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Tran AD, Cho K, Han O. Rice peroxygenase catalyzes lipoxygenase-dependent regiospecific epoxidation of lipid peroxides in the response to abiotic stressors. Bioorg Chem 2023; 131:106285. [PMID: 36450198 DOI: 10.1016/j.bioorg.2022.106285] [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: 08/10/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022]
Abstract
The peroxygenase pathway plays pivotal roles in plant responses to oxidative stress and other environmental stressors. Analysis of a network of co-expressed stress-regulated rice genes demonstrated that expression of OsPXG9 is negatively correlated with expression of genes involved in jasmonic acid biosynthesis. DNA sequence analysis and structure/function studies reveal that OsPXG9 is a caleosin-like peroxygenase with amphipathic α-helices that localizes to lipid droplets in rice cells. Enzymatic studies demonstrate that 12-epoxidation is slightly more favorable with 9(S)-hydroperoxyoctadecatrienoic acid than with 9(S)-hydroperoxyoctadecadienoic acid as substrate. The products of 12-epoxidation are labile, and the epoxide ring is hydrolytically cleaved into corresponding trihydroxy compounds. On the other hand, OsPXG9 catalyzed 15-epoxidation of 13(S)-hydroperoxyoctadecatrienoic acid generates a relatively stable epoxide product. Therefore, the regiospecific 12- or 15-epoxidation catalyzed by OsPXG9 strongly depends on activation of the 9- or 13- peroxygenase reaction pathways, with their respective preferred substrates. The relative abundance of products in the 9-PXG and 13-PXG pathways suggest that the 12-epoxidation involves intramolecular oxygen transfer while the 15-epoxidation can proceed via intramolecular or intermolecular oxygen transfer. Expression of OsPXG9 is up-regulated by abiotic stimuli such as drought and salt stress, but it is down-regulated by biotic stimuli such as flagellin 22 and salicylic acid. The results suggest that the primary function of OsPXG9 is to modulate the level of lipid peroxides to facilitate effective defense responses to abiotic and biotic stressors.
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Affiliation(s)
- Anh Duc Tran
- Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kyoungwon Cho
- Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Oksoo Han
- Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea.
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Ye C, Zheng S, Jiang D, Lu J, Huang Z, Liu Z, Zhou H, Zhuang C, Li J. Initiation and Execution of Programmed Cell Death and Regulation of Reactive Oxygen Species in Plants. Int J Mol Sci 2021; 22:ijms222312942. [PMID: 34884747 PMCID: PMC8657872 DOI: 10.3390/ijms222312942] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/19/2021] [Accepted: 11/24/2021] [Indexed: 12/21/2022] Open
Abstract
Programmed cell death (PCD) plays crucial roles in plant development and defence response. Reactive oxygen species (ROS) are produced during normal plant growth, and high ROS concentrations can change the antioxidant status of cells, leading to spontaneous cell death. In addition, ROS function as signalling molecules to improve plant stress tolerance, and they induce PCD under different conditions. This review describes the mechanisms underlying plant PCD, the key functions of mitochondria and chloroplasts in PCD, and the relationship between mitochondria and chloroplasts during PCD. Additionally, the review discusses the factors that regulate PCD. Most importantly, in this review, we summarise the sites of production of ROS and discuss the roles of ROS that not only trigger multiple signalling pathways leading to PCD but also participate in the execution of PCD, highlighting the importance of ROS in PCD.
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Affiliation(s)
- Chanjuan Ye
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Shaoyan Zheng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Dagang Jiang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jingqin Lu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Zongna Huang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Zhenlan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Hai Zhou
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Chuxiong Zhuang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jing Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, South China Agricultural University, Guangzhou 510642, China; (C.Y.); (S.Z.); (D.J.); (J.L.); (Z.H.); (Z.L.); (H.Z.); (C.Z.)
- Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou 510642, China
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
- Correspondence:
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Gomez RE, Lupette J, Chambaud C, Castets J, Ducloy A, Cacas JL, Masclaux-Daubresse C, Bernard A. How Lipids Contribute to Autophagosome Biogenesis, a Critical Process in Plant Responses to Stresses. Cells 2021; 10:1272. [PMID: 34063958 PMCID: PMC8224036 DOI: 10.3390/cells10061272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/03/2021] [Accepted: 05/17/2021] [Indexed: 01/18/2023] Open
Abstract
Throughout their life cycle, plants face a tremendous number of environmental and developmental stresses. To respond to these different constraints, they have developed a set of refined intracellular systems including autophagy. This pathway, highly conserved among eukaryotes, is induced by a wide range of biotic and abiotic stresses upon which it mediates the degradation and recycling of cytoplasmic material. Central to autophagy is the formation of highly specialized double membrane vesicles called autophagosomes which select, engulf, and traffic cargo to the lytic vacuole for degradation. The biogenesis of these structures requires a series of membrane remodeling events during which both the quantity and quality of lipids are critical to sustain autophagy activity. This review highlights our knowledge, and raises current questions, regarding the mechanism of autophagy, and its induction and regulation upon environmental stresses with a particular focus on the fundamental contribution of lipids. How autophagy regulates metabolism and the recycling of resources, including lipids, to promote plant acclimation and resistance to stresses is further discussed.
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Affiliation(s)
- Rodrigo Enrique Gomez
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Josselin Lupette
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Clément Chambaud
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Julie Castets
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
| | - Amélie Ducloy
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Jean-Luc Cacas
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Céline Masclaux-Daubresse
- Institut Jean-Pierre Bourgin, UMR 1318 AgroParisTech-INRAE, Université Paris-Saclay, 78000 Versailles, France; (A.D.); (J.-L.C.); (C.M.-D.)
| | - Amélie Bernard
- Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, F-33140 Villenave d’Ornon, France; (R.E.G.); (J.L.); (C.C.); (J.C.)
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Adamakis IDS, Eleftheriou EP. Structural Evidence of Programmed Cell Death Induction by Tungsten in Root Tip Cells of Pisum sativum. PLANTS (BASEL, SWITZERLAND) 2019; 8:E62. [PMID: 30862127 PMCID: PMC6473820 DOI: 10.3390/plants8030062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/27/2019] [Accepted: 03/06/2019] [Indexed: 01/22/2023]
Abstract
Previous studies have shown that excess tungsten (W), a rare heavy metal, is toxic to plant cells and may induce a kind of programmed cell death (PCD). In the present study we used transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) to investigate the subcellular malformations caused by W, supplied as 200 mg/L sodium tungstate (Na₂WO₄) for 12 or 24 h, in root tip cells of Pisum sativum (pea), The objective was to provide additional evidence in support of the notion of PCD induction and the presumed involvement of reactive oxygen species (ROS). It is shown ultrastructurally that W inhibited seedling growth, deranged root tip morphology, induced the collapse and deformation of vacuoles, degraded Golgi bodies, increased the incidence of multivesicular and multilamellar bodies, and caused the detachment of the plasma membrane from the cell walls. Plastids and mitochondria were also affected. By TEM, the endoplasmic reticulum appeared in aggregations of straight, curved or concentric cisternae, frequently enclosing cytoplasmic organelles, while by CLSM it appeared in bright ring-like aggregations and was severely disrupted in mitotic cells. However, no evidence of ROS increase was obtained. Overall, these findings support the view of a W-induced vacuolar destructive PCD without ROS enhancement.
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Affiliation(s)
| | - Eleftherios P Eleftheriou
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece.
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Identification of a dioxin-responsive oxylipin signature in roots of date palm: involvement of a 9-hydroperoxide fatty acid reductase, caleosin/peroxygenase PdPXG2. Sci Rep 2018; 8:13181. [PMID: 30181584 PMCID: PMC6123484 DOI: 10.1038/s41598-018-31342-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 07/17/2018] [Indexed: 01/02/2023] Open
Abstract
Dioxins are highly hazardous pollutants that have well characterized impacts on both animal and human health. However, the biological effects of dioxins on plants have yet to be described in detail. Here we describe a dioxin-inducible caleosin/peroxygenase isoform, PdPXG2, that is mainly expressed in the apical zone of date palm roots and specifically reduces 9-hydroperoxide fatty acids. A characteristic spectrum of 18 dioxin-responsive oxylipin (DROXYL) congeners was also detected in date palm roots after exposure to dioxin. Of particular interest, six oxylipins, mostly hydroxy fatty acids, were exclusively formed in response to TCDD. The DROXYL signature was evaluated in planta and validated in vitro using a specific inhibitor of PdPXG2 in a root-protoplast system. Comparative analysis of root suberin showed that levels of certain monomers, especially the mono-epoxides and tri-hydroxides of C16:3 and C18:3, were significantly increased after exposure to TCDD. Specific inhibition of PdPXG2 activity revealed a positive linear relationship between deposition of suberin in roots and their permeability to TCDD. The results highlight the involvement of this peroxygenase in the plant response to dioxin and suggest the use of dioxin-responsive oxylipin signatures as biomarkers for plant exposure to this important class of xenobiotic contaminants.
