1
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Wu D, Lei K, Wang D, Fu ZQ. Effector-triggered and self-regulated plant resistance to insects. Trends Plant Sci 2024; 29:1-3. [PMID: 37838518 DOI: 10.1016/j.tplants.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/16/2023]
Abstract
Despite many years of research, the molecular mechanisms underlying the activation and regulation of host plant resistance (HPR) to insects remain elusive. Recently, Guo et al. reported that a nucleotide-binding leucine-rich repeat NLR protein activates HPR through direct recognition of an insect effector and that autophagy-mediated degradation of this effector negatively regulates HPR.
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Affiliation(s)
- Di Wu
- State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Kang Lei
- State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China
| | - Daowen Wang
- State Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, and Center for Crop Genome Engineering, Henan Agricultural University, Zhengzhou 450002, China.
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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2
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Liu Y, Zhang YM, Tang Y, Chen JQ, Shao ZQ. The evolution of plant NLR immune receptors and downstream signal components. Curr Opin Plant Biol 2023; 73:102363. [PMID: 37094492 DOI: 10.1016/j.pbi.2023.102363] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 03/09/2023] [Accepted: 03/12/2023] [Indexed: 05/03/2023]
Abstract
Along with the emergence of green plants on this planet one billion years ago, the nucleotide binding site leucine-rich repeat (NLR) gene family originated and diverged into at least three subclasses. Two of them, with either characterized N-terminal toll/interleukin-1 receptor (TIR) or coiled-coil (CC) domain, serve as major types of immune receptor of effector-triggered immunity (ETI) in plants, whereas the one having a N-terminal Resistance to powdery mildew8 (RPW8) domain, functions as signal transfer component to them. In this review, we briefly summarized the history of identification of diverse NLR subclasses across Viridiplantae lineages during the establishment of NLR category, and highlighted recent advances on the evolution of NLR genes and several key downstream signal components under the background of ecological adaption.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, China
| | - Yan-Mei Zhang
- Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing, 210014, China
| | - Yao Tang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, China
| | - Jian-Qun Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, China.
| | - Zhu-Qing Shao
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, China.
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3
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Abstract
To fight off diverse pathogens and pests, the plant immune system must recognize these invaders; however, as plant immune receptors evolve to recognize a pathogen, the pathogen often evolves to escape this recognition. Plant-pathogen co-evolution has led to the vast expansion of a family of intracellular immune receptors-nucleotide-binding domain and leucine-rich repeat proteins (NLRs). When an NLR receptor recognizes a pathogen ligand, it activates immune signaling and thus initiates defense responses. However, in contrast with the model of NLRs acting individually to activate resistance, an emerging paradigm holds that plants have complex receptor networks where the large repertoire of functionally specialized NLRs function together to act against the large repertoire of rapidly evolving pathogen effectors. In this article, we highlight key aspects of immune receptor networks in plant NLR biology and discuss NLR network architecture, the advantages of this receptor network system, and the evolution of the NLR network in asterid plants.
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Affiliation(s)
- Hiroaki Adachi
- Laboratory of Crop Evolution, Graduate School of Agriculture, Kyoto University, Mozume, Muko, Kyoto 617-0001, Japan
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, UK
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4
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Li J, Tao X. EDS1 modules as two-tiered receptor complexes for TIR-catalyzed signaling molecules to activate plant immunity. Stress Biol 2022; 2:30. [PMID: 37676367 PMCID: PMC10442000 DOI: 10.1007/s44154-022-00056-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 09/08/2023]
Abstract
Plant intracellular nucleotide-binding leucine-rich repeat (NLR) receptors with an N-terminal Toll/Interleukin-1 receptor (TIR) domain detect pathogen effectors to produce TIR-catalyzed signaling molecules for activation of plant immunity. Plant immune signaling by TIR-containing NLR (TNL) proteins converges on Enhanced Disease Susceptibility 1 (EDS1) and its direct partners Phytoalexin Deficient 4 (PAD4) or Senescence-Associated Gene 101 (SAG101). TNL signaling also require helper NLRs N requirement gene 1 (NRG1) and activated disease resistance 1 (ADR1). In two recent remarkable papers published in Science, the authors show that the TIR-containing proteins catalyze and produce two types of signaling molecules, ADPr-ATP/diADPR and pRib-AMP/ADP. Importantly, they demonstrate that EDS1-SAG101 and EDS1-PAD4 modules are the receptor complexes for ADPr-ATP/diADPRp and Rib-AMP/ADP, respectively, which allosterically promote EDS1-SAG101 interaction with NRG1 and EDS1-PAD4 interaction with ADR1. Thus, two different small molecules catalyzed by TIR-containing proteins selectively activate the downstream two distinct branches of EDS1-mediated immune signalings. These breakthrough studies significantly advance our understanding of TNL downstream signaling pathway.
