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Goggin FL, Fischer HD. Singlet oxygen signalling and its potential roles in plant biotic interactions. PLANT, CELL & ENVIRONMENT 2024; 47:1957-1970. [PMID: 38372069 DOI: 10.1111/pce.14851] [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: 11/13/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/20/2024]
Abstract
Singlet oxygen (SO) is among the most potent reactive oxygen species, and readily oxidizes proteins, lipids and DNA. It can be generated at the plant surface by phototoxins in the epidermis, acting as a direct defense against pathogens and herbivores (including humans). SO can also accumulate within mitochondria, peroxisomes, cytosol and the nucleus through multiple enzymatic and nonenzymatic processes. However, the majority of research on intracellular SO generation in plants has focused on transfer of light energy to triplet oxygen by photopigments from the chloroplast. SO accumulates in response to diverse stresses that perturb chloroplast metabolism, and while its high reactivity limits diffusion distances, it participates in retrograde signalling through the EXECUTER1 sensor, generation of carotenoid metabolites and possibly other unknown pathways. SO thereby reprogrammes nuclear gene expression and modulates hormone signalling and programmed cell death. While SO signalling has long been known to regulate plant responses to high-light stress, recent literature also suggests a role in plant interactions with insects, bacteria and fungi. The goals of this review are to provide a brief overview of SO, summarize evidence for its involvement in biotic stress responses and discuss future directions for the study of SO in defense signalling.
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Affiliation(s)
- Fiona L Goggin
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Hillary D Fischer
- Department of Entomology and Plant Pathology, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
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2
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Jung S, Woo J, Park E. Talk to your neighbors in an emergency: Stromule-mediated chloroplast-nucleus communication in plant immunity. CURRENT OPINION IN PLANT BIOLOGY 2024; 79:102529. [PMID: 38604000 DOI: 10.1016/j.pbi.2024.102529] [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: 11/21/2022] [Revised: 03/08/2024] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Abstract
Hypersensitive response-programmed cell death (HR-PCD) is a response mounted by plants to defend themselves against pathogens. Communication between the chloroplast and the nucleus is critical for the progression of HR-PCD. Tubular protrusions of chloroplasts, known as stromules, are tightly associated with the HR-PCD progression. There is emerging evidence that signaling molecules originating from chloroplasts are transferred to the nucleus through stromules. The translocation of signaling molecules from the chloroplast to the nucleus might trigger defense responses, including transcriptional reprogramming. In this review, we discuss the possible functions of stromules in the rapid transfer of signaling molecules in the chloroplast-nucleus communication.
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Affiliation(s)
- Seungmee Jung
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Jongchan Woo
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Eunsook Park
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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3
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Rai S, Lemke MD, Arias AM, Mendez MFG, Dehesh K, Woodson JD. Plant U-Box 4 regulates chloroplast stress signaling and programmed cell death via Salicylic acid modulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593788. [PMID: 38798329 PMCID: PMC11118471 DOI: 10.1101/2024.05.13.593788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
In response to environmental stress, chloroplasts generate reactive oxygen species, including singlet oxygen (1O2), which regulates nuclear gene expression (retrograde signaling), chloroplast turnover, and programmed cell death (PCD). Yet, the central signaling mechanisms and downstream responses remain poorly understood. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant conditionally accumulates 1O2 and involves Plant U-Box 4 (PUB4), a cytoplasmic E3 ubiquitin ligase, in propagating these signals. To gain insights into 1O2 signaling pathways, we compared transcriptomes of fc2 and fc2 pub4 mutants. The accumulation of 1O2 in fc2 plants broadly repressed genes involved in chloroplast function and photosynthesis, while 1O2 induced genes and transcription factors involved in abiotic and biotic stress, the biosynthesis of jasmonic acid (JA), and Salicylic acid (SA). Elevated JA and SA levels were observed in stressed fc2 plants, but were not responsible for PCD. pub4 reversed the majority of 1O2-induced gene expression in fc2 and reduced the JA content, but maintained elevated levels of SA even in the absence of 1O2 stress. Reducing SA levels in fc2 pub4 restored 1O2 signaling and light sensitivity. Together, this work demonstrates that SA plays a protective role during photo-oxidative stress and that PUB4 mediates 1O2 signaling by modulating its levels.
