
PMID: 33033976
Plants (Basel) , IF:2.762 , 2020 Oct , V9 (11) doi: 10.3390/plants9111417
Strawberry FaNAC2 Enhances Tolerance to Abiotic Stress by Regulating Proline Metabolism.
Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, China.; Key Laboratory of Landscaping Agriculture, Ministry of Agriculture and Rural Affairs, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
The quality and yields of strawberry plants are seriously affected by abiotic stress every year. NAC (NAM, ATAF, CUC) transcription factors are plant-specific, having various functions in plant development and response to stress. In our study, FaNAC2 from strawberry (Fragaria x ananassa, cultivar "Benihoppe") was isolated and found to be a member of the ATAF sub-family, belonging to the NAC family of transcription factors. FaNAC2 was strongly expressed in the shoot apical meristem and older leaves of strawberries, and was induced by cold, high salinity, and drought stress. To investigate how FaNAC2 functions in plant responses to abiotic stress, transgenic Nicotiana benthamiana plants ectopically overexpressing FaNAC2 were generated. The transgenic plants grew better under salt and cold stress, and, during simulated drought treatment, these transgenic lines not only grew better, but also showed higher seed germination rates than wild-type plants. Gene expression analysis revealed that key genes in proline biosynthesis pathways were up-regulated in FaNAC2 overexpression lines, while its catabolic pathway genes were down-regulated and proline was accumulated more with the overexpression of FaNAC2 after stress treatments. Furthermore, the gene expression of abscisic acid biosynthesis was also promoted. Our results demonstrate that FaNAC2 plays an important positive role in response to different abiotic stresses and may be further utilized to improve the stress tolerance of strawberry plants.
PMID: 33114021
Plants (Basel) , IF:2.762 , 2020 Oct , V9 (10) doi: 10.3390/plants9101337
OsmiR535, a Potential Genetic Editing Target for Drought and Salinity Stress Tolerance in Oryza sativa.
Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.; Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Agriculture, Hunan Agricultural University, Changsha 410128, China.
OsmiR535 belongs to the miR156/miR529/miR535 superfamily, a highly conserved miRNA family in plants. OsmiR535 is involved in regulating the cold-stress response, modulating plant development, and determining panicle architecture and grain length. However, the role that OsmiR535 plays in plant responses to drought and salinity are elusive. In the current study, molecular and genetic engineering techniques were used to elucidate the possible role of OsmiR535 in response to NaCl, PEG(Poly ethylene glycol), ABA(Abscisic acid), and dehydration stresses. Our results showed that OsmiR535 is induced under stressed conditions as compared to control. With transgenic and CRISPR/Cas9 knockout system techniques, our results verified that either inhibition or knockout of OsmiR535 in rice could enhance the tolerance of plants to NaCl, ABA, dehydration and PEG stresses. In addition, the overexpression of OsmiR535 significantly reduced the survival rate of rice seedlings during PEG and dehydration post-stress recovery. Our results demonstrated that OsmiR535 negatively regulates the stress response in rice. Moreover, our practical application of CRISPR/Cas9 mediated genome editing created a homozygous 5 bp deletion in the coding sequence of OsmiR535, demonstrating that OsmiR535 could be a useful genetic editing target for drought and salinity tolerance and a new marker for molecular breeding of Oryza sativa.
PMID: 33050518
PeerJ , IF:2.379 , 2020 , V8 : Pe10059 doi: 10.7717/peerj.10059
SlMYB102 expression enhances low-temperature stress resistance in tomato plants.
College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.
Herein, we identified the tomato SlMYB102 gene as a MYB family transcription factor of the R2R3-MYB subfamily. We additionally determined that the SlMYB102 promoter region contains photoresponsive, abiotic stress-responsive, and hormone-responsive regulatory elements, and we detected higher SlMYB102 expression in the reproductive organs of tomato than that in vegetative organs, with the expression being highest in ripe fruits and in roots. SlMYB102 expression was also shown to be cold-inducible. The protein encoded by SlMYB102 localized to the nucleus wherein it was found to mediate the transcriptional activation of target genes through its C-terminal domain. Overexpression of SlMYB102 in tomato plants conferred enhanced tolerance to cold stress. Under such cold stress conditions, we found that proline levels in the leaves of SlMYB102 overexpressing transgenic plants were higher than those in WT plants. In addition, S1MYB102 overexpression was associated with the enhanced expression of cold response genes including SlCBF1, SlCBF3, SlDREB1, SlDEB2, and SlICE1. We also found that the overexpression of SlMYB102 further enhanced the cold-induced upregulation of SlP5CS and SlAPX2. Taken together, these results suggest that SlMYB102 may be involved in the C-repeat binding transcription factor (CBF) and proline synthesis pathways, thereby improving tomato plant cold resistance.
