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Yoo JY, Ko KS, Vu BN, Lee YE, Choi HN, Lee YN, Fanata WID, Harmoko R, Lee SK, Chung WS, Hong JC, Lee KO. IRE1 is implicated in protein synthesis regulation under ER stress conditions in plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 215:108963. [PMID: 39084166 DOI: 10.1016/j.plaphy.2024.108963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/14/2024] [Accepted: 07/22/2024] [Indexed: 08/02/2024]
Abstract
The unfolded protein response (UPR) is a crucial cellular mechanism for maintaining protein folding homeostasis during endoplasmic reticulum (ER) stress. In this study, the role of IRE1, a key component of the UPR, was investigated in protein translation regulation under ER stress conditions in Arabidopsis. We discovered that the loss of IRE1A and IRE1B leads to diminished protein translation, indicating a significant role for IRE1 in this process. However, this regulation was not solely dependent on the interaction with bZIP60, a key transcription factor in the UPR. Interestingly, while chemical chaperones TUDCA and PBA effectively alleviated the translation inhibition observed in ire1a ire1b mutants, this effect was more pronounced than the mitigation observed from suppressing GCN2 expression or introducing a non-phosphorylatable eIF2α variant. Additionally, the kinase and ribonuclease activities of IRE1B were demonstrated to be crucial for plant adaptation and protein synthesis regulation under ER stress conditions. Overall, this study not only highlights the complex regulatory mechanisms of IRE1 in plant ER stress responses but also provides insights into its multifaceted roles in protein translation regulation.
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Affiliation(s)
- Jae Yong Yoo
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Ki Seong Ko
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Bich Ngoc Vu
- Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Young Eun Lee
- Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Ha Na Choi
- Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Yoo Na Lee
- Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Wahyu Indra Duwi Fanata
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Department of Agrotechnology, Faculty of Agriculture, University of Jember, Jember, 68121, Indonesia
| | - Rikno Harmoko
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Research Center for Genetic Engineering, National Research and Innovation Agency, Jl. Raya Jakarta-Bogor, Cibinong, Bogor, 16911, Indonesia
| | - Sang-Kyu Lee
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Woo Sik Chung
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Jong Chan Hong
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea
| | - Kyun Oh Lee
- Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea; Division of Life Science, Division of Applied Life Sciences (BK4 Program) Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, South Korea.
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2
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Lohmann J, Herzog O, Rosenzweig K, Weingartner M. Thermal adaptation in plants: understanding the dynamics of translation factors and condensates. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4258-4273. [PMID: 38630631 DOI: 10.1093/jxb/erae171] [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: 12/15/2023] [Accepted: 04/16/2024] [Indexed: 04/19/2024]
Abstract
Plants, as sessile organisms, face the crucial challenge of adjusting growth and development with ever-changing environmental conditions. Protein synthesis is the fundamental process that enables growth of all organisms. Since elevated temperature presents a substantial threat to protein stability and function, immediate adjustments of protein synthesis rates are necessary to circumvent accumulation of proteotoxic stress and to ensure survival. This review provides an overview of the mechanisms that control translation under high-temperature stress by the modification of components of the translation machinery in plants, and compares them to yeast and metazoa. Recent research also suggests an important role for cytoplasmic biomolecular condensates, named stress granules, in these processes. Current understanding of the role of stress granules in translational regulation and of the molecular processes associated with translation that might occur within stress granules is also discussed.
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Affiliation(s)
- Julia Lohmann
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Oliver Herzog
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Kristina Rosenzweig
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
| | - Magdalena Weingartner
- Institute of Plant Sciences and Microbiology, University of Hamburg, Ohnhorststrasse 18, 22609 Hamburg, Germany
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3
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Ko DK, Brandizzi F. Dynamics of ER stress-induced gene regulation in plants. Nat Rev Genet 2024; 25:513-525. [PMID: 38499769 PMCID: PMC11186725 DOI: 10.1038/s41576-024-00710-4] [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] [Accepted: 02/15/2024] [Indexed: 03/20/2024]
Abstract
Endoplasmic reticulum (ER) stress is a potentially lethal condition that is induced by the abnormal accumulation of unfolded or misfolded secretory proteins in the ER. In eukaryotes, ER stress is managed by the unfolded protein response (UPR) through a tightly regulated, yet highly dynamic, reprogramming of gene transcription. Although the core principles of the UPR are similar across eukaryotes, unique features of the plant UPR reflect the adaptability of plants to their ever-changing environments and the need to balance the demands of growth and development with the response to environmental stressors. The past decades have seen notable progress in understanding the mechanisms underlying ER stress sensing and signalling transduction pathways, implicating the UPR in the effects of physiological and induced ER stress on plant growth and crop yield. Facilitated by sequencing technologies and advances in genetic and genomic resources, recent efforts have driven the discovery of transcriptional regulators and elucidated the mechanisms that mediate the dynamic and precise gene regulation in response to ER stress at the systems level.
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Affiliation(s)
- Dae Kwan Ko
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
| | - Federica Brandizzi
- MSU-DOE Plant Research Lab, Michigan State University, East Lansing, MI, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA.
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4
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Shi X, Du J, Wang X, Zhang X, Yan X, Yang Y, Jia H, Zhang S. NtGCN2 confers cadmium tolerance in Nicotiana tabacum L. by regulating cadmium uptake, efflux, and subcellular distribution. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172695. [PMID: 38663613 DOI: 10.1016/j.scitotenv.2024.172695] [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: 01/10/2024] [Revised: 04/08/2024] [Accepted: 04/21/2024] [Indexed: 05/04/2024]
Abstract
General control non-derepressible-2 (GCN2) is widely expressed in eukaryotes and responds to biotic and abiotic stressors. However, the precise function and mechanism of action of GCN2 in response to cadmium (Cd) stress in Nicotiana tabacum L. (tobacco) remains unclear. We investigated the role of NtGCN2 in Cd tolerance and explored the mechanism by which NtGCN2 responds to Cd stress in tobacco by exposing NtGCN2 transgenic tobacco lines to different concentrations of CdCl2. NtGCN2 was activated under 50 μmol·L-1 CdCl2 stress and enhanced the Cd tolerance and photosynthetic capacities of tobacco by increasing chlorophyll content and antioxidant capacity by upregulating NtSOD, NtPOD, and NtCAT expression and corresponding enzyme activities and decreasing malondialdehyde and O2·- contents. NtGCN2 enhanced the osmoregulatory capacity of tobacco by elevating proline (Pro) and soluble sugar contents and maintaining low levels of relative conductivity. Finally, NtGCN2 enhanced Cd tolerance in tobacco by reducing Cd uptake and translocation, promoting Cd efflux, and regulating Cd subcellular distribution. In conclusion, NtGCN2 improves the tolerance of tobacco to Cd through a series of mechanisms, namely, increasing antioxidant, photosynthetic, and osmoregulation capacities and regulating Cd uptake, translocation, efflux, and subcellular distribution. This study provides a scientific basis for further exploration of the role of NtGCN2 in plant responses to Cd stress and enhancement of the Cd stress signaling network in tobacco.
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Affiliation(s)
- Xiaotian Shi
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Jiao Du
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Xu Wang
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Xiaoquan Zhang
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Xiaoxiao Yan
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Yongxia Yang
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China
| | - Hongfang Jia
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China.
| | - Songtao Zhang
- Key Laboratory of Tobacco Cultivation in Tobacco Industry, National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, Henan, China.
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5
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Wu HYL, Jen J, Hsu PY. What, where, and how: Regulation of translation and the translational landscape in plants. THE PLANT CELL 2024; 36:1540-1564. [PMID: 37437121 PMCID: PMC11062462 DOI: 10.1093/plcell/koad197] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/14/2023]
Abstract
Translation is a crucial step in gene expression and plays a vital role in regulating various aspects of plant development and environmental responses. It is a dynamic and complex program that involves interactions between mRNAs, transfer RNAs, and the ribosome machinery through both cis- and trans-regulation while integrating internal and external signals. Translational control can act in a global (transcriptome-wide) or mRNA-specific manner. Recent advances in genome-wide techniques, particularly ribosome profiling and proteomics, have led to numerous exciting discoveries in both global and mRNA-specific translation. In this review, we aim to provide a "primer" that introduces readers to this fascinating yet complex cellular process and provide a big picture of how essential components connect within the network. We begin with an overview of mRNA translation, followed by a discussion of the experimental approaches and recent findings in the field, focusing on unannotated translation events and translational control through cis-regulatory elements on mRNAs and trans-acting factors, as well as signaling networks through 3 conserved translational regulators TOR, SnRK1, and GCN2. Finally, we briefly touch on the spatial regulation of mRNAs in translational control. Here, we focus on cytosolic mRNAs; translation in organelles and viruses is not covered in this review.
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Affiliation(s)
- Hsin-Yen Larry Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Joey Jen
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Polly Yingshan Hsu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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6
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Chang HH, Huang LC, Browning KS, Huq E, Cheng MC. The phosphorylation of carboxyl-terminal eIF2α by SPA kinases contributes to enhanced translation efficiency during photomorphogenesis. Nat Commun 2024; 15:3467. [PMID: 38658612 PMCID: PMC11043401 DOI: 10.1038/s41467-024-47848-7] [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: 05/12/2023] [Accepted: 04/11/2024] [Indexed: 04/26/2024] Open
Abstract
Light triggers an enhancement of global translation during photomorphogenesis in Arabidopsis, but little is known about the underlying mechanisms. The phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) at a conserved serine residue in the N-terminus has been shown as an important mechanism for the regulation of protein synthesis in mammalian and yeast cells. However, whether the phosphorylation of this residue in plant eIF2α plays a role in regulation of translation remains elusive. Here, we show that the quadruple mutant of SUPPRESSOR OF PHYA-105 family members (SPA1-SPA4) display repressed translation efficiency after light illumination. Moreover, SPA1 directly phosphorylates the eIF2α C-terminus under light conditions. The C-term-phosphorylated eIF2α promotes translation efficiency and photomorphogenesis, whereas the C-term-unphosphorylated eIF2α results in a decreased translation efficiency. We also demonstrate that the phosphorylated eIF2α enhances ternary complex assembly by promoting its affinity to eIF2β and eIF2γ. This study reveals a unique mechanism by which light promotes translation via SPA1-mediated phosphorylation of the C-terminus of eIF2α in plants.
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Affiliation(s)
- Hui-Hsien Chang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Lin-Chen Huang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Karen S Browning
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Mei-Chun Cheng
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
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7
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Thibault E, Brandizzi F. Post-translational modifications: emerging directors of cell-fate decisions during endoplasmic reticulum stress in Arabidopsis thaliana. Biochem Soc Trans 2024; 52:831-848. [PMID: 38600022 PMCID: PMC11088923 DOI: 10.1042/bst20231025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/23/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Homeostasis of the endoplasmic reticulum (ER) is critical for growth, development, and stress responses. Perturbations causing an imbalance in ER proteostasis lead to a potentially lethal condition known as ER stress. In ER stress situations, cell-fate decisions either activate pro-life pathways that reestablish homeostasis or initiate pro-death pathways to prevent further damage to the organism. Understanding the mechanisms underpinning cell-fate decisions in ER stress is critical for crop development and has the potential to enable translation of conserved components to ER stress-related diseases in metazoans. Post-translational modifications (PTMs) of proteins are emerging as key players in cell-fate decisions in situations of imbalanced ER proteostasis. In this review, we address PTMs orchestrating cell-fate decisions in ER stress in plants and provide evidence-based perspectives for where future studies may focus to identify additional PTMs involved in ER stress management.