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Affiliation(s)
- Snigdha Rai
- The School of Plant Sciences, University of Arizona, Tucson, AZ
| | | | - Anika M. Arias
- The School of Plant Sciences, University of Arizona, Tucson, AZ
| | - Maria F. Gomez Mendez
- Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA
| | - Katayoon Dehesh
- Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA
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4
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Geng R, Li X, Huang J, Zhou W. The chloroplast singlet oxygen-triggered biosynthesis of salicylic acid and jasmonic acid is mediated by EX1 and GUN1 in Arabidopsis. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38600785 DOI: 10.1111/pce.14910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/29/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
Reactive oxygen species (ROS) and defence hormones like salicylic acid (SA) and jasmonic acid (JA) play pivotal roles in triggering cell death. However, the precise mechanism governing the interaction between ROS and SA/JA remains elusive. Recently, our research revealed that RNAi mutants with suppressed expression of PROGRAMMED CELL DEATH8 (PCD8) exhibit an overabundance of tetrapyrrole intermediates, particularly uroporphyrinogen III (Uro III), leading to the accumulation of singlet oxygen (1O2) during the transition from darkness to light, thereby instigating leaf necrosis. In this investigation, we uncovered that 1O2 stimulates biosynthesis of SA and JA, activating SA/JA signalling and the expression of responsive genes in PCD8 RNAi (pcd8) mutants. Introducing NahG or knocking out PAD4 or NPR1 significantly alleviates the cell death phenotype of pcd8 mutants, while coi1 partially mitigates the pcd8 phenotype. Further exploration revealed that EX1 and GUN1 can partially rescue the pcd8 phenotype by reducing the levels of Uro III and 1O2. Notably, mutations in EX1 mutations but not GUN1, substantially diminish SA content in pcd8 mutants compared to the wild type, implying that EX1 acts as the primary mediator of 1O2 signalling-mediated SA biosynthesis. Moreover, the triple ex1 gun1 pcd8 displays a phenotype similar to ex1. Overall, our findings underscore that the 1O2-induced cell death phenotype requires EX1/GUN1-mediated retrograde signalling in pcd8 mutants, providing novel insights into the interplay between ROS and SA/JA.
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Affiliation(s)
- Rudan Geng
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Xia Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Wenbin Zhou
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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5
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Shi J, Wang H, Li M, Mi L, Gao Y, Qiang S, Zhang Y, Chen D, Dai X, Ma H, Lu H, Kim C, Chen S. Alternaria TeA toxin activates a chloroplast retrograde signaling pathway to facilitate JA-dependent pathogenicity. PLANT COMMUNICATIONS 2024; 5:100775. [PMID: 38050356 PMCID: PMC10943587 DOI: 10.1016/j.xplc.2023.100775] [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: 07/20/2023] [Revised: 11/05/2023] [Accepted: 11/30/2023] [Indexed: 12/06/2023]
Abstract
The chloroplast is a critical battleground in the arms race between plants and pathogens. Among microbe-secreted mycotoxins, tenuazonic acid (TeA), produced by the genus Alternaria and other phytopathogenic fungi, inhibits photosynthesis, leading to a burst of photosynthetic singlet oxygen (1O2) that is implicated in damage and chloroplast-to-nucleus retrograde signaling. Despite the significant crop damage caused by Alternaria pathogens, our understanding of the molecular mechanism by which TeA promotes pathogenicity and cognate plant defense responses remains fragmentary. We now reveal that A. alternata induces necrotrophic foliar lesions by harnessing EXECUTER1 (EX1)/EX2-mediated chloroplast-to-nucleus retrograde signaling activated by TeA toxin-derived photosynthetic 1O2 in Arabidopsis thaliana. Mutation of the 1O2-sensitive EX1-W643 residue or complete deletion of the EX1 singlet oxygen sensor domain compromises expression of 1O2-responsive nuclear genes and foliar lesions. We also found that TeA toxin rapidly induces nuclear genes implicated in jasmonic acid (JA) synthesis and signaling, and EX1-mediated retrograde signaling appears to be critical for establishing a signaling cascade from 1O2 to JA. The present study sheds new light on the foliar pathogenicity of A. alternata, during which EX1-dependent 1O2 signaling induces JA-dependent foliar cell death.
