Proc Natl Acad Sci U S A , IF:9.412 , 2020 Feb , V117 (6) : P3270-3280 doi: 10.1073/pnas.1919901117
Mapping proteome-wide targets of protein kinases in plant stress responses.
Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 200032 Shanghai, China; pcwang@sibs.ac.cn watao@purdue.edu jkzhu@sibs.ac.cn.; Department of Biochemistry, Purdue University, West Lafayette, IN 47907.; Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 200032 Shanghai, China.; Department of Chemistry, Purdue University, West Lafayette, IN 47907.; Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907.; Department of Biochemistry, Purdue University, West Lafayette, IN 47907; pcwang@sibs.ac.cn watao@purdue.edu jkzhu@sibs.ac.cn.
Protein kinases are major regulatory components in almost all cellular processes in eukaryotic cells. By adding phosphate groups, protein kinases regulate the activity, localization, protein-protein interactions, and other features of their target proteins. It is known that protein kinases are central components in plant responses to environmental stresses such as drought, high salinity, cold, and pathogen attack. However, only a few targets of these protein kinases have been identified. Moreover, how these protein kinases regulate downstream biological processes and mediate stress responses is still largely unknown. In this study, we introduce a strategy based on isotope-labeled in vitro phosphorylation reactions using in vivo phosphorylated peptides as substrate pools and apply this strategy to identify putative substrates of nine protein kinases that function in plant abiotic and biotic stress responses. As a result, we identified more than 5,000 putative target sites of osmotic stress-activated SnRK2.4 and SnRK2.6, abscisic acid-activated protein kinases SnRK2.6 and casein kinase 1-like 2 (CKL2), elicitor-activated protein kinase CDPK11 and MPK6, cold-activated protein kinase MPK6, H2O2-activated protein kinase OXI1 and MPK6, and salt-induced protein kinase SOS1 and MPK6, as well as the low-potassium-activated protein kinase CIPK23. These results provide comprehensive information on the role of these protein kinases in the control of cellular activities and could be a valuable resource for further studies on the mechanisms underlying plant responses to environmental stresses.
PMID: 31992638
Comp Biochem Physiol Part D Genomics Proteomics , IF:7.051 , 2020 Feb , V34 : P100677 doi: 10.1016/j.cbd.2020.100677
Transcriptome analysis of Liriomyza trifolii (Diptera: Agromyzidae) in response to temperature stress.
School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, China.; Plant Protection and Quarantine Station of Jiangsu Province, Nanjing, China.; School of Horticulture and Plant Protection & Institute of Applied Entomology, Yangzhou University, Yangzhou, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China. Electronic address: yzdu@yzu.edu.cn.
The leafminer Liriomyza trifolii is an important insect pest of ornamental and vegetable crops worldwide. Temperature is a critical environmental factor that impacts both the distribution and interspecific competition of Liriomyza spp. In this study, we compared the transcriptomes of L. trifolii exposed to ambient (25 degrees C), hot (43 degrees C), and cold (-7 degrees C) temperatures. RNA-seq revealed 100,041 assembled unigenes, and 50,546 of these were annotated in L. trifolii transcriptome libraries. A total of 207 and 2904 differentially expressed genes (DEGs) were identified in response to hot and cold stress, respectively. Functional classification indicated that "cellular process", "single organism processes" and "metabolic processes" pathways were significantly enriched, along with "binding activity" and "catalytic activity". With respect to clusters of orthologous genes (COG) classification, DEGs were assigned to "post-translational modification, protein turnover, chaperones", "carbohydrate transport and metabolism" and "lipid transport and metabolism" categories. Subsequent annotation and enrichment analyses indicated that genes encoding heat shock proteins (HSPs) and cuticular proteins were significantly up-regulated during heat and cold stress, respectively. This study expands our knowledge of gene expression in L. trifolii during temperature stress and provides a basis for further studies aimed at understanding the mechanism of thermotolerance in this important invasive leafminer fly.
PMID: 32143024
Plant Physiol , IF:6.902 , 2020 Feb , V182 (2) : P1022-1038 doi: 10.1104/pp.19.01195
Treatment Analogous to Seasonal Change Demonstrates the Integration of Cold Responses in Brachypodium distachyon.
McGill University, Department of Plant Science, 21,111 Lakeshore, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada.; Agriculture and Agri-food Canada, Quebec Research and Development Centre, 2560 Hochelaga Boulevard, Quebec G1V 2J3, Canada.; McGill University, Department of Plant Science, 21,111 Lakeshore, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada jean-benoit.charron@mcgill.ca.
Anthropogenic climate change precipitates the need to understand plant adaptation. Crucial in temperate climates, adaptation to winter is characterized by cold acclimation and vernalization, which respectively lead to freezing tolerance and flowering competence. However, the progression of these responses during fall and their interaction with plant development are not completely understood. By identifying key seasonal cues found in the native range of the cereal model Brachypodium distachyon, we designed a diurnal-freezing treatment (DF) that emulates summer-to-winter change. DF induced unique cold acclimation and vernalization responses characterized by low VERNALIZATION1 (VRN1) expression. Flowering under DF is characterized by an up-regulation of FLOWERING LOCUS T (FT) postvernalization independent of VRN1 expression. DF, while conferring flowering competence, favors a high tolerance to freezing and the development of a winter-hardy plant structure. The findings of this study highlight the contribution of phenotypic plasticity to freezing tolerance and demonstrate the integration of key morphological, physiological, and molecular responses in cold adaptation. The results suggest a fundamental role for VRN1 in regulating cold acclimation, vernalization, and morphological development in B. distachyon This study also establishes the usefulness of reproducing natural cues in laboratory settings.
PMID: 31843801
J Exp Bot , IF:5.908 , 2020 Feb , V71 (4) : P1598-1613 doi: 10.1093/jxb/erz523
The DEAD-box RNA helicase SHI2 functions in repression of salt-inducible genes and regulation of cold-inducible gene splicing.
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA.; College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan, China.; School of Life Sciences, Central China Normal University, Wuhan, China.; Plant Stress and Germplasm Development Unit, USDA-ARS, Lubbock, TX, USA.
Gene regulation is central for growth, development, and adaptation to environmental changes in all living organisms. Many genes are induced by environmental cues, and the expression of these inducible genes is often repressed under normal conditions. Here, we show that the SHINY2 (SHI2) gene is important for repressing salt-inducible genes and also plays a role in cold response. The shi2 mutant displayed hypersensitivity to cold, abscisic acid (ABA), and LiCl. Map-based cloning demonstrates that SHI2 encodes a DEAD- (Asp-Glu-Ala-Asp) box RNA helicase with similarity to a yeast splicing factor. Transcriptomic analysis of the shi2 mutant in response to cold revealed that the shi2 mutation decreased the number of cold-responsive genes and the magnitude of their response, and resulted in the mis-splicing of some cold-responsive genes. Under salt stress, however, the shi2 mutation increased the number of salt-responsive genes but had a negligible effect on mRNA splicing. Our results suggest that SHI2 is a component in a ready-for-transcription repressor complex important for gene repression under normal conditions, and for gene activation and transcription under stress conditions. In addition, SHI2 also serves as a splicing factor required for proper splicing of cold-responsive genes and affects 5' capping and polyadenylation site selection.