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Fu YB, Ahmed Z, Yang H, Horbach C. TUNEL Assay and DAPI Staining Revealed Few Alterations of Cellular Morphology in Naturally and Artificially Aged Seeds of Cultivated Flax. PLANTS 2018; 7:plants7020034. [PMID: 29652802 PMCID: PMC6027480 DOI: 10.3390/plants7020034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 11/16/2022]
Abstract
In a search for useful seed aging signals as biomarkers for seed viability prediction, we conducted an experiment using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining to analyze morphological and molecular changes in naturally aged (NA) and artificially aged (AA) flax (Linum usitatissimum L.) seeds. A total of 2546 sections were performed from 112 seeds of 12 NA and AA seed samples with variable germination rates. Analyzing 1384 micrographs generated from TUNEL assay and DAPI staining revealed few alterations of the cellular morphology of the NA and AA seeds. Also, the revealed DNA degradations in the aged flax seeds appeared to be associated with seed samples of low germination rates. These results suggest that oily flax seed aging may alter the cellular morphology differently than starchy wheat seed aging. The results also imply that the TUNEL assay and DAPI staining may not yield informative assessments on cellular alterations and DNA degradation after the aging of oily seeds.
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Affiliation(s)
- Yong-Bi Fu
- Plant Gene Resources of Canada, Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
| | - Zaheer Ahmed
- Plant Gene Resources of Canada, Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
| | - Hui Yang
- Plant Gene Resources of Canada, Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
| | - Carolee Horbach
- Plant Gene Resources of Canada, Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada.
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7
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De Bigault Du Granrut A, Cacas JL. How Very-Long-Chain Fatty Acids Could Signal Stressful Conditions in Plants? FRONTIERS IN PLANT SCIENCE 2016; 7:1490. [PMID: 27803703 PMCID: PMC5067520 DOI: 10.3389/fpls.2016.01490] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 09/20/2016] [Indexed: 05/18/2023]
Abstract
Although encountered in minor amounts in plant cells, very-long-chain fatty acids exert crucial functions in developmental processes. When their levels are perturbed by means of genetic approaches, marked phenotypic consequences that range from severe growth retardation to embryo lethality was indeed reported. More recently, a growing body of findings has also accumulated that points to a potential role for these lipids as signals in governing both biotic and abiotic stress outcomes. In the present work, we discuss the latter theory and explore the ins and outs of very-long-chain fatty acid-based signaling in response to stress, with an attempt to reconcile two supposedly antagonistic parameters: the insoluble nature of fatty acids and their signaling function. To explain this apparent dilemma, we provide new interpretations of pre-existing data based on the fact that sphingolipids are the main reservoir of very-long-chain fatty acids in leaves. Thus, three non-exclusive, molecular scenarii that involve these lipids as membrane-embedded and free entities are proposed.
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Affiliation(s)
- Antoine De Bigault Du Granrut
- UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Centre Institut National de la Recherche Agronomique de Versailles-Grignon, Institut Jean-Pierre BourginVersailles, France
| | - Jean-Luc Cacas
- UMR1318 Institut National de la Recherche Agronomique-AgroParisTech, Centre Institut National de la Recherche Agronomique de Versailles-Grignon, Institut Jean-Pierre BourginVersailles, France
- Département Sciences de la Vie et Santé, AgroParisTech, UFR de Physiologie VégétaleParis, France
- *Correspondence: Jean-Luc Cacas ;
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Fagundes D, Bohn B, Cabreira C, Leipelt F, Dias N, Bodanese-Zanettini MH, Cagliari A. Caspases in plants: metacaspase gene family in plant stress responses. Funct Integr Genomics 2015; 15:639-49. [PMID: 26277721 DOI: 10.1007/s10142-015-0459-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 12/26/2022]
Abstract
Programmed cell death (PCD) is an ordered cell suicide that removes unwanted or damaged cells, playing a role in defense to environmental stresses and pathogen invasion. PCD is component of the life cycle of plants, occurring throughout development from embryogenesis to the death. Metacaspases are cysteine proteases present in plants, fungi, and protists. In certain plant-pathogen interactions, the PCD seems to be mediated by metacaspases. We adopted a comparative genomic approach to identify genes coding for the metacaspases in Viridiplantae. We observed that the metacaspase was divided into types I and II, based on their protein structure. The type I has a metacaspase domain at the C-terminus region, presenting or not a zinc finger motif in the N-terminus region and a prodomain rich in proline. Metacaspase type II does not feature the prodomain and the zinc finger, but has a linker between caspase-like catalytic domains of 20 kDa (p20) and 10 kDa (p10). A high conservation was observed in the zinc finger domain (type I proteins) and in p20 and p10 subunits (types I and II proteins). The phylogeny showed that the metacaspases are divided into three principal groups: type I with and without zinc finger domain and type II metacaspases. The algae and moss are presented as outgroup, suggesting that these three classes of metacaspases originated in the early stages of Viridiplantae, being the absence of the zinc finger domain the ancient condition. The study of metacaspase can clarify their assignment and involvement in plant PCD mechanisms.