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Affiliation(s)
- Jiale Shi
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - He Wang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Mengping Li
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Liru Mi
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Yazhi Gao
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Sheng Qiang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Zhang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Chen
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Xinbin Dai
- Bioinformatics and Computational Biology Laboratory, Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Hongyu Ma
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
| | - Huan Lu
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
| | - Shiguo Chen
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China.
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Zhang ZW, Fu YF, Yang XY, Yuan M, Zheng XJ, Luo XF, Zhang MY, Xie LB, Shu K, Reinbothe S, Reinbothe C, Wu F, Feng LY, Du JB, Wang CQ, Gao XS, Chen YE, Zhang YY, Li Y, Tao Q, Lan T, Tang XY, Zeng J, Chen GD, Yuan S. Singlet oxygen induces cell wall thickening and stomatal density reducing by transcriptome reprogramming. J Biol Chem 2023; 299:105481. [PMID: 38041932 PMCID: PMC10731243 DOI: 10.1016/j.jbc.2023.105481] [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: 10/17/2023] [Revised: 11/12/2023] [Accepted: 11/17/2023] [Indexed: 12/04/2023] Open
Abstract
Singlet oxygen (1O2) has a very short half-life of 10-5 s; however, it is a strong oxidant that causes growth arrest and necrotic lesions on plants. Its signaling pathway remains largely unknown. The Arabidopsis flu (fluorescent) mutant accumulates a high level of 1O2 and shows drastic changes in nuclear gene expression. Only two plastid proteins, EX1 (executer 1) and EX2 (executer 2), have been identified in the singlet oxygen signaling. Here, we found that the transcription factor abscisic acid insensitive 4 (ABI4) binds the promoters of genes responsive to 1O2-signals. Inactivation of the ABI4 protein in the flu/abi4 double mutant was sufficient to compromise the changes of almost all 1O2-responsive-genes and rescued the lethal phenotype of flu grown under light/dark cycles, similar to the flu/ex1/ex2 triple mutant. In addition to cell death, we reported for the first time that 1O2 also induces cell wall thickening and stomatal development defect. Contrastingly, no apparent growth arrest was observed for the flu mutant under normal light/dim light cycles, but the cell wall thickening (doubled) and stomatal density reduction (by two-thirds) still occurred. These results offer a new idea for breeding stress tolerant plants.
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Affiliation(s)
- Zhong-Wei Zhang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Yu-Fan Fu
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Xin-Yue Yang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Ming Yuan
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Xiao-Jian Zheng
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Xiao-Feng Luo
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Meng-Yao Zhang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Lin-Bei Xie
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Kai Shu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Steffen Reinbothe
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
| | - Christiane Reinbothe
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
| | - Fan Wu
- Sichuan Provincial Academy of Natural Resource Sciences, Chengdu, China
| | - Ling-Yang Feng
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
| | - Jun-Bo Du
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
| | - Chang-Quan Wang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Xue-Song Gao
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Yang-Er Chen
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Yan-Yan Zhang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Yang Li
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Qi Tao
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Ting Lan
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Xiao-Yan Tang
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Jian Zeng
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China
| | - Guang-Deng Chen
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China.
| | - Shu Yuan
- College of Resources, Sichuan Agricultural University, Chengdu, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu, China.
