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Adhikari B, Gayral M, Herath V, Bedsole CO, Kumar S, Ball H, Atallah O, Shaw B, Pajerowska-Mukhtar KM, Verchot J. bZIP60 and Bax inhibitor 1 contribute IRE1-dependent and independent roles to potexvirus infection. THE NEW PHYTOLOGIST 2024; 243:1172-1189. [PMID: 38853429 DOI: 10.1111/nph.19882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 05/14/2024] [Indexed: 06/11/2024]
Abstract
IRE1, BI-1, and bZIP60 monitor compatible plant-potexvirus interactions though recognition of the viral TGB3 protein. This study was undertaken to elucidate the roles of three IRE1 isoforms, the bZIP60U and bZIP60S, and BI-1 roles in genetic reprogramming of cells during potexvirus infection. Experiments were performed using Arabidopsis thaliana knockout lines and Plantago asiatica mosaic virus infectious clone tagged with the green fluorescent protein gene (PlAMV-GFP). There were more PlAMV-GFP infection foci in ire1a/b, ire1c, bzip60, and bi-1 knockout than wild-type (WT) plants. Cell-to-cell movement and systemic RNA levels were greater bzip60 and bi-1 than in WT plants. Overall, these data indicate an increased susceptibility to virus infection. Transgenic overexpression of AtIRE1b or StbZIP60 in ire1a/b or bzip60 mutant background reduced virus infection foci, while StbZIP60 expression influences virus movement. Transgenic overexpression of StbZIP60 also confers endoplasmic reticulum (ER) stress resistance following tunicamycin treatment. We also show bZIP60U and TGB3 interact at the ER. This is the first demonstration of a potato bZIP transcription factor complementing genetic defects in Arabidopsis. Evidence indicates that the three IRE1 isoforms regulate the initial stages of virus replication and gene expression, while bZIP60 and BI-1 contribute separately to virus cell-to-cell and systemic movement.
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Affiliation(s)
- Binita Adhikari
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
| | - Mathieu Gayral
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
- Agroécologie, INRAE, Institut Agro Dijon, Université de Bourgogne, 26, bd Docteur Petitjean-BP 87999, Dijon, Cedex, 21079, France
| | - Venura Herath
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
- Department of Agricultural Biology, Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Caleb Oliver Bedsole
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
| | - Sandeep Kumar
- Department of Plant Pathology, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, 751003, India
| | - Haden Ball
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
| | - Osama Atallah
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
| | - Brian Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
| | | | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, 496 Olsen Blvd, College Station, TX, 77845, USA
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Ontiveros I, Fernández-Pozo N, Esteve-Codina A, López-Moya JJ, Díaz-Pendón JA. Enhanced Susceptibility to Tomato Chlorosis Virus (ToCV) in Hsp90- and Sgt1-Silenced Plants: Insights from Gene Expression Dynamics. Viruses 2023; 15:2370. [PMID: 38140611 PMCID: PMC10747942 DOI: 10.3390/v15122370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
The emerging whitefly-transmitted crinivirus tomato chlorosis virus (ToCV) causes substantial economic losses by inducing yellow leaf disorder in tomato crops. This study explores potential resistance mechanisms by examining early-stage molecular responses to ToCV. A time-course transcriptome analysis compared naïve, mock, and ToCV-infected plants at 2, 7, and 14 days post-infection (dpi). Gene expression changes were most notable at 2 and 14 dpi, likely corresponding to whitefly feeding and viral infection. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed key genes and pathways associated with ToCV infection, including those related to plant immunity, flavonoid and steroid biosynthesis, photosynthesis, and hormone signaling. Additionally, virus-derived small interfering RNAs (vsRNAs) originating from ToCV predominantly came from RNA2 and were 22 nucleotides in length. Furthermore, two genes involved in plant immunity, Hsp90 (heat shock protein 90) and its co-chaperone Sgt1 (suppressor of the G2 allele of Skp1) were targeted through viral-induced gene silencing (VIGS), showing a potential contribution to basal resistance against viral infections since their reduction correlated with increased ToCV accumulation. This study provides insights into tomato plant responses to ToCV, with potential implications for developing effective disease control strategies.
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Affiliation(s)
- Irene Ontiveros
- Institute for Mediterranean and Subtropical Horticulture La Mayora (IHSM), CSIC-UMA, 29750 Algarrobo-Costa, Spain; (I.O.); (N.F.-P.)