PMID: 33083130
Plant Biol (Stuttg) , IF:2.167 , 2020 Oct doi: 10.1111/plb.13205
Characterization of the Key Region and Putative Phosphorylation Sites of EcaICE1 in its Molecular Interaction with the EcaHOS1 Protein in Eucalyptus camaldulensis.
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, Guangzhou, 510642, China.; Guangzhou Genedenovo Biotechnology Company Limited, Guangzhou, 510642, China.; Guangdong Academy of Forestry, Guangzhou, 510640, China.
Inducer of CBF expression 1 (ICE1), an MYC-like bHLH transcriptional activator, plays an important role in plants under cold stress by regulating the transcriptional expression of downstream cold-responsive genes. The ubiquitination-proteasome pathway mediated by high expression of osmotically responsive gene1 (HOS1) can effectively induce the degradation of ICE1 and decrease the expression of CBFs and their downstream genes under cold stress response in Arabidopsis, but knowledge of ubiquitination regulation of ICE1 by HOS1 is still limited in woody plants. In this study, a E3 ubiquitin ligase gene EcaHOS1 were amplified from Eucalyptus camaldulensis, the protein interactions between EcaICE1 and EcaHOS1 were analyzed. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assay results showed that EcaICE1 can interact with the EcaHOS1 protein in the nucleus, and further Y2H assay demonstrated that the 126-185 amino acid region at the N-terminus of the EcaICE1 protein was indispensable for its interaction with EcaHOS1 protein. Moreover, we found that the amino acids at positions 145, 158, and 184 within the key interaction region were the putative phosphorylation sites of EcaICE1 based on bioinformatics analysis, and only the substitution of Serine (Ser) 158 by Alanine (Ala) blocked the protein-protein interactions between EcaICE1 and EcaHOS1 based on Y2H and beta-galactosidase activity assays using site-directed mutagenesis. In summary, this is the first report that EcaICE1 can interact with the EcaHOS1 protein in Eucalyptus, and we identified Ser 158 of EcaICE1 as the key putative phosphorylation site for its interaction with the EcaHOS1 protein.
PMID: 33107181
Plant Biol (Stuttg) , IF:2.167 , 2020 Oct doi: 10.1111/plb.13201
The Transcription Factors of Tall Fescue in Response to Temperature Stresses.
Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; Innovation Academy for Seed Design, Chinese Academy of Sciences, Chengdu, 610041, China.
Tall fescue (Festuca arundinacea) is an important grass species worldwide, and the temperature stresses severely affect its distribution and yield. Transcription factors (TFs) as the master switches in sophisticated regulatory networks play essential roles in plant growth development and abiotic stress responses. In this study, we identified 877 TF genes belonging to 35 families in tall fescue under heat stress (40 ), cold stress (-10 ) and control (22 ) conditions. Of them, 784 differentially expressed genes were screened and classified to 33 families, such as bHLH, AP2/ERF, MYB, WRKY, NAC, bZIP, GTF, HD-ZIP, HSF etc. Among them, the expressions of bZIP and GTF family members were up-regulated mainly exposed to both heat and cold, but conversely the most members of WRKY and NAC families were reduced. Upon heat, HSF, GTE families and DREB2Bs were mainly up-regulated. Otherwise, bHLH, MYB, HD-ZIP and ERF families holistically were elevated under cold stress. Function richment analysis indicated that the TFs were involved in the pathways of "Plant hormone signal transduction", "Plant-pathogen interaction", "Circadian rhythm", etc. It showed these pathways were relevant to responding temperature stress. In the main, the temperature threats up-regulated the expressions of the stress tolerance-related genes, whereas down-regulated those genes associated with growth and disease resistance. The results exhibited that the expressions of a slew of TF genes were significantly altered by heat and cold stresses, and different TF families have commonalities and differences in response to the threats, indicating that TFs exert the crucial roles in plant adaption to adverse environment. This study profiled the response pattern of TFs to heat and cold conditions, partially explained the adaptation mechanism of cold-season forages to temperature stress, and screened plenty of candidate stress-tolerant TF genes.