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Affiliation(s)
- Ethan Thibault
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, U.S.A
- Department of Plant Biology, Michigan State University, East Lansing, MI, U.S.A
| | - Federica Brandizzi
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, U.S.A
- Department of Plant Biology, Michigan State University, East Lansing, MI, U.S.A
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, U.S.A
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8
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Yuan S, Zhou G, Xu G. Translation machinery: the basis of translational control. J Genet Genomics 2024; 51:367-378. [PMID: 37536497 DOI: 10.1016/j.jgg.2023.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/23/2023] [Accepted: 07/23/2023] [Indexed: 08/05/2023]
Abstract
Messenger RNA (mRNA) translation consists of initiation, elongation, termination, and ribosome recycling, carried out by the translation machinery, primarily including tRNAs, ribosomes, and translation factors (TrFs). Translational regulators transduce signals of growth and development, as well as biotic and abiotic stresses, to the translation machinery, where global or selective translational control occurs to modulate mRNA translation efficiency (TrE). As the basis of translational control, the translation machinery directly determines the quality and quantity of newly synthesized peptides and, ultimately, the cellular adaption. Thus, regulating the availability of diverse machinery components is reviewed as the central strategy of translational control. We provide classical signaling pathways (e.g., integrated stress responses) and cellular behaviors (e.g., liquid-liquid phase separation) to exemplify this strategy within different physiological contexts, particularly during host-microbe interactions. With new technologies developed, further understanding this strategy will speed up translational medicine and translational agriculture.
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Affiliation(s)
- Shu Yuan
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China
| | - Guilong Zhou
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China
| | - Guoyong Xu
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China; Hubei Hongshan Laboratory, Wuhan, Hubei 430070, 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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Vermeulen A, Takken FLW, Sánchez-Camargo VA. Translation Arrest: A Key Player in Plant Antiviral Response. Genes (Basel) 2023; 14:1293. [PMID: 37372472 DOI: 10.3390/genes14061293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Plants evolved several mechanisms to protect themselves against viruses. Besides recessive resistance, where compatible host factors required for viral proliferation are absent or incompatible, there are (at least) two types of inducible antiviral immunity: RNA silencing (RNAi) and immune responses mounted upon activation of nucleotide-binding domain leucine-rich repeat (NLR) receptors. RNAi is associated with viral symptom recovery through translational repression and transcript degradation following recognition of viral double-stranded RNA produced during infection. NLR-mediated immunity is induced upon (in)direct recognition of a viral protein by an NLR receptor, triggering either a hypersensitive response (HR) or an extreme resistance response (ER). During ER, host cell death is not apparent, and it has been proposed that this resistance is mediated by a translational arrest (TA) of viral transcripts. Recent research indicates that translational repression plays a crucial role in plant antiviral resistance. This paper reviews current knowledge on viral translational repression during viral recovery and NLR-mediated immunity. Our findings are summarized in a model detailing the pathways and processes leading to translational arrest of plant viruses. This model can serve as a framework to formulate hypotheses on how TA halts viral replication, inspiring new leads for the development of antiviral resistance in crops.
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Affiliation(s)
- Annemarie Vermeulen
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Frank L W Takken
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Victor A Sánchez-Camargo
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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11
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Viswanath KK, Kuo SY, Tu CW, Hsu YH, Huang YW, Hu CC. The Role of Plant Transcription Factors in the Fight against Plant Viruses. Int J Mol Sci 2023; 24:ijms24098433. [PMID: 37176135 PMCID: PMC10179606 DOI: 10.3390/ijms24098433] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/20/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Plants are vulnerable to the challenges of unstable environments and pathogen infections due to their immobility. Among various stress conditions, viral infection is a major threat that causes significant crop loss. In response to viral infection, plants undergo complex molecular and physiological changes, which trigger defense and morphogenic pathways. Transcription factors (TFs), and their interactions with cofactors and cis-regulatory genomic elements, are essential for plant defense mechanisms. The transcriptional regulation by TFs is crucial in establishing plant defense and associated activities during viral infections. Therefore, identifying and characterizing the critical genes involved in the responses of plants against virus stress is essential for the development of transgenic plants that exhibit enhanced tolerance or resistance. This article reviews the current understanding of the transcriptional control of plant defenses, with a special focus on NAC, MYB, WRKY, bZIP, and AP2/ERF TFs. The review provides an update on the latest advances in understanding how plant TFs regulate defense genes expression during viral infection.
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Affiliation(s)
- Kotapati Kasi Viswanath
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Song-Yi Kuo
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chin-Wei Tu
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 40227, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
- Advanced Plant Biotechnology Centre, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
- Advanced Plant Biotechnology Centre, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
- Advanced Plant Biotechnology Centre, National Chung Hsing University, Taichung 40227, Taiwan
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12
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Wang H, Li N, Li H, Zhang S, Zhang X, Yan X, Wang Z, Yang Y, Zhang S. Overexpression of NtGCN2 improves drought tolerance in tobacco by regulating proline accumulation, ROS scavenging ability, and stomatal closure. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 198:107665. [PMID: 37018865 DOI: 10.1016/j.plaphy.2023.107665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/18/2023] [Accepted: 03/23/2023] [Indexed: 05/07/2023]
Abstract
Drought stress is a severe threat to plants. Genes that respond to drought stress are essential for plant growth and development. General control nonderepressible 2 (GCN2) encodes a protein kinase that responds to various biotic and abiotic stresses. However, the mechanism of GCN2 in plant drought tolerance remains unclear. In the present study, the promoters of NtGCN2 from Nicotiana tabacum K326, which contained a drought-responsive Cis-acting element MYB that can be activated by drought stress, were cloned. Furthermore, the drought tolerance function of NtGCN2 was investigated using NtGCN2-overexpressed transgenic tobacco plants. NtGCN2-overexpressed transgenic plants were more tolerant to drought stress than wild-type (WT) plants. The transgenic tobacco plants exhibited higher proline and abscisic acid (ABA) contents, antioxidant enzyme activities, leaf relative water content, and expression levels of genes encoding key antioxidant enzymes and proline synthase, but lower levels of malondialdehyde and reactive oxygen species, and reduced stomatal apertures, stomatal densities, and stomatal opening rates compared to WT plants under drought stress. These results indicated that overexpression of NtGCN2 conferred drought tolerance in transgenic tobacco plants. RNA-seq analysis showed that overexpression of NtGCN2 responded to drought stress by regulating the expression of genes related to proline synthesis and catabolism, abscisic acid synthesis and catabolism, antioxidant enzymes, and ion channels in guard cells. These results showed that NtGCN2 might regulate drought tolerance by regulating proline accumulation, reactive oxygen species (ROS) scavenging, and stomatal closure in tobacco and may have the potential for application in the genetic modification of crop drought tolerance.
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Affiliation(s)
- Hao Wang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Ning Li
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Hang Li
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Songjie Zhang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Xiaoquan Zhang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Xiaoxiao Yan
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Zhaojun Wang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Yongxia Yang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China
| | - Songtao Zhang
- National Tobacco Cultivation & Physiology & Biochemistry Research Centre, College of Tobacco Science, Henan Agricultural University, Zhengzhou, 450002, Henan, China.
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13
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Zhigailov AV, Nizkorodova AS, Sharipov KO, Polimbetova NS, Iskakov BK. Glyphosate treatment mediates the accumulation of small discrete 5'- and 3'-terminal fragments of 18S rRNA in plant cells. Vavilovskii Zhurnal Genet Selektsii 2023; 27:93-98. [PMID: 37063515 PMCID: PMC10090119 DOI: 10.18699/vjgb-23-13] [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: 03/09/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 04/18/2023] Open
Abstract
Under many kinds of stress, eukaryotic cells rapidly decrease the overall translation level of the majority of mRNAs. However, some molecular mechanisms of protein synthesis inhibition like phosphorylation of eukaryotic elongation factor 2 (eEF2), which are known to be functional in animals and yeast, are not implemented in plants. We suggest that there is an alternative mechanism for the inhibition of protein synthesis in plant cells and possibly, in other eukaryotes, which is based on the discrete fragmentation of 18S rRNA molecules within small ribosomal subunits. We identified four stress-induced small RNAs, which are 5'- and 3'-terminal fragments of 18S rRNA. In the present work, we studied the induction of 18S rRNA discrete fragmentation and phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) in germinated wheat embryos in the presence of glyphosate, which imitates the condition of amino acid starvation. Using northern and western blotting, we have shown that stress-induced 18S rRNA fragments started to accumulate in wheat embryos at glyphosate concentrations that did not evoke eIF2α phosphorylation. It was also found that cleavage of 18S rRNA near the 5'-terminus began much earlier than eIF2α phosphorylation, which became noticeable only at higher concentration (500 μM) of glyphosate. This result suggests that discrete fragmentation of 18S rRNA may constitute a regulatory mechanism of mRNA translation in response to stress and may occur in plant cells in parallel with and independently of eIF2α phosphorylation. The identified small 5'- and 3'-terminal fragments of 18S rRNA that accumulate during various stresses may serve as stress resistance markers in the breeding of economically important plant crops.
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Affiliation(s)
- A V Zhigailov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Almaty, Kazakhstan
| | - A S Nizkorodova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Almaty, Kazakhstan
| | - K O Sharipov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Almaty, Kazakhstan
| | - N S Polimbetova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Almaty, Kazakhstan
| | - B K Iskakov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Almaty, Kazakhstan
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14
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Wang L, Xu F, Yu F. Two environmental signal-driven RNA metabolic processes: Alternative splicing and translation. PLANT, CELL & ENVIRONMENT 2023; 46:718-732. [PMID: 36609800 DOI: 10.1111/pce.14537] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/29/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Plants live in fixed locations and have evolved adaptation mechanisms that integrate multiple responses to various environmental signals. Among the different components of these response pathways, receptors/sensors represent nodes that recognise environmental signals. Additionally, RNA metabolism plays an essential role in the regulation of gene expression and protein synthesis. With the development of RNA biotechnology, recent advances have been made in determining the roles of RNA metabolism in response to different environmental signals-especially the roles of alternative splicing and translation. In this review, we discuss recent progress in research on how the environmental adaptation mechanisms in plants are affected at the posttranscriptional level. These findings improve our understanding of the mechanism through which plants adapt to environmental changes by regulating the posttranscriptional level and are conducive for breeding stress-tolerant plants to cope with dynamic and rapidly changing environments.
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Affiliation(s)
- Long Wang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, China
| | - Fan Xu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, China
| | - Feng Yu
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, Hunan University, Changsha, China
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
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15
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Zhou Y, Niu R, Tang Z, Mou R, Wang Z, Zhu S, Yang H, Ding P, Xu G. Plant HEM1 specifies a condensation domain to control immune gene translation. NATURE PLANTS 2023; 9:289-301. [PMID: 36797349 DOI: 10.1038/s41477-023-01355-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Translational reprogramming is a fundamental layer of immune regulation, but how such a global regulatory mechanism operates remains largely unknown. Here we perform a genetic screen and identify Arabidopsis HEM1 as a global translational regulator of plant immunity. The loss of HEM1 causes exaggerated cell death to restrict bacterial growth during effector-triggered immunity (ETI). By improving ribosome footprinting, we reveal that the hem1 mutant increases the translation efficiency of pro-death immune genes. We show that HEM1 contains a plant-specific low-complexity domain (LCD) absent from animal homologues. This LCD endows HEM1 with the capability of phase separation in vitro and in vivo. During ETI, HEM1 interacts and condensates with the translation machinery; this activity is promoted by the LCD. CRISPR removal of this LCD causes more ETI cell death. Our results suggest that HEM1 condensation constitutes a brake mechanism of immune activation by controlling the tissue health and disease resistance trade-off during ETI.