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, 08913 Bellaterra, Spain
| | - Noé Fernández-Pozo
- Institute for Mediterranean and Subtropical Horticulture La Mayora (IHSM), CSIC-UMA, 29750 Algarrobo-Costa, Spain; (I.O.); (N.F.-P.)
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain;
| | - Juan José López-Moya
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, 08913 Bellaterra, Spain
| | - Juan Antonio Díaz-Pendón
- Institute for Mediterranean and Subtropical Horticulture La Mayora (IHSM), CSIC-UMA, 29750 Algarrobo-Costa, Spain; (I.O.); (N.F.-P.)
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Herath V, Verchot J. Comprehensive Transcriptome Analysis Reveals Genome-Wide Changes Associated with Endoplasmic Reticulum (ER) Stress in Potato ( Solanum tuberosum L.). Int J Mol Sci 2022; 23:ijms232213795. [PMID: 36430273 PMCID: PMC9696714 DOI: 10.3390/ijms232213795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/11/2022] Open
Abstract
We treated potato (Solanum tuberosum L.) plantlets with TM and performed gene expression studies to identify genome-wide changes associated with endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). An extensive network of responses was identified, including chromatin remodeling, transcriptional reprogramming, as well as changes in the structural components of the endomembrane network system. Limited genome-wide changes in alternative RNA splicing patterns of protein-coding transcripts were also discovered. Significant changes in RNA metabolism, components of the translation machinery, as well as factors involved in protein folding and maturation occurred, which included a broader set of genes than expected based on Arabidopsis research. Antioxidant defenses and oxygen metabolic enzymes are differentially regulated, which is expected of cells that may be experiencing oxidative stress or adapting to protect proteins from oxidation. Surges in protein kinase expression indicated early signal transduction events. This study shows early genomic responses including an array of differentially expressed genes that have not been reported in Arabidopsis. These data describe novel ER stress responses in a solanaceous host.
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Affiliation(s)
- Venura Herath
- Department of Agriculture Biology, Faculty of Agriculture, University of Peradeniya, Peradeniya 20400, Sri Lanka
| | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77802, USA
- Correspondence: ; Tel.: +1-979-568-6369
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Xu Z, Song N, Ma L, Wu J. IRE1-bZIP60 Pathway Is Required for Nicotiana attenuata Resistance to Fungal Pathogen Alternaria alternata. FRONTIERS IN PLANT SCIENCE 2019; 10:263. [PMID: 30941151 PMCID: PMC6434776 DOI: 10.3389/fpls.2019.00263] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 02/19/2019] [Indexed: 05/21/2023]
Abstract
As an endoplasmic reticulum (ER) stress sensor, inositol-requiring enzyme 1 (IRE1) splices the bZIP60 mRNA, and produces an active bZIP60 transcription factor that regulates genes involved in the unfolded protein response (UPR) during ER stresses. This IRE1-bZIP60 pathway is conserved in plant species and recently implicated in plant-pathogen interaction. However, it is unclear whether this IRE1-bZIP60 pathway is involved in Nicotiana attenuata resistance to necrotic fungal pathogen, Alternaria alternata. In this study, transcriptional levels of chaperone protein genes, including luminal binding protein (BiP), protein disulfide isomerase (PDI), calnexin 1-like (CNX 1-like), and calreticulin (CRT), and genes involved in IRE1-bZIP60 pathway, were all significantly induced in N. attenuata leaves after A. alternata inoculation. Silencing IRE1 or bZIP60 led to N. attenuata plants more susceptible to A. alternata, which were associated with reduced gene expressions of Feruloyl-CoA 6'-hydroxylase 1 (F6'H1), a gene encoding a key enzyme for phytoalexin scopoletin and scopolin biosynthesis. Further, electromobility shift assays (EMSA) indicated that bZIP60 protein of spliced form could directly bind to the promoter region of F6'H1 in vitro. JA signaling pathway is required for N. attenuata resistance to A. alternata. Interestingly, the fungus-elicited transcriptional levels of BiP, PDI, CNX 1-like, CRT, IRE1, and bZIP60(s) were all significantly decreased in JA-deficient or JA-insensitive plants. Meanwhile, those genes were significantly induced by methyl jasmonate (MeJA) when applied exogenously. However, the transcriptional levels of JA-regulated genes allene oxide synthase (AOS) and lipoxygenease 3 (LOX3) were not affected in plants impaired with IRE1-bZIP60 pathway. Thus, it is concluded that IRE1-bZIP60 pathway is required for N. attenuata resistance to A. alternata, and JA signaling pathway plays an important role in the elicitation of chaperone protein genes and IRE1-bZIP60 pathway.