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Affiliation(s)
- Jia Li
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
| | - Xiaorong Tao
- The Key Laboratory of Plant Immunity, Department of Plant Pathology, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
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5
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Chang M, Chen H, Liu F, Fu ZQ. PTI and ETI: convergent pathways with diverse elicitors. Trends Plant Sci 2022; 27:113-115. [PMID: 34863646 DOI: 10.1016/j.tplants.2021.11.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
Plants rely on PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) to detect invading pathogens and subsequently activate defense mechanisms. Recently, four Nature papers (Yuan et al., Ngou et al., Pruitt et al., and Tian et al.)demonstrated that important components in PTI and ETI are required for both PTI and ETI, and PTI and ETI potentiate each other to achieve stronger plant defenses.
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Affiliation(s)
- Ming Chang
- The Key Laboratory of Bio-interactions and Plant Health, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Huan Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, Jiangsu 210014, China; Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing, Jiangsu 210014, China.
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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6
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Chen Z, Wu Q, Tong C, Chen H, Miao D, Qian X, Zhao X, Jiang L, Tao X. Characterization of the Roles of SGT1/RAR1, EDS1/NDR1, NPR1, and NRC/ADR1/NRG1 in Sw-5b-Mediated Resistance to Tomato Spotted Wilt Virus. Viruses 2021; 13:1447. [PMID: 34452313 DOI: 10.3390/v13081447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 01/23/2023] Open
Abstract
The tomato Sw-5b gene confers resistance to tomato spotted wilt virus (TSWV) and encodes a nucleotide-binding leucine-rich repeat (NLR) protein with an N-terminal Solanaceae-specific domain (SD). Although our understanding of how Sw-5b recognizes the viral NSm elicitor has increased significantly, the process by which Sw-5b activates downstream defense signaling remains to be elucidated. In this study, we used a tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) system to investigate the roles of the SGT1/RAR1, EDS1/NDR1, NPR1, and NRC/ADR1/NRG1 genes in the Sw-5b-mediated signaling pathway. We found that chaperone SGT1 was required for Sw-5b function, but co-chaperone RAR1 was not. Sw-5b-mediated immune signaling was independent of both EDS1 and NDR1. Silencing NPR1, which is a central component in SA signaling, did not result in TSWV systemic infection in Sw-5b-transgenic N. benthamiana plants. Helper NLR NRCs (NLRs required for cell death) were required for Sw-5b-mediated systemic resistance to TSWV infection. Suppression of NRC2/3/4 compromised the Sw-5b resistance. However, the helper NLRs ADR1 and NRG1 may not participate in the Sw-5b signaling pathway. Silencing ADR1, NRG1, or both genes did not affect Sw-5b-mediated resistance to TSWV. Our findings provide new insight into the requirement for conserved key components in Sw-5b-mediated signaling pathways.
