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De Caroli M, Furini A, DalCorso G, Rojas M, Di Sansebastiano GP. Endomembrane Reorganization Induced by Heavy Metals. PLANTS (BASEL, SWITZERLAND) 2020; 9:E482. [PMID: 32283794 PMCID: PMC7238196 DOI: 10.3390/plants9040482] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/04/2020] [Accepted: 04/07/2020] [Indexed: 12/18/2022]
Abstract
Plant cells maintain plasmatic concentrations of essential heavy metal ions, such as iron, zinc, and copper, within the optimal functional range. To do so, several molecular mechanisms have to be committed to maintain concentrations of non-essential heavy metals and metalloids, such as cadmium, mercury and arsenic below their toxicity threshold levels. Compartmentalization is central to heavy metals homeostasis and secretory compartments, finely interconnected by traffic mechanisms, are determinant. Endomembrane reorganization can have unexpected effects on heavy metals tolerance altering in a complex way membrane permeability, storage, and detoxification ability beyond gene's expression regulation. The full understanding of endomembrane role is propaedeutic to the comprehension of translocation and hyper-accumulation mechanisms and their applicative employment. It is evident that further studies on dynamic localization of these and many more proteins may significantly contribute to the understanding of heavy metals tolerance mechanisms. The aim of this review is to provide an overview about the endomembrane alterations involved in heavy metals compartmentalization and tolerance in plants.
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Affiliation(s)
- Monica De Caroli
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, 73100 Lecce, Italy; (M.D.C.); (M.R.)
| | - Antonella Furini
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (A.F.); (G.D.)
| | - Giovanni DalCorso
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (A.F.); (G.D.)
| | - Makarena Rojas
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, 73100 Lecce, Italy; (M.D.C.); (M.R.)
| | - Gian-Pietro Di Sansebastiano
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, 73100 Lecce, Italy; (M.D.C.); (M.R.)
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Liao CY, Bassham DC. Combating stress: the interplay between hormone signaling and autophagy in plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1723-1733. [PMID: 31725881 PMCID: PMC7067298 DOI: 10.1093/jxb/erz515] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/13/2019] [Indexed: 05/18/2023]
Abstract
Autophagy is a conserved recycling process in which cellular components are delivered to and degraded in the vacuole/lysosome for reuse. In plants, it assists in responding to dynamic environmental conditions and maintaining metabolite homeostasis under normal or stress conditions. Under stress, autophagy is activated to remove damaged components and to recycle nutrients for survival, and the energy sensor kinases target of rapamycin (TOR) and SNF-related kinase 1 (SnRK1) are key to this activation. Here, we discuss accumulating evidence that hormone signaling plays critical roles in regulating autophagy and plant stress responses, although the molecular mechanisms by which this occurs are often not clear. Several hormones have been shown to regulate TOR activity during stress, in turn controlling autophagy. Hormone signaling can also regulate autophagy gene expression, while, reciprocally, autophagy can regulate hormone synthesis and signaling pathways. We highlight how the interplay between major energy sensors, plant hormones, and autophagy under abiotic and biotic stress conditions can assist in plant stress tolerance.
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Affiliation(s)
- Ching-Yi Liao
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Diane C Bassham
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
- Correspondence:
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Seok HY, Nguyen LV, Nguyen DV, Lee SY, Moon YH. Investigation of a Novel Salt Stress-Responsive Pathway Mediated by Arabidopsis DEAD-Box RNA Helicase Gene AtRH17 Using RNA-Seq Analysis. Int J Mol Sci 2020; 21:ijms21051595. [PMID: 32111079 PMCID: PMC7084250 DOI: 10.3390/ijms21051595] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 02/23/2020] [Accepted: 02/25/2020] [Indexed: 12/12/2022] Open
Abstract
Previously, we reported that overexpression of AtRH17, an Arabidopsis DEAD-box RNA helicase gene, confers salt stress-tolerance via a pathway other than the well-known salt stress-responsive pathways. To decipher the salt stress-responsive pathway in AtRH17-overexpressing transgenic plants (OXs), we performed RNA-Sequencing and identified 397 differentially expressed genes between wild type (WT) and AtRH17 OXs. Among them, 286 genes were upregulated and 111 genes were downregulated in AtRH17 OXs relative to WT. Gene ontology annotation enrichment and KEGG pathway analysis showed that the 397 upregulated and downregulated genes are involved in various biological functions including secretion, signaling, detoxification, metabolic pathways, catabolic pathways, and biosynthesis of secondary metabolites as well as in stress responses. Genevestigator analysis of the upregulated genes showed that nine genes, namely, LEA4-5, GSTF6, DIN2/BGLU30, TSPO, GSTF7, LEA18, HAI1, ABR, and LTI30, were upregulated in Arabidopsis under salt, osmotic, and drought stress conditions. In particular, the expression levels of LEA4-5, TSPO, and ABR were higher in AtRH17 OXs than in WT under salt stress condition. Taken together, our results suggest that a high AtRH17 expression confers salt stress-tolerance through a novel salt stress-responsive pathway involving nine genes, other than the well-known ABA-dependent and ABA-independent pathways.
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Affiliation(s)
- Hye-Yeon Seok
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea;
| | - Linh Vu Nguyen
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea (D.V.N.)
| | - Doai Van Nguyen
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea (D.V.N.)
| | - Sun-Young Lee
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA;
| | - Yong-Hwan Moon
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea;
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea (D.V.N.)
- Department of Molecular Biology, Pusan National University, Busan 46241, Korea
- Correspondence: ; Tel.: +82-51-510-2592
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Jurkiewicz P, Senicourt L, Ayeb H, Lequin O, Lacapere JJ, Batoko H. A Plant-Specific N-terminal Extension Reveals Evolutionary Functional Divergence within Translocator Proteins. iScience 2020; 23:100889. [PMID: 32087576 PMCID: PMC7033594 DOI: 10.1016/j.isci.2020.100889] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 11/30/2019] [Accepted: 02/03/2020] [Indexed: 12/13/2022] Open
Abstract
Conserved translocator proteins (TSPOs) mediate cell stress responses possibly in a cell-type-specific manner. This work reports on the molecular function of plant TSPO and their possible evolutionary divergence. Arabidopsis thaliana TSPO (AtTSPO) is stress induced and has a conserved polybasic, plant-specific N-terminal extension. AtTSPO reduces water loss by depleting aquaporin PIP2;7 in the plasma membrane. Herein, AtTSPO was found to bind phosphoinositides in vitro, but only full-length AtTSPO or chimeric mouse TSPO with an AtTSPO N-terminus bound PI(4,5)P2in vitro and modified PIP2;7 levels in vivo. Expression of AtTSPO but not its N-terminally truncated variant enhanced phospholipase C activity and depleted PI(4,5)P2 from the plasma membrane and its enrichment in Golgi membranes. Deletion or point mutations within the AtTSPO N-terminus affected PI(4,5)P2 binding and almost prevented AtTSPO-PIP2;7 interaction in vivo. The findings imply functional divergence of plant TSPOs from bacterial and animal counterparts via evolutionary acquisition of the phospholipid-interacting N-terminus.
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Affiliation(s)
- Pawel Jurkiewicz
- Louvain Institute of Biomolecular Science and Technology (LIBST), University of Louvain (UCLouvain), Croix du Sud 4-5, L7.07.14, 1348 Louvain-la-Neuve, Belgium
| | - Lucile Senicourt
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
| | - Haitham Ayeb
- Louvain Institute of Biomolecular Science and Technology (LIBST), University of Louvain (UCLouvain), Croix du Sud 4-5, L7.07.14, 1348 Louvain-la-Neuve, Belgium
| | - Olivier Lequin
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
| | - Jean-Jacques Lacapere
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
| | - Henri Batoko
- Louvain Institute of Biomolecular Science and Technology (LIBST), University of Louvain (UCLouvain), Croix du Sud 4-5, L7.07.14, 1348 Louvain-la-Neuve, Belgium.
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Cochetel N, Ghan R, Toups HS, Degu A, Tillett RL, Schlauch KA, Cramer GR. Drought tolerance of the grapevine, Vitis champinii cv. Ramsey, is associated with higher photosynthesis and greater transcriptomic responsiveness of abscisic acid biosynthesis and signaling. BMC PLANT BIOLOGY 2020; 20:55. [PMID: 32019503 PMCID: PMC7001288 DOI: 10.1186/s12870-019-2012-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/30/2019] [Indexed: 05/27/2023]
Abstract
BACKGROUND Grapevine is an economically important crop for which yield and berry quality is strongly affected by climate change. Large variations in drought tolerance exist across Vitis species. Some of these species are used as rootstock to enhance abiotic and biotic stress tolerance. In this study, we investigated the physiological and transcriptomic responses to water deficit of four different genotypes that differ in drought tolerance: Ramsey (Vitis champinii), Riparia Gloire (Vitis riparia), Cabernet Sauvignon (Vitis vinifera), and SC2 (Vitis vinifera x Vitis girdiana). RESULTS Ramsey was particularly more drought tolerant than the other three genotypes. Ramsey maintained a higher stomatal conductance and photosynthesis at equivalent levels of moderate water deficit. We identified specific and common transcriptomic responses shared among the four different Vitis species using RNA sequencing analysis. A weighted gene co-expression analysis identified a water deficit core gene set with the ABA biosynthesis and signaling genes, NCED3, RD29B and ABI1 as potential hub genes. The transcript abundance of many abscisic acid metabolism and signaling genes was strongly increased by water deficit along with genes associated with lipid metabolism, galactinol synthases and MIP family proteins. This response occurred at smaller water deficits in Ramsey and with higher transcript abundance than the other genotypes. A number of aquaporin genes displayed differential and unique responses to water deficit in Ramsey leaves. Genes involved in cysteine biosynthesis and metabolism were constitutively higher in the roots of Ramsey; thus, linking the gene expression of a known factor that influences ABA biosynthesis to this genotype's increased NCED3 transcript abundance. CONCLUSION The drought tolerant Ramsey maintained higher photosynthesis at equivalent water deficit than the three other grapevine genotypes. Ramsey was more responsive to water deficit; its transcriptome responded at smaller water deficits, whereas the other genotypes did not respond until more severe water deficits were reached. There was a common core gene network responding to water deficit for all genotypes that included ABA metabolism and signaling. The gene clusters and sub-networks identified in this work represent interesting gene lists to explore and to better understand drought tolerance molecular mechanisms.
