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Abstract
Abscisic acid (ABA) is one of the major phytohormones and regulates various processes in the plant life cycle, for example, seed development and abiotic/biotic stress responses. Recent studies have made significant progress in elucidating ABA signaling and established a simple ABA signaling model consisting of three core components: PYR/PYL/RCAR receptors, 2C-type protein phosphatases, and SnRK2 protein kinases. This model highlights the importance of protein phosphorylation mediated by SnRK2, but the downstream substrates of SnRK2 remain to be determined to complete the model. Previous studies have identified several SnRK2 substrates involving transcription factors and ion channels. Recently, SnRK2 substrates have been further surveyed by a phosphoproteomic approach, giving new insights on the SnRK2 downstream pathway. Other protein kinases, e.g., Ca(2+)-dependent protein kinase (CDPK) and mitogen-activated protein kinase (MAPK), have been identified as ABA signaling factors. Some evidence suggests that the SnRK2 pathway partially interacts with CDPK or MAPK pathways. In this chapter, recent advances in ABA signaling study are summarized, primarily focusing on two major protein kinases, SnRK2 and MAPK. Challenges for further study of the ABA-dependent protein phosphorylation network are also discussed.
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Affiliation(s)
- Taishi Umezawa
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | | | - Kazuo Shinozaki
- RIKEN Center for Sustainable Resource Science, Tsukuba, Japan.
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602
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Stabilization of Arabidopsis DREB2A is required but not sufficient for the induction of target genes under conditions of stress. PLoS One 2013; 8:e80457. [PMID: 24376497 PMCID: PMC3871162 DOI: 10.1371/journal.pone.0080457] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 10/03/2013] [Indexed: 11/21/2022] Open
Abstract
The Arabidopsis thaliana transcription factor DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN2A (DREB2A) controls the expression of many genes involved in the plant's response to dehydration and heat stress. Despite the significance of post-translational regulation in DREB2A activation, the mechanism underlying this activation remains unclear. Here, with the aid of a newly produced antibody against DREB2A, we characterized the regulation of DREB2A stability in plants exposed to stress stimuli. Endogenous DREB2A accumulated in wild-type Arabidopsis plants subjected to dehydration and heat stress. A degradation assay using Arabidopsis T87 suspension-cultured cells revealed that DREB2A protein degradation was inhibited at high temperatures. The proteasome-dependent degradation of DREB2A required the import of this protein into the nucleus. The E3 ligases DRIP1 and DRIP2 were involved in this process under both normal and stressful conditions; however, other E3 ligases may have also been involved, at least during the late stages of the heat stress response. Although the constitutive expression of DREB2A resulted in an overproduction of DREB2A and enhanced target gene induction during stress in transgenic plants, the accumulation of DREB2A caused by proteasome inhibitors did not induce target gene expression. Thus, the stabilization of DREB2A is important but not sufficient to induce target gene expression; further activation processes are required.
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603
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Song JB, Gao S, Sun D, Li H, Shu XX, Yang ZM. miR394 and LCR are involved in Arabidopsis salt and drought stress responses in an abscisic acid-dependent manner. BMC PLANT BIOLOGY 2013; 13:210. [PMID: 24330668 PMCID: PMC3870963 DOI: 10.1186/1471-2229-13-210] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 12/05/2013] [Indexed: 05/19/2023]
Abstract
BACKGROUND MicroRNAs (miRNAs) are a class of short, endogenous non-coding small RNAs that have ability to base pair with their target mRNAs to induce their degradation in plants. miR394a/b are conserved small RNAs and its target gene LCR (LEAF CURLING RESPONSIVENESS) encodes an F-box protein (SKP1-Cullin/CDC53-F-box) but whether miR394a/b and its target gene LCR are involved in regulation of plant response to abscisic acid (ABA) and abiotic stresses is unknown. RESULTS Mature miR394 and precursor miR394a/b are shown to be slightly induced by ABA. By contrast, LCR expression is depressed by ABA. Analysis of LCR and its promoter (pLCR::GUS) revealed that LCR is expressed at all development stages. MIR394a/b over-expression (35S::MIR394a/b) and lcr (LCR loss of function) mutant plants are hypersensitive to salt stress, but LCR over-expressing (35S::m5LCR) plants display the salt-tolerant phenotype. Both 35S::MIR394a/b and lcr plants are highly tolerant to severe drought stress compared with wild-type, but 35S::m5LCR plants are susceptible to water deficiency. Over-expression of MIR394a/b led to ABA hypersensitivity and ABA-associated phenotypes, whereas 35S::m5LCR plants show ABA resistance phenotypes. Moreover, 35S::MIR394a/b plants accumulated higher levels of ABA-induced hydrogen peroxide and superoxide anion radicals than wild-type and 35S::m5LCR plants. Expressions of ABA- and stress-responsive genes, ABI3, ABI4, ABI5, ABF3, and ABF4 are up-regulated in MIR394a/b over-expressing plants but down-regulated in 35S::m5LCR plants. Over-expression of MIR394a in abi4-1 or abi5-1 background resulted in loss of ABA-sensitivity in 35S::MIR394a plants. CONCLUSIONS The silencing of LCR mRNA by miR394 is essential to maintain a certain phenotype favorable for the adaptive response to abiotic stresses. The contrasting phenotypes of salt and drought responses may be mediated by a functional balance between miR394 and LCR. If the balance is perturbed in case of the abiotic stress, an identical phenotype related to the stress response occurs, resulting in either ABA sensitive or insensitive response. Thus, miR394-regulated LCR abundance may allow plants to fine-tune their responses to ABA and abiotic stress.
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Affiliation(s)
- Jian Bo Song
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuai Gao
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Di Sun
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Hua Li
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Xia Xia Shu
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhi Min Yang
- Weigang No. 1, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
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604
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Bai G, Yang DH, Zhao Y, Ha S, Yang F, Ma J, Gao XS, Wang ZM, Zhu JK. Interactions between soybean ABA receptors and type 2C protein phosphatases. PLANT MOLECULAR BIOLOGY 2013; 83:651-64. [PMID: 23934343 PMCID: PMC3834219 DOI: 10.1007/s11103-013-0114-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/11/2013] [Indexed: 05/18/2023]
Abstract
The plant hormone abscisic acid (ABA) plays important roles in regulating plant growth, development, and responses to environmental stresses. Proteins in the PYR/PYL/RCAR family (hereafter referred to as PYLs) are known as ABA receptors. Since most studies thus far have focused on Arabidopsis PYLs, little is known about PYL homologs in crop plants. We report here the characterization of 21 PYL homologs (GmPYLs) in soybean. Twenty-three putative GmPYLs can be found from soybean genome sequence and categorized into three subgroups. GmPYLs interact with AtABI1 and two GmPP2Cs in diverse manners. A lot of the subgroup I GmPYLs interact with PP2Cs in an ABA-dependent manner, whereas most of the subgroup II and III GmPYLs bind to PP2Cs in an ABA-independent manner. The subgroup III GmPYL23, which cannot interact with any of the tested PP2Cs, differs from other GmPYLs. The CL2/gate domain is crucial for GmPYLs-PP2Cs interaction, and a mutation in the conserved proline (P109S) abolishes the interaction between GmPYL1 and AtABI1. Furthermore, the ABA dependence of GmPYLs-PP2Cs interactions are partially correlated with two amino acid residues preceding the CL2/gate domain of GmPYLs. We also show that GmPYL1 interacts with AtABI1 in an ABA-dependent manner in plant cells. Three GmPYLs differentially inhibit AtABI1 and GmPP2C1 in an ABA-dependent or -enhanced manner in vitro. In addition, ectopically expressing GmPYL1 partially restores ABA sensitivity of the Arabidopsis triple mutant pyr1/pyl1/pyl4. Taken together, our results suggest that soybean GmPYLs are ABA receptors that function by interacting and inhibiting PP2Cs.
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Affiliation(s)
- Ge Bai
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, P. R. China, 200240
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Da-Hai Yang
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Yang Zhao
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
| | - Si Ha
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Fen Yang
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Jun Ma
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Xiao-Su Gao
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Zhi-Min Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, P. R. China, 200240
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
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605
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Lu YC, Yang SN, Zhang JJ, Zhang JJ, Tan LR, Yang H. A collection of glycosyltransferases from rice (Oryza sativa) exposed to atrazine. Gene 2013; 531:243-52. [DOI: 10.1016/j.gene.2013.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 08/24/2013] [Accepted: 09/03/2013] [Indexed: 01/01/2023]
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606
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Tang S, Liang H, Yan D, Zhao Y, Han X, Carlson JE, Xia X, Yin W. Populus euphratica: the transcriptomic response to drought stress. PLANT MOLECULAR BIOLOGY 2013; 83:539-57. [PMID: 23857471 DOI: 10.1007/s11103-013-0107-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 07/09/2013] [Indexed: 05/04/2023]
Abstract
Populus euphratica Olivier is widely established in arid and semiarid regions but lags in the availability of transcriptomic resources in response to water deficiency. To investigate the mechanisms that allow P. euphratica to maintain growth in arid regions, the responses of the plant to soil water deficit were analyzed at a systems level using physiological and pyrosequencing approaches. We generated 218,601 and 287,120 reads from non-stressed control and drought-stressed P. euphratica leaves respectively, totaling over 200 million base pairs. After assembly, 24,013 transcripts were yielded with an average length of 1,128 bp. We determined 2,279 simple sequence repeats, which may have possible information for understanding drought adaption of woody plants. Stomatal closure was inhibited under moderate drought to maintain a relatively high rate of CO2 assimilation and water transportation, which was supposed to be important for P. euphratica to maintain normal growth and develop vigorous root systems in an adverse environment. This was accompanied by strong transcriptional remodeling of stress-perception, signaling and transcription regulation, photoprotective system, oxidative stress detoxification, and other stress responsive genes. In addition, genes involved in stomatal closure inhibition, ascorbate-glutathione pathway and ubiquitin-proteasome system that may specially modulate the drought stress responses of P. euphratica are highlighted. Our analysis provides a comprehensive picture of how P. euphratica responds to drought stress at physiological and transcriptome levels which may help to understand molecular mechanisms associated with drought response and could be useful for genetic engineering of woody plants.