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7
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Ordon J, Martin P, Erickson JL, Ferik F, Balcke G, Bonas U, Stuttmann J. Disentangling cause and consequence: genetic dissection of the DANGEROUS MIX2 risk locus, and activation of the DM2h NLR in autoimmunity. Plant J 2021; 106:1008-1023. [PMID: 33629456 DOI: 10.1111/tpj.15215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/07/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Nucleotide-binding domain-leucine-rich repeat-type immune receptors (NLRs) protect plants against pathogenic microbes through intracellular detection of effector proteins. However, this comes at a cost, as NLRs can also induce detrimental autoimmunity in genetic interactions with foreign alleles. This may occur when independently evolved genomes are combined in inter- or intraspecific crosses, or when foreign alleles are introduced by mutagenesis or transgenesis. Most autoimmunity-inducing NLRs are encoded within highly variable NLR gene clusters with no known immune functions, which were termed autoimmune risk loci. Whether risk NLRs differ from sensor NLRs operating in natural pathogen resistance and how risk NLRs are activated in autoimmunity is unknown. Here, we analyzed the DANGEROUS MIX2 risk locus, a major autoimmunity hotspot in Arabidopsis thaliana. By gene editing and heterologous expression, we show that a single gene, DM2h, is necessary and sufficient for autoimmune induction in three independent cases of autoimmunity in accession Landsberg erecta. We focus on autoimmunity provoked by an EDS1-yellow fluorescent protein (YFP)NLS fusion protein to characterize DM2h functionally and determine features of EDS1-YFPNLS activating the immune receptor. Our data suggest that risk NLRs function in a manner reminiscent of sensor NLRs, while autoimmunity-inducing properties of EDS1-YFPNLS in this context are unrelated to the protein's functions as an immune regulator. We propose that autoimmunity, at least in some cases, may be caused by spurious, stochastic interactions of foreign alleles with coincidentally matching risk NLRs.
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Affiliation(s)
- Jana Ordon
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
| | - Patrick Martin
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
| | - Jessica Lee Erickson
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
| | - Filiz Ferik
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
| | - Gerd Balcke
- Department of Cell and Metabolic Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle (Saale), 06120, Germany
| | - Ulla Bonas
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
| | - Johannes Stuttmann
- Institute for Biology, Department of Plant Genetics, Martin Luther University Halle-Wittenberg, Weinbergweg 10, Halle (Saale), 06120, Germany
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8
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De la Concepcion JC, Franceschetti M, MacLean D, Terauchi R, Kamoun S, Banfield MJ. Protein engineering expands the effector recognition profile of a rice NLR immune receptor. eLife 2019; 8:47713. [PMID: 31535976 PMCID: PMC6768660 DOI: 10.7554/elife.47713] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/17/2019] [Indexed: 12/13/2022] Open
Abstract
Plant nucleotide binding, leucine-rich repeat (NLR) receptors detect pathogen effectors and initiate an immune response. Since their discovery, NLRs have been the focus of protein engineering to improve disease resistance. However, this approach has proven challenging, in part due to their narrow response specificity. Previously, we revealed the structural basis of pathogen recognition by the integrated heavy metal associated (HMA) domain of the rice NLR Pikp (Maqbool et al., 2015). Here, we used structure-guided engineering to expand the response profile of Pikp to variants of the rice blast pathogen effector AVR-Pik. A mutation located within an effector-binding interface of the integrated Pikp–HMA domain increased the binding affinity for AVR-Pik variants in vitro and in vivo. This translates to an expanded cell-death response to AVR-Pik variants previously unrecognized by Pikp in planta. The structures of the engineered Pikp–HMA in complex with AVR-Pik variants revealed the mechanism of expanded recognition. These results provide a proof-of-concept that protein engineering can improve the utility of plant NLR receptors where direct interaction between effectors and NLRs is established, particularly where this interaction occurs via integrated domains.