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Affiliation(s)
- Noé Cochetel
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
| | - Ryan Ghan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
| | - Haley S. Toups
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
| | - Asfaw Degu
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
- Present address: College of Agriculture and Environmental Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Richard L. Tillett
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
| | - Karen A. Schlauch
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
| | - Grant R. Cramer
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557 USA
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Coordination and Crosstalk between Autophagosome and Multivesicular Body Pathways in Plant Stress Responses. Cells 2020; 9:cells9010119. [PMID: 31947769 PMCID: PMC7017292 DOI: 10.3390/cells9010119] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 12/14/2022] Open
Abstract
In eukaryotic cells, autophagosomes and multivesicular bodies (MVBs) are two closely related partners in the lysosomal/vacuolar protein degradation system. Autophagosomes are double membrane-bound organelles that transport cytoplasmic components, including proteins and organelles for autophagic degradation in the lysosomes/vacuoles. MVBs are single-membrane organelles in the endocytic pathway that contain intraluminal vesicles whose content is either degraded in the lysosomes/vacuoles or recycled to the cell surface. In plants, both autophagosome and MVB pathways play important roles in plant responses to biotic and abiotic stresses. More recent studies have revealed that autophagosomes and MVBs also act together in plant stress responses in a variety of processes, including deployment of defense-related molecules, regulation of cell death, trafficking and degradation of membrane and soluble constituents, and modulation of plant hormone metabolism and signaling. In this review, we discuss these recent findings on the coordination and crosstalk between autophagosome and MVB pathways that contribute to the complex network of plant stress responses.
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Chandra P, Enespa, Singh R. Soil Salinity and Its Alleviation Using Plant Growth–Promoting Fungi. Fungal Biol 2020. [DOI: 10.1007/978-3-030-48474-3_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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58
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Stephani M, Dagdas Y. Plant Selective Autophagy—Still an Uncharted Territory With a Lot of Hidden Gems. J Mol Biol 2020; 432:63-79. [DOI: 10.1016/j.jmb.2019.06.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/22/2019] [Accepted: 06/24/2019] [Indexed: 11/28/2022]
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Rodriguez-Furlan C, Minina EA, Hicks GR. Remove, Recycle, Degrade: Regulating Plasma Membrane Protein Accumulation. THE PLANT CELL 2019; 31:2833-2854. [PMID: 31628169 PMCID: PMC6925004 DOI: 10.1105/tpc.19.00433] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/23/2019] [Accepted: 10/17/2019] [Indexed: 05/21/2023]
Abstract
Interactions between plant cells and the environment rely on modulation of protein receptors, transporters, channels, and lipids at the plasma membrane (PM) to facilitate intercellular communication, nutrient uptake, environmental sensing, and directional growth. These functions are fine-tuned by cellular pathways maintaining or reducing particular proteins at the PM. Proteins are endocytosed, and their fate is decided between recycling and degradation to modulate localization, abundance, and activity. Selective autophagy is another pathway regulating PM protein accumulation in response to specific conditions or developmental signals. The mechanisms regulating recycling, degradation, and autophagy have been studied extensively, yet we are just now addressing their regulation and coordination. Here, we (1) provide context concerning regulation of protein accumulation, recycling, or degradation by overviewing endomembrane trafficking; (2) discuss pathways regulating recycling and degradation in terms of cellular roles and cargoes; (3) review plant selective autophagy and its physiological significance; (4) focus on two decision-making mechanisms: regulation of recycling versus degradation of PM proteins and coordination between autophagy and vacuolar degradation; and (5) identify future challenges.
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Affiliation(s)
- Cecilia Rodriguez-Furlan
- Department of Botany and Plant Sciences and Institute of Integrative Genome Biology, University of California, Riverside, California 92506
| | - Elena A Minina
- Uppsala Bio Center, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Glenn R Hicks
- Department of Botany and Plant Sciences and Institute of Integrative Genome Biology, University of California, Riverside, California 92506
- Uppsala Bio Center, Swedish University of Agricultural Sciences, Uppsala SE-75007, Sweden
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Chen Q, Shinozaki D, Luo J, Pottier M, Havé M, Marmagne A, Reisdorf-Cren M, Chardon F, Thomine S, Yoshimoto K, Masclaux-Daubresse C. Autophagy and Nutrients Management in Plants. Cells 2019; 8:cells8111426. [PMID: 31726766 PMCID: PMC6912637 DOI: 10.3390/cells8111426] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 02/07/2023] Open
Abstract
Nutrient recycling and mobilization from organ to organ all along the plant lifespan is essential for plant survival under changing environments. Nutrient remobilization to the seeds is also essential for good seed production. In this review, we summarize the recent advances made to understand how plants manage nutrient remobilization from senescing organs to sink tissues and what is the contribution of autophagy in this process. Plant engineering manipulating autophagy for better yield and plant tolerance to stresses will be presented.
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Affiliation(s)
- Qinwu Chen
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Daiki Shinozaki
- Department of Life Science, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan; (D.S.); (K.Y.)
- Life Science Program, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Jie Luo
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Mathieu Pottier
- Institut de Biologie Intégrative de la Cellule, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France; (M.P.); (S.T.)
| | - Marien Havé
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Anne Marmagne
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Michèle Reisdorf-Cren
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Fabien Chardon
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
| | - Sébastien Thomine
- Institut de Biologie Intégrative de la Cellule, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France; (M.P.); (S.T.)
| | - Kohki Yoshimoto
- Department of Life Science, School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan; (D.S.); (K.Y.)
- Life Science Program, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - Céline Masclaux-Daubresse
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France; (Q.C.); (J.L.); (M.H.); (A.M.); (M.R.-C.); (F.C.)
- Correspondence: ; Tel.: +33-13083-3088
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The viral F-box protein P0 induces an ER-derived autophagy degradation pathway for the clearance of membrane-bound AGO1. Proc Natl Acad Sci U S A 2019; 116:22872-22883. [PMID: 31628252 PMCID: PMC6842623 DOI: 10.1073/pnas.1912222116] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The viral suppressor of RNA silencing P0 is known to target plant antiviral ARGONAUTE (AGO) proteins for degradation via an autophagy-related process. Here we utilized P0 to gain insight into the cellular degradation dynamics of AGO1, the major plant effector of RNA silencing. We revealed that P0 targets endoplasmic reticulum (ER)-associated AGO1 by inducing the formation of ER-related bodies that are delivered to the vacuole with both P0 and AGO1 as cargos. This process involves ATG8-interacting proteins 1 and 2 (ATI1 and ATI2) that interact with AGO1 and negatively regulate its transgene-silencing activity. Together, our results reveal a layer of ER-bound AGO1 posttranslational regulation that is manipulated by P0 to subvert plant antiviral defense. RNA silencing is a major antiviral defense mechanism in plants and invertebrates. Plant ARGONAUTE1 (AGO1) is pivotal in RNA silencing, and hence is a major target for counteracting viral suppressors of RNA-silencing proteins (VSRs). P0 from Turnip yellows virus (TuYV) is a VSR that was previously shown to trigger AGO1 degradation via an autophagy-like process. However, the identity of host proteins involved and the cellular site at which AGO1 and P0 interact were unknown. Here we report that P0 and AGO1 associate on the endoplasmic reticulum (ER), resulting in their loading into ER-associated vesicles that are mobilized to the vacuole in an ATG5- and ATG7-dependent manner. We further identified ATG8-Interacting proteins 1 and 2 (ATI1 and ATI2) as proteins that associate with P0 and interact with AGO1 on the ER up to the vacuole. Notably, ATI1 and ATI2 belong to an endogenous degradation pathway of ER-associated AGO1 that is significantly induced following P0 expression. Accordingly, ATI1 and ATI2 deficiency causes a significant increase in posttranscriptional gene silencing (PTGS) activity. Collectively, we identify ATI1 and ATI2 as components of an ER-associated AGO1 turnover and proper PTGS maintenance and further show how the VSR P0 manipulates this pathway.
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Increased autophagy in EphrinB2-deficient osteocytes is associated with elevated secondary mineralization and brittle bone. Nat Commun 2019; 10:3436. [PMID: 31366886 PMCID: PMC6668467 DOI: 10.1038/s41467-019-11373-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/10/2019] [Indexed: 12/30/2022] Open
Abstract
Mineralized bone forms when collagen-containing osteoid accrues mineral crystals. This is initiated rapidly (primary mineralization), and continues slowly (secondary mineralization) until bone is remodeled. The interconnected osteocyte network within the bone matrix differentiates from bone-forming osteoblasts; although osteoblast differentiation requires EphrinB2, osteocytes retain its expression. Here we report brittle bones in mice with osteocyte-targeted EphrinB2 deletion. This is not caused by low bone mass, but by defective bone material. While osteoid mineralization is initiated at normal rate, mineral accrual is accelerated, indicating that EphrinB2 in osteocytes limits mineral accumulation. No known regulators of mineralization are modified in the brittle cortical bone but a cluster of autophagy-associated genes are dysregulated. EphrinB2-deficient osteocytes displayed more autophagosomes in vivo and in vitro, and EphrinB2-Fc treatment suppresses autophagy in a RhoA-ROCK dependent manner. We conclude that secondary mineralization involves EphrinB2-RhoA-limited autophagy in osteocytes, and disruption leads to a bone fragility independent of bone mass. Osteoblasts mediate bone formation, and their differentiation requires expression of EphrinB2. Here, the authors show that EphrinB2 is also expressed by osteocytes, and that its genetic ablation in mice is associated with altered autophagy, elevated mineralization and brittle bone.