PMID: 31745559
J Exp Bot , IF:5.908 , 2020 Feb , V71 (4) : P1363-1374 doi: 10.1093/jxb/erz488
Pre-rRNA processing and its response to temperature stress in maize.
National Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, China.; College of Agronomy, Henan Agricultural University, Zhengzhou, China.; Department of Ornamental Horticulture, China Agricultural University, Beijing, China.
Ribosome biogenesis is a fundamental process in all eukaryotic cells and is coupled with the processing and maturation of pre-rRNAs. Maize is a primary staple crop across the world, but little is known about the exact pre-rRNA processing sites and pathways in this species. In this study, we present a detailed model of the pathway by identifying the critical endonucleolytic cleavage sites and determining the pre-rRNA intermediates by circular reverse-transcription PCR and northern blot analysis. We demonstrate that two pathways coexist in maize to promote the processing of 35S pre-rRNA, and that the processing of 27SA pre-rRNA can proceed via two different pathways, which are distinguished based on the order of ITS1 removal and ITS2 cleavage. Compared with yeast and mammals, this new 27SA pre-rRNA processing mechanism is unique to maize and other higher plants. In addition, we demonstrate that maize can modulate pre-rRNA processing levels in response to chilling and heat stress, as indicated by a significant reduction of the P-A3 intermediate. Our study provides information that will facilitate future research on ribosome biogenesis and pre-rRNA processing in maize.
PMID: 31665749
Int J Mol Sci , IF:4.556 , 2020 Feb , V21 (4) doi: 10.3390/ijms21041284
Genetic Dissection of Germinability under Low Temperature by Building a Resequencing Linkage Map in japonica Rice.
Crop Cultivation and Tillage Institute of Heilongjiang Academy of Agricultural Sciences, Heilongjiang Provincial Key Laboratory of Crop Physiology and Ecology in Cold Region, Heilongjiang Provincial Engineering Technology Research Center of Crop Cold Damage, Harbin 150086, China.; Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.; Rice Research Institute of Shenyang Agricultural University, Shenyang 110866, China.; College of Agronomy, Heilongjiang Bayi Agricultural University, Daqing 163000, China.
Among all cereals, rice is highly sensitive to cold stress, especially at the germination stage, which adversely impacts its germination ability, seed vigor, crop stand establishment, and, ultimately, grain yield. The dissection of novel quantitative trait loci (QTLs) or genes conferring a low-temperature germination (LTG) ability can significantly accelerate cold-tolerant rice breeding to ensure the wide application of rice cultivation through the direct seeding method. In this study, we identified 11 QTLs for LTG using 144 recombinant inbred lines (RILs) derived from a cross between a cold-tolerant variety, Lijiangxintuanheigu (LTH), and a cold-sensitive variety, Shennong265 (SN265). By resequencing two parents and RIL lines, a high-density bin map, including 2,828 bin markers, was constructed using 123,859 single-nucleotide polymorphisms (SNPs) between two parents. The total genetic distance corresponding to all 12 chromosome linkage maps was 2,840.12 cm. Adjacent markers were marked by an average genetic distance of 1.01 cm, corresponding to a 128.80 kb physical distance. Eight and three QTL alleles had positive effects inherited from LTH and SN265, respectively. Moreover, a pleiotropic QTL was identified for a higher number of erected panicles and a higher grain number on Chr-9 near the previously cloned DEP1 gene. Among the LTG QTLs, qLTG3 and qLTG7b were also located at relatively small genetic intervals that define two known LTG genes, qLTG3-1 and OsSAP16. Sequencing comparisons between the two parents demonstrated that LTH possesses qLTG3-1 and OsSAP16 genes, and SN-265 owns the DEP1 gene. These comparison results strengthen the accuracy and mapping resolution power of the bin map and population. Later, fine mapping was done for qLTG6 at 45.80 kb through four key homozygous recombinant lines derived from a population with 1569 segregating plants. Finally, LOC_Os06g01320 was identified as the most possible candidate gene for qLTG6, which contains a missense mutation and a 32-bp deletion/insertion at the promoter between the two parents. LTH was observed to have lower expression levels in comparison with SN265 and was commonly detected at low temperatures. In conclusion, these results strengthen our understanding of the impacts of cold temperature stress on seed vigor and germination abilities and help improve the mechanisms of rice breeding programs to breed cold-tolerant varieties.
PMID: 32074988
Int J Mol Sci , IF:4.556 , 2020 Feb , V21 (4) doi: 10.3390/ijms21041198
Overexpression of a Malus baccata NAC Transcription Factor Gene MbNAC25 Increases Cold and Salinity Tolerance in Arabidopsis.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of Northeast Region, Ministry of Agriculture and Rural Affairs, College of Horticulture & Landscape Architecture, Northeast Agricultural University, Harbin 150030, China.
NAC (no apical meristem (NAM), Arabidopsis thaliana transcription activation factor (ATAF1/2) and cup shaped cotyledon (CUC2)) transcription factors play crucial roles in plant development and stress responses. Nevertheless, to date, only a few reports regarding stress-related NAC genes are available in Malus baccata (L.) Borkh. In this study, the transcription factor MbNAC25 in M. baccata was isolated as a member of the plant-specific NAC family that regulates stress responses. Expression of MbNAC25 was induced by abiotic stresses such as drought, cold, high salinity and heat. The ORF of MbNAC25 is 1122 bp, encodes 373 amino acids and subcellular localization showed that MbNAC25 protein was localized in the nucleus. In addition, MbNAC25 was highly expressed in new leaves and stems using real-time PCR. To analyze the function of MbNAC25 in plants, we generated transgenic Arabidopsis plants that overexpressed MbNAC25. Under low-temperature stress (4 degrees C) and high-salt stress (200 mM NaCl), plants overexpressing MbNAC25 enhanced tolerance against cold and drought salinity conferring a higher survival rate than that of wild-type (WT). Correspondingly, the chlorophyll content, proline content, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly increased, while malondialdehyde (MDA) content was lower. These results indicated that the overexpression of MbNAC25 in Arabidopsis plants improved the tolerance to cold and salinity stress via enhanced scavenging capability of reactive oxygen species (ROS).
PMID: 32054040
Biomolecules , IF:4.082 , 2020 Feb , V10 (2) doi: 10.3390/biom10020327
Characterization of the CRM Gene Family and Elucidating the Function of OsCFM2 in Rice.
State Key Laboratory of Rice Biology / China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China.