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Affiliation(s)
- Zhen Xu
- Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Na Song
- Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lan Ma
- Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Jinsong Wu
- Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Park CJ, Park JM. Endoplasmic Reticulum Plays a Critical Role in Integrating Signals Generated by Both Biotic and Abiotic Stress in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:399. [PMID: 31019523 PMCID: PMC6458287 DOI: 10.3389/fpls.2019.00399] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/15/2019] [Indexed: 05/19/2023]
Abstract
Most studies of environmental adaptations in plants have focused on either biotic or abiotic stress factors in an attempt to understand the defense mechanisms of plants against individual stresses. However, in the natural ecosystem, plants are simultaneously exposed to multiple stresses. Stress-tolerant crops developed in translational studies based on a single stress often fail to exhibit the expected traits in the field. To adapt to abiotic stress, recent studies have identified the need for interactions of plants with various microorganisms. These findings highlight the need to understand the multifaceted interactions of plants with biotic and abiotic stress factors. The endoplasmic reticulum (ER) is an organelle that links various stress responses. To gain insight into the molecular integration of biotic and abiotic stress responses in the ER, we focused on the interactions of plants with RNA viruses. This interaction points toward the relevance of ER in viral pathogenicity as well as plant responses. In this mini review, we explore the molecular crosstalk between biotic and abiotic stress signaling through the ER by elaborating ER-mediated signaling in response to RNA viruses and abiotic stresses. Additionally, we summarize the results of a recent study on phytohormones that induce ER-mediated stress response. These studies will facilitate the development of multi-stress-tolerant transgenic crops in the future.
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Affiliation(s)
- Chang-Jin Park
- Department of Bioresources Engineering, Sejong University, Seoul, South Korea
- Plant Engineering Research Institute, Sejong University, Seoul, South Korea
- *Correspondence: Chang-Jin Park,
| | - Jeong Mee Park
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, South Korea
- Department of Biosystems and Bioengineering, University of Science and Technology (UST), Daejeon, South Korea
- Jeong Mee Park,
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Qian X, Xiang Q, Yang T, Ma H, Ding XS, Tao X. Molecular Co-Chaperone SGT1 Is Critical for Cell-to-Cell Movement and Systemic Infection of Tomato Spotted Wild Virus in Nicotiana benthamiana. Viruses 2018; 10:E647. [PMID: 30453630 PMCID: PMC6267219 DOI: 10.3390/v10110647] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 11/06/2018] [Accepted: 11/15/2018] [Indexed: 12/20/2022] Open
Abstract
Tospovirus is a tripartite negative stranded RNA virus and is considered as one of the most devastating plant viruses. Successful virus infection in plant requires many host factors. To date, very few host factors have been identified as important in Tospovirus infection in plants. We reported earlier that NSm protein encoded by Tomato spotted wilt virus (TSWV), a type species of the genus Orthotospovirus, plays critical roles in viral cell-to-cell and long-distance movement. In this study, we determined that molecular co-chaperone NbSGT1 interacted with TSWV NSm in Nicotianabenthamiana. TSWV infection significantly upregulated the expression of NbSGT1 gene and transient overexpression of NbSGT1 in N.benthamiana leaves accelerated TSWV infection. In contrast, silencing the NbSGT1 gene expression using a virus-induced gene silencing (VIGS) approach strongly inhibited TSWV NSm cell-to-cell movement, as well as TSWV local and systemic infection in N.benthamiana plants. Furthermore, NbSGT1 was found to regulate the infection of both American and Euro/Asia type tospoviruses in N.benthamiana plant. Collectively, our findings presented in this paper and the results published previously indicated that molecular co-chaperone NbSGT1 plays important roles in modulating both positive stranded and tripartite negative stranded RNA virus infection in plants.