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Lv A, Su L, Fan N, Wen W, Wang Z, Zhou P, An Y. Chloroplast-targeted late embryogenesis abundant 1 increases alfalfa tolerance to drought and aluminum. PLANT PHYSIOLOGY 2023; 193:2750-2767. [PMID: 37647543 DOI: 10.1093/plphys/kiad477] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 09/01/2023]
Abstract
Late embryogenesis-abundant (LEA) proteins are important stress-response proteins that participate in protecting plants against abiotic stresses. Here, we investigated LEA group 3 protein MsLEA1, containing the typically disordered and α-helix structure, via overexpression and RNA interference (RNAi) approaches in alfalfa (Medicago sativa L.) under drought and aluminum (Al) stresses. MsLEA1 was highly expressed in leaves and localized in chloroplasts. Overexpressing MsLEA1 increased alfalfa tolerance to drought and Al stresses, but downregulating MsLEA1 decreased the tolerance. We observed a larger stomatal aperture and a lower water use efficiency in MsLEA1 RNAi lines compared with wild-type plants under drought stress. Photosynthetic rate, Rubisco activity, and superoxide dismutase (SOD) activity increased or decreased in MsLEA1-OE or MsLEA1-RNAi lines, respectively, under drought and Al stress. Copper/zinc SOD (Cu/Zn-SOD), iron SOD (Fe-SOD), and Rubisco large subunit proteins (Ms1770) were identified as binding partners of MsLEA1, which protected chloroplast structure and function under drought and Al stress. These results indicate that MsLEA1 recruits and protects its target proteins (SOD and Ms1770) and increases alfalfa tolerance against drought and Al stresses.
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Affiliation(s)
- Aimin Lv
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
- Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine, Zhejiang A&F University, Hangzhou 311300, China
| | - Liantai Su
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Nana Fan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wuwu Wen
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zheng Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Peng Zhou
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuan An
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
- Key Laboratory of Urban Agriculture, Ministry of Agriculture, Shanghai 201101, China
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Yang X, Guan H, Yang Y, Zhang Y, Su W, Song S, Liu H, Chen R, Hao Y. Extra- and intranuclear heat perception and triggering mechanisms in plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1276649. [PMID: 37860244 PMCID: PMC10582638 DOI: 10.3389/fpls.2023.1276649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 09/20/2023] [Indexed: 10/21/2023]
Abstract
The escalating impact of global warming on crop yield and quality poses a significant threat to future food supplies. Breeding heat-resistant crop varieties holds promise, but necessitates a deeper understanding of the molecular mechanisms underlying plant heat tolerance. Recent studies have shed light on the initial events of heat perception in plants. In this review, we provide a comprehensive summary of the recent progress made in unraveling the mechanisms of heat perception and response in plants. Calcium ion (Ca2+), hydrogen peroxide (H2O2), and nitric oxide (NO) have emerged as key participants in heat perception. Furthermore, we discuss the potential roles of the NAC transcription factor NTL3, thermo-tolerance 3.1 (TT3.1), and Target of temperature 3 (TOT3) as thermosensors associated with the plasma membrane. Additionally, we explore the involvement of cytoplasmic HISTONE DEACETYLASE 9 (HDA9), mRNA encoding the phytochrome-interacting factor 7 (PIF7), and chloroplasts in mediating heat perception. This review also highlights the role of intranuclear transcriptional condensates formed by phytochrome B (phyB), EARLY FLOWERING 3 (ELF3), and guanylate-binding protein (GBP)-like GTPase 3 (GBPL3) in heat perception. Finally, we raise the unresolved questions in the field of heat perception that require further investigation in the future.