The chloroplast RNA splicing and ribosome maturation (CRM) domain-containing proteins regulate the expression of chloroplast or mitochondrial genes that influence plant growth and development. Although 14 CRM domain proteins have previously been identified in rice, there are few studies of these gene expression patterns in various tissues and under abiotic stress. In our study, we found that 14 CRM domain-containing proteins have a conservative motif1. Under salt stress, the expression levels of 14 CRM genes were downregulated. However, under drought and cold stress, the expression level of some CRM genes was increased. The analysis of gene expression patterns showed that 14 CRM genes were expressed in all tissues but especially highly expressed in leaves. In addition, we analyzed the functions of OsCFM2 and found that this protein influences chloroplast development by regulating the splicing of a group I and five group II introns. Our study provides information for the function analysis of CRM domain-containing proteins in rice.
PMID: 32085638
Plant Cell Physiol , IF:4.062 , 2020 Feb , V61 (2) : P331-341 doi: 10.1093/pcp/pcz200
ZmDREB1A Regulates RAFFINOSE SYNTHASE Controlling Raffinose Accumulation and Plant Chilling Stress Tolerance in Maize.
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.; The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China.; The Biology Teaching and Research Core Facility, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China.; Department of Horticulture, Seed Biology, College of Agriculture, Food, and Environment, University of Kentucky, Lexington, KY 40546, USA.
Raffinose accumulation is positively correlated with plant chilling stress tolerance; however, the understanding of the function and regulation of raffinose metabolism under chilling stress remains in its infancy. RAFFINOSE SYNTHASE (RAFS) is the key enzyme for raffinose biosynthesis. In this study, we report that two independent maize (Zea mays) zmrafs mutant lines, in which raffinose was completely abolished, were more sensitive to chilling stress and their net photosynthetic product (total soluble sugars and starch) accumulation was significantly decreased compared with controls after chilling stress. A similar characterization of the maize dehydration responsive element (DRE)-binding protein 1A mutant (zmdreb1a) showed that ZmRAFS expression and raffinose content were significantly decreased compared with its control under chilling stress. Overexpression of maize ZmDREB1A in maize leaf protoplasts increased ZmDREB1A amounts, which consequently upregulated the expression of maize ZmRAFS and the Renilla LUCIFERASE (Rluc), which was controlled by the ZmRAFS promoter. Deletion of the single dehydration-responsive element (DRE) in the ZmRAFS promoter abolished ZmDREB1A's influence on Rluc expression, while addition of three copies of the DRE in the ZmRAFS promoter dramatically increased Rluc expression when ZmDREB1A was simultaneously overexpressed. Electrophoretic mobility shift assays and chromatin immunoprecipitation-quantitative PCR demonstrated that ZmDREB1A directly binds to the DRE motif in the promoter of ZmRAFS both in vitro and in vivo. These data demonstrate that ZmRAFS, which was directly regulated by ZmDREB1A, enhances both raffinose biosynthesis and plant chilling stress tolerance.
PMID: 31638155
Sci Rep , IF:3.998 , 2020 Feb , V10 (1) : P2445 doi: 10.1038/s41598-020-58745-6
Expression of RcHSP70, heat shock protein 70 gene from Chinese rose, enhances host resistance to abiotic stresses.
Shanghai Botanical Garden, Shanghai, China.; Shanghai Botanical Garden, Shanghai, China. 498842061@qq.com.
There exist differences in the heat tolerance of Chinese rose varieties, and high temperature in summer can lead to failure of blooming in non-heat-tolerant Chinese rose varieties. We cloned a heat shock protein 70 gene (designated RcHSP70) from heat-tolerant varieties of Chinese rose (Rosa hybrida L.) to elucidate the molecular mechanism of heat tolerance and improve the quality of Chinese rose. Degenerate primers were designed for RcHSP70 according to the 5'- and 3'-end sequences of HSP70 genes in apple and tea. RcHSP70 was cloned from heat-tolerant Chinese rose varieties after heat shock. The heat shock-induced expression patterns of RcHSP70 in different Chinese rose varieties were analyzed by RT-PCR. Following heat shock (38 degrees C/3 h), RcHSP70 was highly expressed in the heat-tolerant varieties but not in the non-heat-tolerant varieties, indicating a close relationship between RcHSP70 and heat resistance in Chinese rose. To verify the function of RcHSP70, we constructed a prokaryotic expression recombinant vector for this gene and transformed it into Escherichia coli BL21. The tolerance of recombinant strains to abiotic stresses, including high temperature, low temperature, high salt, heavy metals, high pH, and oxidation, was evaluated. Additionally, RcHSP70 was transformed into tobacco plants. Because of the overexpression of this gene, transgenic tobacco plants improved their tolerance to high temperature and cold. In addition, transgenic tobacco showed better photosynthetic performance, relative electrical conductivity and proline content than wild tobacco after heat stress and cold stress. Our findings indicate that RcHSP70 is involved in the resistance of Chinese rose to abiotic stresses.
PMID: 32051436
Plant Physiol Biochem , IF:3.72 , 2020 Feb , V147 : P101-112 doi: 10.1016/j.plaphy.2019.12.017
Genome wide characterization of phospholipase A & C families and pattern of lysolipids and diacylglycerol changes under abiotic stresses in Brassica napus L.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China; Department of Agriculture, University of Swabi, Swabi, Khyber Pakhtunkhwa, Pakistan.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China. Electronic address: lusp@mail.hzau.edu.cn.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China. Electronic address: guoliang@mail.hzau.edu.cn.
Plant phospholipase A (PLA) and C (PLC) families are least explored in terms of structure, diversity and their roles in membrane lipid remodeling under stress conditions. In this study, we performed gene family analysis, determined gene expression in different tissues and monitored transcriptional regulation of patatin-related PLA family and PLC family in oil crop Brassica napus under dehydration, salt, abscisic acid and cold stress. The identified 29 BnapPLA genes and 40 BnaPLC genes shared high similarities with Arabidopsis pPLAs and PLCs, respectively. This study highlighted the expression pattern of BnapPLAs and BnaPLCs in different tissues and their expression in response to abiotic stresses in Brassica napus. The results revealed that several members of BnapPLA3, PI-PLC1/2 and NPC1 were actively regulated by abiotic stresses. Lipid changes at different time points under stress conditions were also measured. Lipid profiling revealed that the level of lysophospholipids and diacylglycerol (DAG) showed a varied pattern of changes under different abiotic stress treatments. The change of lipids correlated with the transcriptional regulation of a few specific members of pPLA and PLC families. Our study suggested that A and C-type phospholipases in Brassica napus may have diverse physiological and regulatory roles in abiotic stress response and tolerance.
PMID: 31855816
Mol Plant Microbe Interact , IF:3.696 , 2020 Feb , V33 (2) : P284-295 doi: 10.1094/MPMI-07-19-0183-R
Transcriptomic Profiling of Acute Cold Stress-Induced Disease Resistance (SIDR) Genes and Pathways in the Grapevine Powdery Mildew Pathosystem.
Section of Plant Pathology and Plant-Microbe Biology, Cornell AgriTech, Cornell University, Geneva, NY 14456, U.S.A.; Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY 14623, U.S.A.; United States Department of Agriculture-Agricultural Research Service Grape Genetics Research Unit, Geneva, NY 14456, U.S.A.
