1
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Ngo AH, Angkawijaya AE, Nakamura Y, Kanehara K. Non-specific phospholipase C3 is involved in endoplasmic reticulum stress tolerance in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2024:erae303. [PMID: 39169567 DOI: 10.1093/jxb/erae303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 07/31/2024] [Indexed: 08/23/2024]
Abstract
Non-specific phospholipase C (NPC) is an emerging family of lipolytic enzymes unique to plants and bacteria that play crucial roles in growth and stress responses. Among six copies of NPC isoforms found in Arabidopsis, the role of NPC3 remains elusive to date. Here, we show that NPC3 is a functional non-specific phospholipase C involved in tolerance to tunicamycin (TM)-induced endoplasmic reticulum (ER) stress through the synthesis of phosphocholine (PCho), a reaction product of NPC3. The npc3 mutant exhibited reduced sensitivity to TM treatment. Recombinant NPC3 possessed pronounced phospholipase C activity that hydrolyses phosphatidylcholine (PC). The hyposensitivity of npc3 to TM treatment was complemented by exogenous PCho, suggesting that NPC3-catalysed PCho production is involved in TM-induced ER stress tolerance. NPC3 was localized at the ER and was predominantly expressed in the roots, and it was further induced by TM-induced ER stress. Intriguingly, npc3 mutants showed a markedly reduced PCho content in shoots under ER stress. Our results indicate that ER stress induces NPC3 to produce PCho, which is involved in TM-induced ER stress tolerance.
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Affiliation(s)
- Anh H Ngo
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, Japan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | | | - Yuki Nakamura
- RIKEN Center for Sustainable Resource Science (CSRS), Yokohama, Japan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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2
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Demircan N, Ozgur R, Turkan I, Uzilday B. Heavy metal toxicity leads to accumulation of insoluble proteins and induces endoplasmic reticulum stress-specific unfolded protein response in Arabidopsis thaliana. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:53206-53218. [PMID: 39180659 DOI: 10.1007/s11356-024-34780-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 08/19/2024] [Indexed: 08/26/2024]
Abstract
Unfolded protein accumulation in the endoplasmic reticulum (ER) triggers ER stress, leading to a unique transcriptomic response called unfolded protein response (UPR). While ER stress is linked to various environmental stresses, its role in plant responses to heavy metal toxicity remains unclear. This study aimed to elucidate if heavy metals Fe, Zn, Cu, and As induce ER stress in plants. For this purpose, Arabidopsis thaliana seedlings were treated with Fe (200, 400 µM), Zn (500, 700 µM), Cu (25, 50 µM), and As (250, 500 µM) for 7 days, which resulted in 50-70% decrease in plant growth. All treatments increased insoluble protein levels, indicating unfolded protein accumulation, with the highest induction observed for 50 µM Cu treatment (fivefold). Expressions of genes involved in the perception and signaling of ER stress (IRE1, bZIP28, bZIP60, bZIP17) indicate that Zn toxicity specifically induces bZIP28 but not the IRE1 branch of UPR. All metals except Fe also induced genes associated with protein folding in the ER (BIP1, BIP3, and CNX) and ER-associated protein degradation (ERAD) (HRD1). This finding indicates Zn, Cu, and As but not Fe cause ER stress in plants. Furthermore, increased expression of ER oxidoreductase 1 (ERO1) suggests that metal toxicity also disrupts oxidative protein folding in the ER lumen. This study enhances our understanding of the intricate interplay between essential nutrients, metal toxicity, protein folding machinery, and ER stress, demonstrating that heavy metal toxicity has an ER stress component in plants alongside its established effects on energy metabolism, membrane integrity, and oxidative stress.
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Affiliation(s)
- Nil Demircan
- Department of Biology, Faculty of Science, Ege University, 35100, Bornova, İzmir, Turkey
| | - Rengin Ozgur
- Department of Biology, Faculty of Science, Ege University, 35100, Bornova, İzmir, Turkey
| | - Ismail Turkan
- Department of Soil and Plant Nutrition, Faculty of Agricultural Sciences and Technologies, Yasar University, 35100, Bornova, İzmir, Turkey
| | - Baris Uzilday
- Department of Biology, Faculty of Science, Ege University, 35100, Bornova, İzmir, Turkey.
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3
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Hammel A, Cucos LM, Caras I, Ionescu I, Tucureanu C, Tofan V, Costache A, Onu A, Hoepfner L, Hippler M, Neupert J, Popescu CI, Stavaru C, Branza-Nichita N, Bock R. The red alga Porphyridium as a host for molecular farming: Efficient production of immunologically active hepatitis C virus glycoprotein. Proc Natl Acad Sci U S A 2024; 121:e2400145121. [PMID: 38833465 PMCID: PMC11181018 DOI: 10.1073/pnas.2400145121] [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: 01/08/2024] [Accepted: 05/03/2024] [Indexed: 06/06/2024] Open
Abstract
Microalgae are promising production platforms for the cost-effective production of recombinant proteins. We have recently established that the red alga Porphyridium purpureum provides superior transgene expression properties, due to the episomal maintenance of transformation vectors as multicopy plasmids in the nucleus. Here, we have explored the potential of Porphyridium to synthesize complex pharmaceutical proteins to high levels. Testing expression constructs for a candidate subunit vaccine against the hepatitis C virus (HCV), we show that the soluble HCV E2 glycoprotein can be produced in transgenic algal cultures to high levels. The antigen undergoes faithful posttranslational modification by N-glycosylation and is recognized by conformationally selective antibodies, suggesting that it adopts a proper antigenic conformation in the endoplasmic reticulum of red algal cells. We also report the experimental determination of the structure of the N-glycan moiety that is attached to glycosylated proteins in Porphyridium. Finally, we demonstrate the immunogenicity of the HCV antigen produced in red algae when administered by injection as pure protein or by feeding of algal biomass.