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Affiliation(s)
- Sha Tang
- College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing, 100083, People's Republic of China
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607
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Comparative transcriptome analysis of tomato (Solanum lycopersicum) in response to exogenous abscisic acid. BMC Genomics 2013; 14:841. [PMID: 24289302 PMCID: PMC4046761 DOI: 10.1186/1471-2164-14-841] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 11/27/2013] [Indexed: 12/05/2022] Open
Abstract
Background Abscisic acid (ABA) can regulate the expressions of many stress-responsive genes in plants. However, in defense responses to pathogens, mounting evidence suggests that ABA plays variable roles. Little information exists about genome-wide gene expression in ABA responses in tomato (Solanum lycopersicum L.), a model fruit crop plant. Results Global transcriptome profiles of tomato leaf responses to exogenous ABA were generated using Illumina RNA-sequencing. More than 173 million base pair reads were mapped onto the tomato reference genome and the expression pattern differences between treated and control leaves were assessed. In total, 50,616 transcripts were generated. Among them, 42,583 were functionally annotated in the NCBI non-redundant database and 47,877 in the tomato genome reference. Additionally, 31,107 transcripts were categorized into 57 functional groups based on Gene Ontology terms, and 14,371 were assigned to 310 Kyoto Encyclopedia of Genes and Genomes pathways. In both the ABA treatment and control samples, 39,671 transcripts were available to analyze their expressions, of which 21,712 (54.73%) responded to exogenous ABA. Of these transcripts, 2,787 were significantly differently expressed genes (DEGs). Many known and novel ABA-induced and -repressed genes were found. Exogenous ABA can influence the ABA signaling pathway with PYR/PYL/RCARs-PP2Cs-SnRK2s as the center. Eighteen PYL genes were detected. A large number of genes related to various transcription factors, heat shock proteins, pathogen resistance, and the salicylic acid, jasmonic acid, and ethylene signaling pathways were up-regulated by exogenous ABA. Conclusions The results indicated that ABA has the potential to improve pathogen-resistance and abiotic stress tolerance in tomato. This study presents the global expression analysis of ABA-regulated transcripts in tomato and provides a robust database for investigating the functions of genes induced by ABA. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-14-841) contains supplementary material, which is available to authorized users.
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608
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Álvarez R, Vaz B, Gronemeyer H, de Lera ÁR. Functions, therapeutic applications, and synthesis of retinoids and carotenoids. Chem Rev 2013; 114:1-125. [PMID: 24266866 DOI: 10.1021/cr400126u] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rosana Álvarez
- Departamento de Química Orgánica, Centro de Investigación Biomédica (CINBIO), and Instituto de Investigación Biomédica de Vigo (IBIV), Universidade de Vigo , 36310 Vigo, Spain
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609
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O’Brien JA, Benková E. Cytokinin cross-talking during biotic and abiotic stress responses. FRONTIERS IN PLANT SCIENCE 2013; 4:451. [PMID: 24312105 PMCID: PMC3833016 DOI: 10.3389/fpls.2013.00451] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 10/22/2013] [Indexed: 05/18/2023]
Abstract
As sessile organisms, plants have to be able to adapt to a continuously changing environment. Plants that perceive some of these changes as stress signals activate signaling pathways to modulate their development and to enable them to survive. The complex responses to environmental cues are to a large extent mediated by plant hormones that together orchestrate the final plant response. The phytohormone cytokinin is involved in many plant developmental processes. Recently, it has been established that cytokinin plays an important role in stress responses, but does not act alone. Indeed, the hormonal control of plant development and stress adaptation is the outcome of a complex network of multiple synergistic and antagonistic interactions between various hormones. Here, we review the recent findings on the cytokinin function as part of this hormonal network. We focus on the importance of the crosstalk between cytokinin and other hormones, such as abscisic acid, jasmonate, salicylic acid, ethylene, and auxin in the modulation of plant development and stress adaptation. Finally, the impact of the current research in the biotechnological industry will be discussed.
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Affiliation(s)
- José A. O’Brien
- Department of Plant Systems Biology, VIB, GentBelgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University GentBelgium
| | - Eva Benková
- Department of Plant Systems Biology, VIB, GentBelgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University GentBelgium
- Institute of Science and Technology AustriaKlosterneuburg, Austria
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610
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Huang C, Hu G, Li F, Li Y, Wu J, Zhou X. NbPHAN, a MYB transcriptional factor, regulates leaf development and affects drought tolerance in Nicotiana benthamiana. PHYSIOLOGIA PLANTARUM 2013; 149:297-309. [PMID: 23387304 DOI: 10.1111/ppl.12031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 01/19/2013] [Accepted: 01/19/2013] [Indexed: 05/14/2023]
Abstract
MYB transcriptional factors, characterized by the presence of conserved DNA-binding domains (BDs) (MYB domain), are involved in diverse processes including plant growth, development, metabolic and stress responses. In this study, a new R2R3-type MYB gene, NbPHAN (Nicotiana benthamiana PHANTASTICA), was identified in N. benthamiana. The NbPHAN encodes a protein of 362 amino acids and shares high sequence identities with the AS1-RS2-PHANs (ARPs) from other plant species. The NbPHAN protein targets to and forms homodimers in the nucleus. The MYB domain and C-terminal region of NbPHAN determine its subcellular localization and homodimerization, respectively. Using virus-induced gene silencing, we showed that the NbPHAN-silenced leaves exhibited severe downward curling and abnormal growth of blades along the main veins through suppressing the expression of the NTH20 gene. In addition, we found NbPHAN plays an important role in drought tolerance. The NbPHAN-silenced plants exhibited severe wilting and increased rate of water loss than that found in the non-silenced plants when growing under the water deficit condition. Although abscisic acid accumulation was not altered in the NbPHAN-silenced plants as compared with that in the non-silenced plants, several other stress-inducible genes were clearly repressed under the water deficit condition. Our results provide strong evidence that other than controlling leaf development, the ARP genes can also regulate plant tolerance to drought stress.
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Affiliation(s)
- Changjun Huang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
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611
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Yamburenko MV, Zubo YO, Vanková R, Kusnetsov VV, Kulaeva ON, Börner T. Abscisic acid represses the transcription of chloroplast genes. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4491-502. [PMID: 24078671 PMCID: PMC3808324 DOI: 10.1093/jxb/ert258] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Numerous studies have shown effects of abscisic acid (ABA) on nuclear genes encoding chloroplast-localized proteins. ABA effects on the transcription of chloroplast genes, however, have not been investigated yet thoroughly. This work, therefore, studied the effects of ABA (75 μM) on transcription and steady-state levels of transcripts in chloroplasts of basal and apical segments of primary leaves of barley (Hordeum vulgare L.). Basal segments consist of young cells with developing chloroplasts, while apical segments contain the oldest cells with mature chloroplasts. Exogenous ABA reduced the chlorophyll content and caused changes of the endogenous concentrations not only of ABA but also of cytokinins to different extents in the basal and apical segments. It repressed transcription by the chloroplast phage-type and bacteria-type RNA polymerases and lowered transcript levels of most investigated chloroplast genes drastically. ABA did not repress the transcription of psbD and a few other genes and even increased psbD mRNA levels under certain conditions. The ABA effects on chloroplast transcription were more pronounced in basal vs. apical leaf segments and enhanced by light. Simultaneous application of cytokinin (22 μM 6-benzyladenine) minimized the ABA effects on chloroplast gene expression. These data demonstrate that ABA affects the expression of chloroplast genes differentially and points to a role of ABA in the regulation and coordination of the activities of nuclear and chloroplast genes coding for proteins with functions in photosynthesis.
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Affiliation(s)
- Maria V. Yamburenko
- Department of Biology/Genetics, Humboldt University, Chausseestr. 117, D-10115 Berlin, Germany
- These authors contributed equally to this manuscript
| | - Yan O. Zubo
- Department of Biology/Genetics, Humboldt University, Chausseestr. 117, D-10115 Berlin, Germany
- Timiriazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia
- These authors contributed equally to this manuscript
| | - Radomíra Vanková
- Institute of Experimental Botany, AS CR, Rozvojová 263, 165 02 Prague 6, Czech Republic
| | - Victor V. Kusnetsov
- Timiriazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia
| | - Olga N. Kulaeva
- Timiriazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya 35, Moscow 127276, Russia
| | - Thomas Börner
- Department of Biology/Genetics, Humboldt University, Chausseestr. 117, D-10115 Berlin, Germany
- To whom correspondence should be addressed. E-mail:
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612
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Gayatri G, Agurla S, Raghavendra AS. Nitric oxide in guard cells as an important secondary messenger during stomatal closure. FRONTIERS IN PLANT SCIENCE 2013; 4:425. [PMID: 24194741 PMCID: PMC3810675 DOI: 10.3389/fpls.2013.00425] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 10/08/2013] [Indexed: 05/19/2023]
Abstract
The modulation of guard cell function is the basis of stomatal closure, essential for optimizing water use and CO2 uptake by leaves. Nitric oxide (NO) in guard cells plays a very important role as a secondary messenger during stomatal closure induced by effectors, including hormones. For example, exposure to abscisic acid (ABA) triggers a marked increase in NO of guard cells, well before stomatal closure. In guard cells of multiple species, like Arabidopsis, Vicia and pea, exposure to ABA or methyl jasmonate or even microbial elicitors (e.g., chitosan) induces production of NO as well as reactive oxygen species (ROS). The role of NO in stomatal closure has been confirmed by using NO donors (e.g., SNP) and NO scavengers (like cPTIO) and inhibitors of NOS (L-NAME) or NR (tungstate). Two enzymes: a L-NAME-sensitive, nitric oxide synthase (NOS)-like enzyme and a tungstate-sensitive nitrate reductase (NR), can mediate ABA-induced NO rise in guard cells. However, the existence of true NOS in plant tissues and its role in guard cell NO-production are still a matter of intense debate. Guard cell signal transduction leading to stomatal closure involves the participation of several components, besides NO, such as cytosolic pH, ROS, free Ca(2+), and phospholipids. Use of fluorescent dyes has revealed that the rise in NO of guard cells occurs after the increase in cytoplasmic pH and ROS. The rise in NO causes an elevation in cytosolic free Ca(2+) and promotes the efflux of cations as well as anions from guard cells. Stomatal guard cells have become a model system to study the signaling cascade mechanisms in plants, particularly with NO as a dominant component. The interrelationships and interactions of NO with cytosolic pH, ROS, and free Ca(2+) are quite complex and need further detailed examination. While assessing critically the available literature, the present review projects possible areas of further work related to NO-action in stomatal guard cells.