Temperatures from 2 to 8 degrees C transiently induce quantitative resistance to powdery mildew in several host species (cold stress-induced disease resistance [SIDR]). Although cold SIDR events occur in vineyards worldwide an average of 14 to 21 times after budbreak of grapevine and can significantly delay grapevine powdery mildew (Erysiphe necator) epidemics, its molecular basis was poorly understood. We characterized the biology underlying the Vitis vinifera cold SIDR phenotype-which peaks at 24 h post-cold (hpc) treatment and results in a 22 to 28% reduction in spore penetration success-through highly replicated (n = 8 to 10) RNA sequencing experiments. This phenotype was accompanied by a sweeping transcriptional downregulation of photosynthesis-associated pathways whereas starch and sugar metabolism pathways remained largely unaffected, suggesting a transient imbalance in host metabolism and a suboptimal target for pathogen establishment. Twenty-six cold-responsive genes peaked in their differential expression at the 24-hpc time point. Finally, a subset of genes associated with nutrient and amino acid transport accounted for four of the eight most downregulated transcripts, including two nodulin 1A gene precursors, a nodulin MtN21 precursor, and a Dynein light chain 1 motor protein precursor. Reduced transport could exacerbate localized nutrient sinks that would again be transiently suboptimal for pathogen growth. This study links the transient cold SIDR phenotype to underlying transcriptional changes and provides an experimental framework and library of candidate genes to further explore cold SIDR in several systems, with an ultimate goal of identifying novel breeding or management targets for reduced disease.
PMID: 31556345
BMC Genomics , IF:3.594 , 2020 Feb , V21 (1) : P178 doi: 10.1186/s12864-020-6572-6
Comparative analysis of basic helix-loop-helix gene family among Brassica oleracea, Brassica rapa, and Brassica napus.
Laboratory of Cell and Molecular Biology, Institute of Vegetable Science, Zhejiang University, 866 Yuhangtang Road, Zhejiang, 310058, Hangzhou, China.; Key Laboratory of Horticultural Plant Growth, Development, and Quality Improvement, Ministry of Agriculture, Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang, 310058, Hangzhou, China.; Laboratory of Cell and Molecular Biology, Institute of Vegetable Science, Zhejiang University, 866 Yuhangtang Road, Zhejiang, 310058, Hangzhou, China. xlyu@zju.edu.cn.; Key Laboratory of Horticultural Plant Growth, Development, and Quality Improvement, Ministry of Agriculture, Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang, 310058, Hangzhou, China. xlyu@zju.edu.cn.
BACKGROUND: The basic helix-loop-helix (bHLH) is the second largest gene family in the plant, some members play important roles in pistil development and response to drought, waterlogging, cold stress and salt stress. The bHLH gene family has been identified in many species, except for Brassica oleracea and B. napus thus far. This study aims to identify the bHLH family members in B. oleracea, B. rapa and B. napus, and elucidate the expression, duplication, phylogeny and evolution characters of them. RESULT: A total of 268 bHLH genes in B. oleracea, 440 genes in B. napus, and 251 genes in B. rapa, including 21 new bHLH members, have been identified. Subsequently, the analyses of the phylogenetic trees, conserved motifs and gene structures showed that the members in the same subfamily were highly conserved. Most Ka/Ks values of homologous gene were < 1, which indicated that these genes suffered from strong purifying selection for retention. The retention rates of BrabHLH and BolbHLH genes were 51.6 and 55.1%, respectively. The comparative expression patterns between B. rapa and B. napus showed that they had similar expression patterns in the root and contrasting patterns in the stems, leaves, and reproductive tissues. In addition, there were 41 and 30 differential expression bHLH genes under the treatments of ABA and JA, respectively, and the number of down regulation genes was significantly more than up regulation genes. CONCLUSION: In the present study, we identified and performed the comparative genomics analysis of bHLH gene family among B. oleracea, B. rapa and B. napus, and also investigated their diversity. The expression patterns between B. rapa and B. napus shows that they have the similar expression pattern in the root and opposite patterns in the stems, leaves, and reproduction tissues. Further analysis demonstrated that some bHLH gene members may play crucial roles under the abiotic and biotic stress conditions. This is the first to report on the bHLH gene family analysis in B. oleracea and B. napus, which can offer useful information on the functional analysis of the bHLH gene in plants.
PMID: 32093614
Plant Sci , IF:3.591 , 2020 Feb , V291 : P110346 doi: 10.1016/j.plantsci.2019.110346
The NAC transcription factor CaNAC064 is a regulator of cold stress tolerance in peppers.
College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China.; College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China. Electronic address: rugangchen@126.com.
NAC (NAM, ATAF1/2 and CUC2) proteins are plant-specific transcription factors (TFs) that are important in plant abiotic stress responses. In this study we isolated a NAC gene from Capsicum annuum leaves, designated as CaNAC064. We characterized the amino acid sequence of CaNAC064 and found that it contain conserved domains of the NAC family, including a highly conserved N-terminus domain and a highly variable C-terminus domain. Expression analysis showed that the 4(0)C, 40(0)C, salicylic acid (SA) and abscisic acid (ABA) treatments strongly induced the expression of CaNAC064 through silencing of CaNAC064 in pepper and overexpressing in Arabidopsis. CaNAC064-silenced pepper plants exhibited more serious wilting, higher MDA contents and chilling injury index, lower proline content, and more accumulation of ROS in the leaves after cold stress. The CaNAC064-overexpressing Arabidopsis plants exhibited lower MDA content, chilling injury index and relative electrolyte leakage content as compared to WT plants under cold stress. Transcriptional activation activity analysis indicated that CaNAC064 has transcriptional activation activity in the 691-1071 bp key region. We identified 45 proteins that putatively interact with CaNAC064 using the Yeast Two-Hybrid method. According to the Yeast Two-Hybrid and BIFC results, CaNAC064 interacted with low temperature-induced haplo-proteinase proteins in plant cell. These results suggested that CaNAC064 positively modulates plant cold-tolerance, laying the foundation for future investigations into the role of NACs as regulatory proteins of cold tolerance in plants.
PMID: 31928677
Plant Sci , IF:3.591 , 2020 Feb , V291 : P110363 doi: 10.1016/j.plantsci.2019.110363
Physiological response and transcription profiling analysis reveal the role of glutathione in H2S-induced chilling stress tolerance of cucumber seedlings.
State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: lfjsdnd@126.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: 2522615828@qq.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: 1013849695@qq.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: 2712794591@qq.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: 15621321275@163.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: bhg163@163.com.; State Key Laboratory of Crop Biology/Key Laboratory of Horticultural Crop Biology and Germplasm Innovation, Ministry of Agriculture/Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China. Electronic address: axz@sdau.edu.cn.
