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Arimura SI, Nakazato I. Genome Editing of Plant Mitochondrial and Chloroplast Genomes. PLANT & CELL PHYSIOLOGY 2024; 65:477-483. [PMID: 38113380 PMCID: PMC11094758 DOI: 10.1093/pcp/pcad162] [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: 09/21/2023] [Revised: 11/30/2023] [Accepted: 12/16/2023] [Indexed: 12/21/2023]
Abstract
Plastids (including chloroplasts) and mitochondria are remnants of endosymbiotic bacteria, yet they maintain their own genomes, which encode vital components for photosynthesis and respiration, respectively. Organellar genomes have distinctive features, such as being present as multicopies, being mostly inherited maternally, having characteristic genomic structures and undergoing frequent homologous recombination. To date, it has proven to be challenging to modify these genomes. For example, while CRISPR/Cas9 is a widely used system for editing nuclear genes, it has not yet been successfully applied to organellar genomes. Recently, however, precise gene-editing technologies have been successfully applied to organellar genomes. Protein-based enzymes, especially transcription activator-like effector nucleases (TALENs) and artificial enzymes utilizing DNA-binding domains of TALENs (TALEs), have been successfully used to modify these genomes by harnessing organellar-targeting signals. This short review introduces and discusses the use of targeted nucleases and base editors in organellar genomes, their effects and their potential applications in plant science and breeding.
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Affiliation(s)
- Shin-ichi Arimura
- Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Science, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
| | - Issei Nakazato
- Laboratory of Plant Molecular Genetics, Graduate School of Agricultural and Life Science, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan
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Wang X, Ju Y, Wu T, Kong L, Yuan M, Liu H, Chen X, Chu Z. The clade III subfamily of OsSWEETs directly suppresses rice immunity by interacting with OsHMGB1 and OsHsp20L. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38587024 DOI: 10.1111/pbi.14338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/30/2024] [Accepted: 02/23/2024] [Indexed: 04/09/2024]
Abstract
The clade III subfamily of OsSWEETs includes transmembrane proteins necessary for susceptibility to bacterial blight (BB). These genes are targeted by the specific transcription activator-like effector (TALE) of Xanthomonas oryzae pv. oryzae and mediate sucrose efflux for bacterial proliferation. However, the mechanism through which OsSWEETs regulate rice immunity has not been fully elucidated. Here, we demonstrated that the cytosolic carboxyl terminus of OsSWEET11a/Xa13 is required for complementing susceptibility to PXO99 in IRBB13 (xa13/xa13). Interestingly, the C-terminus of ZmXa13, the maize homologue of OsSWEET11a/Xa13, could perfectly substitute for the C-terminus of OsSWEET11a/Xa13. Furthermore, OsSWEET11a/Xa13 interacted with the high-mobility group B1 (OsHMGB1) protein and the small heat shock-like protein OsHsp20L through the same regions in the C-terminus. Consistent with the physical interactions, knockdown or knockout of either OsHMGB1 or OsHsp20L caused an enhanced PXO99-resistant phenotype similar to that of OsSWEET11a/OsXa13. Surprisingly, the plants in which OsHMGB1 or OsHsp20L was repressed developed increased resistance to PXO86, PXO61 and YN24, which carry TALEs targeting OsSWEET14/Xa41 or OsSWEET11a/Xa13. Additionally, OsHsp20L can interact with all six members of clade III OsSWEETs, whereas OsHMGB1 can interact with five other members in addition to OsSWEET12. Overall, we revealed that OsHMGB1 and OsHsp20L mediate conserved BB susceptibility by interacting with clade III OsSWEETs, which are candidates for breeding broad-spectrum disease-resistant rice.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yanhu Ju
- State Key Laboratory of Wheat Breeding, College of Agronomy, Shandong Agricultural University, Tai'an, China
| | - Tao Wu
- College of Plant Protection, Yangzhou University, Yangzhou, China
| | - Lingguang Kong
- State Key Laboratory of Wheat Breeding, College of Agronomy, Shandong Agricultural University, Tai'an, China
| | - Meng Yuan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| | - Haifeng Liu
- State Key Laboratory of Wheat Breeding, College of Agronomy, Shandong Agricultural University, Tai'an, China
| | - Xiangsong Chen
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhaohui Chu
- State Key Laboratory of Hybrid Rice, Hubei Hongshan Laboratory, College of Life Sciences, Wuhan University, Wuhan, China
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Park HJ, Kim M, Lee D, Kim HJ, Jung HW. CRISPR-Cas9 and beyond: identifying target genes for developing disease-resistant plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:369-377. [PMID: 38363032 DOI: 10.1111/plb.13625] [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: 05/15/2023] [Accepted: 01/23/2024] [Indexed: 02/17/2024]
Abstract
Throughout the history of crop domestication, desirable traits have been selected in agricultural products. However, such selection often leads to crops and vegetables with weaker vitality and viability than their wild ancestors when exposed to adverse environmental conditions. Considering the increasing human population and climate change challenges, it is crucial to enhance crop quality and quantity. Accordingly, the identification and utilization of diverse genetic resources are imperative for developing disease-resistant plants that can withstand unexpected epidemics of plant diseases. In this review, we provide a brief overview of recent progress in genome-editing technologies, including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) technologies. In particular, we classify disease-resistant mutants of Arabidopsis thaliana and several crop plants based on the roles or functions of the mutated genes in plant immunity and suggest potential target genes for molecular breeding of genome-edited disease-resistant plants. Genome-editing technologies are resilient tools for sustainable development and promising solutions for coping with climate change and population increases.