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Li X, Liu Q, Feng H, Deng J, Zhang R, Wen J, Dong J, Wang T. Dehydrin MtCAS31 promotes autophagic degradation under drought stress. Autophagy 2019; 16:862-877. [PMID: 31362589 PMCID: PMC7144882 DOI: 10.1080/15548627.2019.1643656] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Drought stress seriously affects crop yield, and the mechanism underlying plant resistance to drought stress via macroautophagy/autophagy is not clear. Here, we show that a dehydrin, Medicago truncatula MtCAS31 (cold acclimation-specific 31), a positive regulator of drought response, plays a key role in autophagic degradation. A GFP cleavage assay and treatment with an autophagy-specific inhibitor indicated that MtCAS31 participates in the autophagic degradation pathway and that overexpressing MtCAS31 promotes autophagy under drought stress. Furthermore, we discovered that MtCAS31 interacts with the autophagy-related protein ATG8a in the AIM-like motif YXXXI, supporting its function in autophagic degradation. In addition, we identified a cargo protein of MtCAS31, the aquaporin MtPIP2;7, by screening an M. truncatula cDNA library. We found that MtPIP2;7 functions as a negative regulator of drought response. Under drought stress, MtCAS31 facilitated the autophagic degradation of MtPIP2;7 and reduced root hydraulic conductivity, thus reducing water loss and improving drought tolerance. Taken together, our results reveal a novel function of dehydrins in promoting the autophagic degradation of proteins, which extends our knowledge of the function of dehydrins.Abbreviations: AIM: ATG8-interacting motif; ATG: autophagy-related; ATI1: ATG8-interacting protein1; BiFC: Biomolecular fluorescence complementation; CAS31: cold acclimation-specific 31; ConcA: concanamycin A; DSK2: dominant suppressor of KAR2; ER: endoplasmic reticulum; ERAD: ER-associated degradation; NBR1: next to BRCA1 gene 1; PM: plasma membrane; PIPs: plasma membrane intrinsic proteins; TALEN: transcription activator-like effector nuclease; TSPO: tryptophan-rich sensory protein/translocator; UPR: unfolded protein response; VC: vector control.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Qianwen Liu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Hao Feng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jie Deng
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Rongxue Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jiangqi Wen
- Plant Biology Division, Samuel Roberts Noble Research Institute, Ardmore, OK, USA
| | - Jiangli Dong
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Tao Wang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
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Movahed N, Cabanillas DG, Wan J, Vali H, Laliberté JF, Zheng H. Turnip Mosaic Virus Components Are Released into the Extracellular Space by Vesicles in Infected Leaves. PLANT PHYSIOLOGY 2019; 180:1375-1388. [PMID: 31019004 PMCID: PMC6752911 DOI: 10.1104/pp.19.00381] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/11/2019] [Indexed: 05/18/2023]
Abstract
Turnip mosaic virus (TuMV) reorganizes the endomembrane system of the infected cell to generate endoplasmic-reticulum-derived motile vesicles containing viral replication complexes. The membrane-associated viral protein 6K2 plays a key role in the formation of these vesicles. Using confocal microscopy, we observed that this viral protein, a marker for viral replication complexes, localized in the extracellular space of infected Nicotiana benthamiana leaves. Previously, we showed that viral RNA is associated with multivesicular bodies (MVBs). Here, using transmission electron microscopy, we observed the proliferation of MVBs during infection and their fusion with the plasma membrane that resulted in the release of their intraluminal vesicles in the extracellular space. Immunogold labeling with a monoclonal antibody that recognizes double-stranded RNA indicated that the released vesicles contained viral RNA. Focused ion beam-extreme high-resolution scanning electron microscopy was used to generate a three-dimensional image that showed extracellular vesicles in the cell wall. The presence of TuMV proteins in the extracellular space was confirmed by proteomic analysis of purified extracellular vesicles from N benthamiana and Arabidopsis (Arabidopsis thaliana). Host proteins involved in biotic defense and in interorganelle vesicular exchange were also detected. The association of extracellular vesicles with viral proteins and RNA emphasizes the implication of the plant extracellular space in viral infection.
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Affiliation(s)
- Nooshin Movahed
- Department of Biology, McGill University, Montréal, Québec, H3A 1B1, Canada
| | - Daniel Garcia Cabanillas
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Laval, Québec, H7V 1B7, Canada
| | - Juan Wan
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Hojatollah Vali
- Facility for Electron Microscopy Research, McGill University, Montréal, Québec, H3A 0C7, Canada
- Department of Anatomy & Cell Biology, McGill University, Montréal, Québec, H3A 0C7, Canada
| | - Jean-François Laliberté
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Laval, Québec, H7V 1B7, Canada
| | - Huanquan Zheng
- Department of Biology, McGill University, Montréal, Québec, H3A 1B1, Canada
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Champeyroux C, Bellati J, Barberon M, Rofidal V, Maurel C, Santoni V. Regulation of a plant aquaporin by a Casparian strip membrane domain protein-like. PLANT, CELL & ENVIRONMENT 2019; 42:1788-1801. [PMID: 30767240 DOI: 10.1111/pce.13537] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 02/11/2019] [Indexed: 05/11/2023]
Abstract
The absorption of soil water by roots allows plants to maintain their water status. At the endodermis, water transport can be affected by initial formation of a Casparian strip and further deposition of suberin lamellas and regulated by the function of aquaporins. Four Casparian strip membrane domain protein-like (CASPL; CASPL1B1, CASPL1B2, CASPL1D1, and CASPL1D2) were previously shown to interact with PIP2;1. The present work shows that CASPL1B1, CASPL1B2, and CASPL1D2 are exclusively expressed in suberized endodermal cells, suggesting a cell-specific role in suberization and/or water transport regulation. When compared with wild-type plants, and by contrast to caspl1b1*caspl1b2 double loss of function, caspl1d1*caspl1d2 double mutants showed, in some control or NaCl stress experiments and not upon abscisic acid (ABA) treatment, a weak enlargement of the continuous suberization zone. None of the mutants showed root hydraulic conductivity (Lpr ) phenotype, whether in control, NaCl, or ABA treatment conditions. The data suggest a slight negative role for CASPL1D1 and CASPL1D2 in suberization under control or salt stress conditions, with no major impact on whole root transport functions. At the molecular level, CASPL1B1 was able to physically interact with PIP2;1 and potentially could influence the regulation of aquaporins by acting on their phosphorylated form.
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Affiliation(s)
- Chloé Champeyroux
- BPMP, Univ Montpellier, CNRS, INRA, Montpellier SupAgro, Montpellier, France
| | - Jorge Bellati
- BPMP, Univ Montpellier, CNRS, INRA, Montpellier SupAgro, Montpellier, France
| | - Marie Barberon
- Department of Botany and Plant Biology, Université de Genève, Geneva, Switzerland
| | - Valérie Rofidal
- BPMP, Univ Montpellier, CNRS, INRA, Montpellier SupAgro, Montpellier, France
| | - Christophe Maurel
- BPMP, Univ Montpellier, CNRS, INRA, Montpellier SupAgro, Montpellier, France
| | - Véronique Santoni
- BPMP, Univ Montpellier, CNRS, INRA, Montpellier SupAgro, Montpellier, France
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Avin-Wittenberg T. Autophagy and its role in plant abiotic stress management. PLANT, CELL & ENVIRONMENT 2019; 42:1045-1053. [PMID: 29998609 DOI: 10.1111/pce.13404] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/15/2018] [Accepted: 06/18/2018] [Indexed: 05/02/2023]
Abstract
Being unable to move, plants are regularly exposed to changing environmental conditions, among which various types of abiotic stress, such as heat, drought, salt, and so forth. These might have deleterious effects on plant performance and yield. Plants thus need to adapt using appropriate stress responses. One of the outcomes of abiotic stress is the need to degrade and recycle damaged proteins and organelles. Autophagy is a conserved eukaryotic mechanism functioning in the degradation of proteins, protein aggregates, and whole organelles. It was previously shown to have a role in plant abiotic stress. This review will describe the current knowledge regarding the involvement of autophagy in plant abiotic stress response, mechanisms functioning in autophagy induction during stress, and possible direction for future research.
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Affiliation(s)
- Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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67
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The transmembrane autophagy cargo receptors ATI1 and ATI2 interact with ATG8 through intrinsically disordered regions with distinct biophysical properties. Biochem J 2019; 476:449-465. [PMID: 30642888 DOI: 10.1042/bcj20180748] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 01/13/2019] [Accepted: 01/14/2019] [Indexed: 12/12/2022]
Abstract
Selective autophagy has emerged as an important mechanism by which eukaryotic cells control the abundance of specific proteins. This mechanism relies on cargo recruitment to autophagosomes by receptors that bind to both the ubiquitin-like AUTOPHAGY8 (ATG8) protein through ATG8-interacting motifs (AIMs) and to the cargo to be degraded. In plants, two autophagy cargo receptors, ATG8-interacting protein 1 (ATI1) and 2 (ATI2), were identified early on, but their molecular properties remain poorly understood. Here, we show that ATI1 and ATI2 are transmembrane proteins with long N-terminal intrinsically disordered regions (IDRs). The N-terminal IDRs contain the functional AIMs, and we use nuclear magnetic resonance spectroscopy to directly observe the disorder-order transition of the AIM upon ATG8 binding. Our analyses also show that the IDRs of ATI1 and ATI2 are not equivalent, because ATI2 has properties of a fully disordered polypeptide, while ATI1 has properties more consistent with a collapsed pre-molten globule-like conformation, possibly as a consequence of a higher content of π-orbital-containing amino acid residues. Finally, we show that a sizable fraction of ATI2, but not ATI1, is phosphorylated in planta.
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Ariani A, Barozzi F, Sebastiani L, di Toppi LS, di Sansebastiano GP, Andreucci A. AQUA1 is a mercury sensitive poplar aquaporin regulated at transcriptional and post-translational levels by Zn stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 135:588-600. [PMID: 30424909 DOI: 10.1016/j.plaphy.2018.10.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 05/19/2023]
Abstract
Aquaporins are water channel proteins that regulate plant development, growth, and response to environmental stresses. Populus trichocarpa is one of the plants with the highest number of aquaporins in its genome, but only few of them have been characterized at the whole plant functional level. Here we analyzed a putative aquaporin gene, aqua1, a gene that encodes for a protein of 257 amino acid with the typical NPA (Asp-Pro-Ala) signature motif of the aquaporin gene family. aqua1 was down-regulated of ∼10 fold under excess Zn in both leaves and roots, and conferred Zn tolerance when expressed in yeast Zn hypersensitive strain. In vivo localization of AQUA1-GFP in Arabidopsis protoplast showed a heterogeneous distribution of this protein on different membranes destined to form aggregates related to autophagic multivesicular bodies. Zn-dependent AQUA1-GFP re-localization was perturbed by phosphatases' and kinases' inhibitors that could affect both intracellular trafficking and aquaporins' activity. Exposed to high concentration of Zn, AQUA1 also co-localized with AtTIP1;1, a well-known Arabidopsis vacuolar marker, probably in pro-vacuolar multivesicular bodies. These findings suggest that high concentration of Zn down-regulates aqua1 and causes its re-localization in new forming pro-vacuoles. This Zn-dependent re-localization appears to be mediated by mechanisms regulating intracellular trafficking and aquaporins' post-translational modifications. This functional characterization of a poplar aquaporin in response to excess Zn will be a useful reference for understanding aquaporins' roles and regulation in response to high concentration of Zn in poplar.
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Affiliation(s)
- Andrea Ariani
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fabrizio Barozzi
- DISTEBA, Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Prov. le Lecce - Monteroni, 73100, Lecce, Italy
| | - Luca Sebastiani
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy
| | | | - Gian Pietro di Sansebastiano
- DISTEBA, Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Prov. le Lecce - Monteroni, 73100, Lecce, Italy
| | - Andrea Andreucci
- Department of Biology, Università degli Studi di Pisa, I-56126, Pisa, Italy.