Recent reports have uncovered the multifunctional role of H2S in the physiological response of plants to biotic and abiotic stresses. Here, we studied whether NaHS (an H2S donor) pretreatment could provoke the tolerance of cucumber (Cucumis sativus L.) seedlings subsequently exposed to chilling stress and whether glutathione was involved in this process. Results showed that cucumber seedlings sprayed with NaHS exhibited remarkably increased chilling tolerance, as evidenced by the observed plant tolerant phenotype, as well as the lower levels of electrolyte leakage (EL), malondialdehyde (MDA) content, hydrogen peroxide (H2O2) content and RBOH mRNA abundance, compared with the control plants. In addition, NaHS treatment increased the endogenous content of the reduced glutathione (GSH) and the ratio of reduced/oxidized glutathione (GSH/GSSG), meanwhile, the higher net photosynthetic rate (Anet), the light-saturated CO2 assimilation rate (Asat), the photochemical efficiency (Fv/Fm) and the maximum photochemical efficiency of PSII in darkness (capital EF, CyrillicPSII) as well as the mRNA levels and activities of the key photosynthetic enzymes (Rubisco, TK, SBPase and FBA) were observed in NaHS-treated seedlings under chilling stress, whereas this effect of NaHS was weakened by buthionine sulfoximine (BSO, an inhibitor of glutathione) or 6-Aminonicotinamide (6-AN, a specific pentose inhibitor and thus inhibits the NADPH production), which preliminarily proved the interaction between H2S and GSH. Moreover, transcription profiling analysis revealed that the GSH-associated genes (GST Tau, MAAI, APX, GR, GS and MDHAR) were significantly up-regulated in NaHS-treated cucumber seedlings, compared to the H2O-treated seedlings under chilling stress. Thus, novel results highlight the importance of glutathione as a downstream signal of H2S-induced plant tolerance to chilling stress.
PMID: 31928658
BMC Plant Biol , IF:3.497 , 2020 Feb , V20 (1) : P80 doi: 10.1186/s12870-020-2281-1
Transcriptome analysis of postharvest blueberries (Vaccinium corymbosum 'Duke') in response to cold stress.
College of Food, Shenyang Agricultural University, No.120 Dongling Road, Shenhe District, Shenyang City, Liaoning Province, 110866, People's Republic of China.; College of Food, Shenyang Agricultural University, No.120 Dongling Road, Shenhe District, Shenyang City, Liaoning Province, 110866, People's Republic of China. 66zhouqian@syau.edu.cn.
BACKGROUND: Blueberry (Vaccinium spp.) is a small berry with high economic value. Although cold storage can extend the storage time of blueberry to more than 60 days, it leads to chilling injury (CI) displaying as pedicle pits; and the samples of 0 degrees C-30 days was the critical point of CI. However, little is known about the mechanism and the molecular basis response to cold stress in blueberry have not been explained definitely. To comprehensively reveal the CI mechanisms in response to cold stress, we performed high-throughput RNA Seq analysis to investigate the gene regulation network in 0d (control) and 30d chilled blueberry. At the same time, the pitting and decay rate, electrolyte leakage (EL), malondialdehyde (MDA) proline content and GSH content were measured. RESULTS: Two cDNA libraries from 0d (control) and 30d chilled samples were constructed and sequenced, generating a total of 35,060 unigenes with an N50 length of 1348 bp. Of these, 1852 were differentially expressed, with 1167 upregulated and 685 downregulated. Forty-five cold-induced transcription factor (TF) families containing 1023 TFs were identified. The DEGs indicated biological processes such as stress responses; cell wall metabolism; abscisic acid, gibberellin, membrane lipid, energy metabolism, cellular components, and molecular functions were significantly responsed to cold storage. The transcriptional level of 40 DEGs were verified by qRT-PCR. CONCLUSIONS: The postharvest cold storage leads serious CI in blueberry, which substantially decreases the quality, storability and consumer acceptance. The MDA content, proline content, EL increased and the GSH content decreased in this chilled process. The biological processes such as stress responses, hormone metabolic processes were significantly affected by CI. Overall, the results obtained here are valuable for preventing CI under cold storage and could help to perfect the lack of the genetic information of non-model plant species.
PMID: 32075582
BMC Plant Biol , IF:3.497 , 2020 Feb , V20 (1) : P62 doi: 10.1186/s12870-020-2253-5
Genome-wide identification of cold responsive transcription factors in Brassica napus L.
Plant Genomics & Molecular Improvement of Colored Fiber Lab, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.; Crop Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China.; Wenzhou - Kean University, Wenzhou, 325060, China.; Crop Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, China. zhixiongfan@126.com.; Plant Genomics & Molecular Improvement of Colored Fiber Lab, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China. yudl@zstu.edu.cn.
BACKGROUND: Cold stress is one of the primary environmental factors that affect plant growth and productivity, especially for crops like Brassica napus that live through cold seasons. Till recently, although a number of genes and pathways involved in B. napus cold response have been revealed by independent studies, a genome-wide identification of the key regulators and the regulatory networks is still lack. In this study, we investigated the transcriptomes of cold stressed semi-winter and winter type rapeseeds in short day condition, mainly with the purpose to systematically identify the functional conserved transcription factors (TFs) in cold response of B. napus. RESULTS: Global modulation of gene expression was observed in both the semi-winter type line (158A) and the winter type line (SGDH284) rapeseeds, in response to a seven-day chilling stress in short-day condition. Function analysis of differentially expressed genes (DEGs) revealed enhanced stresses response mechanisms and inhibited photosynthesis in both lines, as well as a more extensive inhibition of some primary biological processes in the semi-winter type line. Over 400 TFs were differentially expressed in response to cold stress, including 56 of them showed high similarity to the known cold response TFs and were consistently regulated in 158A and SGDH284, as well as 25 TFs which targets were over-represented in the total DEGs. A further investigation based on their interactions indicated the critical roles of several TFs in cold response of B. napus. CONCLUSION: In summary, our results revealed the alteration of gene expression in cold stressed semi-winter and winter ecotype B. napus lines and provided a valuable collection of candidate key regulators involved in B. napus response to cold stress, which could expand our understanding of plant stress response and benefit the future improvement of the breed of rapeseeds.
PMID: 32028890
Biol Res , IF:3.092 , 2020 Feb , V53 (1) : P8 doi: 10.1186/s40659-020-00276-5
Studies on the cold tolerance of ratoon 'Chaling' common wild rice.