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Affiliation(s)
- Yulu Zhou
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Ruixia Niu
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Zhijuan Tang
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Rui Mou
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Zhao Wang
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Sitao Zhu
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China
| | - Hongchun Yang
- School of Life Sciences, Wuhan University, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
| | - Pingtao Ding
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | - Guoyong Xu
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, China.
- Hubei Hongshan Laboratory, Wuhan, China.
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16
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Hiragori Y, Takahashi H, Karino T, Kaido A, Hayashi N, Sasaki S, Nakao K, Motomura T, Yamashita Y, Naito S, Onouchi H. Genome-wide identification of Arabidopsis non-AUG-initiated upstream ORFs with evolutionarily conserved regulatory sequences that control protein expression levels. PLANT MOLECULAR BIOLOGY 2023; 111:37-55. [PMID: 36044152 DOI: 10.1007/s11103-022-01309-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
This study identified four novel regulatory non-AUG-initiated upstream ORFs (uORFs) with evolutionarily conserved sequences in Arabidopsis and elucidated the mechanism by which a non-AUG-initiated uORF promotes main ORF translation. Upstream open reading frames (uORFs) are short ORFs found in the 5'-untranslated regions (5'-UTRs) of eukaryotic transcripts and can influence the translation of protein-coding main ORFs (mORFs). Recent genome-wide ribosome profiling studies have revealed that hundreds or thousands of uORFs initiate translation at non-AUG start codons. However, the physiological significance of these non-AUG uORFs has so far been demonstrated for only a few of them. In this study, to identify physiologically important regulatory non-AUG uORFs in Arabidopsis, we took an approach that combined bioinformatics and experimental analysis. Since physiologically important non-AUG uORFs are likely to be conserved across species, we first searched the Arabidopsis genome for non-AUG-initiated uORFs with evolutionarily conserved sequences. Then, we examined the effects of the conserved non-AUG uORFs on the expression of the downstream mORFs using transient expression assays. As a result, three inhibitory and one promotive non-AUG uORFs were identified. Among the inhibitory non-AUG uORFs, two exerted repressive effects on mORF expression in an amino acid sequence-dependent manner. These two non-AUG uORFs are likely to encode regulatory peptides that cause ribosome stalling, thereby enhancing their repressive effects. In contrast, one of the identified regulatory non-AUG uORFs promoted mORF expression by alleviating the inhibitory effect of a downstream AUG-initiated uORF. These findings provide insights into the mechanisms that enable non-AUG uORFs to play regulatory roles despite their low translation initiation efficiencies.
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Affiliation(s)
- Yuta Hiragori
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Hiro Takahashi
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
- Graduate School of Horticulture, Chiba University, Matsudo, 271-8510, Japan
| | - Taihei Karino
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Atsushi Kaido
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Noriya Hayashi
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Shun Sasaki
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Kodai Nakao
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Taichiro Motomura
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Yui Yamashita
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Satoshi Naito
- Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
- Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Hitoshi Onouchi
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan.
- Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan.
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17
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Lokdarshi A, von Arnim AG, Akuoko TK. Modulation of GCN2 activity under excess light stress by osmoprotectants and amino acids. PLANT SIGNALING & BEHAVIOR 2022; 17:2115747. [PMID: 36093942 PMCID: PMC9481134 DOI: 10.1080/15592324.2022.2115747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
The protein kinase GCN2 (General Control Nonderepressible2) and its phosphorylation target, the eukaryotic translation initiation factor (eIF)2α represent the core module of the plant's integrated stress response, a signaling pathway widely conserved in eukaryotes that can rapidly regulate translation in response to stressful conditions. Recent findings indicate that the Arabidopsis thaliana GCN2 protein operates under the command of reactive oxygen species (ROS) emanating from the chloroplast under a variety of abiotic stresses such as excess light. To get deeper insights into the mechanism of GCN2 activation under excess light, we assessed the role of amino acids in view of the classic function of GCN2 as a sensor of amino acid status. Additionally, given that osmoprotectants can counteract ROS-related stresses, we tested their ability to mitigate GCN2 activity. Our results demonstrate that certain amino acids and osmoprotectants attenuate eIF2α-phosphorylation under excess light stress to some degree. Future investigations into the biochemical mechanisms of these natural compounds on GCN2 signaling activity will provide better insights into the GCN2-eIF2α regulation.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biology, Valdosta State University, Valdosta, GA, USA
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- UT-ORNL Graduate School of Genome Science and Technology, the University of Tennessee, Knoxville, TN, USA
| | - Teressa K Akuoko
- Department of Biology, Valdosta State University, Valdosta, GA, USA
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18
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García MJ, Angulo M, Lucena C, Pérez-Vicente R, Romera FJ. To grow or not to grow under nutrient scarcity: Target of rapamycin-ethylene is the question. FRONTIERS IN PLANT SCIENCE 2022; 13:968665. [PMID: 36035680 PMCID: PMC9412941 DOI: 10.3389/fpls.2022.968665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
To cope with nutrient scarcity, plants generally follow two main complementary strategies. On the one hand, they can slow down growing, mainly shoot growth, to diminish the demand of nutrients. We can call this strategy as "stop growing." On the other hand, plants can develop different physiological and morphological responses, mainly in their roots, aimed to facilitate the acquisition of nutrients. We can call this second strategy as "searching for nutrients." Both strategies are compatible and can function simultaneously but the interconnection between them is not yet well-known. In relation to the "stop growing" strategy, it is known that the TOR (Target Of Rapamycin) system is a central regulator of growth in response to nutrients in eukaryotic cells. TOR is a protein complex with kinase activity that promotes protein synthesis and growth while some SnRK (Sucrose non-fermenting 1-Related protein Kinases) and GCN (General Control Non-derepressible) kinases act antagonistically. It is also known that some SnRKs and GCNs are activated by nutrient deficiencies while TOR is active under nutrient sufficiency. In relation to the "searching for nutrients" strategy, it is known that the plant hormone ethylene participates in the activation of many nutrient deficiency responses. In this Mini Review, we discuss the possible role of ethylene as the hub connecting the "stop growing" strategy and the "searching for nutrients" strategy since very recent results also suggest a clear relationship of ethylene with the TOR system.
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Affiliation(s)
- María José García
- Department of Agronomy, (DAUCO-María de Maeztu Unit of Excellence), Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Macarena Angulo
- Department of Agronomy, (DAUCO-María de Maeztu Unit of Excellence), Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Carlos Lucena
- Department of Botany, Ecology and Plant Physiology, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Rafael Pérez-Vicente
- Department of Botany, Ecology and Plant Physiology, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
| | - Francisco Javier Romera
- Department of Agronomy, (DAUCO-María de Maeztu Unit of Excellence), Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba, Spain
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19
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Lokdarshi A, von Arnim AG. Review: Emerging roles of the signaling network of the protein kinase GCN2 in the plant stress response. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 320:111280. [PMID: 35643606 PMCID: PMC9197246 DOI: 10.1016/j.plantsci.2022.111280] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/07/2022] [Accepted: 03/30/2022] [Indexed: 06/15/2023]
Abstract
The pan-eukaryotic protein kinase GCN2 (General Control Nonderepressible2) regulates the translation of mRNAs in response to external and metabolic conditions. Although GCN2 and its substrate, translation initiation factor 2 (eIF2) α, and several partner proteins are substantially conserved in plants, this kinase has assumed novel functions in plants, including in innate immunity and retrograde signaling between the chloroplast and cytosol. How exactly some of the biochemical paradigms of the GCN2 system have diverged in the green plant lineage is only partially resolved. Specifically, conflicting data underscore and cast doubt on whether GCN2 regulates amino acid biosynthesis; also whether phosphorylation of eIF2α can in fact repress global translation or activate mRNA specific translation via upstream open reading frames; and whether GCN2 is controlled in vivo by the level of uncharged tRNA. This review examines the status of research on the eIF2α kinase, GCN2, its function in the response to xenobiotics, pathogens, and abiotic stress conditions, and its rather tenuous role in the translational control of mRNAs.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biology, Valdosta State University, Valdosta, GA 31698, USA.
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-1939, USA; UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996-1939, USA.
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20
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Cho HY, Chou MY, Ho HY, Chen WC, Shih MC. Ethylene modulates translation dynamics in Arabidopsis under submergence via GCN2 and EIN2. SCIENCE ADVANCES 2022; 8:eabm7863. [PMID: 35658031 PMCID: PMC9166634 DOI: 10.1126/sciadv.abm7863] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/15/2022] [Indexed: 05/23/2023]
Abstract
General translational repression is a key process that reduces energy consumption under hypoxia. Here, we show that plant stress-activated general control nonderepressible 2 (GCN2) was activated to regulate the reduction in polysome loading during submergence in Arabidopsis. GCN2 signaling was activated by ethylene under submergence. GCN2 activity was reduced in etr1-1, but not in ein2-5 or eil1ein3, under submergence, suggesting that GCN2 activity is regulated by a noncanonical ethylene signaling pathway. Polysome loading was not reduced in ein2-5 under submergence, implying that ethylene modulates translation via both EIN2 and GCN2. Transcriptomic analysis demonstrated that EIN2 and GCN2 regulate not only general translational repression but also translational enhancement of specific mRNAs under submergence. Together, these results demonstrate that during submergence, entrapped ethylene triggers GCN2 and EIN2 to regulate translation dynamics and ensure the translation of stress response proteins.
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21
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Zhigailov AV, Stanbekova GE, Nizkorodova AS, Galiakparov NN, Gritsenko DA, Polimbetova NS, Halford NG, Iskakov BK. Phosphorylation of the alpha-subunit of plant eukaryotic initiation factor 2 prevents its association with polysomes but does not considerably suppress protein synthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 317:111190. [PMID: 35193739 DOI: 10.1016/j.plantsci.2022.111190] [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: 10/21/2021] [Revised: 01/12/2022] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) and subsequent inhibition of protein synthesis is a major survival response to different stresses in animal and yeast cells. However, the role of this regulatory mechanism in plants is not unambiguously established to date. Here we describe a slight reduction of polysome abundance in Nicotiana benthamiana after the transient expression of a cDNA, AteIF2α(S56D), encoding a phosphomimetic form of Arabidopsis thaliana eIF2α. In contrast, the expression of a cDNA, AteIF2α(S56A), that encodes a non-phosphorylatable form of AteIF2α caused slightly elevated polysome formation compared to the control. Recombinant AteIF2α(S56A) was detected in association with 40S ribosomal subunit-containing complexes and also in the polysomal fraction, while recombinant AteIF2α(S56D) was detected mainly in complex with 40S subunits. Intentional phosphorylation of TaeIF2α induced by L-histidinol in a wheat germ (Triticum aestivum) cell-free extract did not reduce the abundance of polysomes. Interestingly, the phosphorylated TaeIF2(αP) was not detected in the polysomal fraction, similar to AteIF2α(S56D) in the in vivo experiment. Using mRNAs with a 'Strepto-tag' in the 3' untranslated region, the 48S pre-initiation complexes isolated from histidinol-treated wheat germ extracts were shown to contain phosphorylated TaeIF2(αP). Thus, the phosphorylation of plant eIF2 does not greatly affect its ability to participate in the initiation of mRNA translation, in contrast to animals and yeast, in which eIF2α phosphorylation results in profound suppression of protein synthesis.