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Affiliation(s)
- Alexander Hammel
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, D-14476Potsdam-Golm, Germany
| | - Lia-Maria Cucos
- Institute of Biochemistry of the Romanian Academy, Department of Viral Glycoproteins, 060031Bucharest, Romania
| | - Iuliana Caras
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Irina Ionescu
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Catalin Tucureanu
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Vlad Tofan
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Adriana Costache
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Adrian Onu
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Lara Hoepfner
- Institute of Plant Biology and Biotechnology, University of Münster, D-48143Münster, Germany
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, D-48143Münster, Germany
- Institute of Plant Science and Resources, Okayama University, Kurashiki710-0046, Japan
| | - Juliane Neupert
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, D-14476Potsdam-Golm, Germany
| | - Costin-Ioan Popescu
- Institute of Biochemistry of the Romanian Academy, Department of Viral Glycoproteins, 060031Bucharest, Romania
| | - Crina Stavaru
- ”Cantacuzino” Medico-Military National Research Institute, 050096Bucharest, Romania
| | - Norica Branza-Nichita
- Institute of Biochemistry of the Romanian Academy, Department of Viral Glycoproteins, 060031Bucharest, Romania
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, D-14476Potsdam-Golm, Germany
- NIBIO, Norwegian Institute of Bioeconomy Research, NO-1431 Ås, Norway
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4
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Imamichi T, Kusumoto N, Aoyama H, Takamatsu S, Honda Y, Muraoka S, Hagiwara-Komoda Y, Chiba Y, Onouchi H, Yamashita Y, Naito S. Phylogeny-linked occurrence of ribosome stalling on the mRNAs of Arabidopsis unfolded protein response factor bZIP60 orthologs in divergent plant species. Nucleic Acids Res 2024; 52:4276-4294. [PMID: 38366760 PMCID: PMC11077094 DOI: 10.1093/nar/gkae101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/18/2024] Open
Abstract
The bZIP60, XBP1 and HAC1 mRNAs encode transcription factors that mediate the unfolded protein response (UPR) in plants, animals and yeasts, respectively. Upon UPR, these mRNAs undergo unconventional cytoplasmic splicing on the endoplasmic reticulum (ER) to produce active transcription factors. Although cytoplasmic splicing is conserved, the ER targeting mechanism differs between XBP1 and HAC1. The ER targeting of HAC1 mRNA occurs before translation, whereas that of XBP1 mRNA involves a ribosome-nascent chain complex that is stalled when a hydrophobic peptide emerges from the ribosome; the corresponding mechanism is unknown for bZIP60. Here, we analyzed ribosome stalling on bZIP60 orthologs of plants. Using a cell-free translation system, we detected nascent peptide-mediated ribosome stalling during the translation elongation of the mRNAs of Arabidopsis, rice and Physcomitrium (moss) orthologs, and the termination-step stalling in the Selaginella (lycopod) ortholog, all of which occurred ∼50 amino acids downstream of a hydrophobic region. Transfection experiments showed that ribosome stalling contributes to cytoplasmic splicing in bZIP60u orthologs of Arabidopsis and Selaginella. In contrast, ribosome stalling was undetectable for liverwort, Klebsormidium (basal land plant), and green algae orthologs. This study highlights the evolutionary diversity of ribosome stalling and its contribution to ER targeting in plants.
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Affiliation(s)
- Tomoya Imamichi
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Nao Kusumoto
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Haruka Aoyama
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Seidai Takamatsu
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yugo Honda
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Shiori Muraoka
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yuka Hagiwara-Komoda
- Department of Sustainable Agriculture, Rakuno Gakuen University, Ebetsu 069-8501, Japan
| | - Yukako Chiba
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Division of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Hitoshi Onouchi
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yui Yamashita
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Satoshi Naito
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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5
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Hamel L, Comeau M, Tardif R, Poirier‐Gravel F, Paré M, Lavoie P, Goulet M, Michaud D, D'Aoust M. Heterologous expression of influenza haemagglutinin leads to early and transient activation of the unfolded protein response in Nicotiana benthamiana. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:1146-1163. [PMID: 38038125 PMCID: PMC11022800 DOI: 10.1111/pbi.14252] [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: 08/16/2023] [Revised: 11/06/2023] [Accepted: 11/16/2023] [Indexed: 12/02/2023]
Abstract
The unfolded protein response (UPR) allows cells to cope with endoplasmic reticulum (ER) stress induced by accumulation of misfolded proteins in the ER. Due to its sensitivity to Agrobacterium tumefaciens, the model plant Nicotiana benthamiana is widely employed for transient expression of recombinant proteins of biopharmaceutical interest, including antibodies and virus surface proteins used for vaccine production. As such, study of the plant UPR is of practical significance, since enforced expression of complex secreted proteins often results in ER stress. After 6 days of expression, we recently reported that influenza haemagglutinin H5 induces accumulation of UPR proteins. Since up-regulation of corresponding UPR genes was not detected at this time, accumulation of UPR proteins was hypothesized to be independent of transcriptional induction, or associated with early but transient UPR gene up-regulation. Using time course sampling, we here show that H5 expression does result in early and transient activation of the UPR, as inferred from unconventional splicing of NbbZIP60 transcripts and induction of UPR genes with varied functions. Transient nature of H5-induced UPR suggests that this response was sufficient to cope with ER stress provoked by expression of the secreted protein, as opposed to an antibody that triggered stronger and more sustained UPR activation. As up-regulation of defence genes responding to H5 expression was detected after the peak of UPR activation and correlated with high increase in H5 protein accumulation, we hypothesize that these immune responses, rather than the UPR, were responsible for onset of the necrotic symptoms on H5-expressing leaves.
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Affiliation(s)
| | | | | | | | | | | | - Marie‐Claire Goulet
- Centre de recherche et d'innovation sur les végétaux, Département de phytologieUniversité LavalQuébecQuebecCanada
| | - Dominique Michaud
- Centre de recherche et d'innovation sur les végétaux, Département de phytologieUniversité LavalQuébecQuebecCanada
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6
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Marathe S, Grotewold E, Otegui MS. Should I stay or should I go? Trafficking of plant extra-nuclear transcription factors. THE PLANT CELL 2024; 36:1524-1539. [PMID: 38163635 PMCID: PMC11062434 DOI: 10.1093/plcell/koad277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/21/2023] [Indexed: 01/03/2024]
Abstract
At the heart of all biological processes lies the control of nuclear gene expression, which is primarily achieved through the action of transcription factors (TFs) that generally contain a nuclear localization signal (NLS) to facilitate their transport into the nucleus. However, some TFs reside in the cytoplasm in a transcriptionally inactive state and only enter the nucleus in response to specific signals, which in plants include biotic or abiotic stresses. These extra-nuclear TFs can be found in the cytosol or associated with various membrane systems, including the endoplasmic reticulum and plasma membrane. They may be integral proteins with transmembrane domains or associate peripherally with the lipid bilayer via acylation or membrane-binding domains. Although over 30 plant TFs, most of them involved in stress responses, have been experimentally shown to reside outside the nucleus, computational predictions suggest that this number is much larger. Understanding how extra-nuclear TFs are trafficked into the nucleus is essential for reconstructing transcriptional regulatory networks that govern major cellular pathways in response to biotic and abiotic signals. Here, we provide a perspective on what is known on plant extranuclear-nuclear TF retention, nuclear trafficking, and the post-translational modifications that ultimately enable them to regulate gene expression upon entering the nucleus.