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Norizuki T, Kanazawa T, Minamino N, Tsukaya H, Ueda T. Marchantia polymorpha, a New Model Plant for Autophagy Studies. FRONTIERS IN PLANT SCIENCE 2019; 10:935. [PMID: 31379911 PMCID: PMC6652269 DOI: 10.3389/fpls.2019.00935] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/03/2019] [Indexed: 05/18/2023]
Abstract
Autophagy is a catabolic process for bulk and selective degradation of cytoplasmic components in the vacuole/lysosome. In Saccharomyces cerevisiae, ATG genes were identified as essential genes for autophagy, and most ATG genes are highly conserved among eukaryotes, including plants. Although reverse genetic analyses have revealed that autophagy is involved in responses to abiotic and biotic stresses in land plants, our knowledge of its molecular mechanism remains limited. This limitation is partly because of the multiplication of some ATG genes, including ATG8, in widely used model plants such as Arabidopsis thaliana, which adds complexity to functional studies. Furthermore, due to limited information on the composition and functions of the ATG genes in basal land plants and charophytes, it remains unclear whether multiplication of ATG genes is associated with neofunctionalization of these genes. To gain insight into the diversification of ATG genes during plant evolution, we compared the composition of ATG genes in plants with a special focus on a liverwort and two charophytes, which have not previously been analyzed. Our results showed that the liverwort Marchantia polymorpha and the charophytes Klebsormidium nitens and Chara braunii harbor fundamental sets of ATG genes with low redundancy compared with those of A. thaliana and the moss Physcomitrella patens, suggesting that multiplication of ATG genes occurred during land plant evolution. We also attempted to establish an experimental system for analyzing autophagy in M. polymorpha. We generated transgenic plants expressing fluorescently tagged MpATG8 to observe its dynamics in M. polymorpha and produced autophagy-defective mutants by genome editing using the CRISPR/Cas9 system. These tools allowed us to demonstrate that MpATG8 is transported into the vacuole in an MpATG2-, MpATG5-, and MpATG7-dependent manner, suggesting that fluorescently tagged MpATG8 can be used as an autophagosome marker in M. polymorpha. M. polymorpha can provide a powerful system for studying the mechanisms and evolution of autophagy in plants.
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Affiliation(s)
- Takuya Norizuki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
| | - Takehiko Kanazawa
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Naoki Minamino
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Takashi Ueda
- Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Japan
- Department of Basic Biology, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
- *Correspondence: Takashi Ueda,
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70
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Ding X, Zhang X, Otegui MS. Plant autophagy: new flavors on the menu. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:113-121. [PMID: 30267997 DOI: 10.1016/j.pbi.2018.09.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/28/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Autophagy mediates the delivery of cytoplasmic content to vacuoles or lysosomes for degradation or storage. The best characterized autophagy route called macroautophagy involves the sequestration of cargo in double-membrane autophagosomes and is conserved in eukaryotes, including plants. Recently, several new receptors, some of them plant-specific, that select cargo for macroautophagy have been identified. Some of these receptors appear to participate in regulation of competing catabolic pathways, for example proteasome-mediated versus autophagic degradation under specific stress conditions. Vacuolar microautophagy, a process by which the vacuole directly engulf cytoplasmic material, also occurs in plants but its underlying molecular mechanisms are yet to be elucidated.
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Affiliation(s)
- Xinxin Ding
- Department of Botany, 430 Lincoln Drive, University of Wisconsin-Madison, WI 53706, United States; Laboratory of Molecular and Cellular Biology, 1525 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Xiaoguo Zhang
- Department of Botany, 430 Lincoln Drive, University of Wisconsin-Madison, WI 53706, United States; Laboratory of Molecular and Cellular Biology, 1525 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Marisa S Otegui
- Department of Botany, 430 Lincoln Drive, University of Wisconsin-Madison, WI 53706, United States; Laboratory of Molecular and Cellular Biology, 1525 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Genetics, 405 Henry Mall, University of Wisconsin-Madison, Madison, WI 53706, United States.
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71
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Jurkiewicz P, Melser S, Maucourt M, Ayeb H, Veljanovski V, Maneta-Peyret L, Hooks M, Rolin D, Moreau P, Batoko H. The multistress-induced Translocator protein (TSPO) differentially modulates storage lipids metabolism in seeds and seedlings. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:274-286. [PMID: 30003614 DOI: 10.1111/tpj.14028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 05/11/2023]
Abstract
Translocator proteins (TSPO) are conserved membrane proteins extensively studied in mammals, but their function is still unclear. Angiosperm TSPO are transiently induced by abiotic stresses in vegetative tissues. We showed previously that constitutive expression of the Arabidopsis TSPO (AtTSPO) could be detrimental to the cell. Degradation of AtTSPO requires an active autophagy pathway. We show here that genetic modifications of TSPO expression in plant and yeast cells reduce the levels of cytoplasmic lipid droplets (LD). Transgenic Arabidopsis seedlings overexpressing AtTSPO contain less LD as compared with wild type (WT). LD levels were increased in Arabidopsis AtTSPO knockout (KO) seedlings. Deletion of the Schizosaccharomyces pombe TSPO resulted in an increase in LD level in the cell. As compared with the WT, the mutant strain was more sensitive to cerulenin, an inhibitor of fatty acids and sterol biosynthesis. We found that in contrast with seedlings, overexpression of AtTSPO (OE) resulted in an up to 50% increase in seeds fatty acids as compared with WT. A time course experiment revealed that after 4 days of seed imbibition, the levels of triacylglycerol (TAG) was still higher in the OE seeds as compared with WT or KO seeds. However, the de novo synthesis of phospholipids and TAG after 24 h of imbibition was substantially reduced in OE seeds as compared with WT or KO seeds. Our findings support a plant TSPO role in energy homeostasis in a tissue-specific manner, enhancing fatty acids and LD accumulation in mature seeds and limiting LD levels in seedlings.
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Affiliation(s)
- Pawel Jurkiewicz
- Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, Croix du Sud 4-5, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Su Melser
- UMR 5200 Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, INRA Bordeaux Aquitaine, 33140, Villenave d'Ornon, France
| | - Mickaël Maucourt
- Plateforme Métabolome Bordeaux, MetaboHUB, Bordeaux Functional Genomic Center, IBVM, CS 20032 F-33140, Villenave d'Ornon, France
| | - Haitham Ayeb
- Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, Croix du Sud 4-5, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Vasko Veljanovski
- Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, Croix du Sud 4-5, L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Lilly Maneta-Peyret
- UMR 5200 Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, INRA Bordeaux Aquitaine, 33140, Villenave d'Ornon, France
| | - Mark Hooks
- Plateforme Métabolome Bordeaux, MetaboHUB, Bordeaux Functional Genomic Center, IBVM, CS 20032 F-33140, Villenave d'Ornon, France
| | - Dominique Rolin
- Plateforme Métabolome Bordeaux, MetaboHUB, Bordeaux Functional Genomic Center, IBVM, CS 20032 F-33140, Villenave d'Ornon, France
| | - Patrick Moreau
- UMR 5200 Membrane Biogenesis Laboratory, CNRS-University of Bordeaux, INRA Bordeaux Aquitaine, 33140, Villenave d'Ornon, France
- Bordeaux Imaging Center, UMS 3420 CNRS, US4 INSERM, University of Bordeaux, 33000, Bordeaux, France
| | - Henri Batoko
- Louvain Institute of Biomolecular Science and Technology (LIBST), UCLouvain, Croix du Sud 4-5, L7.07.14, 1348, Louvain-la-Neuve, Belgium
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72
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Liu C, Shen W, Yang C, Zeng L, Gao C. Knowns and unknowns of plasma membrane protein degradation in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 272:55-61. [PMID: 29807606 DOI: 10.1016/j.plantsci.2018.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/02/2018] [Accepted: 04/10/2018] [Indexed: 06/08/2023]
Abstract
Plasma membrane (PM) not only creates a physical barrier to enclose the intracellular compartments but also mediates the direct communication between plants and the ever-changing environment. A tight control of PM protein homeostasis by selective degradation is thus crucial for proper plant development and plant-environment interactions. Accumulated evidences have shown that a number of plant PM proteins undergo clathrin-dependent or membrane microdomain-associated endocytic routes to vacuole for degradation in a cargo-ubiquitination dependent or independent manner. Besides, several trans-acting determinants involved in the regulation of endocytosis, recycling and multivesicular body-mediated vacuolar sorting have been identified in plants. More interestingly, recent findings have uncovered the participation of selective autophagy in PM protein turnover in plants. Although great progresses have been made to identify the PM proteins that undergo dynamic changes in subcellular localizations and to explore the factors that control the membrane protein trafficking, several questions remain to be answered regarding the molecular mechanisms of PM protein degradation in plants. In this short review article, we briefly summarize recent progress in our understanding of the internalization, sorting and degradation of plant PM proteins. More specifically, we focus on discussing the elusive aspects underlying the pathways of PM protein degradation in plants.
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Affiliation(s)
- Chuanliang Liu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Wenjin Shen
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Chao Yang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China
| | - Lizhang Zeng
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou 510631, China
| | - Caiji Gao
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, China.
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73
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Heydarian Z, Yu M, Gruber M, Coutu C, Robinson SJ, Hegedus DD. Changes in gene expression in Camelina sativa roots and vegetative tissues in response to salinity stress. Sci Rep 2018; 8:9804. [PMID: 29955098 PMCID: PMC6023900 DOI: 10.1038/s41598-018-28204-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/14/2018] [Indexed: 12/19/2022] Open
Abstract
The response of Camelina sativa to salt stress was examined. Salt reduced shoot, but not root length. Root and shoot weight were affected by salt, as was photosynthetic capacity. Salt did not alter micro-element concentration in shoots, but increased macro-element (Ca and Mg) levels. Gene expression patterns in shoots indicated that salt stress may have led to shuttling of Na+ from the cytoplasm to the tonoplast and to an increase in K+ and Ca+2 import into the cytoplasm. In roots, gene expression patterns indicated that Na+ was exported from the cytoplasm by the SOS pathway and that K+ was imported in response to salt. Genes involved in chelation and storage were up-regulated in shoots, while metal detoxification appeared to involve various export mechanisms in roots. In shoots, genes involved in secondary metabolism leading to lignin, anthocyanin and wax production were up-regulated. Partial genome partitioning was observed in roots and shoots based on the expression of homeologous genes from the three C. sativa sub-genomes. Sub-genome I and II were involved in the response to salinity stress to about the same degree, while about 10% more differentially-expressed genes were associated with sub-genome III.
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Affiliation(s)
- Zohreh Heydarian
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
- Department of Biotechnology, School of Agriculture, University of Shiraz, Bajgah, Shiraz, Fars, Iran
| | - Min Yu
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Margaret Gruber
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Cathy Coutu
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Stephen J Robinson
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Dwayne D Hegedus
- Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada.
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada.