Hunan Provincial Key Laboratory of Crop Sterility Mechanism and Sterile Germplasm Resources Innovation, State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, 410081, China. xml2012cs@126.com.; Hunan Provincial Key Laboratory of Crop Sterility Mechanism and Sterile Germplasm Resources Innovation, State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, 410081, China.; Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.; State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
BACKGROUND: Rice is the staple food of many people around the world. However, most rice varieties, especially widely grown indica varieties and hybrids, are sensitive to cold stress. In order to provide a basis for the utilization of a common wild rice (CWR, Oryza rufipogon Griff.) named 'Chaling' CWR in cold-tolerant rice breeding and deepen the understanding of rice cold tolerance, the cold tolerance of ratoon 'Chaling' CWR was studied under the stress of the natural low temperature in winter in Changsha, Hunan province, China, especially under the stress of abnormal natural low temperature in Changsha in 2008, taking other ratoon CWR accessions and ratoon cultivated rice phenotypes as control. RESULTS: The results showed that ratoon 'Chaling' CWR can safely overwinter under the natural conditions in Changsha (28 degrees 22' N), Hunan province, China, which is a further and colder northern place than its habitat, even if it suffers a long-term low temperature stress with ice and snow. In 2008, an extremely cold winter appeared in Changsha, i.e., the average daily mean temperature of 22 consecutive days from January 13 to February 3 was - 1.0 degrees C, and the extreme low temperature was - 4.7 degrees C. After subjected to this long-term cold stress, the overwinter survival rate of ratoon 'Chaling' CWR was 100%, equals to that of ratoon 'Dongxiang' CWR which is northernmost distribution in the word among wild rice populations, higher than those of ratoon 'Fusui' CWR, ratoon 'Jiangyong' CWR, and ratoon 'Liujiang' CWR (63.55-83.5%) as well as those of ratoon 'Hainan' CWR, ratoon 'Hepu' CWR, and all the ratoon cultivated rice phenotypes including 3 japonica ones, 3 javanica ones, and 5 indica ones (0.0%). CONCLUSIONS: The results indicate that ratoon 'Chaling' CWR possesses strong cold tolerance and certain freezing tolerance.
PMID: 32070437
Am J Bot , IF:3.038 , 2020 Feb , V107 (2) : P250-261 doi: 10.1002/ajb2.1385
Genetic and physiological mechanisms of freezing tolerance in locally adapted populations of a winter annual.
Department of Botany and Plant Pathology and the Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA.; MSU-DOE Plant Research Laboratory and the Plant Resilience Institute, Michigan State University, East Lansing, MI, USA.; Department of Plant Biology, and W. K. Kellogg Biological Station, Michigan State University, East Lansing, MI, USA.
PREMISE: Despite myriad examples of local adaptation, the phenotypes and genetic variants underlying such adaptive differentiation are seldom known. Recent work on freezing tolerance and local adaptation in ecotypes of Arabidopsis thaliana from Italy and Sweden provides an essential foundation for uncovering the genotype-phenotype-fitness map for an adaptive response to a key environmental stress. METHODS: We examined the consequences of a naturally occurring loss-of-function (LOF) mutation in an Italian allele of the gene that encodes the transcription factor CBF2, which underlies a major freezing-tolerance locus. We used four lines with a Swedish genetic background, each containing a LOF CBF2 allele. Two lines had introgression segments containing the Italian CBF2 allele, and two contained deletions created using CRISPR-Cas9. We used a growth chamber experiment to quantify freezing tolerance and gene expression before and after cold acclimation. RESULTS: Freezing tolerance was lower in the Italian (11%) compared to the Swedish (72%) ecotype, and all four experimental CBF2 LOF lines had reduced freezing tolerance compared to the Swedish ecotype. Differential expression analyses identified 10 genes for which all CBF2 LOF lines, and the IT ecotype had similar patterns of reduced cold responsive expression compared to the SW ecotype. CONCLUSIONS: We identified 10 genes that are at least partially regulated by CBF2 that may contribute to the differences in cold-acclimated freezing tolerance between the Italian and Swedish ecotypes. These results provide novel insight into the molecular and physiological mechanisms connecting a naturally occurring sequence polymorphism to an adaptive response to freezing conditions.
PMID: 31762012
Gene , IF:2.984 , 2020 Feb , V727 : P144230 doi: 10.1016/j.gene.2019.144230
Polyamine homeostasis in tomato biotic/abiotic stress cross-tolerance.
Institute of Olive Tree, Subtropical Plants and Viticulture, Laboratory of Vegetable Crops, Heraklion, Greece.; Agricultural University of Athens, Department of Crop Science, Laboratory of Pomology, Iera Odos 75, Athens 118 55, Greece.; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas (IMBB-FORTH), Heraklion, Crete, Greece.; Cyprus University of Technology, Department of Agricultural Science, Biotechnology and Food Science, Athinon and Anexartisias 57, Limassol, Cyprus.; Hellenic Mediterranean University, Department of Agriculture, 71004, Estavromenos, Heraklion, Crete, Greece.; University of Peloponnese, Department of Agriculture, Antikalamos, Kalamata, 24100, Greece. Electronic address: delis@teikal.gr.
Adverse conditions and biotic strain can lead to significant losses and impose limitations on plant yield. Polyamines (PAs) serve as regulatory molecules for both abiotic/biotic stress responses and cell protection in unfavourable environments. In this work, the transcription pattern of 24 genes orchestrating PA metabolism was investigated in Cucumber Mosaic Virus or Potato Virus Y infected and cold stressed tomato plants. Expression analysis revealed a differential/pleiotropic pattern of gene regulation in PA homeostasis upon biotic, abiotic or combined stress stimuli, thus revealing a discrete response specific to diverse stimuli: (i) biotic stress-influenced genes, (ii) abiotic stress-influenced genes, and (iii) concurrent biotic/abiotic stress-regulated genes. The results support different roles for PAs against abiotic and biotic stress. The expression of several genes, significantly induced under cold stress conditions, is mitigated by a previous viral infection, indicating a possible priming-like mechanism in tomato plants pointing to crosstalk among stress signalling. Several genes and resulting enzymes of PA catabolism were stimulated upon viral infection. Hence, we suggest that PA catabolism resulting in elevated H2O2 levels could mediate defence against viral infection. However, after chilling, the activities of enzymes implicated in PA catabolism remained relatively stable or slightly reduced. This correlates to an increase in free PA content, designating a per se protective role of these compounds against abiotic stress.
PMID: 31743771
Plants (Basel) , IF:2.762 , 2020 Feb , V9 (2) doi: 10.3390/plants9020281
Exogenous Kinetin Promotes the Nonenzymatic Antioxidant System and Photosynthetic Activity of Coffee (Coffea arabica L.) Plants Under Cold Stress Conditions.
The United Graduate School of Agricultural Sciences, Tottori University, 4-01 Koyama-cho Minami, Tottori 680-8553, Japan.; Sawai Coffee Limited, 278-6, Takenouchi danchi, Sakaiminato City, Tottori 648-0046, Japan.; Tottori Institute of Industrial Technology, 2032-3, Nakano-cho, Sakaiminato-shi, Tottori 684-0041, Japan.; Faculty of Soil Eco-engineering and Plant Nutrition, Shimane University, 1060, Nishikawatsucho, Matsue 690-8504, Japan.; Faculty of Agriculture, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8553, Japan.