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Affiliation(s)
- Sarika Marathe
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824-6473, USA
| | - Marisa S Otegui
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI 53706, USA
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7
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Coppola M, Mach L, Gallois P. Plant cathepsin B, a versatile protease. FRONTIERS IN PLANT SCIENCE 2024; 15:1305855. [PMID: 38463572 PMCID: PMC10920296 DOI: 10.3389/fpls.2024.1305855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 01/19/2024] [Indexed: 03/12/2024]
Abstract
Plant proteases are essential enzymes that play key roles during crucial phases of plant life. Some proteases are mainly involved in general protein turnover and recycle amino acids for protein synthesis. Other proteases are involved in cell signalling, cleave specific substrates and are key players during important genetically controlled molecular processes. Cathepsin B is a cysteine protease that can do both because of its exopeptidase and endopeptidase activities. Animal cathepsin B has been investigated for many years, and much is known about its mode of action and substrate preferences, but much remains to be discovered about this potent protease in plants. Cathepsin B is involved in plant development, germination, senescence, microspore embryogenesis, pathogen defence and responses to abiotic stress, including programmed cell death. This review discusses the structural features, the activity of the enzyme and the differences between the plant and animal forms. We discuss its maturation and subcellular localisation and provide a detailed overview of the involvement of cathepsin B in important plant life processes. A greater understanding of the cell signalling processes involving cathepsin B is needed for applied discoveries in plant biotechnology.
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Affiliation(s)
- Marianna Coppola
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Lukas Mach
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Patrick Gallois
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
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8
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Duan Z, Chen K, Yang T, You R, Chen B, Li J, Liu L. Mechanisms of Endoplasmic Reticulum Protein Homeostasis in Plants. Int J Mol Sci 2023; 24:17599. [PMID: 38139432 PMCID: PMC10743519 DOI: 10.3390/ijms242417599] [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: 11/27/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Maintenance of proteome integrity is essential for cell function and survival in changing cellular and environmental conditions. The endoplasmic reticulum (ER) is the major site for the synthesis of secretory and membrane proteins. However, the accumulation of unfolded or misfolded proteins can perturb ER protein homeostasis, leading to ER stress and compromising cellular function. Eukaryotic organisms have evolved sophisticated and conserved protein quality control systems to ensure protein folding fidelity via the unfolded protein response (UPR) and to eliminate potentially harmful proteins via ER-associated degradation (ERAD) and ER-phagy. In this review, we summarize recent advances in our understanding of the mechanisms of ER protein homeostasis in plants and discuss the crosstalk between different quality control systems. Finally, we will address unanswered questions in this field.
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Affiliation(s)
- Zhihao Duan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Kai Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Tao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Ronghui You
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Binzhao Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Jianming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Linchuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
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9
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Vu BN, Vu TV, Yoo JY, Nguyen NT, Ko KS, Kim JY, Lee KO. CRISPR-Cas-mediated unfolded protein response control for enhancing plant stress resistance. FRONTIERS IN PLANT SCIENCE 2023; 14:1271368. [PMID: 37908833 PMCID: PMC10613997 DOI: 10.3389/fpls.2023.1271368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/02/2023] [Indexed: 11/02/2023]
Abstract
Plants consistently encounter environmental stresses that negatively affect their growth and development. To mitigate these challenges, plants have developed a range of adaptive strategies, including the unfolded protein response (UPR), which enables them to manage endoplasmic reticulum (ER) stress resulting from various adverse conditions. The CRISPR-Cas system has emerged as a powerful tool for plant biotechnology, with the potential to improve plant tolerance and resistance to biotic and abiotic stresses, as well as enhance crop productivity and quality by targeting specific genes, including those related to the UPR. This review highlights recent advancements in UPR signaling pathways and CRISPR-Cas technology, with a particular focus on the use of CRISPR-Cas in studying plant UPR. We also explore prospective applications of CRISPR-Cas in engineering UPR-related genes for crop improvement. The integration of CRISPR-Cas technology into plant biotechnology holds the promise to revolutionize agriculture by producing crops with enhanced resistance to environmental stresses, increased productivity, and improved quality traits.
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Affiliation(s)
- Bich Ngoc Vu
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
- Division of Applied Life Science (BK21 Four), Gyeongsang National University, Jinju, Republic of Korea
| | - Tien Van Vu
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
| | - Jae Yong Yoo
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
| | - Ngan Thi Nguyen
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
- Division of Applied Life Science (BK21 Four), Gyeongsang National University, Jinju, Republic of Korea
| | - Ki Seong Ko
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
| | - Jae-Yean Kim
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
- Division of Applied Life Science (BK21 Four), Gyeongsang National University, Jinju, Republic of Korea
- Nulla Bio Inc., Jinju, Republic of Korea
| | - Kyun Oh Lee
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju, Republic of Korea
- Division of Applied Life Science (BK21 Four), Gyeongsang National University, Jinju, Republic of Korea
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10
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Chen X, Chen H, Shen T, Luo Q, Xu M, Yang Z. The miRNA-mRNA Regulatory Modules of Pinus massoniana Lamb. in Response to Drought Stress. Int J Mol Sci 2023; 24:14655. [PMID: 37834103 PMCID: PMC10572226 DOI: 10.3390/ijms241914655] [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: 08/21/2023] [Revised: 09/20/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Masson pine (Pinus massoniana Lamb.) is a major fast-growing woody tree species and pioneer species for afforestation in barren sites in southern China. However, the regulatory mechanism of gene expression in P. massoniana under drought remains unclear. To uncover candidate microRNAs, their expression profiles, and microRNA-mRNA interactions, small RNA-seq was used to investigate the transcriptome from seedling roots under drought and rewatering in P. massoniana. A total of 421 plant microRNAs were identified. Pairwise differential expression analysis between treatment and control groups unveiled 134, 156, and 96 differential expressed microRNAs at three stages. These constitute 248 unique microRNAs, which were subsequently categorized into six clusters based on their expression profiles. Degradome sequencing revealed that these 248 differentially expressed microRNAs targeted 2069 genes. Gene Ontology enrichment analysis suggested that these target genes were related to translational and posttranslational regulation, cell wall modification, and reactive oxygen species scavenging. miRNAs such as miR482, miR398, miR11571, miR396, miR166, miRN88, and miRN74, along with their target genes annotated as F-box/kelch-repeat protein, 60S ribosomal protein, copper-zinc superoxide dismutase, luminal-binding protein, S-adenosylmethionine synthase, and Early Responsive to Dehydration Stress may play critical roles in drought response. This study provides insights into microRNA responsive to drought and rewatering in Masson pine and advances the understanding of drought tolerance mechanisms in Pinus.