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Affiliation(s)
| | | | - Dan MacLean
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Ryohei Terauchi
- Division of Genomics and Breeding, Iwate Biotechnology Research Center, Iwate, Japan.,Laboratory of Crop Evolution, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Mark J Banfield
- Department of Biological Chemistry, John Innes Centre, Norwich, United Kingdom
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9
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Saur IML, Bauer S, Kracher B, Lu X, Franzeskakis L, Müller MC, Sabelleck B, Kümmel F, Panstruga R, Maekawa T, Schulze-Lefert P. Multiple pairs of allelic MLA immune receptor-powdery mildew AVR A effectors argue for a direct recognition mechanism. eLife 2019; 8:e44471. [PMID: 30777147 PMCID: PMC6414202 DOI: 10.7554/elife.44471] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/13/2019] [Indexed: 01/03/2023] Open
Abstract
Nucleotide-binding domain and leucine-rich repeat (NLR)-containing proteins in plants and animals mediate intracellular pathogen sensing. Plant NLRs typically detect strain-specific pathogen effectors and trigger immune responses often linked to localized host cell death. The barley Mla disease resistance locus has undergone extensive functional diversification in the host population and encodes numerous allelic NLRs each detecting a matching isolate-specific avirulence effector (AVRA) of the fungal pathogen Blumeria graminis f. sp. hordei (Bgh). We report here the isolation of Bgh AVRa7, AVRa9, AVRa10, and AVRa22, which encode small secreted proteins recognized by allelic MLA7, MLA9, MLA10, and MLA22 receptors, respectively. These effectors are sequence-unrelated, except for allelic AVRa10 and AVRa22 that are co-maintained in pathogen populations in the form of a balanced polymorphism. Contrary to numerous examples of indirect recognition of bacterial effectors by plant NLRs, co-expression experiments with matching Mla-AVRa pairs indicate direct detection of the sequence-unrelated fungal effectors by MLA receptors.
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Affiliation(s)
- Isabel ML Saur
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
| | - Saskia Bauer
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
| | - Barbara Kracher
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
| | - Xunli Lu
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
| | - Lamprinos Franzeskakis
- Unit of Plant Molecular Cell Biology, Institute for Biology IRWTH Aachen UniversityAachenGermany
| | - Marion C Müller
- Department of Plant and Microbial BiologyUniversity of ZurichZurichSwitzerland
| | - Björn Sabelleck
- Unit of Plant Molecular Cell Biology, Institute for Biology IRWTH Aachen UniversityAachenGermany
| | - Florian Kümmel
- Unit of Plant Molecular Cell Biology, Institute for Biology IRWTH Aachen UniversityAachenGermany
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology IRWTH Aachen UniversityAachenGermany
| | - Takaki Maekawa
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
| | - Paul Schulze-Lefert
- Department of Plant Microbe InteractionsMax Planck Institute for Plant Breeding ResearchCologneGermany
- Cluster of Excellence on Plant SciencesDüsseldorfGermany
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10
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Cui H, Qiu J, Zhou Y, Bhandari DD, Zhao C, Bautor J, Parker JE. Antagonism of Transcription Factor MYC2 by EDS1/PAD4 Complexes Bolsters Salicylic Acid Defense in Arabidopsis Effector-Triggered Immunity. Mol Plant 2018; 11:1053-1066. [PMID: 29842929 DOI: 10.1016/j.molp.2018.05.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/26/2018] [Accepted: 05/21/2018] [Indexed: 05/20/2023]
Abstract
In plant immunity, pathogen-activated intracellular nucleotide binding/leucine rich repeat (NLR) receptors mobilize disease resistance pathways, but the downstream signaling mechanisms remain obscure. Enhanced disease susceptibility 1 (EDS1) controls transcriptional reprogramming in resistance triggered by Toll-Interleukin1-Receptor domain (TIR)-family NLRs (TNLs). Transcriptional induction of the salicylic acid (SA) hormone defense sector provides one crucial barrier against biotrophic pathogens. Here, we present genetic and molecular evidence that in Arabidopsis an EDS1 complex with its partner PAD4 inhibits MYC2, a master regulator of SA-antagonizing jasmonic acid (JA) hormone pathways. In the TNL immune response, EDS1/PAD4 interference with MYC2 boosts the SA defense sector independently of EDS1-induced SA synthesis, thereby effectively blocking actions of a potent bacterial JA mimic, coronatine (COR). We show that antagonism of MYC2 occurs after COR has been sensed inside the nucleús but before or coincident with MYC2 binding to a target promoter, pANAC019. The stable interaction of PAD4 with MYC2 in planta is competed by EDS1-PAD4 complexes. However, suppression of MYC2-promoted genes requires EDS1 together with PAD4, pointing to an essential EDS1-PAD4 heterodimer activity in MYC2 inhibition. Taken together, these results uncover an immune receptor signaling circuit that intersects with hormone pathway crosstalk to reduce bacterial pathogen growth.