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Affiliation(s)
- Xin Qian
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Qing Xiang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Tongqing Yang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Hongyu Ma
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Xin Shun Ding
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Xiaorong Tao
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
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Gorovits R, Czosnek H. The Involvement of Heat Shock Proteins in the Establishment of Tomato Yellow Leaf Curl Virus Infection. FRONTIERS IN PLANT SCIENCE 2017; 8:355. [PMID: 28360921 PMCID: PMC5352662 DOI: 10.3389/fpls.2017.00355] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/01/2017] [Indexed: 05/07/2023]
Abstract
Tomato yellow leaf curl virus (TYLCV), a begomovirus, induces protein aggregation in infected tomatoes and in its whitefly vector Bemisia tabaci. The interactions between TYLCV and HSP70 and HSP90 in plants and vectors are necessity for virus infection to proceed. In infected host cells, HSP70 and HSP90 are redistributed from a soluble to an aggregated state. These aggregates contain, together with viral DNA/proteins and virions, HSPs and components of the protein quality control system such as ubiquitin, 26S proteasome subunits, and the autophagy protein ATG8. TYLCV CP can form complexes with HSPs in tomato and whitefly. Nonetheless, HSP70 and HSP90 play different roles in the viral cell cycle in the plant host. In the infected host cell, HSP70, but not HSP90, participates in the translocation of CP from the cytoplasm into the nucleus. Viral amounts decrease when HSP70 is inhibited, but increase when HSP90 is downregulated. In the whitefly vector, HSP70 impairs the circulative transmission of TYLCV; its inhibition increases transmission. Hence, the efficiency of virus acquisition by whiteflies depends on the functionality of both plant chaperones and their cross-talk with other protein mechanisms controlling virus-induced aggregation.
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Moon JY, Lee JH, Oh C, Kang H, Park JM. Endoplasmic reticulum stress responses function in the HRT-mediated hypersensitive response in Nicotiana benthamiana. MOLECULAR PLANT PATHOLOGY 2016; 17:1382-1397. [PMID: 26780303 PMCID: PMC6638521 DOI: 10.1111/mpp.12369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 01/10/2016] [Accepted: 01/11/2016] [Indexed: 05/08/2023]
Abstract
HRT is a plant coiled-coil, nucleotide-binding and leucine-rich repeat (CC-NB-LRR) disease resistance protein that triggers the hypersensitive response (HR) on recognition of Turnip crinkle virus (TCV) coat protein (CP). The molecular mechanism and significance of HR-mediated cell death for TCV resistance have not been fully elucidated. To identify the genes involved in HRT/TCV CP-mediated HR in Nicotiana benthamiana, we performed virus-induced gene silencing (VIGS) of 459 expressed sequence tags (ESTs) of pathogen-responsive Capsicum annuum genes. VIGS of CaBLP5, which encodes an endoplasmic reticulum (ER)-associated immunoglobulin-binding protein (BiP), silenced NbBiP4 and NbBiP5 and significantly reduced HRT-mediated HR. The induction of ER stress-responsive genes and the accumulation of ER-targeted BiPs in response to HRT-mediated HR suggest that ER is involved in HR in N. benthamiana. BiP4/5 silencing significantly down-regulated HRT at the mRNA and protein levels, and affected SGT1 and HSP90 expression. Co-expression of TCV CP in BiP4/5-silenced plants completely abolished HRT induction. Transient expression of TCV CP alone induced selected ER stress-responsive gene transcripts only in Tobacco rattle virus (TRV)-infected plants, and most of these genes were induced by HRT/TCV CP, except for bZIP60, which was induced specifically in response to HRT/TCV CP. TCV CP-mediated induction of ER stress-responsive genes still occurred in BiP4/5-silenced plants, but HRT/TCV CP-mediated induction of these genes was defective. Tunicamycin, a chemical that inhibits protein N-glycosylation, inhibited HRT-mediated HR, suggesting that ER has a role in HR regulation. These results indicate that BiP and ER, which modulate pattern recognition receptors in innate immunity, also regulate R protein-mediated resistance.