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Affiliation(s)
| | | | - Agepati S. Raghavendra
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
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613
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Li J, Besseau S, Törönen P, Sipari N, Kollist H, Holm L, Palva ET. Defense-related transcription factors WRKY70 and WRKY54 modulate osmotic stress tolerance by regulating stomatal aperture in Arabidopsis. THE NEW PHYTOLOGIST 2013; 200:457-472. [PMID: 23815736 PMCID: PMC4284015 DOI: 10.1111/nph.12378] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 05/21/2013] [Indexed: 05/20/2023]
Abstract
WRKY transcription factors (TFs) have been mainly associated with plant defense, but recent studies have suggested additional roles in the regulation of other physiological processes. Here, we explored the possible contribution of two related group III WRKY TFs, WRKY70 and WRKY54, to osmotic stress tolerance. These TFs are positive regulators of plant defense, and co-operate as negative regulators of salicylic acid (SA) biosynthesis and senescence. We employed single and double mutants of wrky54 and wrky70, as well as a WRKY70 overexpressor line, to explore the role of these TFs in osmotic stress (polyethylene glycol) responses. Their effect on gene expression was characterized by microarrays and verified by quantitative PCR. Stomatal phenotypes were assessed by water retention and stomatal conductance measurements. The wrky54wrky70 double mutants exhibited clearly enhanced tolerance to osmotic stress. However, gene expression analysis showed reduced induction of osmotic stress-responsive genes in addition to reduced accumulation of the osmoprotectant proline. By contrast, the enhanced tolerance was correlated with improved water retention and enhanced stomatal closure. These findings demonstrate that WRKY70 and WRKY54 co-operate as negative regulators of stomatal closure and, consequently, osmotic stress tolerance in Arabidopsis, suggesting that they have an important role, not only in plant defense, but also in abiotic stress signaling.
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Affiliation(s)
- Jing Li
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Sebastien Besseau
- Université François Rabelais de Tours, EA2106 Biomolécules et Biotechnologies Végétales, 37200, Tours, France
| | - Petri Törönen
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Nina Sipari
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Hannes Kollist
- Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
| | - Liisa Holm
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - E Tapio Palva
- Viikki Biocenter, Division of Genetics, Department of Biosciences, University of Helsinki, FI-00014, Helsinki, Finland
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614
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Laanemets K, Brandt B, Li J, Merilo E, Wang YF, Keshwani MM, Taylor SS, Kollist H, Schroeder JI. Calcium-dependent and -independent stomatal signaling network and compensatory feedback control of stomatal opening via Ca2+ sensitivity priming. PLANT PHYSIOLOGY 2013; 163:504-13. [PMID: 23766366 PMCID: PMC3793032 DOI: 10.1104/pp.113.220343] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Guard cells use compensatory feedback controls to adapt to conditions that produce excessively open stomata.
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615
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Ham DJ, Moon JC, Hwang SG, Jang CS. Molecular characterization of two small heat shock protein genes in rice: their expression patterns, localizations, networks, and heterogeneous overexpressions. Mol Biol Rep 2013; 40:6709-6720. [PMID: 24078098 DOI: 10.1007/s11033-013-2786-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 09/14/2013] [Indexed: 11/29/2022]
Abstract
Heat stress is an example of a severe abiotic stress that plants can suffer in the field, causing a significant detrimental effect on their growth and productivity. Understanding the mechanism of plant response to heat stress is important for improving the productivity of crop plants under global warming. We used a microarray dataset that is deposited in the public database to evaluate plant responses to heat stress, and we selected the top 10 genes that are highly expressed under heat stress in rice. Two genes, OsSHSP1 (Os03g16030) and OsSHSP2 (Os01g04380), were selected for further study. These genes were highly induced in response to salt and drought but not in response to cold. In addition, OsSHSP1 and OsSHSP2 gene transcripts were induced under abscisic acid and salicylic acid but not under jasmonic acid and ethylene. Subcellular localization of proteins of 35S::OsSHSP1 were associated with the cytosol, whereas those of and 35S::OsSHSP2 were associated with the cytosol and nucleus. Heterogeneous overexpression of both genes exhibited higher germination rates than those of wild-type plants under the salt treatment, but not under heat or drought stress, supporting a hypothesis regarding functional specialization of members of small heat-shock protein family over evolutionary time. The network of both genes harboring nine sHSPs as well as at least 13 other chaperone genes might support the idea of a role for sHSPs in the chaperone network. Our findings might provide clues to shed light on the molecular functions of OsSHSP1 and OsSHSP2 in response to abiotic stresses, especially heat stress.
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Affiliation(s)
- Deok-Jae Ham
- Plant Genomics Lab., Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 200-713, Korea
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616
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Aliniaeifard S, van Meeteren U. Can prolonged exposure to low VPD disturb the ABA signalling in stomatal guard cells? JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3551-66. [PMID: 23956410 PMCID: PMC3745724 DOI: 10.1093/jxb/ert192] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The response of stomata to many environmental factors is well documented. Multiple signalling pathways for abscisic acid (ABA)-induced stomatal closure have been proposed over the last decades. However, it seems that exposure of a leaf for a long time (several days) to some environmental conditions generates a sort of memory in the guard cells that results in the loss of suitable responses of the stomata to closing stimuli, such as desiccation and ABA. In this review paper we discuss changes in the normal pattern of signal transduction that could account for disruption of guard cell signalling after long-term exposure to some environmental conditions, with special emphasis on long-term low vapour pressure deficit (VPD).
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Affiliation(s)
- Sasan Aliniaeifard
- Horticultural Production Chains, Department of Plant Sciences, Wageningen University, PO Box 630, 6700 AP Wageningen, The Netherlands.
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617
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Mir R, Hernández ML, Abou-Mansour E, Martínez-Rivas JM, Mauch F, Métraux JP, León J. Pathogen and Circadian Controlled 1 (PCC1) regulates polar lipid content, ABA-related responses, and pathogen defence in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:3385-95. [PMID: 23833195 DOI: 10.1093/jxb/ert177] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pathogen and Circadian Controlled 1 (PCC1) was previously characterized as a regulator of defence against pathogens and stress-activated transition to flowering. Plants expressing an RNA interference construct for the PCC1 gene (iPCC1 plants) showed a pleiotropic phenotype. They were hypersensitive to abscisic acid (ABA) as shown by reduced germination potential and seedling establishment, as well as reduced stomatal aperture and main root length in ABA-supplemented media. In addition, iPCC1 plants displayed alterations in polar lipid contents and their corresponding fatty acids. Importantly, a significant reduction in the content of phosphatidylinositol (PI) was observed in iPCC1 leaves when compared with wild-type plants. A trend in reduced levels of 18:0 and increased levels of 18:2 and particularly 18:3 was also detected in several classes of polar lipids. The enhanced ABA-mediated responses and the reduced content of PI might be responsible for iPCC1 plants displaying a complex pattern of defence against pathogens of different lifestyles. iPCC1 plants were more susceptible to the hemi-biotrophic oomycete pathogen Phytophthora brassicae and more resistant to the necrotrophic fungal pathogen Botrytis cinerea compared with wild-type plants.
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Affiliation(s)
- Ricardo Mir
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Ciudad Politécnica de la Innovación, Edificio 8E, Avda. Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
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618
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Mishra M, Kanwar P, Singh A, Pandey A, Kapoor S, Pandey GK. Plant Omics: Genome-Wide Analysis of ABA Repressor1 (ABR1) Related Genes in Rice During Abiotic Stress and Development. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2013; 17:439-50. [DOI: 10.1089/omi.2012.0074] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Manali Mishra
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Poonam Kanwar
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Amarjeet Singh
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Amita Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Sanjay Kapoor
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Girdhar K. Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
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619
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Structural insights into the abscisic acid stereospecificity by the ABA receptors PYR/PYL/RCAR. PLoS One 2013; 8:e67477. [PMID: 23844015 PMCID: PMC3699650 DOI: 10.1371/journal.pone.0067477] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/15/2013] [Indexed: 02/08/2023] Open
Abstract
The phytohormone abscisic acid ((+)-ABA) plays a key role in many processes. The biological and biochemical activities of unnatural (-)-ABA have been extensively investigated since 1960s. However, the recognition mechanism by which only a few members among PYR/PYL/RCAR (PYLs) family can bind (-)-ABA remains largely unknown. Here we systematically characterized the affinity of PYLs binding to the (-)-ABA and reported the crystal structures of apo-PYL5, PYL3-(-)-ABA and PYL9-(+)-ABA. PYL5 showed the strongest binding affinity with (-)-ABA among all the PYLs. PYL9 is a stringently exclusive (+)-ABA receptor with interchangeable disulfide bonds shared by a subclass of PYLs. PYL3 is a dual receptor to both ABA enantiomers. The binding orientation and pocket of (-)-ABA in PYLs are obviously different from those of (+)-ABA. Steric hindrance and hydrophobic interaction are the two key factors in determining the stereospecificity of PYLs binding to (-)-ABA, which is further confirmed by gain-of-function and loss-of-function mutagenesis. Our results provide novel insights of the bioactivity of ABA enantiomers onto PYLs, and shed light on designing the selective ABA receptors agonists.
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620
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Golldack D, Li C, Mohan H, Probst N. Gibberellins and abscisic acid signal crosstalk: living and developing under unfavorable conditions. PLANT CELL REPORTS 2013; 32:1007-16. [PMID: 23525744 DOI: 10.1007/s00299-013-1409-2] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/27/2013] [Accepted: 03/01/2013] [Indexed: 05/08/2023]
Abstract
Plants adapt to adverse environments by integrating growth and development to environmentally activated cues. Within the adaptive signaling networks, plant hormones tightly control convergent developmental and stress adaptive processes and coordinate cellular responses to external and internal conditions. Recent studies have uncovered novel antagonizing roles of the plant hormones gibberellin (GA) and abscisic acid (ABA) in integrating growth and development in plants with environmental signaling. According to current concepts, GRAS transcription factors of the DELLA and SCARECROW-LIKE (SCL) types have a key role as major growth regulators and have pivotal functions in modulating GA signaling. Significantly, current models emphasize a function of DELLA proteins as central regulators in GA homeostasis. DELLA proteins interact with the cellular GA receptor GID1 (GA-INSENSITIVE DWARF1) and degradation of DELLAs activates the function of GA. Supplementary to the prevailing view of a pivotal role of GRAS family transcriptional factors in plant growth regulation, recent work has suggested that the DELLA and SCL proteins integrate generic GA responses into ABA-controlled abiotic stress tolerance. Here, we review and discuss how GRAS type proteins influence plant development and versatile adaptation as hubs in GA and ABA triggered signaling pathways.