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Affiliation(s)
- Andrey V Zhigailov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
| | - Gulshan E Stanbekova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
| | - Anna S Nizkorodova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
| | - Nurbol N Galiakparov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
| | - Dilyara A Gritsenko
- Institute of Plant Biology and Biotechnology, Science Committee, Ministry of Education and Science, Almaty, 050040, Kazakhstan.
| | - Nailya S Polimbetova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
| | - Nigel G Halford
- Plant Sciences Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
| | - Bulat K Iskakov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan.
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22
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Amino Acid Signaling for TOR in Eukaryotes: Sensors, Transducers, and a Sustainable Agricultural fuTORe. Biomolecules 2022; 12:biom12030387. [PMID: 35327579 PMCID: PMC8945916 DOI: 10.3390/biom12030387] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells monitor and regulate metabolism through the atypical protein kinase target of rapamycin (TOR) regulatory hub. TOR is activated by amino acids in animals and fungi through molecular signaling pathways that have been extensively defined in the past ten years. Very recently, several studies revealed that TOR is also acutely responsive to amino acid metabolism in plants, but the mechanisms of amino acid sensing are not yet established. In this review, we summarize these discoveries, emphasizing the diversity of amino acid sensors in human cells and highlighting pathways that are indirectly sensitive to amino acids, i.e., how TOR monitors changes in amino acid availability without a bona fide amino acid sensor. We then discuss the relevance of these model discoveries to plant biology. As plants can synthesize all proteinogenic amino acids from inorganic precursors, we focus on the possibility that TOR senses both organic metabolites and inorganic nutrients. We conclude that an evolutionary perspective on nutrient sensing by TOR benefits both agricultural and biomedical science, contributing to ongoing efforts to generate crops for a sustainable agricultural future.
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Liu H, Gong X, Deng H, Tan J, Sun Y, Wang F, Wu W, Zhou Z, Xu R, He H, Lo C. The Rice Aspartyl-tRNA Synthetase YLC3 Regulates Amino Acid Homeostasis and Chloroplast Development Under Low Temperature. FRONTIERS IN PLANT SCIENCE 2022; 13:847364. [PMID: 36340382 PMCID: PMC9635353 DOI: 10.3389/fpls.2022.847364] [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: 01/02/2022] [Accepted: 01/31/2022] [Indexed: 05/17/2023]
Abstract
Aminoacyl tRNA synthetases primarily function to attach specific amino acids to the corresponding tRNAs during protein translation. However, their roles in regulating plant growth and development still remain elusive. Here we reported a rice thermo-sensitive mutant yellow leaf chlorosis3 (ylc3) with reduced chlorophyll content, altered thylakoid structure, and substantially elevated levels of free aspartate, asparagine and glutamine in leaves under low temperature condition. Map-based cloning identified that YLC3 encodes an aspartyl-tRNA synthetase which is localized in cytosol and mitochondria. In addition, quantitative proteomics analysis revealed that both nuclear and chloroplast-encoded thylakoid proteins were significantly down-regulated in the mutant. On the other hand, proteins involved in amino acid metabolism and the process of protein synthesis were up-regulated in ylc3, particularly for key enzymes that convert aspartate to asparagine. Moreover, uncharged tRNA-Asp accumulation and phosphorylation of the translation initiation factor eIF2α was detected in the mutant, suggesting that YLC3 regulates the homeostasis of amino acid metabolism and chloroplast thylakoid development through modulation of processes during protein synthesis.
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Affiliation(s)
- Hongjia Liu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- *Correspondence: Hongjia Liu,
| | - Xue Gong
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Hui Deng
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jinjuan Tan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Yanqing Sun
- Institute of Crop Science and Institute of Bioinformatics, Zhejiang University, Hangzhou, China
| | - Fang Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Wenjuan Wu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Zhongjing Zhou
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Rumeng Xu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Haiyan He
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
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Castellano MM, Merchante C. Peculiarities of the regulation of translation initiation in plants. CURRENT OPINION IN PLANT BIOLOGY 2021; 63:102073. [PMID: 34186463 DOI: 10.1016/j.pbi.2021.102073] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/21/2021] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
Protein synthesis is a fundamental process for life and, as such, plays a crucial role in the adaptation to energy, developmentaland environmental conditions. For these reasons, and despite the general conservation of the eukaryotic translational machinery, it is not surprising that organisms with different lifestyles have evolved distinct mechanisms of regulation to adapt translation initiation to their intrinsic growth and development. Plants have clear peculiarities compared with other eukaryotes that have also extended to translation control. This review describes the plant-specific mechanisms for regulation of translation initiation, with a focus on those that modulate the eIF4F complexes, central translational regulatory hubs in all eukaryotes, and highlights the latest discoveries on the signaling pathways that regulate their constituents and activity.
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Affiliation(s)
- M Mar Castellano
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA, CSIC), Campus Montegancedo UPM, Pozuelo de Alarcón, Madrid, 28223, Spain.
| | - Catharina Merchante
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Campus de Teatinos, Universidad de Málaga, Málaga, 29071, Spain.
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25
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Mancera-Martínez E, Dong Y, Makarian J, Srour O, Thiébeauld O, Jamsheer M, Chicher J, Hammann P, Schepetilnikov M, Ryabova LA. Phosphorylation of a reinitiation supporting protein, RISP, determines its function in translation reinitiation. Nucleic Acids Res 2021; 49:6908-6924. [PMID: 34133725 PMCID: PMC8266674 DOI: 10.1093/nar/gkab501] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/14/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
Reinitiation supporting protein, RISP, interacts with 60S (60S ribosomal subunit) and eIF3 (eukaryotic initiation factor 3) in plants. TOR (target-of-rapamycin) mediates RISP phosphorylation at residue Ser267, favoring its binding to eL24 (60S ribosomal protein L24). In a viral context, RISP, when phosphorylated, binds the CaMV transactivator/ viroplasmin, TAV, to assist in an exceptional mechanism of reinitiation after long ORF translation. Moreover, we show here that RISP interacts with eIF2 via eIF2β and TOR downstream target 40S ribosomal protein eS6. A RISP phosphorylation knockout, RISP-S267A, binds preferentially eIF2β, and both form a ternary complex with eIF3a in vitro. Accordingly, transient overexpression in plant protoplasts of RISP-S267A, but not a RISP phosphorylation mimic, RISP-S267D, favors translation initiation. In contrast, RISP-S267D preferentially binds eS6, and, when bound to the C-terminus of eS6, can capture 60S in a highly specific manner in vitro, suggesting that it mediates 60S loading during reinitiation. Indeed, eS6-deficient plants are highly resistant to CaMV due to their reduced reinitiation capacity. Strikingly, an eS6 phosphomimic, when stably expressed in eS6-deficient plants, can fully restore the reinitiation deficiency of these plants in cellular and viral contexts. These results suggest that RISP function in translation (re)initiation is regulated by phosphorylation at Ser267.
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Affiliation(s)
- Eder Mancera-Martínez
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Yihan Dong
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Joelle Makarian
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Ola Srour
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Odon Thiébeauld
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Muhammed Jamsheer
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Johana Chicher
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Philippe Hammann
- Plateforme protéomique Strasbourg Esplanade FRC1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Mikhail Schepetilnikov
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A Ryabova
- Institut de biologie de moléculaire des plantes UPR2357 du CNRS, Université de Strasbourg, Strasbourg, France
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26
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Translational regulation in pathogenic and beneficial plant-microbe interactions. Biochem J 2021; 478:2775-2788. [PMID: 34297042 DOI: 10.1042/bcj20210066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/17/2022]
Abstract
Plants are surrounded by a vast diversity of microorganisms. Limiting pathogenic microorganisms is crucial for plant survival. On the other hand, the interaction of plants with beneficial microorganisms promotes their growth or allows them to overcome nutrient deficiencies. Balancing the number and nature of these interactions is crucial for plant growth and development, and thus, for crop productivity in agriculture. Plants use sophisticated mechanisms to recognize pathogenic and beneficial microorganisms and genetic programs related to immunity or symbiosis. Although most research has focused on characterizing changes in the transcriptome during plant-microbe interactions, the application of techniques such as Translating Ribosome Affinity Purification (TRAP) and Ribosome profiling allowed examining the dynamic association of RNAs to the translational machinery, highlighting the importance of the translational level of control of gene expression in both pathogenic and beneficial interactions. These studies revealed that the transcriptional and the translational responses are not always correlated, and that translational control operates at cell-specific level. In addition, translational control is governed by cis-elements present in the 5'mRNA leader of regulated mRNAs, e.g. upstream open reading frames (uORFs) and sequence-specific motifs. In this review, we summarize and discuss the recent advances made in the field of translational control during pathogenic and beneficial plant-microbe interactions.
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27
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Van Etten ML, Soble A, Baucom RS. Variable inbreeding depression may explain associations between the mating system and herbicide resistance in the common morning glory. Mol Ecol 2021; 30:5422-5437. [PMID: 33604956 DOI: 10.1111/mec.15852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/18/2021] [Accepted: 02/10/2021] [Indexed: 12/12/2022]
Abstract
Inbreeding depression is a central parameter underlying mating system variation in nature and one that can be altered by environmental stress. Although a variety of systems show that inbreeding depression tends to increase under stressful conditions, we have very little understanding across most organisms how the level of inbreeding depression may change as a result of adaptation to stressors. In this work we examined the potential that inbreeding depression varied among lineages of Ipomoea purpurea artificially evolved to exhibit divergent levels of herbicide resistance. We examined inbreeding depression in a variety of fitness-related traits in both the growth chamber and in the field, and paired this work with an examination of gene expression changes. We found that, while inbreeding depression was present across many of the traits, lineages artificially selected for increased herbicide resistance often showed no evidence of inbreeding depression in the presence of herbicide, and in fact, showed evidence of outbreeding depression in some traits compared to nonselected control lines and lineages selected for increased herbicide susceptibility. Further, at the transcriptome level, the resistant selection lines had differing patterns of gene expression according to breeding type (inbred vs. outcrossed) compared to the control and susceptible selection lines. Our data together indicate that inbreeding depression may be lessened in populations that are adapting to regimes of strong selection.
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Affiliation(s)
- Megan L Van Etten
- Biology Department, Pennsylvania State University, Dunmore, Pennsylvania, USA
| | - Anah Soble
- Ecology and Evolutionary Biology Department, University of Michigan, Ann Arbor, Michigan, USA
| | - Regina S Baucom
- Ecology and Evolutionary Biology Department, University of Michigan, Ann Arbor, Michigan, USA
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28
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Besnard J, Sonawala U, Maharjan B, Collakova E, Finlayson SA, Pilot G, McDowell J, Okumoto S. Increased Expression of UMAMIT Amino Acid Transporters Results in Activation of Salicylic Acid Dependent Stress Response. FRONTIERS IN PLANT SCIENCE 2021; 11:606386. [PMID: 33574824 PMCID: PMC7870477 DOI: 10.3389/fpls.2020.606386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/17/2020] [Indexed: 05/29/2023]
Abstract
In addition to their role in the biosynthesis of important molecules such as proteins and specialized metabolites, amino acids are known to function as signaling molecules through various pathways to report nitrogen status and trigger appropriate metabolic and cellular responses. Moreover, changes in amino acid levels through altered amino acid transporter activities trigger plant immune responses. Specifically, loss of function of major amino acid transporter, over-expression of cationic amino acid transporter, or over-expression of the positive regulators of membrane amino acid export all lead to dwarfed phenotypes and upregulated salicylic acid (SA)-induced stress marker genes. However, whether increasing amino acid exporter protein levels lead to similar stress phenotypes has not been investigated so far. Recently, a family of transporters, namely USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTERS (UMAMITs), were identified as amino acid exporters. The goal of this study was to investigate the effects of increased amino acid export on plant development, growth, and reproduction to further examine the link between amino acid transport and stress responses. The results presented here show strong evidence that an increased expression of UMAMIT transporters induces stress phenotypes and pathogen resistance, likely due to the establishment of a constitutive stress response via a SA-dependent pathway.