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Affiliation(s)
- Haitao Cui
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture University, Fuzhou 350002, China
| | - Jingde Qiu
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany
| | - Yue Zhou
- Department of Plant Developmental Biology, Max-Planck Institute for Plant Breeding Research, 50829 Cologne, Germany
| | - Deepak D Bhandari
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany
| | - Chunhui Zhao
- Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture University, Fuzhou 350002, China
| | - Jaqueline Bautor
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany
| | - Jane E Parker
- Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, 50829 Cologne, Germany.
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11
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El Kasmi F, Chung EH, Anderson RG, Li J, Wan L, Eitas TK, Gao Z, Dangl JL. Signaling from the plasma-membrane localized plant immune receptor RPM1 requires self-association of the full-length protein. Proc Natl Acad Sci U S A 2017; 114:E7385-E7394. [PMID: 28808003 PMCID: PMC5584451 DOI: 10.1073/pnas.1708288114] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Plants evolved intracellular immune receptors that belong to the NOD-like receptor (NLR) family to recognize the presence of pathogen-derived effector proteins. NLRs possess an N-terminal Toll-like/IL-1 receptor (TIR) or a non-TIR domain [some of which contain coiled coils (CCs)], a central nucleotide-binding (NB-ARC) domain, and a C-terminal leucine-rich repeat (LRR). Activation of NLR proteins results in a rapid and high-amplitude immune response, eventually leading to host cell death at the infection site, the so-called hypersensitive response. Despite their important contribution to immunity, the exact mechanisms of NLR activation and signaling remain unknown and are likely heterogenous. We undertook a detailed structure-function analysis of the plasma membrane (PM)-localized CC NLR Resistance to Pseudomonas syringae pv. maculicola 1 (RPM1) using both stable transgenic Arabidopsis and transient expression in Nicotiana benthamiana We report that immune signaling is induced only by activated full-length PM-localized RPM1. Our interaction analyses demonstrate the importance of a functional P-loop for in planta interaction of RPM1 with the small host protein RPM1-interacting protein 4 (RIN4), for constitutive preactivation and postactivation self-association of RPM1 and for proper PM localization. Our results reveal an additive effect of hydrophobic conserved residues in the CC domain for RPM1 function and RPM1 self-association and their necessity for RPM1-RIN4 interaction. Thus, our findings considerably extend our understanding of the mechanisms regulating NLR activation at, and signaling from, the PM.
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Affiliation(s)
- Farid El Kasmi
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Eui-Hwan Chung
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Ryan G Anderson
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Jinyue Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, Hubei Province, P. R. China 430072
| | - Li Wan
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Timothy K Eitas
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Zhiyong Gao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, Hubei Province, P. R. China 430072;
| | - Jeffery L Dangl
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280;
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
- Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
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12
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Wu Z, Huang S, Zhang X, Wu D, Xia S, Li X. Regulation of plant immune receptor accumulation through translational repression by a glycine-tyrosine-phenylalanine (GYF) domain protein. eLife 2017; 6:e23684. [PMID: 28362261 PMCID: PMC5403212 DOI: 10.7554/elife.23684] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 03/14/2017] [Indexed: 01/12/2023] Open
Abstract
Plant immunity is tightly regulated to ensure proper defense against surrounding microbial pathogens without triggering autoimmunity, which negatively impacts plant growth and development. Immune receptor levels are intricately controlled by RNA processing and post-translational modification events, such as ubiquitination. It remains unknown whether, and if yes, how, plant immune receptor homeostasis is regulated at the translational level. From a mutant, snc1-enhancing (muse) forward genetic screen, we identified MUSE11/EXA1, which negatively regulates nucleotide-binding leucine-rich repeat (NLR) receptor mediated defence. EXA1 contains an evolutionarily conserved glycine-tyrosine-phenylalanine (GYF) domain that binds proline-rich sequences. Genetic and biochemical analysis revealed that loss of EXA1 leads to heightened NLR accumulation and enhanced resistance against virulent pathogens. EXA1 also associates with eIF4E initiation factors and the ribosome complex, likely contributing to the proper translation of target proteins. In summary, our study reveals a previously unknown mechanism of regulating NLR homeostasis through translational repression by a GYF protein.