Coffee plants are seasonally exposed to low chilling temperatures in many coffee-producing regions. In this study, we investigated the ameliorative effects of kinetin-a cytokinin elicitor compound on the nonenzymatic antioxidants and the photosynthetic physiology of young coffee plants subjected to cold stress conditions. Although net CO2 assimilation rates were not significantly affected amongst the treatments, the subjection of coffee plants to cold stress conditions caused low gas exchanges and photosynthetic efficiency, which was accompanied by membrane disintegration and the breakdown of chlorophyll pigments. Kinetin treatment, on the other hand, maintained a higher intercellular-to-ambient CO2 concentration ratio with concomitant improvement in stomatal conductance and mesophyll efficiency. Moreover, the leaves of kinetin-treated plants maintained slightly higher photochemical quenching (qP) and open photosystem II centers (qL), which was accompanied by higher electron transfer rates (ETRs) compared to their non-treated counterparts under cold stress conditions. The exogenous foliar application of kinetin also stimulated the metabolism of caffeine, trigonelline, 5-caffeoylquinic acid, mangiferin, anthocyanins and total phenolic content. The contents of these nonenzymatic antioxidants were highest under cold stress conditions in kinetin-treated plants than during optimal conditions. Our results further indicated that the exogenous application of kinetin increased the total radical scavenging capacity of coffee plants. Therefore, the exogenous application of kinetin has the potential to reinforce antioxidant capacity, as well as modulate the decline in photosynthetic productivity resulting in improved tolerance under cold stress conditions.
PMID: 32098166
Plants (Basel) , IF:2.762 , 2020 Feb , V9 (2) doi: 10.3390/plants9020213
Variability in the Capacity to Produce Damage-Induced Aldehyde Green Leaf Volatiles among Different Plant Species Provides Novel Insights into Biosynthetic Diversity.
Department of Biology, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
Green leaf volatiles (GLVs) are commonly released by plants upon damage, thereby providing volatile signals for other plants to prepare against the major causes of damage, herbivory, pathogen infection, and cold stress. However, while the biosynthesis of these compounds is generally well understood, little is known about the qualities and quantities that are released by different plant species, nor is it known if release patterns can be associated with different clades of plants. Here, we provide a first study describing the damage-induced release of major GLVs by more than 50 plant species. We found major differences in the quantity and quality of those compounds between different plant species ranging from undetectable levels to almost 100 microg per gram fresh weight. We also found major shifts in the composition that correlate directly to the quantity of emitted GLV. However, we did not find any major patterns that would associate specific GLV release with distinct clades of plants.
PMID: 32041302
Plants (Basel) , IF:2.762 , 2020 Feb , V9 (2) doi: 10.3390/plants9020179
Foliar Application of Polyamines Modulates Winter Oilseed Rape Responses to Increasing Cold.
Nature Research Centre, Laboratory of Plant Physiology, Akademijos Str. 2, LT-08412 Vilnius, Lithuania.; Bulgarian Academy of Sciences, Institute of Plant Physiology and Genetics, Acad. G. Bonchev Str. Bl. 21, Sofia BG-1113, Bulgaria.
Cold stress is one of the most common abiotic stresses experienced by plants and is caused by low temperature extremes and variations. Polyamines (PAs) have been reported to contribute in abiotic stress defense processes in plants. The present study investigates the survival and responses of PA-treated non-acclimated (N) and acclimated (A) winter oilseed rape to increasing cold conditions. The study was conducted under controlled conditions. Seedlings were foliarly sprayed with spermidine (Spd), spermine (Spm), and putrescine (Put) solutions (1 mM) and exposed to four days of cold acclimation (4 degrees C) and two days of increasing cold (from -1 to -3 degrees C). Two cultivars with different cold tolerance were used in this study. The recorded traits included the percentage of survival, H(+)-ATPase activity, proline accumulation, and ethylene emission. Exogenous PA application improved cold resistance, maintained the activity of plasma membrane H(+)-ATPase, increased content of free proline, and delayed stimulation of ethylene emission under increasing cold. The results of the current study on winter oilseed rape revealed that foliar application of PAs may activate a defensive response (act as elicitor to trigger physiological processes), which may compensate the negative impact of cold stress. Thus, cold tolerance of winter oilseed rape can be enhanced by PA treatment.
PMID: 32024174
Cryobiology , IF:2.283 , 2020 Feb , V92 : P76-85 doi: 10.1016/j.cryobiol.2019.11.006
Melatonin-related mitochondrial respiration responses are associated with growth promotion and cold tolerance in plants.
East Anatolian High Technology Application and Research Center, Ataturk University, Erzurum, Turkey. Electronic address: hulyaa.turk@hotmail.com.; Department of Pharmaceutical Botany, Faculty of Pharmacy, Agri Ibrahim Cecen University, Agri, Turkey.
Melatonin has the ability to improve plant growth and strengthened plant tolerance to environmental stresses; however, the effects of melatonin on mitochondrial respiration in plants and the underlying biochemical and molecular mechanisms are still unclear. The objective of the study is to determine possible effects of melatonin on mitochondrial respiration and energy efficiency in maize leaves grown under optimum temperature and cold stress and to reveal the relationship between melatonin-induced possible alterations in mitochondrial respiration and cold tolerance. Melatonin and cold stress, alone and in combination, caused significant increases in activities and gene expressions of pyruvate dehydrogenase, citrate synthase, and malate dehydrogenase, indicating an acceleration in the rate of tricarboxylic acid cycle. Total mitochondrial respiration rate, cytochrome pathway rate, and alternative respiration rate were increased by the application of melatonin and/or cold stress. Similarly, gene expression and protein levels of cytochrome oxidase and alternative oxidase were also enhanced by melatonin and/or cold stress. The highest values for all these parameters were obtained from the seedlings treated with the combined application of melatonin and cold stress. The activity and gene expression of ATP synthase and ATP concentration were augmented by melatonin under control and cold stress. On the other hand, cold stress reduced markedly plant growth parameters, including root length, plant height, leaf surface area, and chlorophyll content and increased the content of reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide and oxidative damage, including malondialdehyde content and electrolyte leakage level; however, melatonin significantly promoted the plant growth parameters and reduced ROS content and oxidative damage under control and cold stress. These data revealed that melatonin-induced growth promotion and cold tolerance in maize is associated with its modulating effect on mitochondrial respiration.
PMID: 31758919
Physiol Mol Biol Plants , IF:2.005 , 2020 Feb , V26 (2) : P219-232 doi: 10.1007/s12298-019-00743-8
Response of photosynthetic capacity and antioxidative system of chloroplast in two wucai (Brassica campestris L.) genotypes against chilling stress.
1Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036 China.grid.411389.60000 0004 1760 4804; Provincial Engineering Laboratory for Horticultural Crop Breeding of Anhui, Hefei, 230036 China.; Wanjiang Vegetable Industrial Technology Institute, Maanshan, 243000 Anhui China.