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Affiliation(s)
- David Fagundes
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Bianca Bohn
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Caroline Cabreira
- Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
| | - Fábio Leipelt
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Nathalia Dias
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | | | - Alexandro Cagliari
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
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The membrane-associated transcription factor NAC089 controls ER-stress-induced programmed cell death in plants. PLoS Genet 2014; 10:e1004243. [PMID: 24675811 PMCID: PMC3967986 DOI: 10.1371/journal.pgen.1004243] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 02/02/2014] [Indexed: 12/20/2022] Open
Abstract
The unfolded protein response (UPR) is activated to sustain cell survival by reducing misfolded protein accumulation in the endoplasmic reticulum (ER). The UPR also promotes programmed cell death (PCD) when the ER stress is severe; however, the underlying molecular mechanisms are less understood, especially in plants. Previously, two membrane-associated transcriptions factors (MTFs), bZIP28 and bZIP60, were identified as the key regulators for cell survival in the plant ER stress response. Here, we report the identification of another MTF, NAC089, as an important PCD regulator in Arabidopsis (Arabidopsis thaliana) plants. NAC089 relocates from the ER membrane to the nucleus under ER stress conditions. Inducible expression of a truncated form of NAC089, in which the transmembrane domain is deleted, induces PCD with increased caspase 3/7-like activity and DNA fragmentation. Knock-down NAC089 in Arabidopsis confers ER stress tolerance and impairs ER-stress-induced caspase-like activity. Transcriptional regulation analysis and ChIP-qPCR reveal that NAC089 plays important role in regulating downstream genes involved in PCD, such as NAC094, MC5 and BAG6. Furthermore, NAC089 is up-regulated by ER stress, which is directly controlled by bZIP28 and bZIP60. These results show that nuclear relocation of NAC089 promotes ER-stress-induced PCD, and both pro-survival and pro-death signals are elicited by bZIP28 and bZIP60 during plant ER stress response. Protein folding is fundamentally important for development and responses to environmental stresses in eukaryotes. When excess misfolded proteins are accumulated in the endoplasmic reticulum (ER), the unfolded protein response (UPR) is triggered to promote cell survival through optimizing protein folding, and also promote programmed cell death (PCD) when the stress is severe. However, the link from ER-stress-sensing to PCD is largely unknown. Here, we report the identification of one membrane-associated transcription factor NAC089 as an important regulator of ER stress-induced PCD in plants. We have established a previously unrecognized molecular connection between ER stress sensors and PCD regulators. We have shown that organelle-to-organelle translocation of a transcription factor is important for its function in transcriptional regulation. Our results have provided novel insights into the molecular mechanisms of PCD in plants, especially under ER stress conditions.