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Affiliation(s)
- Xinhua Chen
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, 682 Guangshan Road 1, Guangzhou 510520, China;
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China;
- Engineering Research Center of Masson Pine of State Forestry Administration, Engineering Research Center of Masson Pine of Guangxi, Guangxi Key Laboratory of Superior Timber Trees Resource Cultivation, Guangxi Forestry Research Institute, 23 Yongwu Road, Nanning 530002, China; (H.C.); (Q.L.)
| | - Hu Chen
- Engineering Research Center of Masson Pine of State Forestry Administration, Engineering Research Center of Masson Pine of Guangxi, Guangxi Key Laboratory of Superior Timber Trees Resource Cultivation, Guangxi Forestry Research Institute, 23 Yongwu Road, Nanning 530002, China; (H.C.); (Q.L.)
| | - Tengfei Shen
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China;
| | - Qunfeng Luo
- Engineering Research Center of Masson Pine of State Forestry Administration, Engineering Research Center of Masson Pine of Guangxi, Guangxi Key Laboratory of Superior Timber Trees Resource Cultivation, Guangxi Forestry Research Institute, 23 Yongwu Road, Nanning 530002, China; (H.C.); (Q.L.)
| | - Meng Xu
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of Forest Genetics and Biotechnology Ministry of Education, College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China;
| | - Zhangqi Yang
- Engineering Research Center of Masson Pine of State Forestry Administration, Engineering Research Center of Masson Pine of Guangxi, Guangxi Key Laboratory of Superior Timber Trees Resource Cultivation, Guangxi Forestry Research Institute, 23 Yongwu Road, Nanning 530002, China; (H.C.); (Q.L.)
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11
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Li JY, Yang C, Xu J, Lu HP, Liu JX. The hot science in rice research: How rice plants cope with heat stress. PLANT, CELL & ENVIRONMENT 2023; 46:1087-1103. [PMID: 36478590 DOI: 10.1111/pce.14509] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 11/13/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Global climate change has great impacts on plant growth and development, reducing crop productivity worldwide. Rice (Oryza sativa L.), one of the world's most important food crops, is susceptible to high-temperature stress from seedling stage to reproductive stage. In this review, we summarize recent advances in understanding the molecular mechanisms underlying heat stress responses in rice, including heat sensing and signalling, transcriptional regulation, transcript processing, protein translation, and post-translational regulation. We also highlight the irreversible effects of high temperature on reproduction and grain quality in rice. Finally, we discuss challenges and opportunities for future research on heat stress responses in rice.
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Affiliation(s)
- Jin-Yu Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Chuang Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jiming Xu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Hai-Ping Lu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian-Xiang Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
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12
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Zhang Y, Song X, Zhang W, Liu F, Wang C, Liu Y, Dirk LMA, Downie AB, Zhao T. Maize PIMT2 repairs damaged 3-METHYLCROTONYL COA CARBOXYLASE in mitochondria, affecting seed vigor. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023. [PMID: 36999611 DOI: 10.1111/tpj.16225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/13/2023] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
PROTEIN l-ISOASPARTYL O-METHYLTRANSFERASE (PIMT) affects seed vigor by repairing damaged proteins. While PIMT is capable of isoaspartyl (isoAsp) repair in all proteins, those proteins most susceptible to isoAsp formation have not been well characterized, and the mechanisms by which PIMT affects seed vigor remain largely unknown. Using co-immunoprecipitation and LC-MS/MS, we found that maize (Zea mays) PIMT2 (ZmPIMT2) interacted predominantly with both subunits of maize 3-METHYLCROTONYL COA CARBOXYLASE (ZmMCC). ZmPIMT2 is specifically expressed in the maize embryo. Both mRNA and protein levels of ZmPIMT2 increased during seed maturation and declined during imbibition. Maize seed vigor was decreased in the zmpimt2 mutant line, while overexpression of ZmPIMT2 in maize and Arabidopsis thaliana increased seed vigor upon artificial aging. ZmPIMT2 was localized in the mitochondria, as determined by subcellular localization assays using maize protoplasts. ZmPIMT2 binding to ZmMCCα was confirmed by luciferase complementation tests in both tobacco (Nicotiana benthamiana) leaves and maize protoplasts. Knockdown of ZmMCCα decreased maize seed aging tolerance. Furthermore, overexpression of ZmPIMT2 decreased the accumulation of isoAsp of ZmMCCα protein in seed embryos that underwent accelerated aging treatment. Taken together, our results demonstrate that ZmPIMT2 binds ZmMCCα in mitochondria, repairs isoAsp damage, and positively affects maize seed vigor.
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Affiliation(s)
- Yumin Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xianbo Song
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Wenli Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Feijun Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Chunmei Wang
- Biology Experimental Teaching Center, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Ying Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Lynnette M A Dirk
- Department of Horticulture, Seed Biology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, 40546, USA
| | - A Bruce Downie
- Department of Horticulture, Seed Biology, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, 40546, USA
| | - Tianyong Zhao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- The Key Laboratory of Biology and Genetics Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
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13
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Zhao L, Wang B, Yang T, Yan H, Yu Q, Wang J. Genome-wide identification and analysis of the evolution and expression pattern of the HVA22 gene family in three wild species of tomatoes. PeerJ 2023; 11:e14844. [PMID: 36815985 PMCID: PMC9933743 DOI: 10.7717/peerj.14844] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 01/11/2023] [Indexed: 02/15/2023] Open
Abstract
Wild tomato germplasm is a valuable resource for improving biotic and abiotic stresses in tomato breeding. The HVA22 is widely present in eukaryotes and involved in growth and development as well as stress response, such as cold, salt, drought, and biotic stress. In the present study, we identified 45 HVA22 genes in three wild species of tomatoes. The phylogenetic relationships, gene localization to chromosomes, gene structure, gene collinearity, protein interactions, and cis-acting element prediction of all 45 HVA22 genes (14 in Solanum pennellii, 15 in S. pimpinellifolium, and 16 in S. lycopersicoides) were analyzed. The phylogenetic analysis showed that the all HVA22 proteins from the family Solanaceae were divided into three branches. The identified 45 HVA22 genes were grouped into four subfamilies, which displayed similar number of exons and expanded in a fragmentary replication manner. The distribution of HVA22 genes on the chromosomes of the three wild tomato species was also highly similar. RNA-seq and qRT-PCR revealed that HVA22 genes were expressed in different tissues and induced by drought, salt, and phytohormone treatments. These results might be useful for explaining the evolution, expression patterns, and functional divergence of HVA22 genes in Lycopersicon.