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Affiliation(s)
- Dortje Golldack
- Department of Biochemistry and Physiology of Plants, Faculty of Biology, Bielefeld University, 33615 Bielefeld, Germany.
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621
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Nakashima K, Yamaguchi-Shinozaki K. ABA signaling in stress-response and seed development. PLANT CELL REPORTS 2013; 32:959-70. [PMID: 23535869 DOI: 10.1007/s00299-013-1418-1] [Citation(s) in RCA: 410] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/01/2013] [Accepted: 03/06/2013] [Indexed: 05/18/2023]
Abstract
KEY MESSAGE : We review the recent progress on ABA signaling, especially ABA signaling for ABA-dependent gene expression, including the AREB/ABF regulon, SnRK2 protein kinase, 2C-type protein phosphatases and ABA receptors. Drought negatively impacts plant growth and the productivity of crops. Drought causes osmotic stress to organisms, and the osmotic stress causes dehydration in plant cells. Abscisic acid (ABA) is produced under osmotic stress conditions, and it plays an important role in the stress response and tolerance of plants. ABA regulates many genes under osmotic stress conditions. It also regulates gene expression during seed development and germination. The ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. ABRE-binding protein (AREB)/ABRE-binding factor (ABF) transcription factors (TFs) regulate ABRE-dependent gene expression. Other TFs are also involved in ABA-responsive gene expression. SNF1-related protein kinases 2 are the key regulators of ABA signaling including the AREB/ABF regulon. Recently, ABA receptors and group A 2C-type protein phosphatases were shown to govern the ABA signaling pathway. Moreover, recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress-response and seed development. The control of the expression of ABA signaling factors may improve tolerance to environmental stresses.
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Affiliation(s)
- Kazuo Nakashima
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences JIRCAS, Tsukuba, Ibaraki 305-8686, Japan
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622
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Kohli A, Sreenivasulu N, Lakshmanan P, Kumar PP. The phytohormone crosstalk paradigm takes center stage in understanding how plants respond to abiotic stresses. PLANT CELL REPORTS 2013; 32:945-57. [PMID: 23749097 DOI: 10.1007/s00299-013-1461-y] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 05/18/2013] [Accepted: 05/18/2013] [Indexed: 05/04/2023]
Abstract
The highly coordinated, dynamic nature of growth requires plants to perceive and react to various environmental signals in an interactive manner. Elaborate signaling networks mediate this plasticity in growth and the ability to adapt to changing environmental conditions. The fluctuations of stress-responsive hormones help alter the cellular dynamics and hence play a central role in coordinately regulating the growth responses under stress. Recent experimental data unequivocally demonstrated that interactions among various phytohormones are the rule rather than exception in integrating the diverse input signals and readjusting growth as well as acquiring stress tolerance. The presence of multiple and often redundant signaling intermediates for each phytohormone appears to help in such crosstalk. Furthermore, there are several examples of similar developmental changes occurring in response to distinct abiotic stress signals, which can be explained by the crosstalk in phytohormone signaling. Therefore, in this brief review, we have highlighted the major phytohormone crosstalks with a focus on the response of plants to abiotic stresses. The recent findings have made it increasingly apparent that such crosstalk will also explain the extreme pleiotropic responses elicited by various phytohormones. Indeed, it would not be presumptuous to expect that in the coming years this paradigm will take a central role in explaining developmental regulation.
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Affiliation(s)
- Ajay Kohli
- Genetics and Biotechnology Division, Plant Breeding, International Rice Research Institute, 7777 Manila, Philippines
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623
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Zhang W, Fan S, Pang C, Wei H, Ma J, Song M, Yu S. Molecular cloning and function analysis of two SQUAMOSA-Like MADS-box genes from Gossypium hirsutum L. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:597-607. [PMID: 23718551 DOI: 10.1111/jipb.12075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/16/2013] [Indexed: 05/15/2023]
Abstract
The MADS-box genes encode a large family of transcription factors having diverse roles in plant development. The SQUAMOSA (SQUA)/APETALA1 (AP1)/FRUITFULL (FUL) subfamily genes are essential regulators of floral transition and floral organ identity. Here we cloned two MADS-box genes, GhMADS22 and GhMADS23, belonging to the SQUA/AP1/FUL subgroup from Gossypium hirsutum L. Phylogenetic analysis and sequence alignment showed that GhMADS22 and GhMADS23 belonged to the euFUL and euAP1 subclades, respectively. The two genes both had eight exons and seven introns from the start codon to the stop codon according to the alignment between the obtained cDNA sequence and the Gossypium raimondii L. genome sequence. Expression profile analysis showed that GhMADS22 and GhMADS23 were highly expressed in developing shoot apices, bracts, and sepals. Gibberellic acid promoted GhMADS22 and GhMADS23 expression in the shoot apex. Transgenic Arabidopsis lines overexpressing 35S::GhMADS22 had abnormal flowers and bolted earlier than wild type under long-day conditions (16 h light/8 h dark). Moreover, GhMADS22 overexpression delayed floral organ senescence and abscission and it could also respond to abscisic acid. In summary, GhMADS22 may have functions in promoting flowering, improving resistance and delaying senescence for cotton and thus it may be a candidate target for promoting early-maturation in cotton breeding.
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Affiliation(s)
- Wenxiang Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agriculture Sciences, Anyang, 455000, China
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624
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Takahashi Y, Ebisu Y, Kinoshita T, Doi M, Okuma E, Murata Y, Shimazaki KI. bHLH transcription factors that facilitate K⁺ uptake during stomatal opening are repressed by abscisic acid through phosphorylation. Sci Signal 2013; 6:ra48. [PMID: 23779086 DOI: 10.1126/scisignal.2003760] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Stomata open in response to light and close after exposure to abscisic acid (ABA). They regulate gas exchange between plants and the atmosphere, enabling plants to adapt to changing environmental conditions. ABA binding to receptors initiates a signaling cascade that involves protein phosphorylation. We show that ABA induced the phosphorylation of three basic helix-loop-helix (bHLH) transcription factors, called AKSs (ABA-responsive kinase substrates; AKS1, AKS2, and AKS3), in Arabidopsis guard cells. In their unphosphorylated state, AKSs facilitated stomatal opening through the transcription of genes encoding inwardly rectifying K⁺ channels. aks1aks2-1 double mutant plants showed decreases in light-induced stomatal opening, K⁺ accumulation in response to light, activity of inwardly rectifying K⁺ channels, and transcription of genes encoding major inwardly rectifying K⁺ channels without affecting ABA-mediated stomatal closure. Overexpression of potassium channel in Arabidopsis thaliana 1 (KAT1), which encodes a major inwardly rectifying K⁺ channel in guard cells, rescued the phenotype of aks1aks2-1 plants. AKS1 bound directly to the promoter of KAT1, an interaction that was attenuated after ABA-induced phosphorylation. The ABA agonist pyrabactin induced phosphorylation of AKSs. Our results demonstrate that the AKS family of bHLH transcription factors facilitates stomatal opening through the transcription of genes encoding inwardly rectifying K⁺ channels and that ABA suppresses the activity of these channels by triggering the phosphorylation of AKS family transcription factors.
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Affiliation(s)
- Yohei Takahashi
- Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan
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625
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Boursiac Y, Léran S, Corratgé-Faillie C, Gojon A, Krouk G, Lacombe B. ABA transport and transporters. TRENDS IN PLANT SCIENCE 2013; 18:325-33. [PMID: 23453706 DOI: 10.1016/j.tplants.2013.01.007] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/15/2013] [Accepted: 01/28/2013] [Indexed: 05/19/2023]
Abstract
Abscisic acid (ABA) metabolism, perception, and transport form a triptych allowing higher plants to use ABA as a signaling molecule. The molecular bases of ABA metabolism are now well described and, over the past few years, several ABA receptors have been discovered. Although ABA transport has long been demonstrated in planta, the first breakthroughs in identifying plasma membrane-localized ABA transporters came in 2010, with the identification of two ATP-binding cassette (ABC) proteins. More recently, two ABA transporters in the nitrate transporter 1/peptide transporter (NRT1/PTR) family have been identified. In this review, we discuss the role of these different ABA transporters and examine the scientific impact of their identification. Given that the NRT1/PTR family is involved in the transport of nitrogen (N) compounds, further work should determine whether an interaction between ABA and N signaling or nutrition occurs.
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Affiliation(s)
- Yann Boursiac
- Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes 'Claude Grignon', UMR CNRS/INRA/SupAgro/UM2, Place Viala, 34060 Montpellier Cedex, France
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626
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Westfall CS, Muehler AM, Jez JM. Enzyme action in the regulation of plant hormone responses. J Biol Chem 2013; 288:19304-11. [PMID: 23709222 DOI: 10.1074/jbc.r113.475160] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plants synthesize a chemically diverse range of hormones that regulate growth, development, and responses to environmental stresses. The major classes of plant hormones are specialized metabolites with exquisitely tailored perception and signaling systems, but equally important are the enzymes that control the dose and exposure to the bioactive forms of these molecules. Here, we review new insights into the role of enzyme families, including the SABATH methyltransferases, the methylesterases, the GH3 acyl acid-amido synthetases, and the hormone peptidyl hydrolases, in controlling the biosynthesis and modifications of plant hormones and how these enzymes contribute to the network of chemical signals responsible for plant growth, development, and environmental adaptation.