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Affiliation(s)
- H J Park
- Institute of Agricultural Life Science, Dong-A University, Busan, Korea
- Department of Biological Sciences and Research Center of Ecomimetics, Chonnam National University, Gwangju, Korea
| | - M Kim
- Department of Applied Bioscience, Dong-A University, Busan, Korea
| | - D Lee
- Department of Applied Bioscience, Dong-A University, Busan, Korea
| | - H J Kim
- Department of Molecular Genetics, Dong-A University, Busan, Korea
| | - H W Jung
- Institute of Agricultural Life Science, Dong-A University, Busan, Korea
- Department of Applied Bioscience, Dong-A University, Busan, Korea
- Department of Molecular Genetics, Dong-A University, Busan, Korea
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Li L, Chen J, Sun Z. Exploring the shared pathogenic strategies of independently evolved effectors across distinct plant viruses. Trends Microbiol 2024:S0966-842X(24)00058-1. [PMID: 38521726 DOI: 10.1016/j.tim.2024.03.001] [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: 01/17/2024] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 03/25/2024]
Abstract
Plants have developed very diverse strategies to defend themselves against viral pathogens, among which plant hormones play pivotal roles. In response, some viruses have also deployed multifunctional viral effectors that effectively hijack key component hubs to counter or evade plant immune surveillance. Although significant progress has been made toward understanding counter-defense strategies that manipulate plant hormone regulatory molecules, these efforts have often been limited to an individual virus or specific host target/pathway. This review provides new insights into broad-spectrum antiviral responses in rice triggered by key components of phytohormone signaling, and highlights the common features of counter-defense strategies employed by distinct rice-infecting RNA viruses. These strategies involve the secretion of multifunctional virulence effectors that target the sophisticated phytohormone system, dampening immune responses by engaging with the same host targets. Additionally, the review provides an in-depth exploration of various viral effectors, emphasizing tertiary structure-based research and shared host targets. Understanding these conserved characteristics in detail may pave the way for molecular drug design, opening new opportunities to enhance broad-spectrum antiviral trials through precise engineering.
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Affiliation(s)
- Lulu Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Jianping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China
| | - Zongtao Sun
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, 315211, China.
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Xu Z, Xu X, Li Y, Liu L, Wang Q, Wang Y, Wang Y, Yan J, Cheng G, Zou L, Zhu B, Chen G. Tal6b/AvrXa27A, a hidden TALE targeting the susceptibility gene OsSWEET11a and the resistance gene Xa27 in rice. PLANT COMMUNICATIONS 2024; 5:100721. [PMID: 37735868 PMCID: PMC10873877 DOI: 10.1016/j.xplc.2023.100721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 07/12/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) secretes transcription activator-like effectors (TALEs) to activate rice susceptibility (S) genes, causing bacterial blight (BB), as well as resistance (R) genes, leading to defense against BB. This activation follows a gene-for-gene paradigm that results in an arms race between the TALE of the pathogen and effector-binding elements (EBEs) in the promoters of host genes. In this study, we characterized a novel TALE, designated Tal6b/AvrXa27A, that activates the rice S gene OsSWEET11a and the rice R gene Xa27. Tal6b/AvrXa27A is a member of the AvrXa27/TalAO class and contains 16 repeat variable diresidues (RVDs); one RVD is altered and one is deleted in Tal6b/AvrXa27A compared with AvrXa27, a known avirulence (avr) effector of Xa27. Tal6b/AvrXa27A can transcriptionally activate the expression of Xa27 and OsSWEET11a via EBEs in their corresponding promoters, leading to effector-triggered immunity and susceptibility, respectively. The 16 RVDs in Tal6b/AvrXa27A have no obvious similarity to the 24 RVDs in the effector PthXo1, but EBETal6b and EBEPthXo1 are overlapped in the OsSWEET11a promoter. Tal6b/AvrXa27A is prevalent among Asian Xoo isolates, but PthXo1 has only been reported in the Philippine strain PXO99A. Genome editing of EBETal6b in the OsSWEET11a promoter further confirmed the requirement for OsSWEET11a expression in Tal6b/AvrXa27A-dependent susceptibility to Xoo. Moreover, Tal6b/AvrXa27A resulted in higher transcription of Xa27 than of OsSWEET11a, which led to a strong, rapid resistance response that blocked disease development. These findings suggest that Tal6b/AvrXa27A has a dual function: triggering resistance by activating Xa27 gene expression as an avirulence factor and inducing transcription of the S gene OsSWEET11a, resulting in virulence. Intriguingly, Tal6b/AvrXa27A, but not AvrXa27, can bind to the promoter of OsSWEET11a. The underlying recognition mechanism for this binding remains unclear but appears to deviate from the currently accepted TALE code.