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Affiliation(s)
| | | | | | | | | | | | | | - Riyuan Chen
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yanwei Hao
- College of Horticulture, South China Agricultural University, Guangzhou, China
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Seo S, Kim Y, Park K. NPR1 Translocation from Chloroplast to Nucleus Activates Plant Tolerance to Salt Stress. Antioxidants (Basel) 2023; 12:antiox12051118. [PMID: 37237984 DOI: 10.3390/antiox12051118] [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: 04/05/2023] [Revised: 05/08/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Chloroplasts play crucial roles in biotic and abiotic stress responses, regulated by nuclear gene expression through changes in the cellular redox state. Despite lacking the N-terminal chloroplast transit peptide (cTP), nonexpressor of pathogenesis-related genes 1 (NPR1), a redox-sensitive transcriptional coactivator was consistently found in the tobacco chloroplasts. Under salt stress and after exogenous application of H2O2 or aminocyclopropane-1-carboxylic acid, an ethylene precursor, transgenic tobacco plants expressing green fluorescent protein (GFP)-tagged NPR1 (NPR1-GFP) showed significant accumulation of monomeric nuclear NPR1, irrespective of the presence of cTP. Immunoblotting and fluorescence image analyses indicated that NPR1-GFP, with and without cTP, had similar molecular weights, suggesting that the chloroplast-targeted NPR1-GFP is likely translocated from the chloroplasts to the nucleus after processing in the stroma. Translation in the chloroplast is essential for nuclear NPR1 accumulation and stress-related expression of nuclear genes. An overexpression of chloroplast-targeted NPR1 enhanced stress tolerance and photosynthetic capacity. In addition, compared to the wild-type lines, several genes encoding retrograde signaling-related proteins were severely impaired in the Arabidopsis npr1-1 mutant, but were enhanced in NPR1 overexpression (NPR1-Ox) transgenic tobacco line. Taken together, chloroplast NPR1 acts as a retrograding signal that enhances the adaptability of plants to adverse environments.
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Affiliation(s)
- Soyeon Seo
- Department of Biomedical Science, Sunchon National University, Suncheon 57922, Jeollanam-do, Republic of Korea
| | - Yumi Kim
- Department of Biomedical Science, Sunchon National University, Suncheon 57922, Jeollanam-do, Republic of Korea
| | - Kyyoung Park
- Department of Biomedical Science, Sunchon National University, Suncheon 57922, Jeollanam-do, Republic of Korea
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10
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Méteignier LV. Exfiltration from the chloroplast: A shuttle protein shows the way to the nucleus. THE PLANT CELL 2023; 35:634-635. [PMID: 36427254 PMCID: PMC9940861 DOI: 10.1093/plcell/koac332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Affiliation(s)
- Louis-Valentin Méteignier
- Assistant Features Editor, The Plant Cell, American Society of Plant Biologists, USA
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, Montpellier, France
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11
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Cresta A, D’Alessandro S. Arabidopsis ANAC102, Chloroplastic or Nucleocytosolic Localization? Genes (Basel) 2023; 14:438. [PMID: 36833365 PMCID: PMC9956179 DOI: 10.3390/genes14020438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
ANAC102 is a transcription factor involved in stress response and brassinosteroids signaling, with circadian regulation controlled by phytochromes. ANAC102 has been proposed to have a role in downregulating chloroplast transcription, which may be very useful in reducing photosynthesis and chloroplast energy demand under stress conditions. However, its localization in the chloroplast has mainly been demonstrated by using constitutive promoters. In this work, we recapitulate the literature, clarify which are ANAC102 isoforms in Arabidopsis and analyze their expressions under control conditions and in response to stress. Based on our results, the most highly expressed ANAC102 isoform encodes for a nucleocytoplasmic protein and the N-terminal chloroplast-targeting peptide appears to be present only in Brassicaceae, and not involved in stress response.
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Affiliation(s)
| | - Stefano D’Alessandro
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Università degli Studi di Torino, 10135 Turin, Italy
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