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Affiliation(s)
- LaiPeng Zhao
- Institute of Horticultural Crops, Xinjiang Academy of Agricultural Science (Key Laboratory of Horticulture Crop Genomics Research and Genetic Improvement in Xinjiang), Urumqi, Xinjiang, China,College of Horticulture, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Baike Wang
- Institute of Horticultural Crops, Xinjiang Academy of Agricultural Science (Key Laboratory of Horticulture Crop Genomics Research and Genetic Improvement in Xinjiang), Urumqi, Xinjiang, China
| | - Tao Yang
- Institute of Horticultural Crops, Xinjiang Academy of Agricultural Science (Key Laboratory of Horticulture Crop Genomics Research and Genetic Improvement in Xinjiang), Urumqi, Xinjiang, China
| | - Huizhuan Yan
- College of Horticulture, Xinjiang Agricultural University, Urumqi, Xinjiang, China
| | - Qinghui Yu
- Institute of Horticultural Crops, Xinjiang Academy of Agricultural Science (Key Laboratory of Horticulture Crop Genomics Research and Genetic Improvement in Xinjiang), Urumqi, Xinjiang, China
| | - Juan Wang
- Institute of Horticultural Crops, Xinjiang Academy of Agricultural Science (Key Laboratory of Horticulture Crop Genomics Research and Genetic Improvement in Xinjiang), Urumqi, Xinjiang, China
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14
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Musetti R, Pagliari L, Mian G, De Oliveira Cantao FR, Bernardini C, Santi S, van Bel AJE. The sieve-element endoplasmic reticulum: A focal point of phytoplasma-host plant interaction? Front Microbiol 2023; 14:1030414. [PMID: 36819061 PMCID: PMC9932721 DOI: 10.3389/fmicb.2023.1030414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/13/2023] [Indexed: 02/05/2023] Open
Abstract
The rough endoplasmic reticulum (r-ER) is of paramount importance for adaptive responses to biotic stresses due to an increased demand for de novo synthesis of immunity-related proteins and signaling components. In nucleate cells, disturbance of r-ER integrity and functionality leads to the "unfolded protein response" (UPR), which is an important component of innate plant immune signalling. In contrast to an abundance of reports on r-ER responses to biotic challenges, sieve-element endoplasmic reticulum (SE-ER) responses to phytoplasma infection have not been investigated. We found that morphological SE-ER changes, associated with phytoplasma infection, are accompanied by differential expression of genes encoding proteins involved in shaping and anchoring the reticulum. Phytoplasma infection also triggers an increased release of bZIP signals from the (SE-ER)/r-ER and consequent differential expression of UPR-related genes. The modified expression patterns seem to reflect a trade-off between survival of host cells, needed for the phytoplasmic biotrophic lifestyle, and phytoplasmas. Specialized plasmodesmata between sieve element and companion cell may provide a corridor for transfer of phytoplasma effectors inducing UPR-related gene expression in companion cells.
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Affiliation(s)
- Rita Musetti
- Department of Land, Environment, Agriculture and Forestry (TESAF), Università di Padova, via dell' Università, Legnaro, Italy,*Correspondence: Rita Musetti,
| | - Laura Pagliari
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, Udine, Italy
| | - Giovanni Mian
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, Udine, Italy
| | - Fernando R. De Oliveira Cantao
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, Udine, Italy
| | - Chiara Bernardini
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, Udine, Italy
| | - Simonetta Santi
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, Udine, Italy
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15
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Giordano L, Schimmerling M, Panabières F, Allasia V, Keller H. The exodomain of the impaired oomycete susceptibility 1 receptor mediates both endoplasmic reticulum stress responses and abscisic acid signalling during downy mildew infection of Arabidopsis. MOLECULAR PLANT PATHOLOGY 2022; 23:1783-1791. [PMID: 36103373 PMCID: PMC9644275 DOI: 10.1111/mpp.13265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/13/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
The phytohormone abscisic acid (ABA) regulates cell growth and plant development, and contributes to defence responses to pathogens. We previously showed that the Arabidopsis malectin-like domain leucine-rich repeat receptor-like kinase (MLD-LRR-RLK) impaired oomycete susceptibility 1 (IOS1) attenuates ABA signalling during infection with the oomycete downy mildew pathogen Hyaloperonospora arabidopsidis. The exodomain of IOS1 with its MLD retains the receptor in the endoplasmic reticulum (ER), where it interacts with the ribophorin HAP6 to dampen a pathogen-induced ER stress response called the unfolded protein response (UPR). The down-regulation of both ABA and UPR signalling probably provides the pathogen with an advantage for infection. Here, we show that ABA-related phenotypes of the ios1-1 mutant, such as up-regulated expression of ABA-responsive genes and hypersensitivity to exogenous ABA application, were reverted by expression of the IOS1 exodomain in the mutant background. Furthermore, knockdown mutants for ER-resident HAP6 showed similarly reduced UPR and ABA signalling, indicating that HAP6 positively regulates both pathways. Our data suggest that the IOS1 exodomain and HAP6 contribute in the ER to the IOS1-mediated interference with ABA and UPR signalling.
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Affiliation(s)
- Laïla Giordano
- Université Côte d'Azur, INRAE, CNRS, UMR1355‐7254, ISASophia AntipolisFrance
| | - Marion Schimmerling
- Université Côte d'Azur, INRAE, CNRS, UMR1355‐7254, ISASophia AntipolisFrance
| | - Franck Panabières
- Université Côte d'Azur, INRAE, CNRS, UMR1355‐7254, ISASophia AntipolisFrance
| | - Valérie Allasia
- Université Côte d'Azur, INRAE, CNRS, UMR1355‐7254, ISASophia AntipolisFrance
| | - Harald Keller
- Université Côte d'Azur, INRAE, CNRS, UMR1355‐7254, ISASophia AntipolisFrance
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16
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Kim JS, Mochida K, Shinozaki K. ER Stress and the Unfolded Protein Response: Homeostatic Regulation Coordinate Plant Survival and Growth. PLANTS (BASEL, SWITZERLAND) 2022; 11:3197. [PMID: 36501237 PMCID: PMC9735958 DOI: 10.3390/plants11233197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The endoplasmic reticulum (ER), a eukaryotic organelle, is the major site of protein biosynthesis. The disturbance of ER function by biotic or abiotic stress triggers the accumulation of misfolded or unfolded proteins in the ER. The unfolded protein response (UPR) is the best-studied ER stress response. This transcriptional regulatory system senses ER stress, activates downstream genes that function to mitigate stress, and restores homeostasis. In addition to its conventional role in stress responses, recent reports indicate that the UPR is involved in plant growth and development. In this review, we summarize the current knowledge of ER stress sensing and the activation and downstream regulation of the UPR. We also describe how the UPR modulates both plant growth and stress tolerance by maintaining ER homeostasis. Lastly, we propose that the UPR is a major component of the machinery that balances the trade-off between plant growth and survival in a dynamic environment.