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Affiliation(s)
- Zhengyin Xu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiameng Xu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ying Li
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Linlin Liu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yijie Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yong Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiali Yan
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Guanyun Cheng
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lifang Zou
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bo Zhu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Gongyou Chen
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China.
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Ventura C, Banerjee A, Zacharopoulou M, Itzhaki LS, Bahar I. Tandem-repeat proteins conformational mechanics are optimized to facilitate functional interactions and complexations. Curr Opin Struct Biol 2024; 84:102744. [PMID: 38134536 DOI: 10.1016/j.sbi.2023.102744] [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: 09/03/2023] [Revised: 10/30/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023]
Abstract
The architectures of tandem-repeat proteins are distinct from those of globular proteins. Individual modules, each comprising small structural motifs of 20-40 residues, are arrayed in a quasi one-dimensional fashion to form striking, elongated, horseshoe-like, and superhelical architectures, stabilized solely by short-range interaction. The spring-like shapes of repeat arrays point to elastic modes of action, and these proteins function as adapter molecules or 'hubs,' propagating signals within multi-subunit assemblies in diverse biological contexts. This flexibility is apparent in the dramatic variability observed in the structures of tandem-repeat proteins in different complexes. Here, using computational analysis, we demonstrate the striking ability of just one or a few global motions to recapitulate these structures. These findings show how the mechanics of repeat arrays are robustly enabled by their unique architecture. Thus, the repeating architecture has been optimized by evolution to favor functional modes of motions. The global motions enabling functional transitions can be fully visualized at http://bahargroup.org/tr_web.
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Affiliation(s)
- Carlos Ventura
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, 11794, USA; Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Anupam Banerjee
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Maria Zacharopoulou
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK. https://twitter.com/maria_zach_
| | - Laura S Itzhaki
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK.
| | - Ivet Bahar
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, 11794, USA; Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794, USA.
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Goettelmann F, Koebnik R, Roman-Reyna V, Studer B, Kölliker R. High genomic plasticity and unique features of Xanthomonas translucens pv. graminis revealed through comparative analysis of complete genome sequences. BMC Genomics 2023; 24:741. [PMID: 38053038 DOI: 10.1186/s12864-023-09855-8] [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: 07/05/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023] Open
Abstract
BACKGROUND Xanthomonas translucens pv. graminis (Xtg) is a major bacterial pathogen of economically important forage grasses, causing severe yield losses. So far, genomic resources for this pathovar consisted mostly of draft genome sequences, and only one complete genome sequence was available, preventing comprehensive comparative genomic analyses. Such comparative analyses are essential in understanding the mechanisms involved in the virulence of pathogens and to identify virulence factors involved in pathogenicity. RESULTS In this study, we produced high-quality, complete genome sequences of four strains of Xtg, complementing the recently obtained complete genome sequence of the Xtg pathotype strain. These genomic resources allowed for a comprehensive comparative analysis, which revealed a high genomic plasticity with many chromosomal rearrangements, although the strains were highly related. A high number of transposases were exclusively found in Xtg and corresponded to 413 to 457 insertion/excision transposable elements per strain. These mobile genetic elements are likely to be involved in the observed genomic plasticity and may play an important role in the adaptation of Xtg. The pathovar was found to lack a type IV secretion system, and it possessed the smallest set of type III effectors in the species. However, three XopE and XopX family effectors were found, while in the other pathovars of the species two or less were present. Additional genes that were specific to the pathovar were identified, including a unique set of minor pilins of the type IV pilus, 17 TonB-dependent receptors (TBDRs), and 11 plant cell wall degradative enzymes. CONCLUSION These results suggest a high adaptability of Xtg, conferred by the abundance of mobile genetic elements, which could play a crucial role in pathogen adaptation. The large amount of such elements in Xtg compared to other pathovars of the species could, at least partially, explain its high virulence and broad host range. Conserved features that were specific to Xtg were identified, and further investigation will help to determine genes that are essential to pathogenicity and host adaptation of Xtg.