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74
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Dietrich D. Hydrotropism: how roots search for water. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2759-2771. [PMID: 29529239 DOI: 10.1093/jxb/ery034] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/18/2018] [Indexed: 05/25/2023]
Abstract
Fresh water is an increasingly scarce resource for agriculture. Plant roots mediate water uptake from the soil and have developed a number of adaptive traits such as hydrotropism to aid water foraging. Hydrotropism modifies root growth to respond to a water potential gradient in soil and grow towards areas with a higher moisture content. Abscisic acid (ABA) and a small number of genes, including those encoding ABA signal transducers, MIZ2/GNOM, and the hydrotropism-specific MIZ1, are known to be necessary for the response in Arabidopsis thaliana, whereas the role of auxin in hydrotropism appears to vary depending on the plant species. This review will describe recent progress characterizing the hormonal regulation of hydrotropism. Recent advances in identifying the sites of hydrotropic perception and response, together with its interaction with gravitropism, will also be discussed. Finally, I will describe putative mechanisms for perception of the water potential gradient and a potential role for hydrotropism in acclimatizing plants to drought conditions.
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Affiliation(s)
- Daniela Dietrich
- Centre for Plant Integrative Biology and Plant & Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
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75
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The modulation of acetic acid pathway genes in Arabidopsis improves survival under drought stress. Sci Rep 2018; 8:7831. [PMID: 29777132 PMCID: PMC5959891 DOI: 10.1038/s41598-018-26103-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 05/02/2018] [Indexed: 12/12/2022] Open
Abstract
The Arabidopsis histone deacetylase 6 (HDA6) mutant exhibits increased tolerance to drought stress by negatively regulating the expression of ALDH2B7 and PDC1. Therefore, it was logical to determine if transgenic Arabidopsis plants expressing PDC1 or ALDH2B7 using a suitable promoter would also exhibit tolerance to drought stress. An analysis of published microarray data indicated the up-regulation of the TSPO gene, which encodes an outer membrane tryptophan-rich sensory protein (TSPO), by drought stress. RT-qPCR, as well as GUS analysis of the promoter, confirmed the up-regulation of TSPO by drought stress in Arabidopsis roots and shoots. Thus, the TSPO promoter was used to drive drought-responsive expression of ALDH2B7 and PDC1. RT-qPCR analysis confirmed that the expression of PDC1 and ALDH2B7 was up-regulated, relative to WT plants, by drought stress in homozygous pTSPO-PDC1 and pTSPO-ALDH2B7 plant lines. pTSPO-ALDH2B7 and pTSPO-PDC1 transgenic lines showed prolonged survival under drought stress. Microarray analyses revealed transcriptomic changes related to metabolism in pTSPO-PDC1 plants, indicating that selective regulation of metabolism may occur; resulting in the acquisition of drought stress tolerance. These results confirmed that TSPO promoter can be used to elevate the expression of acetic acid biosynthesis pathway genes; ensuring prolonged survival under drought stress in Arabidopsis.
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Abstract
Plants have evolved sophisticated mechanisms to recycle intracellular constituents, which are essential for developmental and metabolic transitions; for efficient nutrient reuse; and for the proper disposal of proteins, protein complexes, and even entire organelles that become obsolete or dysfunctional. One major route is autophagy, which employs specialized vesicles to encapsulate and deliver cytoplasmic material to the vacuole for breakdown. In the past decade, the mechanics of autophagy and the scores of components involved in autophagic vesicle assembly have been documented. Now emerging is the importance of dedicated receptors that help recruit appropriate cargo, which in many cases exploit ubiquitylation as a signal. Although operating at a low constitutive level in all plant cells, autophagy is upregulated during senescence and various environmental challenges and is essential for proper nutrient allocation. Its importance to plant metabolism and energy balance in particular places autophagy at the nexus of robust crop performance, especially under suboptimal conditions.
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Affiliation(s)
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA;
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77
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Avin-Wittenberg T, Baluška F, Bozhkov PV, Elander PH, Fernie AR, Galili G, Hassan A, Hofius D, Isono E, Le Bars R, Masclaux-Daubresse C, Minina EA, Peled-Zehavi H, Coll NS, Sandalio LM, Satiat-Jeunemaitre B, Sirko A, Testillano PS, Batoko H. Autophagy-related approaches for improving nutrient use efficiency and crop yield protection. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1335-1353. [PMID: 29474677 DOI: 10.1093/jxb/ery069] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/16/2018] [Indexed: 05/18/2023]
Abstract
Autophagy is a eukaryotic catabolic pathway essential for growth and development. In plants, it is activated in response to environmental cues or developmental stimuli. However, in contrast to other eukaryotic systems, we know relatively little regarding the molecular players involved in autophagy and the regulation of this complex pathway. In the framework of the COST (European Cooperation in Science and Technology) action TRANSAUTOPHAGY (2016-2020), we decided to review our current knowledge of autophagy responses in higher plants, with emphasis on knowledge gaps. We also assess here the potential of translating the acquired knowledge to improve crop plant growth and development in a context of growing social and environmental challenges for agriculture in the near future.
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Affiliation(s)
- Tamar Avin-Wittenberg
- Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Frantisek Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Pernilla H Elander
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg, Potsdam-Golm, Germany
| | - Gad Galili
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Ammar Hassan
- Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden
| | - Erika Isono
- Department of Biology, University of Konstanz, Universitätsstrasse, Konstanz, Germany
| | - Romain Le Bars
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Céline Masclaux-Daubresse
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot Israel
| | - Núria S Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra-Cerdanyola del Valles, Catalonia, Spain
| | - Luisa M Sandalio
- Departmento de Bioquímica, Biología Celular y Molecular de Plantas Experimental del Zaidín, CSIC, Granada, Spain
| | - Béatrice Satiat-Jeunemaitre
- Cell Biology Pôle Imagerie-Gif, Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Agnieszka Sirko
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, ul. Pawinskiego, Warsaw, Poland
| | - Pilar S Testillano
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas, Biological Research Centre (CIB), CSIC, Ramiro de Maeztu, Madrid, Spain
| | - Henri Batoko
- Université Catholique de Louvain, Institute of Life Sciences, Croix du Sud, Louvain-la-Neuve, Belgium
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78
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Zhou J, Wang Z, Wang X, Li X, Zhang Z, Fan B, Zhu C, Chen Z. Dicot-specific ATG8-interacting ATI3 proteins interact with conserved UBAC2 proteins and play critical roles in plant stress responses. Autophagy 2018; 14:487-504. [PMID: 29313416 DOI: 10.1080/15548627.2017.1422856] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Selective macroautophagy/autophagy targets specific cargo by autophagy receptors through interaction with ATG8 (autophagy-related protein 8)/MAP1LC3 (microtubule associated protein 1 light chain 3) for degradation in the vacuole. Here, we report the identification and characterization of 3 related ATG8-interacting proteins (AT1G17780/ATI3A, AT2G16575/ATI3B and AT1G73130/ATI3C) from Arabidopsis. ATI3 proteins contain a WxxL LC3-interacting region (LIR) motif at the C terminus required for interaction with ATG8. ATI3 homologs are found only in dicots but not in other organisms including monocots. Disruption of ATI3A does not alter plant growth or development but compromises both plant heat tolerance and resistance to the necrotrophic fungal pathogen Botrytis cinerea. The critical role of ATI3A in plant stress tolerance and disease resistance is dependent on its interaction with ATG8. Disruption of ATI3B and ATI3C also significantly compromises plant heat tolerance. ATI3A interacts with AT3G56740/UBAC2A and AT2G41160/UBAC2B (Ubiquitin-associated [UBA] protein 2a/b), 2 conserved proteins implicated in endoplasmic reticulum (ER)-associated degradation. Disruption of UBAC2A and UBAC2B also compromised heat tolerance and resistance to B. cinerea. Overexpression of UBAC2 induces formation of ATG8- and ATI3-labeled punctate structures under normal conditions, likely reflecting increased formation of phagophores or autophagosomes. The ati3 and ubac2 mutants are significantly compromised in sensitivity to tunicamycin, an ER stress-inducing agent, but are fully competent in autophagy-dependent ER degradation under conditions of ER stress when using an ER lumenal marker for detection. We propose that ATI3 and UBAC2 play an important role in plant stress responses by mediating selective autophagy of specific unknown ER components.
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Affiliation(s)
- Jie Zhou
- a Department of Horticulture, Zijingang Campus , Zhejiang University , Hangzhou , China.,b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA
| | - Zhe Wang
- b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA
| | - Xiaoting Wang
- b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA.,c National Center for Soybean Improvement, College of Agriculture , Nanjing Agricultural University , Nanjing , China
| | - Xifeng Li
- a Department of Horticulture, Zijingang Campus , Zhejiang University , Hangzhou , China
| | - Zhenchao Zhang
- b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA.,d Zhenjiang Agricultural Research Institute , Jurong City , Jiangsu , China
| | - Baofang Fan
- b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA
| | - Cheng Zhu
- e College of Life Sciences , China Jiliang University , Hangzhou , China
| | - Zhixiang Chen
- a Department of Horticulture, Zijingang Campus , Zhejiang University , Hangzhou , China.,b Department of Botany and Plant Pathology and Purdue Center for Plant Biology , Purdue University , West Lafayette , IN , USA.,e College of Life Sciences , China Jiliang University , Hangzhou , China
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79
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Laloux T, Junqueira B, Maistriaux LC, Ahmed J, Jurkiewicz A, Chaumont F. Plant and Mammal Aquaporins: Same but Different. Int J Mol Sci 2018; 19:E521. [PMID: 29419811 PMCID: PMC5855743 DOI: 10.3390/ijms19020521] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 02/06/2023] Open
Abstract
Aquaporins (AQPs) constitute an ancient and diverse protein family present in all living organisms, indicating a common ancient ancestor. However, during evolution, these organisms appear and evolve differently, leading to different cell organizations and physiological processes. Amongst the eukaryotes, an important distinction between plants and animals is evident, the most conspicuous difference being that plants are sessile organisms facing ever-changing environmental conditions. In addition, plants are mostly autotrophic, being able to synthesize carbohydrates molecules from the carbon dioxide in the air during the process of photosynthesis, using sunlight as an energy source. It is therefore interesting to analyze how, in these different contexts specific to both kingdoms of life, AQP function and regulation evolved. This review aims at highlighting similarities and differences between plant and mammal AQPs. Emphasis is given to the comparison of isoform numbers, their substrate selectivity, the regulation of the subcellular localization, and the channel activity.