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Affiliation(s)
- June-Sik Kim
- RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
| | - Keiichi Mochida
- RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
- Microalgae Production Control Technology Laboratory, RIKEN Baton Zone Program, Yokohama 230-0045, Japan
- School of Information and Data Sciences, Nagasaki University, Nagasaki 852-8521, Japan
- Graduate School of Nanobioscience, Yokohama City University, Yokohama 236-0027, Japan
| | - Kazuo Shinozaki
- RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
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17
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Xie C, Yang L, Jia G, Yan K, Zhang S, Yang G, Wu C, Gai Y, Zheng C, Huang J. Maize HEAT UP-REGULATED GENE 1 plays vital roles in heat stress tolerance. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:6417-6433. [PMID: 35709944 DOI: 10.1093/jxb/erac262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Increasing temperature is one of the major threats to maize growth and yield globally. Under heat stress conditions, intracellular protein homeostasis is seriously disturbed, leading to accumulation of abnormally folded proteins, especially in the endoplasmic reticulum (ER). Molecular chaperones are vital players in the renaturation process and in preventing protein aggregation. However, heat stress tolerance-associated chaperones are not well documented in maize. Here, we characterized the biological roles of HEAT UP-REGULATED GENE 1 (ZmHUG1) in maize. ZmHUG1 encodes a heat-inducible holdase-type molecular chaperone localized in the ER. Knockout mutant of ZmHUG1 exhibited remarkably enhanced sensitivity to heat stress. Accordingly, the zmhug1 mutant showed severe ER stress under high temperature. MAIZE PRENYLATED RAB ACCEPTOR 1.C1 (ZmPRA1.C1) was identified as a client of ZmHUG1, and heat-induced aggregation of ZmPRA1.C1 was accelerated in the zmhug1 mutant. Furthermore, the expression of ZmHUG1 was rapidly transactivated by ER stress sensor BASIC LEUCINE ZIPPER DOMAIN 60 (bZIP60) when heat stress occurred. This study reveals a ZmHUG1-based thermo-protective mechanism in maize.
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Affiliation(s)
- Chen Xie
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Liu Yang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Guixian Jia
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Kang Yan
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Shizhong Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Guodong Yang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Changai Wu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Yingping Gai
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Chengchao Zheng
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
| | - Jinguang Huang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China
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18
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Ribeiro B, Erffelinck ML, Lacchini E, Ceulemans E, Colinas M, Williams C, Van Hamme E, De Clercq R, Perassolo M, Goossens A. Interference between ER stress-related bZIP-type and jasmonate-inducible bHLH-type transcription factors in the regulation of triterpene saponin biosynthesis in Medicago truncatula. FRONTIERS IN PLANT SCIENCE 2022; 13:903793. [PMID: 36247618 PMCID: PMC9562455 DOI: 10.3389/fpls.2022.903793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 09/07/2022] [Indexed: 06/01/2023]
Abstract
Triterpene saponins (TS) are a structurally diverse group of metabolites that are widely distributed in plants. They primarily serve as defense compounds and their production is often triggered by biotic stresses through signaling cascades that are modulated by phytohormones such as the jasmonates (JA). Two JA-modulated basic helix-loop-helix (bHLH) transcription factors (TFs), triterpene saponin biosynthesis activating regulator 1 (TSAR1) and TSAR2, have previously been identified as direct activators of TS biosynthesis in the model legume Medicago truncatula. Here, we report on the involvement of the core endoplasmic reticulum (ER) stress-related basic leucine zipper (bZIP) TFs bZIP17 and bZIP60 in the regulation of TS biosynthesis. Expression and processing of M. truncatula bZIP17 and bZIP60 proteins were altered in roots with perturbed TS biosynthesis or treated with JA. Accordingly, such roots displayed an altered ER network structure. M. truncatula bZIP17 and bZIP60 proteins were shown to localize in the nucleus and appeared to be capable of interfering with the TSAR-mediated transactivation of TS biosynthesis genes. Furthermore, interference between ER stress-related bZIP and JA-modulated bHLH TFs in the regulation of JA-dependent terpene biosynthetic pathways may be widespread in the plant kingdom, as we demonstrate that it also occurs in the regulation of monoterpene indole alkaloid biosynthesis in the medicinal plant Catharanthus roseus.
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Affiliation(s)
- Bianca Ribeiro
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Marie-Laure Erffelinck
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Elia Lacchini
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Evi Ceulemans
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Maite Colinas
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Clara Williams
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | | | - Rebecca De Clercq
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Maria Perassolo
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
- Cátedra de Biotecnología, Departamento de Microbiología, Inmunología y Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Nanobiotecnología (NANOBIOTEC), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alain Goossens
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
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19
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Chloroplasts Protein Quality Control and Turnover: A Multitude of Mechanisms. Int J Mol Sci 2022; 23:ijms23147760. [PMID: 35887108 PMCID: PMC9319218 DOI: 10.3390/ijms23147760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/16/2022] Open
Abstract
As the organelle of photosynthesis and other important metabolic pathways, chloroplasts contain up to 70% of leaf proteins with uniquely complex processes in synthesis, import, assembly, and turnover. Maintaining functional protein homeostasis in chloroplasts is vitally important for the fitness and survival of plants. Research over the past several decades has revealed a multitude of mechanisms that play important roles in chloroplast protein quality control and turnover under normal and stress conditions. These mechanisms include: (i) endosymbiotically-derived proteases and associated proteins that play a vital role in maintaining protein homeostasis inside the chloroplasts, (ii) the ubiquitin-dependent turnover of unimported chloroplast precursor proteins to prevent their accumulation in the cytosol, (iii) chloroplast-associated degradation of the chloroplast outer-membrane translocon proteins for the regulation of chloroplast protein import, (iv) chloroplast unfolded protein response triggered by accumulated unfolded and misfolded proteins inside the chloroplasts, and (v) vesicle-mediated degradation of chloroplast components in the vacuole. Here, we provide a comprehensive review of these diverse mechanisms of chloroplast protein quality control and turnover and discuss important questions that remain to be addressed in order to better understand and improve important chloroplast functions.