Chilling stress during the growing season could cause a series of changes in wucai (Brassica campestris L.). WS-1 (chilling-tolerant genotype) and Ta2 (chilling-sensitive genotype) were sampled in present study to explore the chilling tolerance mechanisms. Our results indicated that photosynthetic parameters exhibited lower level in Ta2 than in WS-1 under chilling stress. The rapid chlorophyll fluorescence dynamics curve showed that chilling resulted in a greater inactivation of photosystem II reaction center in Ta2. Reactive oxygen species and malondialdehyde content of chloroplast in Ta2 were higher than WS-1. The ascorbate-glutathione cycle in chloroplast of WS-1 played a more crucial role than Ta2, which was confirmed by higher activities of antioxidant enzymes including Ascorbate peroxidase, Glutathione reductase, Monodehydroascorbate reductase and Dehydroascorbate reductase and higher content of AsA and GSH. In addition, the ultrastructure of chloroplasts in Ta2 was more severely damaged. After low temperature stress, the shape of starch granules in Ta2 changed from elliptical to round and the volume became larger than that of WS-1. The thylakoid structure of Ta2 also became dispersed from the original tight arrangement. Combined with our previous study under heat stress, WS-1 can tolerant both chilling stress and heat stress, which was partly due to a stable photosynthetic system and the higher active antioxidant system in plants, in comparison to Ta2.
PMID: 32158130
3 Biotech , IF:1.798 , 2020 Feb , V10 (2) : P72 doi: 10.1007/s13205-019-2039-3
Comparative study of DAM, Dof, and WRKY gene families in fourteen species and their expression in Vitis vinifera.
1Department of Horticulture, Nanjing Agricultural University, Nanjing, 210095 Jiangsu People's Republic of China.0000 0000 9750 7019grid.27871.3b; Fruit Crop Genetic Improvement and Seedling Propagation Engineering Center of Jiangsu Province, Nanjing, 210095 People's Republic of China.; Department of Agriculture and Horticulture, Jiangsu Vocational College of Agriculture and Forestry, Jurong, 212499 Jiangsu People's Republic of China.; 4Department of Life Science, Tarim University, Xinjiang Uygur Autonomous region, Aral city, 843300 People's Republic of China.grid.443240.5
Bud dormancy is one of the most important defensive mechanisms through which plants resist cold stress during harsh winter weather. DAM, Dof, and WRKY have been reported to be involved in many biological processes, including bud dormancy. In the present study, grapevine (Vitis vinifera) and other thirteen plants (six woody plants and seven herbaceous plants) were analyzed for the quantity, sequence structure, and evolution patterns of their DAM, Dof, and WRKY gene family members. Moreover, the expression of VvDAM, VvDof, and VvWRKY genes was also investigated. Thus, 51 DAM, 1,205 WRKY, and 489 Dof genes were isolated from selected genomes, while 5 DAM, 114 WRKY, and 50 Dof duplicate gene pairs were identified in 10 genomes. Moreover, WGD and segmental duplication events were associated with the majority of the expansions of Dof and WRKY gene families. The VvDAM, VvDof, and VvWRKY genes significantly differentially expressed throughout bud dormancy outnumbered those significantly differentially expressed throughout fruit development or under abiotic stresses. Interestingly, multiple stress responsive genes were identified, such as VvDAM (VIT_00s0313g00070), two VvDof genes (VIT_18s0001g11310 and VIT_02s0025g02250), and two VvWRKY genes (VIT_07s0031g01710 and VIT_11s0052g00450). These data provide candidate genes for molecular biology research investigating bud dormancy and responses to abiotic stresses (namely salt, drought, copper, and waterlogging).
PMID: 32030341
Plant Direct , IF:1.725 , 2020 Feb , V4 (2) : Pe00199 doi: 10.1002/pld3.199
Involvement of five catalytically active Arabidopsis beta-amylases in leaf starch metabolism and plant growth.
Department of Biology James Madison University Harrisonburg Virginia.
Starch degradation in chloroplasts requires beta-amylase (BAM) activity, but in Arabidopsis, there are nine BAM proteins, five of which are thought to be catalytic. Although single-gene knockouts revealed the necessity of BAM3 for starch degradation, contributions of other BAMs are poorly understood. Moreover, it is not possible to detect the contribution of individual BAMs in plants containing multiple active BAMs. Therefore, we constructed a set of five quadruple mutants each expressing only one catalytically active BAM, and a quintuple mutant missing all of these BAMs (B-Null). Using these mutants, we assessed the influence of each individual BAM on plant growth and on leaf starch degradation. Both BAM1 and BAM3 alone support wild-type (WT) levels of growth. BAM3 alone is sufficient to degrade leaf starch completely whereas BAM1 alone can only partially degrade leaf starch. In contrast, BAM2, BAM5, and BAM6 have no detectable effect on starch degradation or plant growth, being comparable with the B-Null plants. B-Null plant extracts contained no measurable amylase activity, whereas BAM3 and BAM1 contributed about 70% and 14% of the WT activity, respectively. BAM2 activity was low but detectable and BAM6 contributed no measurable activity. Interestingly, activity of BAM1 and BAM3 in the mutants varied little developmentally or diurnally, and did not increase appreciably in response to osmotic or cold stress. With these genetic lines, we now have new opportunities to investigate members of this diverse gene family.
PMID: 32072133
Plant Direct , IF:1.725 , 2020 Feb , V4 (2) : Pe00202 doi: 10.1002/pld3.202
A metabolomics study of ascorbic acid-induced in situ freezing tolerance in spinach (Spinacia oleracea L.).
Department of Horticulture Iowa State University Ames IA USA.; Department of Genetic, Development, and Cell Biology Iowa State University Ames IA USA.
Freeze-thaw stress is one of the major environmental constraints that limit plant growth and reduce productivity and quality. Plants exhibit a variety of cellular dysfunctions following freeze-thaw stress, including accumulation of reactive oxygen species (ROS). This means that enhancement of antioxidant capacity by exogenous application of antioxidants could potentially be one of the strategies for improving freezing tolerance (FT) of plants. Exogenous application of ascorbic acid (AsA), as an antioxidant, has been shown to improve plant tolerance against abiotic stresses but its effect on FT has not been investigated. We evaluated the effect of AsA-feeding on FT of spinach (Spinacia oleracea L.) at whole plant and excised-leaf level, and conducted metabolite profiling of leaves before and after AsA treatment to explore metabolic explanation for change in FT. AsA application did not impede leaf growth, instead slightly promoted it. Temperature-controlled freeze-thaw tests revealed AsA-fed plants were more freezing tolerant as indicated by: (a) less visual damage/mortality; (b) lower ion leakage; and (c) less oxidative injury, lower abundance of free radicals ( O 2 . - and H2O2). Comparative leaf metabolite profiling revealed clear separation of metabolic phenotypes for control versus AsA-fed leaves. Specifically, AsA-fed leaves had greater abundance of antioxidants (AsA, glutathione, alpha- & gamma-tocopherol) and compatible solutes (proline, galactinol, and myo-inositol). AsA-fed leaves also had higher activity of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, and catalase). These changes, together, may improve FT via alleviating freeze-induced oxidative stress as well as protecting membranes from freeze desiccation. Additionally, improved FT by AsA-feeding may potentially include enhanced cell wall/lignin augmentation and bolstered secondary metabolism as indicated by diminished level of phenylalanine and increased abundance of branched amino acids, respectively.
PMID: 32104753