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Affiliation(s)
- Timothée Laloux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Bruna Junqueira
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Laurie C Maistriaux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Jahed Ahmed
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Agnieszka Jurkiewicz
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - François Chaumont
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
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80
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Jurkiewicz P, Batoko H. Protein degradation mechanisms modulate abscisic acid signaling and responses during abiotic stress. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 267:48-54. [PMID: 29362098 DOI: 10.1016/j.plantsci.2017.10.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/24/2017] [Accepted: 10/26/2017] [Indexed: 05/20/2023]
Abstract
Abiotic stresses such as salinity, drought, high temperature or freezing can be perceived, in part, as a transient or permanent hyperosmotic stress by the plant cell. As sessile organisms, the detrimental effects of these environmental insults limit plants productivity but also their geographical distribution. Sensing and signaling events that detect the hyperosmotic (or simply osmotic) stress involve the cellular increase of active abscisic acid (ABA). The stress phytohormone ABA regulates fundamental growth and developmental processes in the plant by marshalling metabolic and gene-expression reprogramming. Among the ABA-responsive genes, some are strictly ABA-dependent in that their expression is almost undetectable in absence of elevated levels of cellular ABA, thus their physiological role may be required only transiently. In addition, ABA-dependent modulation of some of the signaling effectors can be irreversible. In this review, without any pretention to being exhaustive, we use specific examples to illustrate how mechanistically conserved eukaryotic cell proteolytic pathways affect ABA-dependent signaling. We describe how defined proteolysis mechanisms in the plant cell, including Regulated Intramembrane Proteolysis (RIP), the Ubiquitin 26S Proteasomal System (UPS), the endocytic and autophagy pathways, contribute to regulate the spatiotemporal level and activity of PP2Cs (protein phosphatases 2C), and how an intriguing ABA-induced protein, the plant Translocator protein (TSPO), is targeted for degradation. Degradation of regulatory or effector molecules modulates or desensitizes ABA-dependent signaling and reestablishes cellular homeostasis.
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Affiliation(s)
- Pawel Jurkiewicz
- Institut des Sciences de la Vie (ISV), Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Institut des Sciences de la Vie (ISV), Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
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81
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Marion J, Le Bars R, Besse L, Batoko H, Satiat-Jeunemaitre B. Multiscale and Multimodal Approaches to Study Autophagy in Model Plants. Cells 2018; 7:E5. [PMID: 29315263 PMCID: PMC5789278 DOI: 10.3390/cells7010005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/05/2018] [Accepted: 01/05/2018] [Indexed: 12/31/2022] Open
Abstract
Autophagy is a catabolic process used by eukaryotic cells to maintain or restore cellular and organismal homeostasis. A better understanding of autophagy in plant biology could lead to an improvement of the recycling processes of plant cells and thus contribute, for example, towards reducing the negative ecological consequences of nitrogen-based fertilizers in agriculture. It may also help to optimize plant adaptation to adverse biotic and abiotic conditions through appropriate plant breeding or genetic engineering to incorporate useful traits in relation to this catabolic pathway. In this review, we describe useful protocols for studying autophagy in the plant cell, taking into account some specificities of the plant model.
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Affiliation(s)
- Jessica Marion
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Romain Le Bars
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Laetitia Besse
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
| | - Henri Batoko
- Institute of Life Sciences, UCL/ISV, University of Louvain, Croix du Sud 4, L7.07.14, 1348 Louvain-la-Neuve, Belgium
| | - Béatrice Satiat-Jeunemaitre
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91 198 Gif-sur-Yvette, France; (J.M.); (R.L.B.); (L.B.); (B.S.-J.)
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82
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Üstün S, Hafrén A, Hofius D. Autophagy as a mediator of life and death in plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:122-130. [PMID: 28946008 DOI: 10.1016/j.pbi.2017.08.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 05/20/2023]
Abstract
Autophagy is a major pathway for degradation and recycling of cytoplasmic material, including individual proteins, aggregates, and entire organelles. Autophagic processes serve mainly survival functions in cellular homeostasis, stress adaptation and immune responses but can also have death-promoting activities in different eukaryotic organisms. In plants, the role of autophagy in the regulation of programmed cell death (PCD) remained elusive and a subject of debate. More recent evidence, however, has resulted in the consensus that autophagy can either promote or restrict different forms of PCD. Here, we present latest advances in understanding the molecular mechanisms and functions of plant autophagy and discuss their implications for life and death decisions in the context of developmental and pathogen-induced PCD.
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Affiliation(s)
- Suayib Üstün
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU) and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU) and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden
| | - Daniel Hofius
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU) and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden.
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83
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Yu F, Xie Q. Non-26S Proteasome Endomembrane Trafficking Pathways in ABA Signaling. TRENDS IN PLANT SCIENCE 2017; 22:976-985. [PMID: 28919033 DOI: 10.1016/j.tplants.2017.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/24/2017] [Accepted: 08/25/2017] [Indexed: 05/26/2023]
Abstract
The phytohormone abscisic acid (ABA) is a vital endogenous messenger that regulates diverse physiological processes in plants. The regulation of ABA signaling has been well studied at both the transcriptional and translational levels. Post-translational modification of key regulators in ABA signaling by the 26S ubiquitin proteasome pathway is well known. Recently, increasing evidence demonstrates that atypical turnover of key regulators by the endocytic trafficking pathway and autophagy also play vital roles in ABA perception, signaling, and action. We summarize and synthesize here recent findings in the field of ABA signaling.
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Affiliation(s)
- Feifei Yu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Number 1 West Beichen Road, Chaoyang District, Beijing 100101, PR China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Number 1 West Beichen Road, Chaoyang District, Beijing 100101, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
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84
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Fox AR, Maistriaux LC, Chaumont F. Toward understanding of the high number of plant aquaporin isoforms and multiple regulation mechanisms. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 264:179-187. [PMID: 28969798 DOI: 10.1016/j.plantsci.2017.07.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/14/2017] [Accepted: 07/21/2017] [Indexed: 05/20/2023]
Abstract
Since the discovery of the first plant aquaporin (AQP) in 1993, our conception of the way plants control cell water homeostasis as well as their global water balance has been revisited. Plant AQPs constitute a large family of evolutionarily related channels that, in addition to water, can also facilitate the membrane diffusion of a number of small solutes, such as urea, CO2, H2O2, ammonia, metalloids, and even ions, indicating a wide range of cellular functions. At the cellular level, AQPs are subject to various regulation mechanisms leading to active/inactive channels in their target membranes. In this review, we discuss several specific questions that need to be addressed in future research. Why are so many different AQPs simultaneously expressed in specific cellular types? How is their selectivity to different solutes controlled (in particular in the case of multiple permeation properties)? What does the molecular interaction between AQPs and other molecules tell us about their regulation and their involvement in specific cellular and physiological processes? Resolving these questions will definitely help us better understand the physiological advantages that plants have to express and regulate so many AQP isoforms.
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Affiliation(s)
- Ana Romina Fox
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la-Neuve, Belgium
| | - Laurie C Maistriaux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la-Neuve, Belgium
| | - François Chaumont
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la-Neuve, Belgium.
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85
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Anding AL, Baehrecke EH. Cleaning House: Selective Autophagy of Organelles. Dev Cell 2017; 41:10-22. [PMID: 28399394 DOI: 10.1016/j.devcel.2017.02.016] [Citation(s) in RCA: 414] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/12/2016] [Accepted: 02/16/2017] [Indexed: 10/19/2022]
Abstract
The selective clearance of organelles by autophagy is critical for the regulation of cellular homeostasis in organisms from yeast to humans. Removal of damaged organelles clears the cell of potentially toxic byproducts and enables reuse of organelle components for bioenergetics. Thus, defects in organelle clearance may be detrimental to the health of the cells, contributing to cancer, neurodegeneration, and inflammatory diseases. Organelle-specific autophagy can clear mitochondria, peroxisomes, lysosomes, ER, chloroplasts, and the nucleus. Here, we review our understanding of the mechanisms that regulate the clearance of organelles by autophagy and highlight gaps in our knowledge of these processes.
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Affiliation(s)
- Allyson L Anding
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Eric H Baehrecke
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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86
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Zargar SM, Nagar P, Deshmukh R, Nazir M, Wani AA, Masoodi KZ, Agrawal GK, Rakwal R. Aquaporins as potential drought tolerance inducing proteins: Towards instigating stress tolerance. J Proteomics 2017; 169:233-238. [PMID: 28412527 DOI: 10.1016/j.jprot.2017.04.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/22/2017] [Accepted: 04/04/2017] [Indexed: 11/18/2022]
Abstract
Aquaporins (AQPs) are primarily involved in maintaining cellular water homeostasis. Their role in diverse physiological processes has fascinated plant scientists for more than a decade, particularly concerning abiotic stresses. Increasing examples of evidence in various crop plants indicate that the AQPs are responsible for precise regulation of water movement and consequently play a crucial role in the drought stress tolerance. Since drought is one of the major abiotic stresses affecting agricultural production worldwide, it has become a critical agenda to focus research on the development of drought tolerant crop plants. AQPs can act as key candidate molecules to confront this issue. Hence, there is an important need to explore the potential of AQPs by understanding the molecular mechanisms and pathways through which they induce drought tolerance. Moreover, the signalling network/s involved in such pathways needs to be mined and understood correctly, and that may lead to the development of drought tolerance in crop plants. In the present review, opportunity and challenges regarding the efficient utilization of AQP-related information is presented and discussed. The complied information and the discussion will be helpful for designing future experiments and to set the specific goals for the enhancement of drought tolerance in crop plants. Biological Significance Knowledge on the role of AQPs in maintaining cellular water homeostasis has given new hope for developing drought tolerance in crop plants. Since drought is one of the major abiotic stresses affecting agricultural production worldwide, it has become a critical agenda to focus research on the development of drought-tolerant crop plants. AQPs can act as key candidate molecules to solve this problem through genetic engineering. For this, it is important to understand the molecular mechanisms and inter-related pathways through which AQPs induce drought tolerance and to explore the signaling network/s involved in such pathways.