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Genome variations associated with viral susceptibility and calcification in Emiliania huxleyi. PLoS One 2013; 8:e80684. [PMID: 24260453 PMCID: PMC3834299 DOI: 10.1371/journal.pone.0080684] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 10/10/2013] [Indexed: 11/19/2022] Open
Abstract
Emiliania huxleyi, a key player in the global carbon cycle is one of the best studied coccolithophores with respect to biogeochemical cycles, climatology, and host-virus interactions. Strains of E. huxleyi show phenotypic plasticity regarding growth behaviour, light-response, calcification, acidification, and virus susceptibility. This phenomenon is likely a consequence of genomic differences, or transcriptomic responses, to environmental conditions or threats such as viral infections. We used an E. huxleyi genome microarray based on the sequenced strain CCMP1516 (reference strain) to perform comparative genomic hybridizations (CGH) of 16 E. huxleyi strains of different geographic origin. We investigated the genomic diversity and plasticity and focused on the identification of genes related to virus susceptibility and coccolith production (calcification). Among the tested 31940 gene models a core genome of 14628 genes was identified by hybridization among 16 E. huxleyi strains. 224 probes were characterized as specific for the reference strain CCMP1516. Compared to the sequenced E. huxleyi strain CCMP1516 variation in gene content of up to 30 percent among strains was observed. Comparison of core and non-core transcripts sets in terms of annotated functions reveals a broad, almost equal functional coverage over all KOG-categories of both transcript sets within the whole annotated genome. Within the variable (non-core) genome we identified genes associated with virus susceptibility and calcification. Genes associated with virus susceptibility include a Bax inhibitor-1 protein, three LRR receptor-like protein kinases, and mitogen-activated protein kinase. Our list of transcripts associated with coccolith production will stimulate further research, e.g. by genetic manipulation. In particular, the V-type proton ATPase 16 kDa proteolipid subunit is proposed to be a plausible target gene for further calcification studies.
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11
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Adamakis IDS, Panteris E, Eleftheriou EP. Tungsten Toxicity in Plants. PLANTS (BASEL, SWITZERLAND) 2012; 1:82-99. [PMID: 27137642 PMCID: PMC4844263 DOI: 10.3390/plants1020082] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/09/2012] [Accepted: 11/13/2012] [Indexed: 11/17/2022]
Abstract
Tungsten (W) is a rare heavy metal, widely used in a range of industrial, military and household applications due to its unique physical properties. These activities inevitably have accounted for local W accumulation at high concentrations, raising concerns about its effects for living organisms. In plants, W has primarily been used as an inhibitor of the molybdoenzymes, since it antagonizes molybdenum (Mo) for the Mo-cofactor (MoCo) of these enzymes. However, recent advances indicate that, beyond Mo-enzyme inhibition, W has toxic attributes similar with those of other heavy metals. These include hindering of seedling growth, reduction of root and shoot biomass, ultrastructural malformations of cell components, aberration of cell cycle, disruption of the cytoskeleton and deregulation of gene expression related with programmed cell death (PCD). In this article, the recent available information on W toxicity in plants and plant cells is reviewed, and the knowledge gaps and the most pertinent research directions are outlined.
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Affiliation(s)
| | - Emmanuel Panteris
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece.
| | - Eleftherios P Eleftheriou
- Department of Botany, School of Biology, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece.
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Radchuk V, Kumlehn J, Rutten T, Sreenivasulu N, Radchuk R, Rolletschek H, Herrfurth C, Feussner I, Borisjuk L. Fertility in barley flowers depends on Jekyll functions in male and female sporophytes. THE NEW PHYTOLOGIST 2012; 194:142-157. [PMID: 22269089 DOI: 10.1111/j.1469-8137.2011.04032.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
• Owing to its evolutional plasticity and adaptability, barley (Hordeum vulgare) is one of the most widespread crops in the world. Despite this evolutionary success, sexual reproduction of small grain cereals is poorly investigated, making discovery of novel genes and functions a challenging priority. Barley gene Jekyll appears to be a key player in grain development; however, its role in flowers has remained unknown. • Here, we studied RNAi lines of barley, where Jekyll expression was repressed to different extents. The impact of Jekyll on flower development was evaluated based on differential gene expression analysis applied to anthers and gynoecia of wildtype and transgenic plants, as well as using isotope labeling experiments, hormone analysis, immunogold- and TUNEL-assays and in situ hybridization. • Jekyll is expressed in nurse tissues mediating gametophyte-sporophyte interaction in anthers and gynoecia, where JEKYLL was found within the intracellular membranes. The repression of Jekyll impaired pollen maturation, anther dehiscence and induced a significant loss of fertility. The presence of JEKYLL on the pollen surface also hints at possible involvement in the fertilization process. • We conclude that the role of Jekyll in cereal sexual reproduction is clearly much broader than has been hitherto realized.
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Affiliation(s)
- Volodymyr Radchuk
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Jochen Kumlehn
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Twan Rutten
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Nese Sreenivasulu
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Ruslana Radchuk
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Hardy Rolletschek
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Cornelia Herrfurth
- Georg August University, Albrecht von Haller Institute, Department of Plant Biochemistry, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Ivo Feussner
- Georg August University, Albrecht von Haller Institute, Department of Plant Biochemistry, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Ljudmilla Borisjuk
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
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