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Affiliation(s)
- Julien Besnard
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, United States
- Department of Soil and Crop Sciences, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, United States
| | - Unnati Sonawala
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, United States
| | - Bal Maharjan
- Department of Soil and Crop Sciences, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, United States
| | - Eva Collakova
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Scott A. Finlayson
- Department of Soil and Crop Sciences, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, United States
- Faculty of Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX, United States
| | - Guillaume Pilot
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - John McDowell
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Sakiko Okumoto
- Department of Plant Pathology, Physiology and Weed Science, Virginia Tech, Blacksburg, VA, United States
- Department of Soil and Crop Sciences, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, United States
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29
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Cui X, Gao K, Wang L, Lv M, Li Z, Zheng D, Wu W, Yao W, Ding L, Li X, Zhu JK, Zhang H. General Control Non-derepressible 1 (AtGCN1) Is Important for Flowering Time, Plant Growth, Seed Development, and the Transcription/Translation of Specific Genes in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2021; 12:630311. [PMID: 33868334 PMCID: PMC8045761 DOI: 10.3389/fpls.2021.630311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/01/2021] [Indexed: 05/12/2023]
Abstract
We have previously demonstrated that General Control Non-derepressible 1 (AtGCN1) is essential for translation inhibition under cold stress through interacting with GCN2 to phosphorylate eukaryotic translation initiation factor 2 (eIF2). Here, we report that the flower time of the atgcn1 mutant is later than that of the wild type (WT), and some siliques of atgcn1 cannot develop and produce seeds. Total and polysomal RNA of atgcn1-1 and wild type (WT) after cold treatments were sequenced. The sequencing results show that the mutation of atgcn1 selectively alters the expression of genes at both transcriptional and translational levels. The classification of AtGCN1 target genes reveals that AtGCN1 regulated gens are involved in flower development, seed dormancy and seed development, response to osmotic stress, amino acid biosynthesis, photosynthesis, cell wall organization, protein transport and localization, lipid biosynthesis, transcription, macroautophagy, proteolysis and cell death. Further analysis of AtGCN1 regulated genes at translational levels shows that the Kozak sequence and uORFs (upstream open reading frame) of transcripts affect translation selection. These results show that AtGCN1 is required for the expression of selective genes in Arabidopsis.
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Affiliation(s)
- Xiaona Cui
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Kaili Gao
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Linjuan Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Mengyang Lv
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Ziwen Li
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Donghua Zheng
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Wenwu Wu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Wen Yao
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Liying Ding
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Xiao Li
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, United States
| | - Hairong Zhang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
- *Correspondence: Hairong Zhang,
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30
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Urquidi-Camacho RA, Lokdarshi A, von Arnim AG. Translational gene regulation in plants: A green new deal. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1597. [PMID: 32367681 PMCID: PMC9258721 DOI: 10.1002/wrna.1597] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 01/09/2023]
Abstract
The molecular machinery for protein synthesis is profoundly similar between plants and other eukaryotes. Mechanisms of translational gene regulation are embedded into the broader network of RNA-level processes including RNA quality control and RNA turnover. However, over eons of their separate history, plants acquired new components, dropped others, and generally evolved an alternate way of making the parts list of protein synthesis work. Research over the past 5 years has unveiled how plants utilize translational control to defend themselves against viruses, regulate translation in response to metabolites, and reversibly adjust translation to a wide variety of environmental parameters. Moreover, during seed and pollen development plants make use of RNA granules and other translational controls to underpin developmental transitions between quiescent and metabolically active stages. The economics of resource allocation over the daily light-dark cycle also include controls over cellular protein synthesis. Important new insights into translational control on cytosolic ribosomes continue to emerge from studies of translational control mechanisms in viruses. Finally, sketches of coherent signaling pathways that connect external stimuli with a translational response are emerging, anchored in part around TOR and GCN2 kinase signaling networks. These again reveal some mechanisms that are familiar and others that are different from other eukaryotes, motivating deeper studies on translational control in plants. This article is categorized under: Translation > Translation Regulation RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Ricardo A. Urquidi-Camacho
- UT-ORNL Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996
| | - Ansul Lokdarshi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology and UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996
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31
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Schwarzenbacher RE, Wardell G, Stassen J, Guest E, Zhang P, Luna E, Ton J. The IBI1 Receptor of β-Aminobutyric Acid Interacts with VOZ Transcription Factors to Regulate Abscisic Acid Signaling and Callose-Associated Defense. MOLECULAR PLANT 2020; 13:1455-1469. [PMID: 32717347 PMCID: PMC7550849 DOI: 10.1016/j.molp.2020.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/30/2020] [Accepted: 07/19/2020] [Indexed: 05/02/2023]
Abstract
External and internal signals can prime the plant immune system for a faster and/or stronger response to pathogen attack. β-aminobutyric acid (BABA) is an endogenous stress metabolite that induces broad-spectrum disease resistance in plants. BABA perception in Arabidopsis is mediated by the aspartyl tRNA synthetase IBI1, which activates priming of multiple immune responses, including callose-associated cell wall defenses that are under control by abscisic acid (ABA). However, the immediate signaling components after BABA perception by IBI1, as well as the regulatory role of ABA therein, remain unknown. Here, we have studied the early signaling events controlling IBI1-dependent BABA-induced resistance (BABA-IR), using untargeted transcriptome and protein interaction analyses. Transcriptome analysis revealed that IBI1-dependent expression of BABA-IR against the biotrophic oomycete Hyaloperonospora arabidopsidis is associated with suppression of ABA-inducible abiotic stress genes. Protein interaction studies identified the VOZ1 and VOZ2 transcription factors (TFs) as IBI1-interacting partners, which are transcriptionally induced by ABA but suppress pathogen-induced expression of ABA-dependent genes. Furthermore, we show that VOZ TFs require nuclear localization for their contribution to BABA-IR by mediating augmented expression of callose-associated defense. Collectively, our study indicates that the IBI1-VOZ signaling module channels pathogen-induced ABA signaling toward cell wall defense while simultaneously suppressing abiotic stress-responsive genes.
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Affiliation(s)
- Roland E Schwarzenbacher
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Grace Wardell
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Joost Stassen
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Emily Guest
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Peijun Zhang
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Estrella Luna
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK
| | - Jurriaan Ton
- P3 Institute for Plant and Soil Biology, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield S10 2TN, UK.
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32
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Zhang J, Coaker G, Zhou JM, Dong X. Plant Immune Mechanisms: From Reductionistic to Holistic Points of View. MOLECULAR PLANT 2020; 13:1358-1378. [PMID: 32916334 PMCID: PMC7541739 DOI: 10.1016/j.molp.2020.09.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 05/19/2023]
Abstract
After three decades of the amazing progress made on molecular studies of plant-microbe interactions (MPMI), we have begun to ask ourselves "what are the major questions still remaining?" as if the puzzle has only a few pieces missing. Such an exercise has ultimately led to the realization that we still have many more questions than answers. Therefore, it would be an impossible task for us to project a coherent "big picture" of the MPMI field in a single review. Instead, we provide our opinions on where we would like to go in our research as an invitation to the community to join us in this exploration of new MPMI frontiers.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, College of Advanced Agricutural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gitta Coaker
- Department of Plant Pathology, University of California, One Shields Avenue, Davis, CA 95616, USA
| | - Jian-Min Zhou
- CAS Center for Excellence in Biotic Interactions, College of Advanced Agricutural Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xinnian Dong
- Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA; Department of Biology, Duke University, PO Box 90338, Durham, NC 27708, USA.
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33
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Berrocal-Lobo M, Toribio R, Castellano MM. eIF2α Phosphorylation by GCN2 Is Induced in the Presence of Chitin and Plays an Important Role in Plant Defense against B. cinerea Infection. Int J Mol Sci 2020; 21:ijms21197335. [PMID: 33020405 PMCID: PMC7582497 DOI: 10.3390/ijms21197335] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/23/2020] [Accepted: 10/01/2020] [Indexed: 01/04/2023] Open
Abstract
Translation plays an important role in plant adaptation to different abiotic and biotic stresses; however, the mechanisms involved in translational regulation during each specific response and their effect in translation are poorly understood in plants. In this work, we show that GCN2 promotes eIF2α phosphorylation upon contact with Botrytis cinerea spores, and that this phosphorylation is required for the proper establishment of plant defense against the fungus. In fact, independent gcn2 mutants display an enhanced susceptibility to B. cinerea infection, which is highlighted by an increased cell death and reduced expression of ethylene- and jasmonic-related genes in the gcn2 mutants. eIF2α phosphorylation is not only triggered in the presence of the fungus, but interestingly, is also achieved in the sole presence of the microbe-associated molecular pattern (MAMP) chitin. Moreover, analysis of de novo protein synthesis by 35SMet-35SCys incorporation indicates that chitin treatment promotes a global inhibition of translation. Taken together, these results suggest that eIF2α phosphorylation by GCN2 is promoted in the presence of chitin and plays an important role in plant defense against B. cinerea infection.
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Affiliation(s)
- Marta Berrocal-Lobo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)—Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo UPM, 28223 Pozuelo de Alarcón, Madrid, Spain;
- Departamento de Sistemas y Recursos Naturales, E.T.S.I. Montes, Forestal y del Medio Natural, Ciudad Universitaria s/n, 28040 Madrid, Spain
- Correspondence: (M.B.-L.); (M.M.C.); Tel.: +34-910-679-181 (M.M.C.)
| | - René Toribio
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)—Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo UPM, 28223 Pozuelo de Alarcón, Madrid, Spain;
| | - M. Mar Castellano
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)—Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo UPM, 28223 Pozuelo de Alarcón, Madrid, Spain;
- Correspondence: (M.B.-L.); (M.M.C.); Tel.: +34-910-679-181 (M.M.C.)
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Kanodia P, Vijayapalani P, Srivastava R, Bi R, Liu P, Miller WA, Howell SH. Control of translation during the unfolded protein response in maize seedlings: Life without PERKs. PLANT DIRECT 2020; 4:e00241. [PMID: 32743235 PMCID: PMC7390965 DOI: 10.1002/pld3.241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/17/2020] [Indexed: 05/05/2023]
Abstract
The accumulation of misfolded proteins in the endoplasmic reticulum (ER) defines a condition called ER stress that induces the unfolded protein response (UPR). The UPR in mammalian cells attenuates protein synthesis initiation, which prevents the piling up of misfolded proteins in the ER. Mammalian cells rely on Protein Kinase RNA-Like Endoplasmic Reticulum Kinase (PERK) phosphorylation of eIF2α to arrest protein synthesis, however, plants do not have a PERK homolog, so the question is whether plants control translation in response to ER stress. We compared changes in RNA levels in the transcriptome to the RNA levels protected by ribosomes and found a decline in translation efficiency, including many UPR genes, in response to ER stress. The decline in translation efficiency is due to the fact that many mRNAs are not loaded onto polyribosomes (polysomes) in proportion to their increase in total RNA, instead some of the transcripts accumulate in stress granules (SGs). The RNAs that populate SGs are not derived from the disassembly of polysomes because protein synthesis remains steady during stress. Thus, the surge in transcription of UPR genes in response to ER stress is accompanied by the formation of SGs, and the sequestration of mRNAs in SGs may serve to temporarily relieve the translation load during ER stress.