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Affiliation(s)
- Florian Goettelmann
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Veronica Roman-Reyna
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA, USA
| | - Bruno Studer
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland
| | - Roland Kölliker
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zurich, Zurich, Switzerland.
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Erkes A, Grove RP, Žarković M, Krautwurst S, Koebnik R, Morgan RD, Wilson GG, Hölzer M, Marz M, Boch J, Grau J. Assembling highly repetitive Xanthomonas TALomes using Oxford Nanopore sequencing. BMC Genomics 2023; 24:151. [PMID: 36973643 PMCID: PMC10045945 DOI: 10.1186/s12864-023-09228-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/06/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Most plant-pathogenic Xanthomonas bacteria harbor transcription activator-like effector (TALE) genes, which function as transcriptional activators of host plant genes and support infection. The entire repertoire of up to 29 TALE genes of a Xanthomonas strain is also referred to as TALome. The DNA-binding domain of TALEs is comprised of highly conserved repeats and TALE genes often occur in gene clusters, which precludes the assembly of TALE-carrying Xanthomonas genomes based on standard sequencing approaches. RESULTS Here, we report the successful assembly of the 5 Mbp genomes of five Xanthomonas strains from Oxford Nanopore Technologies (ONT) sequencing data. For one of these strains, Xanthomonas oryzae pv. oryzae (Xoo) PXO35, we illustrate why Illumina short reads and longer PacBio reads are insufficient to fully resolve the genome. While ONT reads are perfectly suited to yield highly contiguous genomes, they suffer from a specific error profile within homopolymers. To still yield complete and correct TALomes from ONT assemblies, we present a computational correction pipeline specifically tailored to TALE genes, which yields at least comparable accuracy as Illumina-based polishing. We further systematically assess the ONT-based pipeline for its multiplexing capacity and find that, combined with computational correction, the complete TALome of Xoo PXO35 could have been reconstructed from less than 20,000 ONT reads. CONCLUSIONS Our results indicate that multiplexed ONT sequencing combined with a computational correction of TALE genes constitutes a highly capable tool for characterizing the TALomes of huge collections of Xanthomonas strains in the future.
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Affiliation(s)
- Annett Erkes
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany
| | - René P Grove
- Department of Plant Biotechnology, Leibniz Universität Hannover, 30419, Hannover, Germany
| | - Milena Žarković
- Bioinformatics/High-Throughput Analysis, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Sebastian Krautwurst
- Bioinformatics/High-Throughput Analysis, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, Univ Montpellier, IRD, CIRAD, INRAE, Institut Agro, 34090, Montpellier, France
| | | | | | - Martin Hölzer
- Methodology and Research Infrastructure, MF1 Bioinformatics, Robert Koch Institute, 13353, Berlin, Germany
| | - Manja Marz
- Bioinformatics/High-Throughput Analysis, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Jens Boch
- Department of Plant Biotechnology, Leibniz Universität Hannover, 30419, Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120, Halle, Germany.
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Zhang B, Liu M, Wang Y, Yuan W, Zhang H. Plant NLRs: Evolving with pathogen effectors and engineerable to improve resistance. Front Microbiol 2022; 13:1018504. [PMID: 36246279 PMCID: PMC9554439 DOI: 10.3389/fmicb.2022.1018504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Pathogens are important threats to many plants throughout their lifetimes. Plants have developed different strategies to overcome them. In the plant immunity system, nucleotide-binding domain and leucine-rich repeat-containing proteins (NLRs) are the most common components. And recent studies have greatly expanded our understanding of how NLRs function in plants. In this review, we summarize the studies on the mechanism of NLRs in the processes of effector recognition, resistosome formation, and defense activation. Typical NLRs are divided into three groups according to the different domains at their N termini and function in interrelated ways in immunity. Atypical NLRs contain additional integrated domains (IDs), some of which directly interact with pathogen effectors. Plant NLRs evolve with pathogen effectors and exhibit specific recognition. Meanwhile, some NLRs have been successfully engineered to confer resistance to new pathogens based on accumulated studies. In summary, some pioneering processes have been obtained in NLR researches, though more questions arise as a result of the huge number of NLRs. However, with a broadened understanding of the mechanism, NLRs will be important components for engineering in plant resistance improvement.
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