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Affiliation(s)
- Corey S Westfall
- Department of Biology, Washington University in St Louis, St Louis, Missouri 63130, USA
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627
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miR172b controls the transition to autotrophic development inhibited by ABA in Arabidopsis. PLoS One 2013; 8:e64770. [PMID: 23717657 PMCID: PMC3662786 DOI: 10.1371/journal.pone.0064770] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 04/18/2013] [Indexed: 01/28/2023] Open
Abstract
Seedling establishment is a critical phase in the life of plants when they are the most vulnerable to environment. Growth arrest at post-germinative stage under stress is the major adaptive strategy to help germinating seedlings to survive a spectrum of stressful conditions. ABA signaling is the key pathway to control stress-induced developmental arrest. However, mechanisms controlling the phase transition under abiotic stress are not fully understood. Here, we described miR172b as a new key regulator controlling transition of germinating seedlings from heterotrophic to autotrophic growth under osmotic stress in Arabidopsis. We showed that miR172b and its target SNZ were co-expressed during early seedling development. Expression of miR172b and SNZ was low after radicle emergence and sharply increased at the checkpoint to autotrophic development under normal conditions. Interestingly, activation of miR172b and SNZ was completely abolished by ABA and osmotic stress. miR172b overexpression and snz-1 exhibited increased sensitivity to ABA and osmotic stress during specific post-germinative stage, and resulted in higher expression of ABI3, ABI5 and downstream genes, such as Em6 and RAB18, than wild type under ABA treatment. Our results revealed that miR172b is a critical regulator specifically controlling cotyledon greening during post-germinative growth by directly targeting SNZ under ABA treatment and osmotic stress.
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628
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Miyakawa T, Fujita Y, Yamaguchi-Shinozaki K, Tanokura M. Structure and function of abscisic acid receptors. TRENDS IN PLANT SCIENCE 2013; 18:259-66. [PMID: 23265948 DOI: 10.1016/j.tplants.2012.11.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/26/2012] [Accepted: 11/01/2012] [Indexed: 05/18/2023]
Abstract
The phytohormone abscisic acid (ABA) plays a crucial role in adaptive responses to environmental stresses, such as drought and high salinity, as well as in plant development, such as seed maturation and dormancy. PYR/PYL/RCAR has been identified as a bona fide ABA receptor (ABAR) that constitutes the core regulatory component of ABA signaling networks in plants. Here, we review recent structural and functional studies of the ABAR that have elucidated its activation mechanism, early signaling components, and physiological responses. A crucial event in the receptor's activation was found to be an open-to-closed conformational change in the gate loop of the receptor protein. More recent progress has provided strategies for controlling the gate's closure using chemical agonists or protein engineering approaches.
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Affiliation(s)
- Takuya Miyakawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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629
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Zhang X, Zhang Q, Wang G. Crystallization and initial X-ray data of abscisic acid receptor PYL3 in the presence of (-)-ABA. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:540-3. [PMID: 23695572 PMCID: PMC3660896 DOI: 10.1107/s1744309113008051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 03/23/2013] [Indexed: 11/10/2022]
Abstract
Abscisic acid (ABA) modulates many complicated developmental processes and responses to environmental stimuli. Recently, several (+)-ABA signalling mechanisms by the RCAR/PYR1/PYL family of proteins (PYLs) have been proposed. However, the mechanism of the recognition and binding of the unnatural ligand (-)-ABA by PYLs has not yet been elucidated. In the present study, the expression, purification and crystallization of PYL3 in complex with (-)-ABA are reported. Diffraction data were refined to 2.65 Å resolution for this complex in space group P65. These findings will help to explain the stereospecificity of PYLs for (-)-ABA and to explore the selective ABA agonists.
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Affiliation(s)
- Xingliang Zhang
- Clinical Medicine Research Center, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong 524001, PR China.
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630
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Umezawa T, Sugiyama N, Takahashi F, Anderson JC, Ishihama Y, Peck SC, Shinozaki K. Genetics and phosphoproteomics reveal a protein phosphorylation network in the abscisic acid signaling pathway in Arabidopsis thaliana. Sci Signal 2013; 6:rs8. [PMID: 23572148 DOI: 10.1126/scisignal.2003509] [Citation(s) in RCA: 258] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abscisic acid (ABA) is a phytohormone that regulates diverse plant processes, including seed germination and the response to dehydration. In Arabidopsis thaliana, protein kinases of the SNF1-related protein kinase 2 (SnRK2) family are believed to transmit ABA- or dehydration-induced signals through phosphorylation of downstream substrates. By mass spectrometry, we identified proteins that were phosphorylated in Arabidopsis wild-type plants, but not in mutants lacking all three members of the SnRK2 family (srk2dei), treated with ABA or subjected to dehydration stress. The number of differentially phosphorylated peptides was greater in srk2dei plants treated with ABA than in the ones subjected to dehydration, suggesting that SnRK2 was mainly involved in ABA signaling rather than dehydration. We identified 35 peptides that were differentially phosphorylated in wild-type but not in srk2dei plants treated with ABA. Biochemical and genetic studies of candidate SnRK2-regulated phosphoproteins showed that SnRK2 promoted the ABA-induced activation of the mitogen-activated protein kinases AtMPK1 and AtMPK2; that SnRK2 mediated phosphorylation of Ser(45) in a bZIP transcription factor, AREB1 (ABA-responsive element binding protein 1), and stimulated ABA-responsive gene expression; and that a previously unknown protein, SnRK2-substrate 1 (SNS1), was phosphorylated in vivo by ABA-activated SnRK2s. Reverse genetic analysis revealed that SNS1 inhibited ABA responses in Arabidopsis. Thus, by integrating genetics with phosphoproteomics, we identified multiple components of the ABA-responsive protein phosphorylation network.
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Affiliation(s)
- Taishi Umezawa
- Faculty of Agriculture and Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
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631
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Hahn A, Kilian J, Mohrholz A, Ladwig F, Peschke F, Dautel R, Harter K, Berendzen KW, Wanke D. Plant core environmental stress response genes are systemically coordinated during abiotic stresses. Int J Mol Sci 2013; 14:7617-41. [PMID: 23567274 PMCID: PMC3645707 DOI: 10.3390/ijms14047617] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/28/2013] [Accepted: 03/29/2013] [Indexed: 11/16/2022] Open
Abstract
Studying plant stress responses is an important issue in a world threatened by global warming. Unfortunately, comparative analyses are hampered by varying experimental setups. In contrast, the AtGenExpress abiotic stress experiment displays intercomparability. Importantly, six of the nine stresses (wounding, genotoxic, oxidative, UV-B light, osmotic and salt) can be examined for their capacity to generate systemic signals between the shoot and root, which might be essential to regain homeostasis in Arabidopsis thaliana. We classified the systemic responses into two groups: genes that are regulated in the non-treated tissue only are defined as type I responsive and, accordingly, genes that react in both tissues are termed type II responsive. Analysis of type I and II systemic responses suggest distinct functionalities, but also significant overlap between different stresses. Comparison with salicylic acid (SA) and methyl-jasmonate (MeJA) responsive genes implies that MeJA is involved in the systemic stress response. Certain genes are predominantly responding in only one of the categories, e.g., WRKY genes respond mainly non-systemically. Instead, genes of the plant core environmental stress response (PCESR), e.g., ZAT10, ZAT12, ERD9 or MES9, are part of different response types. Moreover, several PCESR genes switch between the categories in a stress-specific manner.
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Affiliation(s)
| | | | - Anne Mohrholz
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Friederike Ladwig
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Florian Peschke
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Rebecca Dautel
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Klaus Harter
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Kenneth W. Berendzen
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
| | - Dierk Wanke
- Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tübingen, Auf der Morgenstelle 1, Tübingen 72076, Germany; E-Mails: (A.H.); (J.K.); (A.M.); (F.L.); (F.P.); (R.D.); (K.H.); (K.W.B.)
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632
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Du ZY, Chen MX, Chen QF, Xiao S, Chye ML. Arabidopsis acyl-CoA-binding protein ACBP1 participates in the regulation of seed germination and seedling development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:294-309. [PMID: 23448237 DOI: 10.1111/tpj.12121] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 12/20/2012] [Accepted: 01/14/2013] [Indexed: 05/08/2023]
Abstract
A family of six genes encoding acyl-CoA-binding proteins (ACBPs), ACBP1-ACBP6, has been characterized in Arabidopsis thaliana. In this study, we demonstrate that ACBP1 promotes abscisic acid (ABA) signaling during germination and seedling development. ACBP1 was induced by ABA, and transgenic Arabidopsis ACBP1-over-expressors showed increased sensitivity to ABA during germination and seedling development, whereas the acbp1 mutant showed decreased ABA sensitivity during these processes. Subsequent RNA assays showed that ACBP1 over-production in 12-day-old seedlings up-regulated the expression of PHOSPHOLIPASE Dα1 (PLDα1) and three ABA/stress-responsive genes: ABA-RESPONSIVE ELEMENT BINDING PROTEIN1 (AREB1), RESPONSE TO DESICCATION29A (RD29A) and bHLH-TRANSCRIPTION FACTOR MYC2 (MYC2). The expression of AREB1 and PLDα1 was suppressed in the acbp1 mutant in comparison with the wild type following ABA treatment. PLDα1 has been reported to promote ABA signal transduction by producing phosphatidic acid, an important lipid messenger in ABA signaling. Using lipid profiling, seeds and 12-day-old seedlings of ACBP1-over-expressing lines were shown to accumulate more phosphatidic acid after ABA treatment, in contrast to lower phosphatidic acid in the acbp1 mutant. Bimolecular fluorescence complementation assays indicated that ACBP1 interacts with PLDα1 at the plasma membrane. Their interaction was further confirmed by yeast two-hybrid analysis. As recombinant ACBP1 binds phosphatidic acid and phosphatidylcholine, ACBP1 probably promotes PLDα1 action. Taken together, these results suggest that ACBP1 participates in ABA-mediated seed germination and seedling development.