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Affiliation(s)
- Ju Yeon Moon
- Molecular Biofarming Research CenterKRIBBDaejeon305‐600South Korea
- Department of Biosystems and BioengineeringUSTDaejeon305‐350South Korea
| | - Jeong Hee Lee
- Molecular Biofarming Research CenterKRIBBDaejeon305‐600South Korea
| | - Chang‐Sik Oh
- Department of HorticultureKyung Hee UniversityYongin446‐701South Korea
| | - Hong‐Gu Kang
- Department of BiologyTexas State UniversitySan MarcosTX78666USA
| | - Jeong Mee Park
- Molecular Biofarming Research CenterKRIBBDaejeon305‐600South Korea
- Department of Biosystems and BioengineeringUSTDaejeon305‐350South Korea
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Wan S, Jiang L. Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) in plants. PROTOPLASMA 2016; 253:753-764. [PMID: 26060134 DOI: 10.1007/s00709-015-0842-1] [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: 05/29/2015] [Accepted: 05/30/2015] [Indexed: 05/03/2023]
Abstract
Being a major factory for protein synthesis, assembly, and export, the endoplasmic reticulum (ER) has a precise and robust ER quality control (ERQC) system monitoring its product line. However, when organisms are subjected to environmental stress, whether biotic or abiotic, the levels of misfolded proteins may overwhelm the ERQC system, tilting the balance between the capacity of and demand for ER quality control and resulting in a scenario termed ER stress. Intense or prolonged ER stress may cause damage to the ER as well as to other organelles, or even lead to cell death in extreme cases. To avoid such serious consequences, cells activate self-rescue programs to restore protein homeostasis in the ER, either through the enhancement of protein-folding and degradation competence or by alleviating the demands for such reactions. These are collectively called the unfolded protein response (UPR). Long investigated in mammalian cells and yeasts, the UPR is also of great interest to plant scientists. Among the three branches of UPR discovered in mammals, two have been studied in plants with plant homologs existing of the ER-membrane-associated activating transcription factor 6 (ATF6) and inositol-requiring enzyme 1 (IRE1). This review discusses the molecular mechanisms of these two types of UPR in plants, as well as the consequences of insufficient UPR, with a focus on experiments using model plants.
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Affiliation(s)
- Shucen Wan
- Molecular Biotechnology Program, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
| | - Liwen Jiang
- Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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SGT1 is required in PcINF1/SRC2-1 induced pepper defense response by interacting with SRC2-1. Sci Rep 2016; 6:21651. [PMID: 26898479 PMCID: PMC4761932 DOI: 10.1038/srep21651] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 01/28/2016] [Indexed: 02/06/2023] Open
Abstract
PcINF1 was previously found to induce pepper defense response by interacting with SRC2-1, but the underlying mechanism remains uninvestigated. Herein, we describe the involvement of SGT1 in the PcINF1/SRC2-1-induced immunity. SGT1 was observed to be up-regulated by Phytophthora capsici inoculation and synergistically transient overexpression of PcINF1/SRC2-1 in pepper plants. SGT1-silencing compromised HR cell death, blocked H2O2 accumulation, and downregulated HR-associated and hormones-dependent marker genes’ expression triggered by PcINF1/SRC2-1 co-overexpression. The interaction between SRC2-1 and SGT1 was found by the yeast two hybrid system and was further confirmed by bimolecular fluorescence complementation and co-immunoprecipitation analyses. The SGT1/SRC2-1 interaction was enhanced by transient overexpression of PcINF1 and Phytophthora capsici inoculation, and SGT1-silencing attenuated PcINF1/SRC2-1 interaction. Additionally, by modulating subcellular localizations of SRC2-1, SGT1, and the interacting complex of SGT1/SRC2-1, it was revealed that exclusive nuclear targeting of the SGT1/SRC2-1 complex blocks immunity triggered by formation of SGT1/SRC2-1, and a translocation of the SGT1/SRC2-1 complex from the plasma membrane and cytoplasm to the nuclei upon the inoculation of P. capsici. Our data demonstrate that the SGT1/SRC2-1 interaction, and its nucleocytoplasmic partitioning, is involved in pepper’s immunity against P. capsici, thus providing a molecular link between Ca2+ signaling associated SRC2-1 and SGT1-mediated defense signaling.