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20
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Endoplasmic Reticulum Stress and Reactive Oxygen Species in Plants. Antioxidants (Basel) 2022; 11:antiox11071240. [PMID: 35883731 PMCID: PMC9311536 DOI: 10.3390/antiox11071240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/16/2022] [Accepted: 06/22/2022] [Indexed: 12/25/2022] Open
Abstract
The endoplasmic reticulum (ER) is a key compartment responsible for protein processing and folding, and it also participates in many signal transduction and metabolic processes. Reactive oxygen species (ROS) are important signaling messengers involved in the redox equilibrium and stress response. A number of abiotic and biotic stresses can trigger the accumulation of unfolded or misfolded proteins and lead to ER stress. In recent years, a number of studies have reported that redox metabolism and ROS are closely related to ER stress. ER stress can benefit ROS generation and even cause oxidative burden in plants, finally leading to oxidative stress depending on the degree of ER stress. Moreover, ER stress activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated ROS signaling, increases antioxidant defense mechanisms, and alters the glutathione (GSH) redox state. Meanwhile, the accumulation of ROS plays a special role in inducing the ER stress response. Given these factors, plants have evolved a series of complex regulatory mechanisms to interact with ROS in response to ER stress. In this review, we summarize the perceptions and responses of plant ER stress and oxidative protein folding in the ER. In addition, we analyze the production and signaling of ROS under ER stress in detail in order to provide a theoretical basis for reducing ER stress to improve the crop survival rate in agricultural applications.
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21
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Yu CY, Cho Y, Sharma O, Kanehara K. What's unique? The unfolded protein response in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1268-1276. [PMID: 34849719 DOI: 10.1093/jxb/erab513] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/22/2021] [Indexed: 06/13/2023]
Abstract
The investigation of a phenomenon called the unfolded protein response (UPR) started approximately three decades ago, and we now know that the UPR is involved in a number of cellular events among metazoans, higher plants, and algae. The relevance of the UPR in human diseases featuring protein folding defects, such as Alzheimer's and Huntington's diseases, has drawn much attention to the response in medical research to date. While metazoans and plants share similar molecular mechanisms of the UPR, recent studies shed light on the uniqueness of the plant UPR, with plant-specific protein families appearing to play pivotal roles. Given the considerable emphasis on the original discoveries of key factors in metazoans, this review highlights the uniqueness of the plant UPR based on current knowledge.
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Affiliation(s)
- Chao-Yuan Yu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yueh Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Oshin Sharma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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22
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OsbZIP60-mediated unfolded protein response regulates grain chalkiness in rice. J Genet Genomics 2022; 49:414-426. [DOI: 10.1016/j.jgg.2022.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 02/01/2022] [Accepted: 02/07/2022] [Indexed: 12/21/2022]
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23
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Lohani N, Singh MB, Bhalla PL. Rapid Transcriptional Reprogramming Associated With Heat Stress-Induced Unfolded Protein Response in Developing Brassica napus Anthers. FRONTIERS IN PLANT SCIENCE 2022; 13:905674. [PMID: 35755714 PMCID: PMC9218420 DOI: 10.3389/fpls.2022.905674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 05/11/2022] [Indexed: 05/13/2023]
Abstract
Climate change associated increases in the frequency and intensity of extreme temperature events negatively impact agricultural productivity and global food security. During the reproductive phase of a plant's life cycle, such high temperatures hinder pollen development, preventing fertilization, and seed formation. At the molecular level, heat stress-induced accumulation of misfolded proteins activates a signaling pathway called unfolded protein response (UPR) in the endoplasmic reticulum (ER) and the cytoplasm to enhance the protein folding capacity of the cell. Here, we report transcriptional responses of Brassica napus anthers exposed to high temperature for 5, 15, and 30 min to decipher the rapid transcriptional reprogramming associated with the unfolded protein response. Functional classification of the upregulated transcripts highlighted rapid activation of the ER-UPR signaling pathway mediated by ER membrane-anchored transcription factor within 5 min of heat stress exposure. KEGG pathway enrichment analysis also identified "Protein processing in ER" as the most significantly enriched pathway, indicating that the unfolded protein response (UPR) is an immediate heat stress-responsive pathway during B. napus anther development. Five minutes of heat stress also led to robust induction of the cytosolic HSF-HSP heat response network. Our results present a perspective of the rapid and massive transcriptional reprogramming during heat stress in pollen development and highlight the need for investigating the nature and function of very early stress-responsive networks in plant cells. Research focusing on very early molecular responses of plant cells to external stresses has the potential to reveal new stress-responsive gene networks that can be explored further for developing climate change resilient crops.
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24
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Lima KRP, Cavalcante FLP, Paula-Marinho SDO, Pereira IMC, Lopes LDS, Nunes JVS, Coutinho ÍAC, Gomes-Filho E, Carvalho HHD. Metabolomic profiles exhibit the influence of endoplasmic reticulum stress on sorghum seedling growth over time. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 170:192-205. [PMID: 34902782 DOI: 10.1016/j.plaphy.2021.11.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/25/2021] [Accepted: 11/27/2021] [Indexed: 06/14/2023]
Abstract
Environmental stresses disturb the endoplasmic reticulum (ER) protein folding. However, primary metabolic responses induced by ER stress remain unclear. Thus, we investigated the morphophysiological and metabolomic changes under ER stress, induced by dithiothreitol (DTT) and tunicamycin (TM) treatments in sorghum seedlings from 24 to 96 h. The ER stress caused lipid peroxidation and increased the expression of SbBiP1, SbPDI, and SbIRE1. The development impairment was more pronounced in roots than in shoots as distinct metabolomic profiles were observed. DTT decreased root length, lateral roots, and root hair, while TM decreased mainly the root length. At 24 h, under ER stresses, the glutamic acid and o-acetyl-serine were biomarkers in the shoots. While homoserine, pyroglutamic acid, and phosphoric acid were candidates for roots. At the latest time (96 h), kestose and galactinol were key metabolites for shoots under DTT and TM, respectively. In roots, palatinose, trehalose, and alanine were common markers for DTT and TM late exposure. The accumulation of sugars such as arabinose and kestose occurred mainly in roots in the presence of DTT at a later time, which also inhibited glycolysis and the tricarboxylic acid cycle (TCA). Amino acid metabolism was induced, which also contributed TCA components decreasing, such as succinate in shoots and citrate in roots. Thus, our study may provide new insights into primary metabolism modulated by ER stress and seedling development.
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Affiliation(s)
- Karollyny Roger Pereira Lima
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP-60440-554, Fortaleza, CE, Brazil
| | | | | | - Isabelle Mary Costa Pereira
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP-60440-554, Fortaleza, CE, Brazil
| | - Lineker de Sousa Lopes
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP-60440-554, Fortaleza, CE, Brazil
| | | | | | - Enéas Gomes-Filho
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP-60440-554, Fortaleza, CE, Brazil
| | - Humberto Henrique de Carvalho
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, CEP-60440-554, Fortaleza, CE, Brazil.