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Affiliation(s)
- Pulkit Kanodia
- Plant Pathology and Microbiology DepartmentIowa State UniversityAmesIAUSA
- Interdepartmental Genetics and Genomics MajorIowa State UniversityAmesIAUSA
| | | | | | - Ran Bi
- Statistics DepartmentIowa State UniversityAmesIAUSA
| | - Peng Liu
- Plant Science InstituteIowa State UniversityAmesIAUSA
- Statistics DepartmentIowa State UniversityAmesIAUSA
| | - W. Allen Miller
- Plant Pathology and Microbiology DepartmentIowa State UniversityAmesIAUSA
- Interdepartmental Genetics and Genomics MajorIowa State UniversityAmesIAUSA
- Plant Science InstituteIowa State UniversityAmesIAUSA
| | - Stephen H. Howell
- Interdepartmental Genetics and Genomics MajorIowa State UniversityAmesIAUSA
- Plant Science InstituteIowa State UniversityAmesIAUSA
- Genetics, Development and Cell Biology DepartmentIowa State UniversityAmesIAUSA
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Zhigailov AV, Alexandrova AM, Nizkorodova AS, Stanbekova GE, Kryldakov RV, Karpova OV, Polimbetova NS, Halford NG, Iskakov BK. Evidence That Phosphorylation of the α-Subunit of eIF2 Does Not Essentially Inhibit mRNA Translation in Wheat Germ Cell-Free System. FRONTIERS IN PLANT SCIENCE 2020; 11:936. [PMID: 32655610 PMCID: PMC7324750 DOI: 10.3389/fpls.2020.00936] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 06/09/2020] [Indexed: 05/30/2023]
Abstract
A mechanism based on reversible phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) has been confirmed as an important regulatory pathway for the inhibition of protein synthesis in mammalian and yeast cells, while plants constitute the significant exception. We studied the induction of TaeIF2α phosphorylation in germinated wheat (Triticum aestivum) embryos subjected to different adverse conditions. Data confirmed that formation of TaeIF2(αP) was not a general response, as no phosphorylation was observed under salt, oxidative, or heat stress. Nevertheless, treatment by salicylic acid, UV-light, cold shock and histidinol did induce phosphorylation of TaeIF2α of wheat as has been established previously for AteIF2α in Arabidopsis (Arabidopsis thaliana). The influence of TaeIF2α phosphorylation on translation of reporter mRNA with different 5'-untranslated regions (5'UTRs) was studied in wheat germ cell-free system (WG-CFS), in which TaeIF2α was first phosphorylated either by heterologous recombinant human protein kinase, HsPKR (activated by double-stranded (ds)RNA), or by endogenous protein kinase TaGCN2 (activated by histidinol). Pretreatment of WG-CFS with HsPKR in the presence of dsRNA or with histidinol resulted in intense phosphorylation of TaeIF2α; however, the translation levels of all tested mRNAs decreased by only 10-15% and remained relatively high. In addition, factor OceIF2 from rabbit (Oryctolagus cuniculus) bound GDP much more strongly than the homologous factor TaeIF2 from wheat germ. Furthermore, factor OceIF2B was able to stimulate guanine nucleotide exchange (GDP→GTP) on OceIF2 but had no effect on a similar exchange on TaeIF2. These results suggest that the mechanism of stress response via eIF2α phosphorylation is not identical in all eukaryotes, and further research is required to find and study in detail new plant-specific mechanisms that may inhibit overall protein synthesis in plants under stress.
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Affiliation(s)
- Andrey V. Zhigailov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Alena M. Alexandrova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Anna S. Nizkorodova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Gulshan E. Stanbekova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Ruslan V. Kryldakov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
- Institute of Plant Biology and Biotechnology, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Oxana V. Karpova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Nailya S. Polimbetova
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
| | - Nigel G. Halford
- Plant Sciences Department, Rothamsted Research, Harpenden, United Kingdom
| | - Bulat K. Iskakov
- M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
- Institute of Plant Biology and Biotechnology, Science Committee, Ministry of Education and Science, Almaty, Kazakhstan
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Lokdarshi A, Morgan PW, Franks M, Emert Z, Emanuel C, von Arnim AG. Light-Dependent Activation of the GCN2 Kinase Under Cold and Salt Stress Is Mediated by the Photosynthetic Status of the Chloroplast. FRONTIERS IN PLANT SCIENCE 2020; 11:431. [PMID: 32411155 PMCID: PMC7201089 DOI: 10.3389/fpls.2020.00431] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/24/2020] [Indexed: 05/12/2023]
Abstract
Regulation of cytosolic mRNA translation is a key node for rapid adaptation to environmental stress conditions. In yeast and animals, phosphorylation of the α-subunit of eukaryotic translation initiation factor eIF2 is the most thoroughly characterized event for regulating global translation under stress. In plants, the GCN2 kinase (General Control Nonderepressible-2) is the only known kinase for eIF2α. GCN2 is activated under a variety of stresses including reactive oxygen species (ROS). Here, we provide new evidence that the GCN2 kinase in Arabidopsis is also activated rapidly and in a light-dependent manner by cold and salt treatments. These treatments alone did not repress global mRNA ribosome loading in a major way. The activation of GCN2 was accompanied by a more oxidative environment and was attenuated by inhibitors of photosynthetic electron transport, suggesting that it is gated by the redox poise or the reactive oxygen status of the chloroplast. In keeping with these results, gcn2 mutant seedlings were more sensitive than wild type to both cold and salt in a root elongation assay. These data suggest that cold and salt stress may both affect the status of the cytosolic translation apparatus via the conserved GCN2-eIF2α module. The potential role of the GCN2 kinase pathway in the global repression of translation under abiotic stress is discussed.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Philip W. Morgan
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Michelle Franks
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Zoe Emert
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Catherine Emanuel
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Albrecht G. von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Knoxville, TN, United States
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Knoxville, TN, United States
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Lokdarshi A, Guan J, Urquidi Camacho RA, Cho SK, Morgan PW, Leonard M, Shimono M, Day B, von Arnim AG. Light Activates the Translational Regulatory Kinase GCN2 via Reactive Oxygen Species Emanating from the Chloroplast. THE PLANT CELL 2020; 32:1161-1178. [PMID: 32079667 PMCID: PMC7145473 DOI: 10.1105/tpc.19.00751] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/03/2020] [Accepted: 02/16/2020] [Indexed: 05/12/2023]
Abstract
Cytosolic mRNA translation is subject to global and mRNA-specific controls. Phosphorylation of the translation initiation factor eIF2α anchors a reversible regulatory switch that represses cytosolic translation globally. The stress-responsive GCN2 kinase is the only known kinase for eIF2α serine 56 in Arabidopsis (Arabidopsis thaliana). Here, we show that conditions that generate reactive oxygen species (ROS) in the chloroplast, including dark-light transitions, high light, and the herbicide methyl viologen, rapidly activated GCN2 kinase, whereas mitochondrial and endoplasmic reticulum stress did not. GCN2 activation was light dependent and mitigated by photosynthesis inhibitors and ROS quenchers. Accordingly, the seedling growth of multiple Arabidopsis gcn2 mutants was retarded under excess light conditions, implicating the GCN2-eIF2α pathway in responses to light and associated ROS. Once activated, GCN2 kinase preferentially suppressed the ribosome loading of mRNAs for functions such as mitochondrial ATP synthesis, the chloroplast thylakoids, vesicle trafficking, and translation. The gcn2 mutant overaccumulated transcripts functionally related to abiotic stress, including oxidative stress, as well as innate immune responses. Accordingly, gcn2 displayed defects in immune priming by the fungal elicitor, chitin. Therefore, we provide evidence that reactive oxygen species produced by the photosynthetic apparatus help activate the highly conserved GCN2 kinase, leading to eIF2α phosphorylation and thus affecting the status of the cytosolic protein synthesis apparatus.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Ju Guan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Ricardo A Urquidi Camacho
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee 37996
| | - Sung Ki Cho
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Philip W Morgan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Madison Leonard
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
| | - Masaki Shimono
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824
| | - Brad Day
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996
- UT-ORNL Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee 37996
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Afrin T, Diwan D, Sahawneh K, Pajerowska-Mukhtar K. Multilevel regulation of endoplasmic reticulum stress responses in plants: where old roads and new paths meet. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1659-1667. [PMID: 31679034 DOI: 10.1093/jxb/erz487] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 10/21/2019] [Indexed: 05/20/2023]
Abstract
The sessile lifestyle of plants requires them to cope with a multitude of stresses in situ. In response to diverse environmental and intracellular cues, plant cells respond by massive reprogramming of transcription and translation of stress response regulators, many of which rely on endoplasmic reticulum (ER) processing. This increased protein synthesis could exceed the capacity of precise protein quality control, leading to the accumulation of unfolded and/or misfolded proteins that triggers the unfolded protein response (UPR). Such cellular stress responses are multilayered and executed in different cellular compartments. Here, we will discuss the three main branches of UPR signaling in diverse eukaryotic systems, and describe various levels of ER stress response regulation that encompass transcriptional gene regulation by master transcription factors, post-transcriptional activities including cytoplasmic splicing, translational control, and multiple post-translational events such as peptide modifications and cleavage. In addition, we will discuss the roles of plant ER stress sensors in abiotic and biotic stress responses and speculate on the future prospects of engineering these signaling events for heightened stress tolerance.
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Affiliation(s)
- Taiaba Afrin
- Department of Biology, University of Alabama at Birmingham, Birmingham, USA
| | - Danish Diwan
- Department of Biology, University of Alabama at Birmingham, Birmingham, USA
| | - Katrina Sahawneh
- Department of Biology, University of Alabama at Birmingham, Birmingham, USA
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Tcherkez G, Carroll A, Abadie C, Mainguet S, Davanture M, Zivy M. Protein synthesis increases with photosynthesis via the stimulation of translation initiation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 291:110352. [PMID: 31928674 DOI: 10.1016/j.plantsci.2019.110352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/13/2019] [Accepted: 11/21/2019] [Indexed: 05/09/2023]
Abstract
Leaf protein synthesis is an essential process at the heart of plant nitrogen (N) homeostasis and turnover that preferentially takes place in the light, that is, when N and CO2 fixation occur. The carbon allocation to protein synthesis in illuminated leaves generally accounts for ca. 1 % of net photosynthesis. It is likely that protein synthesis activity varies with photosynthetic conditions (CO2/O2 atmosphere composition) since changes in photorespiration and carbon provision should in principle impact on amino acid supply as well as metabolic regulation via leaf sugar content. However, possible changes in protein synthesis and translation activity when gaseous conditions vary are virtually unknown. Here, we address this question using metabolomics, isotopic techniques, phosphoproteomics and polysome quantitation, under different photosynthetic conditions that were varied with atmospheric CO2 and O2 mole fraction, using illuminated Arabidopsis rosettes under controlled gas exchange conditions. We show that carbon allocation to proteins is within 1-2.5 % of net photosynthesis, increases with photosynthesis rate and is unrelated to total amino acid content. In addition, photosynthesis correlates to polysome abundance and phosphorylation of ribosomal proteins and translation initiation factors. Our results demonstrate that translation activity follows photosynthetic activity, showing the considerable impact of metabolism (carboxylation-oxygenation balance) on protein synthesis.