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Williams B, Verchot J, Dickman MB. When supply does not meet demand-ER stress and plant programmed cell death. FRONTIERS IN PLANT SCIENCE 2014; 5:211. [PMID: 24926295 DOI: 10.3389/fpls.2014.00211/abstract] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/29/2014] [Indexed: 05/24/2023]
Abstract
The endoplasmic reticulum (ER) is the central organelle in the eukaryotic secretory pathway. The ER functions in protein synthesis and maturation and is crucial for proper maintenance of cellular homeostasis and adaptation to adverse environments. Acting as a cellular sentinel, the ER is exquisitely sensitive to changing environments principally via the ER quality control machinery. When perturbed, ER-stress triggers a tightly regulated and highly conserved, signal transduction pathway known as the unfolded protein response (UPR) that prevents the dangerous accumulation of unfolded/misfolded proteins. In situations where excessive UPR activity surpasses threshold levels, cells deteriorate and eventually trigger programmed cell death (PCD) as a way for the organism to cope with dysfunctional or toxic signals. The programmed cell death that results from excessive ER stress in mammalian systems contributes to several important diseases including hypoxia, neurodegeneration, and diabetes. Importantly, hallmark features and markers of cell death that are associated with ER stress in mammals are also found in plants. In particular, there is a common, conserved set of chaperones that modulate ER cell death signaling. Here we review the elements of plant cell death responses to ER stress and note that an increasing number of plant-pathogen interactions are being identified in which the host ER is targeted by plant pathogens to establish compatibility.
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Affiliation(s)
- Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology Brisbane, QLD, Australia
| | - Jeanmarie Verchot
- Department of Entomology and Plant Pathology, Oklahoma State University Stillwater, OK, USA
| | - Martin B Dickman
- Department of Plant Pathology and Microbiology, Institute for Plant Genomics and Biotechnology, Texas A&M University College Station, TX, USA
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Williams B, Verchot J, Dickman MB. When supply does not meet demand-ER stress and plant programmed cell death. FRONTIERS IN PLANT SCIENCE 2014; 5:211. [PMID: 24926295 PMCID: PMC4045240 DOI: 10.3389/fpls.2014.00211] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 04/29/2014] [Indexed: 05/10/2023]
Abstract
The endoplasmic reticulum (ER) is the central organelle in the eukaryotic secretory pathway. The ER functions in protein synthesis and maturation and is crucial for proper maintenance of cellular homeostasis and adaptation to adverse environments. Acting as a cellular sentinel, the ER is exquisitely sensitive to changing environments principally via the ER quality control machinery. When perturbed, ER-stress triggers a tightly regulated and highly conserved, signal transduction pathway known as the unfolded protein response (UPR) that prevents the dangerous accumulation of unfolded/misfolded proteins. In situations where excessive UPR activity surpasses threshold levels, cells deteriorate and eventually trigger programmed cell death (PCD) as a way for the organism to cope with dysfunctional or toxic signals. The programmed cell death that results from excessive ER stress in mammalian systems contributes to several important diseases including hypoxia, neurodegeneration, and diabetes. Importantly, hallmark features and markers of cell death that are associated with ER stress in mammals are also found in plants. In particular, there is a common, conserved set of chaperones that modulate ER cell death signaling. Here we review the elements of plant cell death responses to ER stress and note that an increasing number of plant-pathogen interactions are being identified in which the host ER is targeted by plant pathogens to establish compatibility.