PMID: 33078492
Genes Genomics , IF:1.188 , 2020 Oct doi: 10.1007/s13258-020-01010-x
Natural variation in glycine-rich region of Brassica oleracea cold shock domain protein 5 (BoCSDP5) is associated with low temperature tolerance.
Department of Biological Sciences, College of Biological Science and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea.; Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea.; Biotechnology and Breeding Institute of Asia Seed Co., Icheon-si, Gyeonggi-do, 17414, Republic of Korea.; Department of Biological Sciences, College of Biological Science and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea. hankuil.yi@cnu.ac.kr.; Department of Biological Sciences, College of Biological Science and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea. ykhur@cnu.ac.kr.
BACKGROUND: Low temperature (LT) or cold stress is a major environmental stress that seriously affects plant growth and development, limiting crop productivity. Cold shock domain proteins (CSDPs), which are present in most living organism, are involved in RNA metabolisms influencing abiotic stress tolerance. OBJECTIVE: The aims of this study are to identify target gene for LT-tolerance, like CSDPs, characterize genetics, and develop molecular marker distinguishing LT-tolerance in cabbage (Brassica oleracea var. capitata). METHODS: Semi-quantitative RT-PCR or qRT-PCR was used in gene expression study. LT-tolerance was determined by electrolyte leakage and PCR with allelic specific primers. RESULTS: Allelic variation was found in BoCSDP5 coding sequence (CDs) between LT-tolerant (BN106 and BN553) and -susceptible inbred lines (BN107 and BN554). LT-tolerant inbred lines contained variant type of BoCSDP5 (named as BoCSDP5v) which encodes extra CCHC zinc finger domain at C-terminus. Association of LT-tolerance with BoCSDP5v was confirmed by electrolyte leakage and segregation using genetic population derived from BN553 and BN554 cross. Allelic variation in BoCSDP5 gene does not influence the rate of gene expression, but produces different proteins with different number of CCHC zinc finger domains. LT-tolerance marker designed on the basis of polymorphism between BoCSDP5 and BoCSDP5v was confirmed with samples used in previous B. oleracea CIRCADIAN CLOCK ASSOCIATED 1 (BoCCA1) marker validation. CONCLUSIONS: LT-tolerant allele (BoCSDP5v) is dominant and independent of CBF pathway, and sufficient to generate molecular markers to identify LT-tolerant cabbage when it is used in combination with another marker, like BoCCA1-derived one. Production and analysis of overexpressing plants of BoCSDP1, BoCSDP3, BoCSDP5 and BoCSDP5v will be required for elucidating the function of CCHC zinc finger domains in LT-tolerance.
PMID: 33094377
Dokl Biochem Biophys , IF:0.672 , 2020 Sep , V494 (1) : P235-239 doi: 10.1134/S160767292005004X
Cold Stress Activates the Expression of Genes of the Chloroplast Transcription Apparatus in Arabidopsis thaliana Plants.
Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia. Ivan.a.b@mail.ru.; Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia.
The physiological and molecular responses of Arabidopsis thaliana plants to cold stress were studied. Exposure to a low non-freezing temperature (4 degrees C, 5 days) caused a decrease in the physiological functions and activity of a number of photosynthetic genes and elevation in expression of the cold stress gene COR15a, the product of which protects chloroplasts. It was shown for the first time that in parallel to a general inhibition of physiological functions under hypothermia, an increase in the expression of most genes for the chloroplast transcription apparatus was observed. This is obviously one of the compensatory mechanisms of adaptation aimed to maintain cellular homeostasis and physiological functions under hypothermia.
PMID: 33119824