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Affiliation(s)
- Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Sciences, Australian National University, 2601, Canberra, ACT, Australia(1); Institut de Recherche en Horticulture et Semences, INRA, Université d'Angers, 42 rue Georges Morel, 49070, Beaucouzé, France(2).
| | - Adam Carroll
- Joint Mass Spectrometry Facility, Research School of Chemistry, Australian National University, 2601, Canberra, ACT, Australia
| | - Cyril Abadie
- Institut de Recherche en Horticulture et Semences, INRA, Université d'Angers, 42 rue Georges Morel, 49070, Beaucouzé, France(2)
| | - Samuel Mainguet
- Institute of Plant Sciences of Saclay, INRA, University Paris-Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Marlène Davanture
- Plateforme d'Analyse de Protéomique Paris Sud-Ouest (PAPPSO), GQE Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Ferme du Moulon, 91190, Gif-sur-Yvette, France
| | - Michel Zivy
- Plateforme d'Analyse de Protéomique Paris Sud-Ouest (PAPPSO), GQE Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Ferme du Moulon, 91190, Gif-sur-Yvette, France
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40
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Le Deunff E, Beauclair P, Deleu C, Lecourt J. Inhibition of Aminotransferases by Aminoethoxyvinylglycine Triggers a Nitrogen Limitation Condition and Deregulation of Histidine Homeostasis That Impact Root and Shoot Development and Nitrate Uptake. FRONTIERS IN PLANT SCIENCE 2019; 10:1387. [PMID: 31787993 PMCID: PMC6855093 DOI: 10.3389/fpls.2019.01387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/08/2019] [Indexed: 06/02/2023]
Abstract
Background and Aims: Although AVG (aminoethoxyvinylglycine) is intensely used to decipher signaling in ethylene/indol-3-acetic acid (IAA) interactions on root morphogenesis, AVG is not a specific inhibitor of aminocyclopropane-1-carboxylate synthase (ACS) and tryptophan aminotransferase (TAA) and tryptophan aminotransferase related (TAR) activities since it is able to inhibit several aminotransferases involved in N metabolism. Indeed, 1 mM glutamate (Glu) supply to the roots in plants treated with 10 μM AVG partially restores the root growth. Here, we highlight the changes induced by AVG and AVG + Glu treatments on the N metabolism impairment and root morphogenetic program. Methods: Root nitrate uptake induced by AVG and AVG + Glu treatments was measured by a differential labeling with 15NO3 - and 15Nglutamate. In parallel a profiling of amino acids (AA) was performed to decipher the impairment of AA metabolism. Key Results: 10 μM AVG treatment increases K15NO3 uptake and 15N translocation during root growth inhibition whereas 10 μM AVG + 1 mM 15Nglutamate treatment inhibits K15NO3 uptake and increases 15Nglutamate uptake during partial root growth restoration. This is explained by a nitrogen (N) limitation condition induced by AVG treatment and a N excess condition induced by AVG + Glu treatment. AA levels were mainly impaired by AVG treatment in roots, where levels of Ser, Thr, α-Ala, β-Ala, Val, Asn and His were significantly increased. His was the only amino acid for which no restoration was observed in roots and shoots after glutamate treatment suggesting important control of His homeostasis on aminotransferase network. Results were discussed in light of recent findings on the interconnection between His homeostasis and the general amino acid control system (GAAC) in eukaryotes. Conclusions: These results demonstrate that AVG concentration above 5 μM is a powerful pharmacological tool for unraveling the involvement of GAAC system or new N sensory system in morphological and metabolic changes of the roots in leguminous and non-leguminous plants.
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Affiliation(s)
| | - Patrick Beauclair
- INRA Unité Expérimentale Fourrages Environnement Ruminants (FERLUS) et Système d’Observation et d’Expérimentation pour la Recherche en Environnement (SOERE), Les Verrines CS 80006, Lusignan, France
| | - Carole Deleu
- INRA—Agrocampus Ouest—Université de Rennes 1, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes (IGEPP) Université de Rennes 1, Rennes, France
| | - Julien Lecourt
- NIAB EMR, Crop Science and Production Systems New Road, East Malling, United Kingdom
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Raffan S, Halford NG. Acrylamide in food: Progress in and prospects for genetic and agronomic solutions. THE ANNALS OF APPLIED BIOLOGY 2019; 175:259-281. [PMID: 31866690 PMCID: PMC6899951 DOI: 10.1111/aab.12536] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/12/2019] [Accepted: 07/13/2019] [Indexed: 05/12/2023]
Abstract
Acrylamide is a processing contaminant and Group 2a carcinogen that was discovered in foodstuffs in 2002. Its presence in a range of popular foods has become one of the most difficult problems facing the food industry and its supply chain. Wheat, rye and potato products are major sources of dietary acrylamide, with biscuits, breakfast cereals, bread (particularly toasted), crispbread, batter, cakes, pies, French fries, crisps and snack products all affected. Here we briefly review the history of the issue, detection methods, the levels of acrylamide in popular foods and the risk that dietary acrylamide poses to human health. The pathways for acrylamide formation from free (non-protein) asparagine are described, including the role of reducing sugars such as glucose, fructose and maltose and the Maillard reaction. The evolving regulatory situation in the European Union and elsewhere is discussed, noting that food businesses and their suppliers must plan to comply not only with current regulations but with possible future regulatory scenarios. The main focus of the review is on the genetic and agronomic approaches being developed to reduce the acrylamide-forming potential of potatoes and cereals and these are described in detail, including variety selection, plant breeding, biotechnology and crop management. Obvious targets for genetic interventions include asparagine synthetase genes, and the asparagine synthetase gene families of different crop species are compared. Current knowledge on crop management best practice is described, including maintaining optimum storage conditions for potatoes and ensuring sulphur sufficiency and disease control for wheat.
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Affiliation(s)
- Sarah Raffan
- Plant Sciences DepartmentRothamsted ResearchHarpendenUK
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42
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Niehl A, Heinlein M. Perception of double-stranded RNA in plant antiviral immunity. MOLECULAR PLANT PATHOLOGY 2019; 20:1203-1210. [PMID: 30942534 PMCID: PMC6715784 DOI: 10.1111/mpp.12798] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
RNA silencing and antiviral pattern-triggered immunity (PTI) both rely on recognition of double-stranded (ds)RNAs as defence-inducing signals. While dsRNA recognition by dicer-like proteins during antiviral RNA silencing is thoroughly investigated, the molecular mechanisms involved in dsRNA perception leading to antiviral PTI are just about to be untangled. Parallels to antimicrobial PTI thereby only partially facilitate our view on antiviral PTI. PTI against microbial pathogens involves plasma membrane bound receptors; however, dsRNAs produced during virus infection occur intracellularly. Hence, how dsRNA may be perceived during this immune response is still an open question. In this short review, we describe recent discoveries in PTI signalling upon sensing of microbial patterns and endogenous 'danger' molecules with emphasis on immune signalling-associated subcellular trafficking processes in plants. Based on these studies, we develop different scenarios how dsRNAs could be sensed during antiviral PTI.
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Affiliation(s)
- Annette Niehl
- Julius Kühn‐Institute, Institute for Epidemiology and Pathogen DiagnosticsMesseweg 11‐12D‐38104BraunschweigGermany
| | - Manfred Heinlein
- Université de Strasbourg, CNRS, IBMP UPR235712 rue du Général ZimmerF‐67000StrasbourgFrance
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43
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Liu X, Afrin T, Pajerowska-Mukhtar KM. Arabidopsis GCN2 kinase contributes to ABA homeostasis and stomatal immunity. Commun Biol 2019; 2:302. [PMID: 31428690 PMCID: PMC6687712 DOI: 10.1038/s42003-019-0544-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 06/28/2019] [Indexed: 12/28/2022] Open
Abstract
General Control Non-derepressible 2 (GCN2) is an evolutionarily conserved serine/threonine kinase that modulates amino acid homeostasis in response to nutrient deprivation in yeast, human and other eukaryotes. However, the GCN2 signaling pathway in plants remains largely unknown. Here, we demonstrate that in Arabidopsis, bacterial infection activates AtGCN2-mediated phosphorylation of eIF2α and promotes TBF1 translational derepression. Consequently, TBF1 regulates a subset of abscisic acid signaling components to modulate pre-invasive immunity. We show that GCN2 fine-tunes abscisic acid accumulation and signaling during both pre-invasive and post-invasive stages of an infection event. Finally, we also demonstrate that AtGCN2 participates in signaling triggered by phytotoxin coronatine secreted by P. syringae. During the preinvasive phase, AtGCN2 regulates stomatal immunity by affecting pathogen-triggered stomatal closure and coronatine-mediated stomatal reopening. Our conclusions support a conserved role of GCN2 in various forms of immune responses across kingdoms, highlighting GCN2's importance in studies on both plant and mammalian immunology.
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Affiliation(s)
- Xiaoyu Liu
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Birmingham, AL 35294 USA
- Present Address: Bayer Crop Science, 800 N Lindbergh Blvd., Creve Coeur, MO 63144 USA
| | - Taiaba Afrin
- Department of Biology, University of Alabama at Birmingham, 1300 University Blvd., Birmingham, AL 35294 USA
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44
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Bi C, Ma Y, Jiang SC, Mei C, Wang XF, Zhang DP. Arabidopsis translation initiation factors eIFiso4G1/2 link repression of mRNA cap-binding complex eIFiso4F assembly with RNA-binding protein SOAR1-mediated ABA signaling. THE NEW PHYTOLOGIST 2019; 223:1388-1406. [PMID: 31050354 DOI: 10.1111/nph.15880] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 04/18/2019] [Indexed: 05/06/2023]
Abstract
The translation initiation factor eIF4E-binding protein-mediated regulation of protein translation by interfering with assembly of mRNA cap-binding complex eIF4F is well described in mammalian and yeast cells. However, it remains unknown whether a signaling regulator or pathway interacts directly with any translation initiation factor to modulate assembly of eIF4F in plant cells. Here, we report that the two isoforms of Arabidopsis eIF4G, eIFiso4G1 and eIFiso4G2, interact with a cytoplasmic-nuclear dual-localized pentatricopeptide repeat protein SOAR1 to regulate abscisic acid (ABA) signaling. SOAR1 inhibits interactions of eIFiso4E, eIF4Es, eIF4A1, eIF4B2 and poly(A)-binding protein PAB6 with eIFiso4G1 and eIFiso4G2, thereby inhibiting eIFiso4F/mixed eIF4F assembly and repressing translation initiation. SOAR1 binds mRNA of a key ABA-responsive gene ABI5 and cooperates with eIFiso4G1/2 to repress translation of ABI5. The binding of SOAR1 to ABI5 mRNA is likely to inhibit the interaction of SOAR1 with eIFiso4G1/2, suggesting a regulatory loop. Our findings identify a novel translation initiation repressor interfering with cap-binding complex assembly, and establish a link between cap-binding complex assembly and ABA signaling.