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Affiliation(s)
- Zhi-Yan Du
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China
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633
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Pokhilko A, Mas P, Millar AJ. Modelling the widespread effects of TOC1 signalling on the plant circadian clock and its outputs. BMC SYSTEMS BIOLOGY 2013; 7:23. [PMID: 23506153 PMCID: PMC3614443 DOI: 10.1186/1752-0509-7-23] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 03/08/2013] [Indexed: 11/30/2022]
Abstract
Background 24-hour biological clocks are intimately connected to the cellular signalling network, which complicates the analysis of clock mechanisms. The transcriptional regulator TOC1 (TIMING OF CAB EXPRESSION 1) is a founding component of the gene circuit in the plant circadian clock. Recent results show that TOC1 suppresses transcription of multiple target genes within the clock circuit, far beyond its previously-described regulation of the morning transcription factors LHY (LATE ELONGATED HYPOCOTYL) and CCA1 (CIRCADIAN CLOCK ASSOCIATED 1). It is unclear how this pervasive effect of TOC1 affects the dynamics of the clock and its outputs. TOC1 also appears to function in a nested feedback loop that includes signalling by the plant hormone Abscisic Acid (ABA), which is upregulated by abiotic stresses, such as drought. ABA treatments both alter TOC1 levels and affect the clock’s timing behaviour. Conversely, the clock rhythmically modulates physiological processes induced by ABA, such as the closing of stomata in the leaf epidermis. In order to understand the dynamics of the clock and its outputs under changing environmental conditions, the reciprocal interactions between the clock and other signalling pathways must be integrated. Results We extended the mathematical model of the plant clock gene circuit by incorporating the repression of multiple clock genes by TOC1, observed experimentally. The revised model more accurately matches the data on the clock’s molecular profiles and timing behaviour, explaining the clock’s responses in TOC1 over-expression and toc1 mutant plants. A simplified representation of ABA signalling allowed us to investigate the interactions of ABA and circadian pathways. Increased ABA levels lengthen the free-running period of the clock, consistent with the experimental data. Adding stomatal closure to the model, as a key ABA- and clock-regulated downstream process allowed to describe TOC1 effects on the rhythmic gating of stomatal closure. Conclusions The integrated model of the circadian clock circuit and ABA-regulated environmental sensing allowed us to explain multiple experimental observations on the timing and stomatal responses to genetic and environmental perturbations. These results crystallise a new role of TOC1 as an environmental sensor, which both affects the pace of the central oscillator and modulates the kinetics of downstream processes.
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Affiliation(s)
- Alexandra Pokhilko
- School of Biological Sciences, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3JH, UK
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634
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Ellenberger S, Schuster S, Wstemeyer J. Correlation between sequence, structure and function for trisporoid processing proteins in the model zygomycete Mucor mucedo. J Theor Biol 2013; 320:66-75. [DOI: 10.1016/j.jtbi.2012.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 11/29/2012] [Accepted: 12/06/2012] [Indexed: 10/27/2022]
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635
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de Ollas C, Hernando B, Arbona V, Gómez-Cadenas A. Jasmonic acid transient accumulation is needed for abscisic acid increase in citrus roots under drought stress conditions. PHYSIOLOGIA PLANTARUM 2013; 147:296-306. [PMID: 22671923 DOI: 10.1111/j.1399-3054.2012.01659.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/02/2012] [Indexed: 05/18/2023]
Abstract
Phytohormones are central players in sensing and signaling numerous environmental conditions like drought stress. In this work, an experimental system based on severe drought was established and hormone profiling together with gene expression of key enzymes involved in abscisic acid (ABA) and jasmonic acid (JA) biosynthesis was studied in roots of citrumelo CPB 4475 (a commercial citrus rootstock) plants. JA concentration transiently increased after a few hours of stress, returning to control levels 30 h after the onset of the condition. A more progressive ABA accumulation was observed, with the onset of this increase at the same time or right after the JA transient accumulation. Molecular data suggested that, at least, part of the hormonal regulation takes place at the biosynthetic level. These observations also pointed to a possible involvement of JA on ABA biosynthesis under stress. To test this hypothesis, JA and ABA biosynthesis were chemically inhibited and subsequently phenotypes rescued by the addition of exogenous hormones. Results showed that the early JA accumulation was necessary for the subsequent ABA increase in roots under stress whereas the opposite could not be stated. The model includes a burst of JA in roots of citrus under severe drought stress conditions that leads to a more progressive ABA accumulation that will induce later plant responses. The present work adds a new level of interaction between JA and ABA at the biosynthetic level that together with the previously described interaction between signal transduction cascades of the two hormones would allow plants to fine-tune specific responses to different stimuli.
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Affiliation(s)
- Carlos de Ollas
- Departament de Ciències Agràries i del Medi Natural, Universitat Jaume I, E-12071, Castelló de la Plana, Spain
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636
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Vilela B, Moreno-Cortés A, Rabissi A, Leung J, Pagès M, Lumbreras V. The maize OST1 kinase homolog phosphorylates and regulates the maize SNAC1-type transcription factor. PLoS One 2013; 8:e58105. [PMID: 23469147 PMCID: PMC3585266 DOI: 10.1371/journal.pone.0058105] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 02/01/2013] [Indexed: 12/30/2022] Open
Abstract
The Arabidopsis kinase OPEN STOMATA 1 (OST1) plays a key role in regulating drought stress signalling, particularly stomatal closure. We have identified and investigated the functions of the OST1 ortholog in Z. mays (ZmOST1). Ectopic expression of ZmOST1 in the Arabidopsis ost1 mutant restores the stomatal closure phenotype in response to drought. Furthermore, we have identified the transcription factor, ZmSNAC1, which is directly phosphorylated by ZmOST1 with implications on its localization and protein stability. Interestingly, ZmSNAC1 binds to the ABA-box of ZmOST1, which is conserved in SnRK2s activated by ABA and is part of the contact site for the negative-regulating clade A PP2C phosphatases. Taken together, our results indicate that ZmSNAC1 is a substrate of ZmOST1 and delineate a novel osmotic stress transcriptional pathway in maize.
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Affiliation(s)
- Belmiro Vilela
- Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain
| | - Alicia Moreno-Cortés
- Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain
| | - Agnese Rabissi
- Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain
| | - Jeffrey Leung
- Institut de Sciences du Végétal, Centre national de la recherche scientifique, Gif-sur-Yvette, France
| | - Montserrat Pagès
- Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain
| | - Victoria Lumbreras
- Centre for Research in Agricultural Genomics, Bellaterra, Cerdanyola del Vallés, Spain
- * E-mail:
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637
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Zhang F, Lu X, Lv Z, Zhang L, Zhu M, Jiang W, Wang G, Sun X, Tang K. Overexpression of the Artemisia orthologue of ABA receptor, AaPYL9, enhances ABA sensitivity and improves artemisinin content in Artemisia annua L. PLoS One 2013; 8:e56697. [PMID: 23437216 PMCID: PMC3577733 DOI: 10.1371/journal.pone.0056697] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 01/14/2013] [Indexed: 01/10/2023] Open
Abstract
The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. In this study, we cloned an ABA receptor orthologue, AaPYL9, from Artemisia annua L. AaPYL9 is expressed highly in leaf and flower. AaPYL9 protein can be localized in both nucleus and cytoplasm. Yeast two-hybrid assay shows AaPYL9 can specifically interact with AtABI1 but not with AtABI2, AtHAB1 or AtHAB2. ABA can enhance the interaction between AaPYL9 and AtABI1 while AaPYL9-89 Pro→Ser and AaPYL9-116 His→Ala point mutations abolishes the interaction. BiFC assay shows that AaPYL9 interacts with AtABI1 in nucleus in planta. Transgenic Arabidopsis plants over-expressing AaPYL9 are more sensitive to ABA in the seed germination and primary root growth than wild type. Consistent with this, ABA report genes have higher expression in AaPYL9 overexpressing plants compared to wild type after ABA treatment. Moreover, overexpression of AaPYL9 in A. annua increases not only drought tolerance, but also artemisinin content after ABA treatment, with significant enhancement of the expression of key genes in artemisinin biosynthesis. This study provides a way to develop A. annua with high-yielding artemisinin and high drought resistance.
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Affiliation(s)
- Fangyuan Zhang
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Xu Lu
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Zongyou Lv
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Ling Zhang
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Mengmeng Zhu
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Weiming Jiang
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Guofeng Wang
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Xiaofen Sun
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Kexuan Tang
- Plant Biotechnology Research Center, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- * E-mail:
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638
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Leung J, Valon C, Moreau B, Boeglin M, Lefoulon C, Joshi-Saha A, Chérel I. [The ABC of abscisic acid action in plant drought stress responses]. Biol Aujourdhui 2013; 206:301-12. [PMID: 23419257 DOI: 10.1051/jbio/2012029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Indexed: 11/14/2022]
Abstract
The combined daily consumption of fresh water ranges from 200 to 700 liters per capita per day in most developed countries, with about 70% being used for agricultural needs. Unlike other resources such as the different forms of energy, water has no other alternatives. With the looming prospect of global water crisis, the recent laudable success in deciphering the early steps in the signal transduction of the "stress hormone" abscisic acid (ABA) has ignited hopes that crops can be engineered with the capacity to maintain productivity while requiring less water input. Although ABA was first discovered in plants, it has resurfaced in the human brain (and many other non-plant organisms : sea sponge, some parasites, hydra to name a few), suggesting that its existence may be widespread. In humans, more amazingly, ABA has shown anti-inflammatory and antiviral properties. Even its receptors and key signaling intermediates have homologs in the human genome suggesting that evolution has re-fashioned these same proteins into new functional contexts. Thus, learning about the molecular mechanisms of ABA in action using the more flexible plant model will be likely beneficial to other organisms, and especially in human diseases, which is topical in the medical circle. ABA can accumulate up to 10 to 30-fold in plants under drought stress relative to unstressed conditions. The built up of the hormone then triggers diverse adaptive pathways permitting plants to withstand temporary bouts of water shortage. One favorite experimental model to unravel ABA signaling mechanisms in all of its intimate detail is based on the hormone's ability to elicit stomatal closure - a rapid cellular response of land plants to limit water loss through transpiration. Each microscopic stoma, or pore, is contoured by two specialized kidney-shaped cells called the guard cells. Because land plants are protected by a waxy cuticle impermeable to gas exchange, the stomatal pores are thus the primary portals for photosynthetic CO(2) uptake. Drought, by biasing pathways that lead to rapid closure of these pores, has therefore a negative impact on photosynthesis, and consequently, biomass as well. The stomatal aperture widens and narrows by expansion and contraction, respectively, of these flanking guard cells caused by changes in the intracellular concentrations of ion fluxes. These transport mechanisms most likely share fundamental principles with any excitable cell. These events require coordination of channels, vacuolar and membrane transporters that generate a specific pattern of electrical signals that relay the ABA stimulus. Research on ABA begun in the 1960's has now been crowned by the achievement of having identified the soluble ABA receptor that turns on and off the activities of a kinase/phosphatase pair, as the heart of the signaling complex. Results distilled from the latest structural studies on these ABA receptors, characterized by the so-called START domain, are beginning to tender the most exciting promise for rational design of agonists and antagonists towards modulating stress adaptive ability in plants. This review will chart the recent extraordinary progress that has enlightened us on how ABA controls membrane transport mechanisms that evoke the fast stomatal closing pathway.