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Affiliation(s)
- Zhongshou Wu
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Shuai Huang
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Xiaobo Zhang
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- Hunan Provincial Key Laboratory of Phytohormones, Hunan Agricultural University, Changsha, China
| | - Di Wu
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Shitou Xia
- Hunan Provincial Key Laboratory of Phytohormones, Hunan Agricultural University, Changsha, China
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
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Verchot J. Plant Virus Infection and the Ubiquitin Proteasome Machinery: Arms Race along the Endoplasmic Reticulum. Viruses 2016; 8:E314. [PMID: 27869775 DOI: 10.3390/v8110314] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/29/2016] [Accepted: 11/08/2016] [Indexed: 12/24/2022] Open
Abstract
The endoplasmic reticulum (ER) is central to plant virus replication, translation, maturation, and egress. Ubiquitin modification of ER associated cellular and viral proteins, alongside the actions of the 26S proteasome, are vital for the regulation of infection. Viruses can arrogate ER associated ubiquitination as well as cytosolic ubiquitin ligases with the purpose of directing the ubiquitin proteasome system (UPS) to new targets. Such targets include necessary modification of viral proteins which may stabilize certain complexes, or modification of Argonaute to suppress gene silencing. The UPS machinery also contributes to the regulation of effector triggered immunity pattern recognition receptor immunity. Combining the results of unrelated studies, many positive strand RNA plant viruses appear to interact with cytosolic Ub-ligases to provide novel avenues for controlling the deleterious consequences of disease. Viral interactions with the UPS serve to regulate virus infection in a manner that promotes replication and movement, but also modulates the levels of RNA accumulation to ensure successful biotrophic interactions. In other instances, the UPS plays a central role in cellular immunity. These opposing roles are made evident by contrasting studies where knockout mutations in the UPS can either hamper viruses or lead to more aggressive diseases. Understanding how viruses manipulate ER associated post-translational machineries to better manage virus–host interactions will provide new targets for crop improvement.
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Copeland C, Woloshen V, Huang Y, Li X. AtCDC48A is involved in the turnover of an NLR immune receptor. Plant J 2016; 88:294-305. [PMID: 27340941 DOI: 10.1111/tpj.13251] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 05/27/2016] [Accepted: 06/21/2016] [Indexed: 05/20/2023]
Abstract
Plants rely on different immune receptors to recognize pathogens and defend against pathogen attacks. Nucleotide-binding domain and leucine-rich repeat (NLR) proteins play a major role as intracellular immune receptors. Their homeostasis must be maintained at optimal levels in order to effectively recognize pathogens without causing autoimmunity. Previous studies have shown that the activity of the ubiquitin-proteasome system is essential to prevent excessive accumulation of NLR proteins such as Suppressor of NPR1, Constitutive 1 (SNC1). Attenuation of the ubiquitin E3 ligase SCFCPR1 (Constitutive expressor of Pathogenesis Related genes 1) or the E4 protein MUSE3 (Mutant, SNC1-Enhancing 3) leads to NLR accumulation and autoimmunity. In the current study, we report the identification of AtCDC48A as a negative regulator of NLR-mediated immunity. Plants carrying Atcdc48A-4, a partial loss-of-function allele of AtCDC48A, exhibit dwarf morphology and enhanced disease resistance to the oomycete pathogen Hyaloperonospora arabidopsidis (H.a.) Noco2. The SNC1 level is increased in Atcdc48A-4 plants and AtCDC48A interacts with MUSE3 in co-immunoprecipitation experiments, supporting a role for AtCDC48A in NLR turnover. While Arabidopsis contains four other paralogs of AtCDC48A, knockout mutants of these genes do not show obvious immunity-related phenotypes, suggesting functional divergence within this family. As an AAA-ATPase, AtCDC48A likely serves to process the poly-ubiquitinated NLR substrate for final protein degradation by the 26S proteasome.
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Affiliation(s)
- Charles Copeland
- Michael Smith Laboratories and Botany Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Virginia Woloshen
- Michael Smith Laboratories and Botany Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Yan Huang
- Michael Smith Laboratories and Botany Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Xin Li
- Michael Smith Laboratories and Botany Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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