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Affiliation(s)
- Chao Bi
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yu Ma
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Shang-Chuan Jiang
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Chao Mei
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiao-Fang Wang
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Da-Peng Zhang
- MOE Systems Biology and Bioinformatics Laboratory, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
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45
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The Tug-of-War between Plants and Viruses: Great Progress and Many Remaining Questions. Viruses 2019; 11:v11030203. [PMID: 30823402 PMCID: PMC6466000 DOI: 10.3390/v11030203] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/18/2019] [Accepted: 02/23/2019] [Indexed: 12/19/2022] Open
Abstract
Plants are persistently challenged by various phytopathogens. To protect themselves, plants have evolved multilayered surveillance against all pathogens. For intracellular parasitic viruses, plants have developed innate immunity, RNA silencing, translation repression, ubiquitination-mediated and autophagy-mediated protein degradation, and other dominant resistance gene-mediated defenses. Plant viruses have also acquired diverse strategies to suppress and even exploit host defense machinery to ensure their survival. A better understanding of the defense and counter-defense between plants and viruses will obviously benefit from the development of efficient and broad-spectrum virus resistance for sustainable agriculture. In this review, we summarize the cutting edge of knowledge concerning the defense and counter-defense between plants and viruses, and highlight the unexploited areas that are especially worth investigating in the near future.
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Llabata P, Richter J, Faus I, Słomiňska-Durdasiak K, Zeh LH, Gadea J, Hauser MT. Involvement of the eIF2α Kinase GCN2 in UV-B Responses. FRONTIERS IN PLANT SCIENCE 2019; 10:1492. [PMID: 31850012 PMCID: PMC6892979 DOI: 10.3389/fpls.2019.01492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/28/2019] [Indexed: 05/12/2023]
Abstract
GCN2 (general control nonrepressed 2) is a serine/threonine-protein kinase that regulates translation in response to stressors such as amino acid and purin deprivation, cold shock, wounding, cadmium, and UV-C exposure. Activated GCN2 phosphorylates the α-subunit of the eukaryotic initiation factor 2 (eIF2) leading to a drastic inhibition of protein synthesis and shifting translation to specific mRNAs. To investigate the role of GCN2 in responses to UV-B radiation its activity was analyzed through eIF2α phosphorylation assays in mutants of the specific UV-B and stress signaling pathways of Arabidopsis thaliana. EIF2α phosphorylation was detectable 30 min after UV-B exposure, independent of the UV-B photoreceptor UV RESISTANCE LOCUS8 and its downstream signaling components. GCN2 dependent phosphorylation of eIF2α was also detectable in mutants of the stress related MAP kinases, MPK3 and MPK6 and their negative regulator map kinase phosphatase1 (MKP1). Transcription of downstream components of the UV-B signaling pathway, the Chalcone synthase (CHS) was constitutively higher in gcn2-1 compared to wildtype and further increased upon UV-B while GLUTATHIONE PEROXIDASE7 (GPX7) behaved similarly to wildtype. The UVR8 independent FAD-LINKED OXIDOREDUCTASE (FADox) had a lower basal expression in gcn2-1 which was increased upon UV-B. Since high fluence rates of UV-B induce DNA damage the expression of the RAS ASSOCIATED WITH DIABETES PROTEIN51 (RAD51) was quantified before and after UV-B. While the basal expression was similar to wildtype it was significantly less induced upon UV-B in the gcn2-1 mutant. This expression pattern correlates with the finding that gcn2 mutants develop less cyclobutane pyrimidine dimers after UV-B exposure. Quantification of translation with the puromycination assay revealed that gcn2 mutants have an increased rate of translation which was also higher upon UV-B. Growth of gcn2 mutants to chronic UV-B exposure supports GCN2's role as a negative regulator of UV-B responses. The elevated resistance of gcn2 mutants towards repeated UV-B exposure points to a critical role of GCN2 in the regulation of translation upon UV-B.
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Affiliation(s)
- Paula Llabata
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- Bellvitge Biomedical Research Institute IDIBELL, Barcelona, Spain
| | - Julia Richter
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Isabel Faus
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
| | - Karolina Słomiňska-Durdasiak
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Lukas Hubert Zeh
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Jose Gadea
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
| | - Marie-Theres Hauser
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- *Correspondence: Marie-Theres Hauser,
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Dong Y, Teleman AA, Jedmowski C, Wirtz M, Hell R. The Arabidopsis THADA homologue modulates TOR activity and cold acclimation. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21 Suppl 1:77-83. [PMID: 30098100 DOI: 10.1111/plb.12893] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/02/2018] [Indexed: 05/21/2023]
Abstract
Low temperature is one of the most important environmental factors that affect global survival of humans and animals and equally importantly the distribution of plants and crop productivity. Survival of metazoan cells under cold stress requires regulation of the sensor-kinase Target Of Rapamycin (TOR). TOR controls growth of eukaryotic cells by adjusting anabolic and catabolic metabolism. Previous studies identified the Thyroid Adenoma Associated (THADA) gene as the major effect locus by positive selection in the evolution of modern human adapted to cold. Here we investigate the role of THADA in TOR signaling and cold acclimation of plants. We applied BLAST searches and homology modeling to identify the AtTHADA (AT3G55160) in Arabidopsis thaliana as the highly probable orthologue protein. Reverse genetics approaches were combined with immunological detection of TOR activity and metabolite profiling to address the role of the TOR and THADA for growth regulation and cold acclimation. Depletion of the AtTHADA gene caused complete or partial loss of full-length mRNA, respectively, and significant retardation of growth under non-stressed conditions. Furthermore, depletion of AtTHADA caused hypersensitivity towards low-temperatures. Atthada displayed a lowered energy charge. This went along with decreased TOR activity, which offers a molecular explanation for the slow growth phenotype of Atthada. Finally, we used TOR RNAi lines to identify the de-regulation of TOR activity as one determinant for sensitivity towards low-temperatures. Taken together our results provide evidence for a conserved function of THADA in cold acclimation of eukaryotes and suggest that cold acclimation in plants requires regulation of TOR.
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Affiliation(s)
- Y Dong
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - A A Teleman
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - M Wirtz
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
| | - R Hell
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany
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Van Ruyskensvelde V, Van Breusegem F, Van Der Kelen K. Post-transcriptional regulation of the oxidative stress response in plants. Free Radic Biol Med 2018; 122:181-192. [PMID: 29496616 DOI: 10.1016/j.freeradbiomed.2018.02.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/30/2022]
Abstract
Due to their sessile lifestyle, plants can be exposed to several kinds of stresses that will increase the production of reactive oxygen species (ROS), such as hydrogen peroxide, singlet oxygen, and hydroxyl radicals, in the plant cells and activate several signaling pathways that cause alterations in the cellular metabolism. Nevertheless, when ROS production outreaches a certain level, oxidative damage to nucleic acids, lipids, metabolites, and proteins will occur, finally leading to cell death. Until now, the most comprehensive and detailed readout of oxidative stress responses is undoubtedly obtained at the transcriptome level. However, transcript levels often do not correlate with the corresponding protein levels. Indeed, together with transcriptional regulations, post-transcriptional, translational, and/or post-translational regulations will shape the active proteome. Here, we review the current knowledge on the post-transcriptional gene regulation during the oxidative stress responses in planta.
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Affiliation(s)
- Valerie Van Ruyskensvelde
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.
| | - Katrien Van Der Kelen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium
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49
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Li N, Zhang SJ, Zhao Q, Long Y, Guo H, Jia HF, Yang YX, Zhang HY, Ye XF, Zhang ST. Overexpression of Tobacco GCN2 Stimulates Multiple Physiological Changes Associated With Stress Tolerance. FRONTIERS IN PLANT SCIENCE 2018; 9:725. [PMID: 29910821 PMCID: PMC5992440 DOI: 10.3389/fpls.2018.00725] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 05/14/2018] [Indexed: 05/23/2023]
Abstract
General control non-derepressible-2 (GCN2) is a ubiquitous protein kinase that phosphorylates the α subunit of the eukaryotic initiation factor, eIF2, preventing the initiation of a new cycle of protein synthesis, subsequently reducing the global protein biosynthesis. GCN2 can also regulate the response of plants to biotic and abiotic stresses. In this study, two GCN2 homologs, NtGCN2-1 and NtGCN2-2, were cloned from Nicotiana tabacum, and were predicted to have been derived from their progenitors in N. tomentosiformis and N. sylvestris, respectively. The phosphorylation of NteIF2α could be activated by promoting the expression of NtGCN2 with plant hormones, including salicylic acid (SA), azelaic acid (AZA), methyl jasmonate (MeJA), and by imposition of different stresses (Bemisia tabaci infection, drought, and cold), indicating that NtGCN2 is involved in the response of plants to multiple biotic and abiotic stresses. We also observed that the overexpression of NtGCN2-1 significantly influenced different physiological processes. It promoted seed germination and root elongation. The content of total soluble sugars and reducing sugars were decreased, whereas those of chlorophyll a and b were increased in the GCN2 overexpressing plants. In addition, the overexpressing plants had lower content of reactive oxygen species and exhibited higher antioxidant activities. These physiological alterations could be attributed to the changes in the endogenous phytohormones, decrease in the SA and abscisic acid content, and accumulation of MeJA and AZA. It indicated that the overexpression of NtGCN2 in tobacco, stimulated the plant defense responses via phosphorylation of NteIF2α and regulation of plant hormones, and changes in the antioxidant ability and plant nutrient status.
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Izquierdo Y, Kulasekaran S, Benito P, López B, Marcos R, Cascón T, Hamberg M, Castresana C. Arabidopsis nonresponding to oxylipins locus NOXY7 encodes a yeast GCN1 homolog that mediates noncanonical translation regulation and stress adaptation. PLANT, CELL & ENVIRONMENT 2018; 41:1438-1452. [PMID: 29499090 DOI: 10.1111/pce.13182] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 02/16/2018] [Accepted: 02/22/2018] [Indexed: 05/10/2023]
Abstract
Stress adaptation and translational regulation was studied using noxy7 (nonresponding to oxylipins7) from a series of Arabidopsis thaliana mutants. We identified the noxy7 mutation in At1g64790, which encodes a homolog of the yeast translational regulator General Control Nonderepressible1 (GCN1) that activates the GCN2 kinase; GCN2 in turn phosphorylates the α subunit of the translation initiation factor eIF2. This regulatory circuit is conserved in yeast and mammals, in which phosphorylated eIF2α (P-eIF2α) facilitates stress adaptation by inhibiting protein synthesis. In phenotypic and de novo protein synthesis studies with Arabidopsis mutants, we found that NOXY7/GCN1 and GCN2 mediate P-eIF2α formation and adaptation to amino acid deprivation; however, P-eIF2α formation is not linked to general protein synthesis arrest. Additional evidence suggested that NOXY7/GCN1 but not GCN2 regulates adaptation to mitochondrial dysfunction, high boron concentration, and activation of plant immunity to infection by Pseudomonas syringae pv tomato (Pst). In these responses, NOXY7/GCN1 acts with GCN20 to regulate translation in a noncanonical pathway independently of GCN2 and P-eIF2α. These results show the lesser functional relevance of GCN2 and P-eIF2α in plants relative to other eukaryotes and highlight the prominent role of NOXY7/GCN1 and GCN20 in regulation of translation and stress adaptation in plants.
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Affiliation(s)
- Yovanny Izquierdo
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
| | - Satish Kulasekaran
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
- School of Life Sciences, University of Warwick, Gibbett Hill Campus, Coventry, CV4 7AL, UK
| | - Pablo Benito
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
| | - Bran López
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
| | - Ruth Marcos
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
| | - Tomás Cascón
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
| | - Mats Hamberg
- Division of Physiological Chemistry II, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, S-171 77, Sweden
| | - Carmen Castresana
- Centro Nacional de Biotecnología (CNB-CSIC), Cantoblanco, Madrid, E-28049, Spain
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