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25
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Simoni EB, Oliveira CC, Fraga OT, Reis PAB, Fontes EPB. Cell Death Signaling From Endoplasmic Reticulum Stress: Plant-Specific and Conserved Features. FRONTIERS IN PLANT SCIENCE 2022; 13:835738. [PMID: 35185996 PMCID: PMC8850647 DOI: 10.3389/fpls.2022.835738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/10/2022] [Indexed: 05/06/2023]
Abstract
The endoplasmic reticulum (ER) stress response is triggered by any condition that disrupts protein folding and promotes the accumulation of unfolded proteins in the lumen of the organelle. In eukaryotic cells, the evolutionarily conserved unfolded protein response is activated to clear unfolded proteins and restore ER homeostasis. The recovery from ER stress is accomplished by decreasing protein translation and loading into the organelle, increasing the ER protein processing capacity and ER-associated protein degradation activity. However, if the ER stress persists and cannot be reversed, the chronically prolonged stress leads to cellular dysfunction that activates cell death signaling as an ultimate attempt to survive. Accumulating evidence implicates ER stress-induced cell death signaling pathways as significant contributors for stress adaptation in plants, making modulators of ER stress pathways potentially attractive targets for stress tolerance engineering. Here, we summarize recent advances in understanding plant-specific molecular mechanisms that elicit cell death signaling from ER stress. We also highlight the conserved features of ER stress-induced cell death signaling in plants shared by eukaryotic cells.
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26
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Kohlhase DR, McCabe CE, Singh AK, O’Rourke JA, Graham MA. Comparing Early Transcriptomic Responses of 18 Soybean ( Glycine max) Genotypes to Iron Stress. Int J Mol Sci 2021; 22:11643. [PMID: 34769077 PMCID: PMC8583884 DOI: 10.3390/ijms222111643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 11/21/2022] Open
Abstract
Iron deficiency chlorosis (IDC) is an abiotic stress that negatively affects soybean (Glycine max [L.] Merr.) production. Much of our knowledge of IDC stress responses is derived from model plant species. Gene expression, quantitative trait loci (QTL) mapping, and genome-wide association studies (GWAS) performed in soybean suggest that stress response differences exist between model and crop species. Our current understanding of the molecular response to IDC in soybeans is largely derived from gene expression studies using near-isogenic lines differing in iron efficiency. To improve iron efficiency in soybeans and other crops, we need to expand gene expression studies to include the diversity present in germplasm collections. Therefore, we collected 216 purified RNA samples (18 genotypes, two tissue types [leaves and roots], two iron treatments [sufficient and deficient], three replicates) and used RNA sequencing to examine the expression differences of 18 diverse soybean genotypes in response to iron deficiency. We found a rapid response to iron deficiency across genotypes, most responding within 60 min of stress. There was little evidence of an overlap of specific differentially expressed genes, and comparisons of gene ontology terms and transcription factor families suggest the utilization of different pathways in the stress response. These initial findings suggest an untapped genetic potential within the soybean germplasm collection that could be used for the continued improvement of iron efficiency in soybean.
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Affiliation(s)
- Daniel R. Kohlhase
- Department of Agronomy, Iowa State University, Ames, IA 50011, USA; (D.R.K.); (A.K.S.)
| | - Chantal E. McCabe
- U.S. Department of Agriculture (USDA)—Agricultural Research Service (ARS), Corn Insects and Crop Genetics Research Unit, Ames, IA 50011, USA;
| | - Asheesh K. Singh
- Department of Agronomy, Iowa State University, Ames, IA 50011, USA; (D.R.K.); (A.K.S.)
| | - Jamie A. O’Rourke
- U.S. Department of Agriculture (USDA)—Agricultural Research Service (ARS), Corn Insects and Crop Genetics Research Unit, Ames, IA 50011, USA;
| | - Michelle A. Graham
- U.S. Department of Agriculture (USDA)—Agricultural Research Service (ARS), Corn Insects and Crop Genetics Research Unit, Ames, IA 50011, USA;
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27
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Diwan D, Liu X, Andrews CF, Pajerowska-Mukhtar KM. A Quantitative Arabidopsis IRE1a Ribonuclease-Dependent in vitro mRNA Cleavage Assay for Functional Studies of Substrate Splicing and Decay Activities. FRONTIERS IN PLANT SCIENCE 2021; 12:707378. [PMID: 34354728 PMCID: PMC8329651 DOI: 10.3389/fpls.2021.707378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 06/29/2021] [Indexed: 06/03/2023]
Abstract
The unfolded protein response (UPR) is an adaptive eukaryotic reaction that controls the protein folding capacities of the endoplasmic reticulum (ER). The most ancient and well-conserved component of the UPR is Inositol-Requiring Enzyme 1 (IRE1). Arabidopsis IRE1a (AtIRE1) is a transmembrane sensor of ER stress equipped with dual protein kinase and ribonuclease (RNase) activities, encoded by its C-terminal domain. In response to both physiological stresses and pathological perturbations, AtIRE1a directly cleaves bZIP60 (basic leucine zipper 60) mRNA. Here, we developed a quantitative in vitro cleavage assay that combines recombinant AtIRE1a protein that is expressed in Nicotiana benthamiana and total RNA isolated from Arabidopsis leaves. Wild-type AtIRE1a as well as its variants containing point mutations in the kinase or RNase domains that modify its cleavage activity were employed to demonstrate their contributions to cleavage activity levels. We show that, when exposed to total RNA in vitro, the AtIRE1a protein cleaves bZIP60 mRNA. Depletion of the bZIP60 transcript in the reaction mixture can be precisely quantified by a qRT-PCR-mediated assay. This method facilitates the functional studies of novel plant IRE1 variants by allowing to quickly and precisely assess the effects of protein mutations on the substrate mRNA cleavage activity before advancing to more laborious, stable transgenic approaches in planta. Moreover, this method is readily adaptable to other plant IRE1 paralogs and orthologs, and can also be employed to test additional novel mRNA substrates of plant IRE1, such as transcripts undergoing degradation through the process of regulated IRE1-dependent decay (RIDD). Finally, this method can also be modified and expanded to functional testing of IRE1 interactors and inhibitors, as well as for studies on the molecular evolution of IRE1 and its substrates, providing additional insights into the mechanistic underpinnings of IRE1-mediated ER stress homeostasis in plant tissues.
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