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Affiliation(s)
- Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of TechnologyBrisbane, QLD, Australia
| | - Jeanmarie Verchot
- Department of Entomology and Plant Pathology, Oklahoma State UniversityStillwater, OK, USA
| | - Martin B. Dickman
- Department of Plant Pathology and Microbiology, Institute for Plant Genomics and Biotechnology, Texas A&M UniversityCollege Station, TX, USA
- *Correspondence: Martin B. Dickman, Department of Plant Pathology and Microbiology, Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA e-mail:
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Park MR, Seo JK, Kim KH. Viral and nonviral elements in potexvirus replication and movement and in antiviral responses. Adv Virus Res 2013; 87:75-112. [PMID: 23809921 DOI: 10.1016/b978-0-12-407698-3.00003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In Potato virus X, a member of the genus Potexvirus, special sequences and structures at the 5' and 3' ends of the nontranslated region function as cis-acting elements for viral replication. These elements greatly affect interactions between viral RNAs and those between viral RNAs and host factors. The potexvirus genome encodes five open-reading frames. Viral replicase, which is required for the synthesis of viral RNA, binds viral RNA elements and host factors to form a viral replication complex at the host cellular membrane. The coat protein (CP) and three viral movement proteins (TGB1, TGB2, and TGB3) have critical roles in mediating cell-to-cell viral movement through plasmodesmata by virion formation or by nonvirion ribonucleoprotein (RNP) complex formation with viral movement proteins (TGBs). The RNP complex, like TGB1-CP-viral RNA, is associated with viral replicase and used for immediate reinitiation of viral replication in newly invaded cells. Higher plants have defense mechanisms against potexviruses such as Rx-mediated resistance and RNA silencing. The CP acts as an avirulence effector for plant defense mechanisms, while TGB1 functions as a viral suppressor of RNA silencing, which is the mechanism of innate immune resistance. Here, we describe recent findings concerning the involvement of viral and host factors in potexvirus replication and in antiviral responses to potexvirus infection.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology, Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
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14
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Solovieva AD, Frolova OY, Solovyev AG, Morozov SY, Zamyatnin AA. Effect of mitochondria-targeted antioxidant SkQ1 on programmed cell death induced by viral proteins in tobacco plants. BIOCHEMISTRY. BIOKHIMIIA 2013; 78:1006-12. [PMID: 24228922 DOI: 10.1134/s000629791309006x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Programmed cell death (PCD) is the main defense mechanism in plants to fight various pathogens including viruses. The best-studied example of virus-induced PCD in plants is Tobacco mosaic virus (TMV)-elicited hypersensitive response in tobacco plants containing the N resistance gene. It was previously reported that the animal mitochondrial protein Bcl-xL, which lacks a homolog in plants, effectively suppresses plant PCD induced by TMV p50 - the elicitor of hypersensitive response in Nicotiana tabacum carrying the N gene. Our studies show that the mitochondria-targeted antioxidant SkQ1 effectively suppresses p50-induced PCD in tobacco plants. On the other hand, SkQ1 did not affect Poa semilatent virus TGB3-induced endoplasmic reticulum stress, which is followed by PCD, in Nicotiana benthamiana epidermal cells. These data suggest that mitochondria-targeted antioxidant SkQ1 can be used to study molecular mechanisms of PCD suppression in plants.
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Affiliation(s)
- A D Solovieva
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
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15
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Carmo LST, Resende RO, Silva LP, Ribeiro SG, Mehta A. Identification of host proteins modulated by the virulence factor AC2 of Tomato chlorotic mottle virus in Nicotiana benthamiana. Proteomics 2013; 13:1947-60. [PMID: 23533094 DOI: 10.1002/pmic.201200547] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/08/2013] [Accepted: 02/25/2013] [Indexed: 11/09/2022]
Abstract
Tomato, one of the most important crops cultivated worldwide, has been severely affected by begomoviruses such as the Tomato chlorotic mottle virus (ToCMoV). Virulence factor AC2 is considered crucial for a successful virus-plant interaction and is known to act as a transcriptional activator and in some begomoviruses to function as an RNA silencing suppressor factor. However, the exact functions of the AC2 protein of the begomovirus ToCMoV are not yet established. The aim of the present study was to identify differentially expressed proteins of the model plant Nicotiana benthamiana in response to the expression of the AC2 gene, isolated from ToCMoV. N. benthamiana plants were inoculated with Agrobacterium tumefaciens containing the viral vector Potato virus X (PVX) and with the PVX-AC2 construction. 2DE was performed and proteins were identified by MS. The results showed that the expression of ToCMoV AC2 alters the levels of several host proteins, which are important for normal plant development, causing an imbalance in cellular homeostasis. This study highlights the effect of AC2 in the modulation of plant defense processes by increasing the expression of several oxidative stress-related and pathogenesis-related proteins, as well as its role in modulating the proteome of the photosynthesis and energy production systems.