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Affiliation(s)
- Jeffrey Leung
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, Unité Propre de Recherche 2355, 1 Avenue de la Terrasse Bât. 23, 91198 Gif-sur-Yvette Cedex, France.
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639
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DU ZY, Chen MX, Chen QF, Xiao S, Chye ML. Overexpression of Arabidopsis acyl-CoA-binding protein ACBP2 enhances drought tolerance. PLANT, CELL & ENVIRONMENT 2013; 36:300-14. [PMID: 22788984 DOI: 10.1111/j.1365-3040.2012.02574.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana acyl-CoA-binding protein 2 (ACBP2) is a stress-responsive protein that is also important in embryogenesis. Here, we assign a role for ACBP2 in abscisic acid (ABA) signalling during seed germination, seedling development and the drought response. ACBP2 was induced by ABA and drought, and transgenic Arabidopsis overexpressing ACBP2 (ACBP2-OXs) showed increased sensitivity to ABA treatment during germination and seedling development. ACBP2-OXs also displayed improved drought tolerance and ABA-mediated reactive oxygen species (ROS) production in guard cells, thereby promoting stomatal closure, reducing water loss and enhancing drought tolerance. In contrast, acbp2 mutant plants showed decreased sensitivity to ABA in root development and were more sensitive to drought stress. RNA analyses revealed that ACBP2 overexpression up-regulated the expression of Respiratory Burst Oxidase Homolog D (AtrbohD) and AtrbohF, two NAD(P)H oxidases essential for ABA-mediated ROS production, whereas the expression of Hypersensitive to ABA1 (HAB1), an important negative regulator in ABA signalling, was down-regulated. In addition, transgenic plants expressing ACBP2pro:GUS showed beta-glucuronidase (GUS) staining in guard cells, confirming a role for ACBP2 at the stomata. These observations support a positive role for ACBP2 in promoting ABA signalling in germination, seedling development and the drought response.
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Affiliation(s)
- Zhi-Yan DU
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
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640
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Westwood JH, McCann L, Naish M, Dixon H, Murphy AM, Stancombe MA, Bennett MH, Powell G, Webb AAR, Carr JP. A viral RNA silencing suppressor interferes with abscisic acid-mediated signalling and induces drought tolerance in Arabidopsis thaliana. MOLECULAR PLANT PATHOLOGY 2013; 14:158-70. [PMID: 23083401 PMCID: PMC6638696 DOI: 10.1111/j.1364-3703.2012.00840.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Cucumber mosaic virus (CMV) encodes the 2b protein, which plays a role in local and systemic virus movement, symptom induction and suppression of RNA silencing. It also disrupts signalling regulated by salicylic acid and jasmonic acid. CMV induced an increase in tolerance to drought in Arabidopsis thaliana. This was caused by the 2b protein, as transgenic plants expressing this viral factor showed increased drought tolerance, but plants infected with CMVΔ2b, a viral mutant lacking the 2b gene, did not. The silencing effector ARGONAUTE1 (AGO1) controls a microRNA-mediated drought tolerance mechanism and, in this study, we noted that plants (dcl2/3/4 triple mutants) lacking functional short-interfering RNA-mediated silencing were also drought tolerant. However, drought tolerance engendered by CMV may be independent of the silencing suppressor activity of the 2b protein. Although CMV infection did not alter the accumulation of the drought response hormone abscisic acid (ABA), 2b-transgenic and ago1-mutant seeds were hypersensitive to ABA-mediated inhibition of germination. However, the induction of ABA-regulated genes in 2b-transgenic and CMV-infected plants was inhibited more strongly than in ago1-mutant plants. The virus engenders drought tolerance by altering the characteristics of the roots and not of the aerial tissues as, compared with the leaves of silencing mutants, leaves excised from CMV-infected or 2b-transgenic plants showed greater stomatal permeability and lost water more rapidly. This further indicates that CMV-induced drought tolerance is not mediated via a change in the silencing-regulated drought response mechanism. Under natural conditions, virus-induced drought tolerance may serve viruses by aiding susceptible hosts to survive periods of environmental stress.
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Affiliation(s)
- Jack H Westwood
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
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641
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Smith AP. Systemic Signaling in the Maintenance of Phosphate Homeostasis. LONG-DISTANCE SYSTEMIC SIGNALING AND COMMUNICATION IN PLANTS 2013. [DOI: 10.1007/978-3-642-36470-9_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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642
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Blanco-Ulate B, Vincenti E, Powell ALT, Cantu D. Tomato transcriptome and mutant analyses suggest a role for plant stress hormones in the interaction between fruit and Botrytis cinerea. FRONTIERS IN PLANT SCIENCE 2013; 4:142. [PMID: 23717322 PMCID: PMC3653111 DOI: 10.3389/fpls.2013.00142] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/25/2013] [Indexed: 05/19/2023]
Abstract
Fruit-pathogen interactions are a valuable biological system to study the role of plant development in the transition from resistance to susceptibility. In general, unripe fruit are resistant to pathogen infection but become increasingly more susceptible as they ripen. During ripening, fruit undergo significant physiological and biochemical changes that are coordinated by complex regulatory and hormonal signaling networks. The interplay between multiple plant stress hormones in the interaction between plant vegetative tissues and microbial pathogens has been documented extensively, but the relevance of these hormones during infections of fruit is unclear. In this work, we analyzed a transcriptome study of tomato fruit infected with Botrytis cinerea in order to profile the expression of genes for the biosynthesis, modification and signal transduction of ethylene (ET), salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA), hormones that may be not only involved in ripening, but also in fruit interactions with pathogens. The changes in relative expression of key genes during infection and assays of susceptibility of fruit with impaired synthesis or perception of these hormones were used to formulate hypotheses regarding the involvement of these regulators in the outcome of the tomato fruit-B. cinerea interaction.
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Affiliation(s)
- Barbara Blanco-Ulate
- Department of Plant Sciences, University of California, DavisDavis, CA, USA
- Department of Viticulture and Enology, University of California, DavisDavis, CA, USA
| | - Estefania Vincenti
- Department of Plant Sciences, University of California, DavisDavis, CA, USA
| | - Ann L. T. Powell
- Department of Plant Sciences, University of California, DavisDavis, CA, USA
| | - Dario Cantu
- Department of Viticulture and Enology, University of California, DavisDavis, CA, USA
- *Correspondence: Dario Cantu, Department of Viticulture and Enology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA. e-mail:
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643
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Fujita Y, Yoshida T, Yamaguchi-Shinozaki K. Pivotal role of the AREB/ABF-SnRK2 pathway in ABRE-mediated transcription in response to osmotic stress in plants. PHYSIOLOGIA PLANTARUM 2013; 147:15-27. [PMID: 22519646 DOI: 10.1111/j.1399-3054.2012.01635.x] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Water availability is one of the main limiting factors for plant growth and development. The phytohormone abscisic acid (ABA) fulfills a critical role in coordinating the responses to reduced water availability as well as in multiple developmental processes. Endogenous ABA levels increase in response to osmotic stresses such as drought and high salinity, and ABA activates the expression of many genes via ABA-responsive elements (ABREs) in their promoter regions. ABRE-binding protein/ABRE-binding factor (AREB/ABF) transcription factors (TFs) regulate the ABRE-mediated transcription of downstream target genes. Three subclass III sucrose non-fermenting-1 related protein kinase 2 (SnRK2) protein kinases (SRK2D/SnRK2.2, SRK2E/SnRK2.6/OST1 and SRK2I/SnRK2.3) phosphorylate and positively control the AREB/ABF TFs. Substantial progress has been made in our understanding of the ABA-sensing system mediated by Pyrabactin resistance1/PYR1-like/regulatory components of ABA receptor (PYR/PYL/RCAR)-protein phosphatase 2C complexes. In addition to PP2C-PYR/PYL/RCAR ABAreceptor complex, the AREB/ABF-SnRK2 pathway, which is well conserved in land plants, was recently shown to play a major role as a positive regulator of ABA/stress signaling through ABRE-mediated transcription of target genes implicated in the osmotic stress response. This review focuses on current progress in the study of the AREB/ABF-SnRK2 positive regulatory pathway in plants and describes additional signaling factors implicated in the AREB/ABF-SnRK2 pathway. Moreover, to help promote the link between basic and applied studies, the nomenclature and phylogenetic relationships between the AREB/ABFs and SnRK2s are summarized and discussed.
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Affiliation(s)
- Yasunari Fujita
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences-JIRCAS, Tsukuba, Ibaraki 305-8686, Japan
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644
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Arbuscular Mycorrhizal Fungi and the Tolerance of Plants to Drought and Salinity. SOIL BIOLOGY 2013. [DOI: 10.1007/978-3-642-39317-4_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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645
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Aroca R, Ruiz-Lozano JM, Zamarreño AM, Paz JA, García-Mina JM, Pozo MJ, López-Ráez JA. Arbuscular mycorrhizal symbiosis influences strigolactone production under salinity and alleviates salt stress in lettuce plants. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:47-55. [PMID: 23102876 DOI: 10.1016/j.jplph.2012.08.020] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 08/23/2012] [Accepted: 08/23/2012] [Indexed: 05/05/2023]
Abstract
Arbuscular mycorrhizal (AM) symbiosis can alleviate salt stress in plants. However the intimate mechanisms involved, as well as the effect of salinity on the production of signalling molecules associated to the host plant-AM fungus interaction remains largely unknown. In the present work, we have investigated the effects of salinity on lettuce plant performance and production of strigolactones, and assessed its influence on mycorrhizal root colonization. Three different salt concentrations were applied to mycorrhizal and non-mycorrhizal plants, and their effects, over time, analyzed. Plant biomass, stomatal conductance, efficiency of photosystem II, as well as ABA content and strigolactone production were assessed. The expression of ABA biosynthesis genes was also analyzed. AM plants showed improved growth rates and a better performance of physiological parameters such as stomatal conductance and efficiency of photosystem II than non-mycorrhizal plants under salt stress since very early stages - 3 weeks - of plant colonization. Moreover, ABA levels were lower in those plants, suggesting that they were less stressed than non-colonized plants. On the other hand, we show that both AM symbiosis and salinity influence strigolactone production, although in a different way in AM and non-AM plants. The results suggest that AM symbiosis alleviates salt stress by altering the hormonal profiles and affecting plant physiology in the host plant. Moreover, a correlation between strigolactone production, ABA content, AM root colonization and salinity level is shown. We propose here that under these unfavourable conditions, plants increase strigolactone production in order to promote symbiosis establishment to cope with salt stress.