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Affiliation(s)
- Sajad Majeed Zargar
- Division of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences & Technology of Kashmir, Shalimar, Srinagar, Jammu and Kashmir 190025, India.
| | - Preeti Nagar
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi 110021, India
| | - Rupesh Deshmukh
- Departement de Phytologie, Université Laval, Quebec City, Canada
| | - Muslima Nazir
- Division of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences & Technology of Kashmir, Shalimar, Srinagar, Jammu and Kashmir 190025, India
| | - Aijaz Ahmad Wani
- Department of Botany, University of Kashmir, Hazratbal, Srinagar, Jammu and Kashmir 190006, India
| | - Khalid Zaffar Masoodi
- Division of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences & Technology of Kashmir, Shalimar, Srinagar, Jammu and Kashmir 190025, India
| | - Ganesh Kumar Agrawal
- Research Laboratory for Biotechnology and Biochemistry (RLABB), GPO 13265, Kathmandu, Nepal; GRADE (Global Research Arch for Developing Education) Academy Pvt. Ltd., Adarsh Nagar-13, Birgunj, Nepal
| | - Randeep Rakwal
- Research Laboratory for Biotechnology and Biochemistry (RLABB), GPO 13265, Kathmandu, Nepal; GRADE (Global Research Arch for Developing Education) Academy Pvt. Ltd., Adarsh Nagar-13, Birgunj, Nepal; Faculty of Health and Sport Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8574, Ibaraki, Japan
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87
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Busch AWU, Montgomery BL. Distinct light-, stress-, and nutrient-dependent regulation of multiple tryptophan-rich sensory protein (TSPO) genes in the cyanobacterium Fremyella diplosiphon. PLANT SIGNALING & BEHAVIOR 2017; 12:e1293221. [PMID: 28277971 PMCID: PMC5399897 DOI: 10.1080/15592324.2017.1293221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 01/30/2017] [Accepted: 02/04/2017] [Indexed: 06/06/2023]
Abstract
The cyanobacterium Fremyella diplosiphon possesses 3 genes encoding homologs of the tryptophan-rich sensory protein (TSPO). TSPO proteins are membrane proteins implicated in stress responses across a range of organisms from bacteria to humans. Diverse TSPO proteins appear to generally bind tetrapyrrole ligands. Previously, we reported that one of these homologs, FdTSPO1, is involved in salt-, osmotic- and oxidative stress responses in F. diplosiphon. Here, we show distinct regulation of cellular mRNA levels of all 3 FdTSPO homologs by different abiotic stresses. Given the prior finding that all 3 FdTSPO proteins are capable of binding tetrapyrroles of functional relevance in F. diplosiphon and the observation of a ligand-dependent functional role for FdTSPO1 in vivo, FdTSPO1, FdTSPO2, and FdTSPO3 appear to have distinct, yet overlapping, roles in vivo. We propose that these proteins regulate tetrapyrrole homeostasis and/or tetrapyrrole-modulated functions in F. diplosiphon in response to multiple environmental stresses.
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Affiliation(s)
- Andrea W. U. Busch
- Department of Energy — Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Beronda L. Montgomery
- Department of Energy — Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
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88
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Busch AWU, WareJoncas Z, Montgomery BL. Tryptophan-Rich Sensory Protein/Translocator Protein (TSPO) from Cyanobacterium Fremyella diplosiphon Binds a Broad Range of Functionally Relevant Tetrapyrroles. Biochemistry 2016; 56:73-84. [PMID: 27990801 DOI: 10.1021/acs.biochem.6b01019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tryptophan-rich sensory protein/translocator protein (TSPO) is a membrane protein involved in stress adaptation in the cyanobacterium Fremyella diplosiphon. Characterized mammalian and proteobacterial TSPO homologues bind tetrapyrroles and cholesterol ligands. We investigated the ligand binding properties of TSPO from F. diplosiphon (FdTSPO1), which was functionally characterized in prior genetic studies. Two additional TSPO proteins (FdTSPO2 and FdTSPO3) are present in F. diplosiphon; they are similar in size to reported bacterial TSPOs and smaller than FdTSPO1. The longer cyanobacterial TSPO1 is found almost exclusively in filamentous cyanobacteria and has a relatively low degree of homology to bacterial and mammalian TSPO homologues with confirmed tetrapyrrole binding. To probe distinctions of long-form TSPOs, we tested the binding of porphyrin and bilin to FdTSPO1 and measured binding affinities in the low micromolar range, with the highest binding affinity detected for heme. Although tetrapyrrole ligands bound FdTSPO1 with affinities similar to those previously reported for proteobacterial TSPO, binding of cholesterol to FdTSPO1 was particularly poor and was not improved by introducing an amino acid motif known to enhance cholesterol binding in other bacterial TSPO homologues. Additionally, we detected limited binding of bacterial hopanoids to FdTSPO1. Cyanobacterial TSPO1 from the oxygenic photosynthetic F. diplosiphon, thus, binds a range of tetrapyrroles of functional relevance with efficiencies similar to those of mammalian and proteobacterial homologues, but the level of cholesterol binding is greatly reduced compared to that of mammalian TSPO. Furthermore, the ΔFdTSPO1 mutant exhibits altered growth in the presence of biliverdin compared to that of wild-type cells under green light. Together, these results suggest that TSPO molecules may play roles in bilin homeostasis or trafficking in cyanobacteria.
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Affiliation(s)
- Andrea W U Busch
- Plant Research Laboratory, Department of Energy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Zachary WareJoncas
- Plant Research Laboratory, Department of Energy, Michigan State University , East Lansing, Michigan 48824, United States
| | - Beronda L Montgomery
- Plant Research Laboratory, Department of Energy, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Microbiology & Molecular Genetics, Michigan State University , East Lansing, Michigan 48824, United States
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91
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Pou A, Jeanguenin L, Milhiet T, Batoko H, Chaumont F, Hachez C. Salinity-mediated transcriptional and post-translational regulation of the Arabidopsis aquaporin PIP2;7. PLANT MOLECULAR BIOLOGY 2016; 92:731-744. [PMID: 27671160 DOI: 10.1007/s11103-016-0542-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 09/08/2016] [Indexed: 05/23/2023]
Abstract
Salt stress triggers a simultaneous transcriptional repression and aquaporin internalization to modify root cell water conductivity. Plasma membrane intrinsic proteins (PIPs) are involved in the adjustment of plant water balance in response to changing environmental conditions. In this study, Arabidopsis wild-type (Col-0) and transgenic lines overexpressing PIP2;7 were used to investigate and compare their response to salt stress. Hydraulic conductivity measurements using a high-pressure flowmeter (HPFM) revealed that overexpression of PIP2;7 induced a sixfold increase in root hydraulic conductivity of four week-old Arabidopsis thaliana plants compared to WT. Exposure to a high salt stress (150 mM NaCl) triggered a rapid repression of overall aquaporin activity in both genotypes. Response to salt stress was also investigated in 8 day-old seedlings. Exposure to salt led to a repression of PIP2;7 promoter activity and a significant decrease in PIP2;7 mRNA abundance within 2 h. Concomitantly, a rapid internalization of fluorescently-tagged PIP2;7 proteins was observed but removal from the cell membrane was not accompanied by further degradation of the protein within 4 h of exposure to salinity stress. These data suggest that PIP transcriptional repression and channel internalization act in concert during salt stress conditions to modulate aquaporin activity, thereby significantly altering the plant hydraulic parameters in the short term.
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Affiliation(s)
- Alicia Pou
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Linda Jeanguenin
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Thomas Milhiet
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - Henri Batoko
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium
| | - François Chaumont
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium.
| | - Charles Hachez
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, 1348, Louvain-la-Neuve, Belgium.
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92
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Bellati J, Champeyroux C, Hem S, Rofidal V, Krouk G, Maurel C, Santoni V. Novel Aquaporin Regulatory Mechanisms Revealed by Interactomics. Mol Cell Proteomics 2016; 15:3473-3487. [PMID: 27609422 PMCID: PMC5098044 DOI: 10.1074/mcp.m116.060087] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 08/31/2016] [Indexed: 12/22/2022] Open
Abstract
PIP1;2 and PIP2;1 are aquaporins that are highly expressed in roots and bring a major contribution to root water transport and its regulation by hormonal and abiotic factors. Interactions between cellular proteins or with other macromolecules contribute to forming molecular machines. Proteins that molecularly interact with PIP1;2 and PIP2;1 were searched to get new insights into regulatory mechanisms of root water transport. For that, a immuno-purification strategy coupled to protein identification and quantification by mass spectrometry (IP-MS) of PIPs was combined with data from the literature, to build thorough PIP1;2 and PIP2;1 interactomes, sharing about 400 interacting proteins. Such interactome revealed PIPs to behave as a platform for recruitment of a wide range of transport activities and provided novel insights into regulation of PIP cellular trafficking by osmotic and oxidative treatments. This work also pointed a role of lipid signaling in PIP function and enhanced our knowledge of protein kinases involved in PIP regulation. In particular we show that 2 members of the receptor-like kinase (RLK) family (RKL1 (At1g48480) and Feronia (At3g51550)) differentially modulate PIP activity through distinct molecular mechanisms. The overall work opens novel perspectives in understanding PIP regulatory mechanisms and their role in adjustment of plant water status.
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Affiliation(s)
- Jorge Bellati
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Chloé Champeyroux
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Sonia Hem
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Valérie Rofidal
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Gabriel Krouk
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Christophe Maurel
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
| | - Véronique Santoni
- From the ‡Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier, F-34060 Montpellier, Cedex 2, France
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93
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Calvo-Polanco M, Sánchez-Castro I, Cantos M, García JL, Azcón R, Ruiz-Lozano JM, Beuzón CR, Aroca R. Effects of different arbuscular mycorrhizal fungal backgrounds and soils on olive plants growth and water relation properties under well-watered and drought conditions. PLANT, CELL & ENVIRONMENT 2016; 39:2498-2514. [PMID: 27448529 DOI: 10.1111/pce.12807] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 05/21/2023]
Abstract
The adaptation capacity of olive trees to different environments is well recognized. However, the presence of microorganisms in the soil is also a key factor in the response of these trees to drought. The objective of the present study was to elucidate the effects of different arbuscular mycorrhizal (AM) fungi coming from diverse soils on olive plant growth and water relations. Olive plants were inoculated with native AM fungal populations from two contrasting environments, that is, semi-arid - Freila (FL) and humid - Grazalema (GZ) regions, and subjected to drought stress. Results showed that plants grew better on GZ soil inoculated with GZ fungi, indicating a preference of AM fungi for their corresponding soil. Furthermore, under these conditions, the highest AM fungal diversity was found. However, the highest root hydraulic conductivity (Lpr ) value was achieved by plants inoculated with GZ fungi and growing in FL soil under drought conditions. So, this AM inoculum also functioned in soils from different origins. Nine novel aquaporin genes were also cloned from olive roots. Diverse correlation and association values were found among different aquaporin expressions and abundances and Lpr , indicating how the interaction of different aquaporins may render diverse Lpr values.
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Affiliation(s)
- Monica Calvo-Polanco
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), C/Profesor Albareda, Granada, 18008, Spain
- Biochimie et Physiologie Moléculaire des Plantes, SupAgro/INRA UMR 5004. 2, Place Viala, Montpellier, Cedex 2 34060, France
| | - Iván Sánchez-Castro
- Department of Microbiology, University of Granada, Av. Fuentenueva s/n, Granada, 18071, Spain
| | - Manuel Cantos
- Department of Plant Biotechnology, Instituto de Recursos Naturales y Agrobiología (CSIC), Av. Reina Mercedes, 10, Sevilla, 41012, Spain
| | - José Luis García
- Department of Plant Biotechnology, Instituto de Recursos Naturales y Agrobiología (CSIC), Av. Reina Mercedes, 10, Sevilla, 41012, Spain
| | - Rosario Azcón
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), C/Profesor Albareda, Granada, 18008, Spain
| | - Juan Manuel Ruiz-Lozano
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), C/Profesor Albareda, Granada, 18008, Spain
| | - Carmen R Beuzón
- Department of Cellular Biology, Genetics and Physiology, Campus de Teatinos, University of Málaga, Málaga, 29010, Spain
| | - Ricardo Aroca
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (CSIC), C/Profesor Albareda, Granada, 18008, Spain.