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16
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Ye CM, Chen S, Payton M, Dickman MB, Verchot J. TGBp3 triggers the unfolded protein response and SKP1-dependent programmed cell death. MOLECULAR PLANT PATHOLOGY 2013; 14:241-55. [PMID: 23458484 PMCID: PMC6638746 DOI: 10.1111/mpp.12000] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The Potato virus X (PVX) triple gene block protein 3 (TGBp3), an 8-kDa membrane binding protein, aids virus movement and induces the unfolded protein response (UPR) during PVX infection. TGBp3 was expressed from the Tobacco mosaic virus (TMV) genome (TMV-p3), and we noted the up-regulation of SKP1 and several endoplasmic reticulum (ER)-resident chaperones, including the ER luminal binding protein (BiP), protein disulphide isomerase (PDI), calreticulin (CRT) and calmodulin (CAM). Local lesions were seen on leaves inoculated with TMV-p3, but not TMV or PVX. Such lesions were the result of TGBp3-elicited programmed cell death (PCD), as shown by an increase in reactive oxygen species, DNA fragmentation and induction of SKP1 expression. UPR-related gene expression occurred within 8 h of TMV-p3 inoculation and declined before the onset of PCD. TGBp3-mediated cell death was suppressed in plants that overexpressed BiP, indicating that UPR induction by TGBp3 is a pro-survival mechanism. Anti-apoptotic genes Bcl-xl, CED-9 and Op-IAP were expressed in transgenic plants and suppressed N gene-mediated resistance to TMV, but failed to alleviate TGBp3-induced PCD. However, TGBp3-mediated cell death was reduced in SKP1-silenced Nicotiana benthamiana plants. The combined data suggest that TGBp3 triggers the UPR and elicits PCD in plants.
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Affiliation(s)
- Chang-Ming Ye
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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17
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Ye CM, Chen S, Payton M, Dickman MB, Verchot J. TGBp3 triggers the unfolded protein response and SKP1-dependent programmed cell death. MOLECULAR PLANT PATHOLOGY 2013. [PMID: 23458484 DOI: 10.1111/mpp.12000 [epub ahead of print]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Potato virus X (PVX) triple gene block protein 3 (TGBp3), an 8-kDa membrane binding protein, aids virus movement and induces the unfolded protein response (UPR) during PVX infection. TGBp3 was expressed from the Tobacco mosaic virus (TMV) genome (TMV-p3), and we noted the up-regulation of SKP1 and several endoplasmic reticulum (ER)-resident chaperones, including the ER luminal binding protein (BiP), protein disulphide isomerase (PDI), calreticulin (CRT) and calmodulin (CAM). Local lesions were seen on leaves inoculated with TMV-p3, but not TMV or PVX. Such lesions were the result of TGBp3-elicited programmed cell death (PCD), as shown by an increase in reactive oxygen species, DNA fragmentation and induction of SKP1 expression. UPR-related gene expression occurred within 8 h of TMV-p3 inoculation and declined before the onset of PCD. TGBp3-mediated cell death was suppressed in plants that overexpressed BiP, indicating that UPR induction by TGBp3 is a pro-survival mechanism. Anti-apoptotic genes Bcl-xl, CED-9 and Op-IAP were expressed in transgenic plants and suppressed N gene-mediated resistance to TMV, but failed to alleviate TGBp3-induced PCD. However, TGBp3-mediated cell death was reduced in SKP1-silenced Nicotiana benthamiana plants. The combined data suggest that TGBp3 triggers the UPR and elicits PCD in plants.
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Affiliation(s)
- Chang-Ming Ye
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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18
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Solovyev AG, Kalinina NO, Morozov SY. Recent advances in research of plant virus movement mediated by triple gene block. FRONTIERS IN PLANT SCIENCE 2012; 3:276. [PMID: 23248633 PMCID: PMC3520053 DOI: 10.3389/fpls.2012.00276] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 11/23/2012] [Indexed: 05/19/2023]
Abstract
The aim of this short review was to summarize recent advances in the field of viral cell-to-cell movement mediated by the triple gene block (TGB). The growing body of new research has uncovered links between virus cell-to-cell trafficking and replication, silencing suppression, virus spread over the plant, as well as suggested the roles of nucleus/nucleolus in plant virus transport and revealed protein-membrane associations occurring during subcellular targeting and cell-to-cell movement. In this context, our review briefly summarized current views on several potentially important functions of TGB proteins and on the development of new experimental systems that improved understanding of the molecular events during TGB-mediated virus movement.
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Affiliation(s)
- Andrey G. Solovyev
- Belozersky Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
| | - Natalia O. Kalinina
- Belozersky Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
| | - Sergey Y. Morozov
- Belozersky Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
- *Correspondence: Sergey Y. Morozov, Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia. e-mail:
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