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Affiliation(s)
- Ricardo Aroca
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas (EEZ-CSIC), Profesor Albareda 1, 18008 Granada, Spain
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646
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Batelli G, Massarelli I, Van Oosten M, Nurcato R, Vannini C, Raimondi G, Leone A, Zhu JK, Maggio A, Grillo S. Asg1 is a stress-inducible gene which increases stomatal resistance in salt stressed potato. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1849-57. [PMID: 22854180 PMCID: PMC3586823 DOI: 10.1016/j.jplph.2012.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/06/2012] [Accepted: 07/07/2012] [Indexed: 05/08/2023]
Abstract
The identification of critical components in plant salt stress adaptation has greatly benefitted, in the last two decades, from fundamental discoveries in Arabidopsis and close model systems. Nevertheless, this approach has also highlighted a non-complete overlap between stress tolerance mechanisms in Arabidopsis and agricultural crops. Within a long-running research program aimed at identifying salt stress genetic determinants in potato by functional screening in Escherichia coli, we isolated Asg1, a stress-related gene with an unknown function. Asg1 is induced by salt stress in both potato and Arabidopsis and by abscisic acid in Arabidopsis. Asg1 is actively transcribed in all plant tissues. Furthermore, Asg1 promoter analysis confirmed its ubiquitous expression, which was remarkable in pollen, a plant tissue that undergoes drastic dehydration/hydration processes. Fusion of Asg1 with green fluorescent protein showed that the encoded protein is localized close to the plasma membrane with a non-continuous pattern of distribution. In addition, Arabidopsis knockout asg1 mutants were insensitive to both NaCl and sugar hyperosmotic environments during seed germination. Transgenic potato plants over-expressing the Asg1 gene revealed a stomatal hypersensitivity to NaCl stress which, however, did not result in a significantly improved tuber yield in stress conditions. Altogether, these data suggest that Asg1 might interfere with components of the stress signaling pathway by promoting stomatal closure and participating in stress adaptation.
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Affiliation(s)
- Giorgia Batelli
- CNR Institute of Plant Genetics (CNR-IGV), Via Universita’, 133 80055 Portici, Italy
| | - Immacolata Massarelli
- CNR Institute of Plant Genetics (CNR-IGV), Via Universita’, 133 80055 Portici, Italy
| | - Michael Van Oosten
- Department of Agricultural Engineering and Agronomy, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
| | - Roberta Nurcato
- CNR Institute of Plant Genetics (CNR-IGV), Via Universita’, 133 80055 Portici, Italy
| | - Candida Vannini
- Department of Environment, Health and Safety, University of Insubria, Via J. H. Dunant, 3, 21100 Varese, Italy
| | - Giampaolo Raimondi
- Department of Agricultural Engineering and Agronomy, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
| | - Antonella Leone
- Department of Pharmaceutical and Biomedical Sciences, University of Salerno, Via Ponte Don Melillo, 84084 Fisciano, Italy
| | - Jian-Kang Zhu
- Department of Horticulture and Landscape Architecture, Purdue University, 47907 West Lafayette, IN, USA
| | - Albino Maggio
- Department of Agricultural Engineering and Agronomy, University of Naples Federico II, Via Università 100, 80055 Portici, Italy
| | - Stefania Grillo
- CNR Institute of Plant Genetics (CNR-IGV), Via Universita’, 133 80055 Portici, Italy
- Corresponding author at: National Research Council, Institute of Plant Genetics (CNR-IGV), Via Universita’, 133 80055 Portici (NA), Italy. Tel.: +39 081 2539213/2539205; fax: +39 081 7753579., (S. Grillo)
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647
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Sánchez-Vallet A, López G, Ramos B, Delgado-Cerezo M, Riviere MP, Llorente F, Fernández PV, Miedes E, Estevez JM, Grant M, Molina A. Disruption of abscisic acid signaling constitutively activates Arabidopsis resistance to the necrotrophic fungus Plectosphaerella cucumerina. PLANT PHYSIOLOGY 2012; 160:2109-24. [PMID: 23037505 PMCID: PMC3510135 DOI: 10.1104/pp.112.200154] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 10/01/2012] [Indexed: 05/20/2023]
Abstract
Plant resistance to necrotrophic fungi is regulated by a complex set of signaling pathways that includes those mediated by the hormones salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and abscisic acid (ABA). The role of ABA in plant resistance remains controversial, as positive and negative regulatory functions have been described depending on the plant-pathogen interaction analyzed. Here, we show that ABA signaling negatively regulates Arabidopsis (Arabidopsis thaliana) resistance to the necrotrophic fungus Plectosphaerella cucumerina. Arabidopsis plants impaired in ABA biosynthesis, such as the aba1-6 mutant, or in ABA signaling, like the quadruple pyr/pyl mutant (pyr1pyl1pyl2pyl4), were more resistant to P. cucumerina than wild-type plants. In contrast, the hab1-1abi1-2abi2-2 mutant impaired in three phosphatases that negatively regulate ABA signaling displayed an enhanced susceptibility phenotype to this fungus. Comparative transcriptomic analyses of aba1-6 and wild-type plants revealed that the ABA pathway negatively regulates defense genes, many of which are controlled by the SA, JA, or ET pathway. In line with these data, we found that aba1-6 resistance to P. cucumerina was partially compromised when the SA, JA, or ET pathway was disrupted in this mutant. Additionally, in the aba1-6 plants, some genes encoding cell wall-related proteins were misregulated. Fourier transform infrared spectroscopy and biochemical analyses of cell walls from aba1-6 and wild-type plants revealed significant differences in their Fourier transform infrared spectratypes and uronic acid and cellulose contents. All these data suggest that ABA signaling has a complex function in Arabidopsis basal resistance, negatively regulating SA/JA/ET-mediated resistance to necrotrophic fungi.
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648
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Han SK, Sang Y, Rodrigues A, Wu MF, Rodriguez PL, Wagner D. The SWI2/SNF2 chromatin remodeling ATPase BRAHMA represses abscisic acid responses in the absence of the stress stimulus in Arabidopsis. THE PLANT CELL 2012; 24:4892-906. [PMID: 23209114 PMCID: PMC3556964 DOI: 10.1105/tpc.112.105114] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 10/30/2012] [Accepted: 11/11/2012] [Indexed: 05/17/2023]
Abstract
The survival of plants as sessile organisms depends on their ability to cope with environmental challenges. Of key importance in this regard is the phytohormone abscisic acid (ABA). ABA not only promotes seed dormancy but also triggers growth arrest in postgermination embryos that encounter water stress. This is accompanied by increased desiccation tolerance. Postgermination ABA responses in Arabidopsis thaliana are mediated in large part by the ABA-induced basic domain/leucine zipper transcription factor ABA INSENSITIVE5 (ABI5). Here, we show that loss of function of the SWI2/SNF2 chromatin remodeling ATPase BRAHMA (BRM) causes ABA hypersensitivity during postgermination growth arrest. ABI5 expression was derepressed in brm mutants in the absence of exogenous ABA and accumulated to high levels upon ABA sensing. This effect was likely direct; chromatin immunoprecipitation revealed BRM binding to the ABI5 locus. Moreover, loss of BRM activity led to destabilization of a nucleosome likely to repress ABI5 transcription. Finally, the abi5 null mutant was epistatic to BRM in postgermination growth arrest. In addition, vegetative growth defects typical of brm mutants in the absence of ABA treatment could be partially overcome by reduction of ABA responses, and brm mutants displayed increased drought tolerance. We propose a role for BRM in the balance between growth or stress responses.
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Affiliation(s)
- Soon-Ki Han
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Yi Sang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Americo Rodrigues
- Instituto de Biologia Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas–Universidad Politecnica de Valencia, ES-46022 Valencia, Spain
| | - BIOL425 F2010
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Miin-Feng Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Pedro L. Rodriguez
- Instituto de Biologia Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas–Universidad Politecnica de Valencia, ES-46022 Valencia, Spain
| | - Doris Wagner
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
- Address correspondence to
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649
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Akpinar BA, Avsar B, Lucas SJ, Budak H. Plant abiotic stress signaling. PLANT SIGNALING & BEHAVIOR 2012; 7:1450-5. [PMID: 22990453 PMCID: PMC3548870 DOI: 10.4161/psb.21894] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Stress signaling is central to plants which--as immobile organisms--have to endure environmental fluctuations that constantly interfere with vigorous growth. As a result, plant-specific, elaborate mechanisms have evolved to perceive and respond to stress conditions. Currently, these stress responses are plausibly being revealed to involve crosstalks with energy signaling pathways as any growth-limiting factor alters plant's energy status. Among these, autophagy, conventionally regarded as the mechanism whereby plants recycle and remobilize nutrients in bulk, has frequently been associated with stress responses. With the recent discoveries, however, autophagy has attained a novel role in stress signaling. In this review, major elements of abitoic stress signaling are summarized along with autophagy pathway, and in the light of recent discoveries, a putative, state-of-art role of autophagy is discussed.
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650
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Kocabay O, Emregul E, Aydın SS, Aras S. Detection of superoxide radicals in tomato plants exposed to salinity, drought, cold and heavy metal stress using CMC-G-SOD biosensor. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2012; 41:352-8. [DOI: 10.3109/10731199.2012.717944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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