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94
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Martínez-Ballesta MDC, Carvajal M. Mutual Interactions between Aquaporins and Membrane Components. FRONTIERS IN PLANT SCIENCE 2016; 7:1322. [PMID: 27625676 PMCID: PMC5003842 DOI: 10.3389/fpls.2016.01322] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/18/2016] [Indexed: 05/08/2023]
Abstract
In recent years, a number of studies have been focused on the structural evaluation of protein complexes in order to get mechanistic insights into how proteins communicate at the molecular level within the cell. Specific sites of protein-aquaporin interaction have been evaluated and new forms of regulation of aquaporins described, based on these associations. Heterotetramerizations of aquaporin isoforms are considered as novel regulatory mechanisms for plasma membrane (PIPs) and tonoplast (TIPs) proteins, influencing their intrinsic permeability and trafficking dynamics in the adaptive response to changing environmental conditions. However, protein-protein interaction is an extensive theme that is difficult to tackle and new methodologies are being used to study the physical interactions involved. Bimolecular fluorescence complementation and the identification of cross-linked peptides based on tandem mass spectra, that are complementary to other methodologies such as heterologous expression, co-precipitation assays or confocal fluorescence microscopy, are discussed in this review. The chemical composition and the physical characteristics of the lipid bilayer also influence many aspects of membrane aquaporins, including their functionality. The molecular driving forces stabilizing the positions of the lipids around aquaporins could define their activity, thereby altering the conformational properties. Therefore, an integrative approach to the relevance of the membrane-aquaporin interaction to different processes related to plant cell physiology is provided. Finally, it is described how the interactions between aquaporins and copolymer matrixes or biological compounds offer an opportunity for the functional incorporation of aquaporins into new biotechnological advances.
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Affiliation(s)
| | - Micaela Carvajal
- Plant Nutrition Department, Aquaporins Group, Centro de Edafología y Biología Aplicada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC)Murcia, Spain
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95
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Autophagy-associated alpha-arrestin signaling is required for conidiogenous cell development in Magnaporthe oryzae. Sci Rep 2016; 6:30963. [PMID: 27498554 PMCID: PMC4976345 DOI: 10.1038/srep30963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 07/10/2016] [Indexed: 01/06/2023] Open
Abstract
Conidiation patterning is evolutionarily complex and mechanism concerning conidiogenous cell differentiation remains largely unknown. Magnaporthe oryzae conidiates in a sympodial way and uses its conidia to infect host and disseminate blast disease. Arrestins are multifunctional proteins that modulate receptor down-regulation and scaffold components of intracellular trafficking routes. We here report an alpha-arrestin that regulates patterns of conidiation and contributes to pathogenicity in M. oryzae. We show that disruption of ARRDC1 generates mutants which produce conidia in an acropetal array and ARRDC1 significantly affects expression profile of CCA1, a virulence-related transcription factor required for conidiogenous cell differentiation. Although germ tubes normally develop appressoria, penetration peg formation is dramatically impaired and Δarrdc1 mutants are mostly nonpathogenic. Fluorescent analysis indicates that EGFP-ARRDC1 puncta are well colocalized with DsRed2-Atg8, and this distribution profile could not be altered in Δatg9 mutants, suggesting ARRDC1 enters into autophagic flux before autophagosome maturation. We propose that M. oryzae employs ARRDC1 to regulate specific receptors in response to conidiation-related signals for conidiogenous cell differentiation and utilize autophagosomes for desensitization of conidiogenous receptor, which transmits extracellular signal to the downstream elements of transcription factors. Our investigation extends novel significance of autophagy-associated alpha-arrestin signaling to fungal parasites.
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96
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Li F, Liu J, Liu N, Kuhn LA, Garavito RM, Ferguson-Miller S. Translocator Protein 18 kDa (TSPO): An Old Protein with New Functions? Biochemistry 2016; 55:2821-31. [PMID: 27074410 DOI: 10.1021/acs.biochem.6b00142] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translocator protein 18 kDa (TSPO) was previously known as the peripheral benzodiazepine receptor (PBR) in eukaryotes, where it is mainly localized to the mitochondrial outer membrane. Considerable evidence indicates that it plays regulatory roles in steroidogenesis and apoptosis and is involved in various human diseases, such as metastatic cancer, Alzheimer's and Parkinson's disease, inflammation, and anxiety disorders. Ligands of TSPO are widely used as diagnostic tools and treatment options, despite there being no clear understanding of the function of TSPO. An ortholog in the photosynthetic bacterium Rhodobacter was independently discovered as the tryptophan-rich sensory protein (TspO) and found to play a role in the response to changes in oxygen and light conditions that regulate photosynthesis and respiration. As part of this highly conserved protein family found in all three kingdoms, the rat TSPO is able to rescue the knockout phenotype in Rhodobacter, indicating functional as well as structural conservation. Recently, a major breakthrough in the field was achieved: the determination of atomic-resolution structures of TSPO from different species by several independent groups. This now allows us to reexamine the function of TSPO with a molecular perspective. In this review, we focus on recently determined structures of TSPO and their implications for potential functions of this ubiquitous multifaceted protein. We suggest that TSPO is an ancient bacterial receptor/stress sensor that has developed additional interactions, partners, and roles in its mitochondrial outer membrane environment in eukaryotes.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Nan Liu
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States.,Department of Chemistry, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - Leslie A Kuhn
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States.,Department of Computer Science and Engineering, Michigan State University , East Lansing, Michigan 48824-1319, United States
| | - R Michael Garavito
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University , East Lansing, Michigan 48824, United States
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97
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Guilarte TR, Loth MK, Guariglia SR. TSPO Finds NOX2 in Microglia for Redox Homeostasis. Trends Pharmacol Sci 2016; 37:334-343. [PMID: 27113160 DOI: 10.1016/j.tips.2016.02.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 01/22/2016] [Accepted: 02/25/2016] [Indexed: 10/21/2022]
Abstract
During the past decade, translocator protein 18 kDa (TSPO), previously named peripheral benzodiazepine receptor, has gained a great deal of attention based on its use as a clinical biomarker of neuroinflammation with therapeutic potential. However, there is a paucity of knowledge on the function(s) of TSPO in glial cells. Here, we identify a novel function of TSPO in microglia that is not associated with steroidogenesis. We propose that a TSPO interaction with NADPH oxidase (NOX2) links the generation of reactive oxygen species (ROS) to the induction of an antioxidant response to maintain redox homeostasis. This line of investigation may provide a greater understanding of TSPO glial cell biology, and the knowledge gained may prove beneficial in devising therapeutic strategies.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA.
| | - Meredith K Loth
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Sara R Guariglia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
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98
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The Roles of Aquaporins in Plant Stress Responses. J Dev Biol 2016; 4:jdb4010009. [PMID: 29615577 PMCID: PMC5831814 DOI: 10.3390/jdb4010009] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 01/30/2016] [Accepted: 02/01/2016] [Indexed: 12/26/2022] Open
Abstract
Aquaporins are membrane channel proteins ubiquitously present in all kingdoms of life. Although aquaporins were originally discovered as water channels, their roles in the transport of small neutral solutes, gasses, and metal ions are now well established. Plants contain the largest number and greatest diversity of aquaporin homologs with diverse subcellular localization patterns, gating properties, and solute specificity. The roles of aquaporins in physiological functions throughout plant growth and development are well known. As an integral regulator of plant–water relations, they are presumed to play an important role in plant defense responses against biotic and abiotic stressors. This review highlights involvement of various aquaporin homologs in plant stress responses against a variety of environmental stresses that disturb plant cell osmotic balance and nutrient homeostasis.
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99
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Michaeli S, Galili G, Genschik P, Fernie AR, Avin-Wittenberg T. Autophagy in Plants--What's New on the Menu? TRENDS IN PLANT SCIENCE 2016; 21:134-144. [PMID: 26598298 DOI: 10.1016/j.tplants.2015.10.008] [Citation(s) in RCA: 153] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/22/2015] [Accepted: 10/13/2015] [Indexed: 05/02/2023]
Abstract
Autophagy is a major cellular degradation pathway in eukaryotes. Recent studies have revealed the importance of autophagy in many aspects of plant life, including seedling establishment, plant development, stress resistance, metabolism, and reproduction. This is manifested by the dual ability of autophagy to execute bulk degradation under severe environmental conditions, while simultaneously to be highly selective in targeting specific compartments and protein complexes to regulate key cellular processes, even during favorable growth conditions. Delivery of cellular components to the vacuole enables their recycling, affecting the plant metabolome, especially under stress. Recent research in Arabidopsis has further unveiled fundamental mechanistic aspects in autophagy which may have relevance in non-plant systems. We review the most recent discoveries concerning autophagy in plants, touching upon all these aspects.
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Affiliation(s)
- Simon Michaeli
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique (CNRS)/Institut National de la Recherche Agronomique (INRA)/Université de Montpellier 2 (UM2)/SupAgro, 2 Place Viala, 34060 Montpellier, France
| | - Gad Galili
- Weizmann Institute of Science, 234 Herzl Street, 7610001 Rehovot, Israel
| | - Pascal Genschik
- Institut de Biologie Moléculaire des Plantes, CNRS Unité Propre de Recherche 2357, Conventionné avec l'Université de Strasbourg, 67084 Strasbourg, France
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Tamar Avin-Wittenberg
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam, Germany.
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100
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Wang W, Xu M, Wang G, Galili G. Autophagy: An Important Biological Process That Protects Plants from Stressful Environments. FRONTIERS IN PLANT SCIENCE 2016; 7:2030. [PMID: 28123390 PMCID: PMC5225088 DOI: 10.3389/fpls.2016.02030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/19/2016] [Indexed: 05/20/2023]
Affiliation(s)
- Wenyi Wang
- Department of Plant Science, Weizmann Institute of ScienceRehovot, Israel
- College of Horticulture, South China Agricultural UniversityGuangzhou, China
| | - Mengyun Xu
- College of Horticulture, South China Agricultural UniversityGuangzhou, China
| | - Guoping Wang
- College of Horticulture, South China Agricultural UniversityGuangzhou, China
- *Correspondence: Guoping Wang
| | - Gad Galili
- Department of Plant Science, Weizmann Institute of ScienceRehovot, Israel
- Gad Galili
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