1
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Wang H, Chen Q, Feng W. The Emerging Role of 2OGDs as Candidate Targets for Engineering Crops with Broad-Spectrum Disease Resistance. PLANTS (BASEL, SWITZERLAND) 2024; 13:1129. [PMID: 38674537 PMCID: PMC11054871 DOI: 10.3390/plants13081129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/09/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024]
Abstract
Plant diseases caused by pathogens result in a marked decrease in crop yield and quality annually, greatly threatening food production and security worldwide. The creation and cultivation of disease-resistant cultivars is one of the most effective strategies to control plant diseases. Broad-spectrum resistance (BSR) is highly preferred by breeders because it confers plant resistance to diverse pathogen species or to multiple races or strains of one species. Recently, accumulating evidence has revealed the roles of 2-oxoglutarate (2OG)-dependent oxygenases (2OGDs) as essential regulators of plant disease resistance. Indeed, 2OGDs catalyze a large number of oxidative reactions, participating in the plant-specialized metabolism or biosynthesis of the major phytohormones and various secondary metabolites. Moreover, several 2OGD genes are characterized as negative regulators of plant defense responses, and the disruption of these genes via genome editing tools leads to enhanced BSR against pathogens in crops. Here, the recent advances in the isolation and identification of defense-related 2OGD genes in plants and their exploitation in crop improvement are comprehensively reviewed. Also, the strategies for the utilization of 2OGD genes as targets for engineering BSR crops are discussed.
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Affiliation(s)
- Han Wang
- School of Breeding and Multiplication, School of Tropical Agriculture and Forestry, Hainan University, Sanya 572025, China;
- College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Qinghe Chen
- School of Breeding and Multiplication, School of Tropical Agriculture and Forestry, Hainan University, Sanya 572025, China;
| | - Wanzhen Feng
- School of Breeding and Multiplication, School of Tropical Agriculture and Forestry, Hainan University, Sanya 572025, China;
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2
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Hudson A, Mullens A, Hind S, Jamann T, Balint-Kurti P. Natural variation in the pattern-triggered immunity response in plants: Investigations, implications and applications. MOLECULAR PLANT PATHOLOGY 2024; 25:e13445. [PMID: 38528659 DOI: 10.1111/mpp.13445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/26/2024] [Accepted: 03/01/2024] [Indexed: 03/27/2024]
Abstract
The pattern-triggered immunity (PTI) response is triggered at the plant cell surface by the recognition of microbe-derived molecules known as microbe- or pathogen-associated molecular patterns or molecules derived from compromised host cells called damage-associated molecular patterns. Membrane-localized receptor proteins, known as pattern recognition receptors, are responsible for this recognition. Although much of the machinery of PTI is conserved, natural variation for the PTI response exists within and across species with respect to the components responsible for pattern recognition, activation of the response, and the strength of the response induced. This review describes what is known about this variation. We discuss how variation in the PTI response can be measured and how this knowledge might be utilized in the control of plant disease and in developing plant varieties with enhanced disease resistance.
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Affiliation(s)
- Asher Hudson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Alexander Mullens
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Sarah Hind
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Tiffany Jamann
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Peter Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
- Plant Science Research Unit, USDA-ARS, Raleigh, North Carolina, USA
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3
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Gou M, Balint-Kurti P, Xu M, Yang Q. Quantitative disease resistance: Multifaceted players in plant defense. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:594-610. [PMID: 36448658 DOI: 10.1111/jipb.13419] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
In contrast to large-effect qualitative disease resistance, quantitative disease resistance (QDR) exhibits partial and generally durable resistance and has been extensively utilized in crop breeding. The molecular mechanisms underlying QDR remain largely unknown but considerable progress has been made in this area in recent years. In this review, we summarize the genes that have been associated with plant QDR and their biological functions. Many QDR genes belong to the canonical resistance gene categories with predicted functions in pathogen perception, signal transduction, phytohormone homeostasis, metabolite transport and biosynthesis, and epigenetic regulation. However, other "atypical" QDR genes are predicted to be involved in processes that are not commonly associated with disease resistance, such as vesicle trafficking, molecular chaperones, and others. This diversity of function for QDR genes contrasts with qualitative resistance, which is often based on the actions of nucleotide-binding leucine-rich repeat (NLR) resistance proteins. An understanding of the diversity of QDR mechanisms and of which mechanisms are effective against which classes of pathogens will enable the more effective deployment of QDR to produce more durably resistant, resilient crops.
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Affiliation(s)
- Mingyue Gou
- State Key Laboratory of Wheat and Maize Crop Science, Collaborative Innovation Center of Henan Grain Crops, Center for Crop Genome Engineering, College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China
- The Shennong Laboratory, Zhengzhou, 450002, China
| | - Peter Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
- Plant Science Research Unit, USDA-ARS, Raleigh, NC, 27695, USA
| | - Mingliang Xu
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, College of Agronomy, China Agricultural University, Beijing, 100193, China
| | - Qin Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Key Laboratory of Maize Biology and Genetic Breeding in Arid Area of Northwest Region of the Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, 712100, China
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4
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Receptor-mediated nonhost resistance in plants. Essays Biochem 2022; 66:435-445. [PMID: 35388900 PMCID: PMC9528085 DOI: 10.1042/ebc20210080] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 01/23/2023]
Abstract
Nonhost resistance (NHR) is a plant immune response that prevents many microorganisms in the plant's environment from pathogenicity against the plant. Since successful pathogens have adapted to overcome the immune systems of their host, the durable nature of NHR has potential in the management of plant disease. At present, there is genetic and molecular evidence that the underlying molecular mechanisms of NHR are similar to the plant immune responses that occur in host plants following infection by adapted pathogens. We consider that the molecular basis of NHR is multilayered, conferred by physicochemical barriers and defense responses that are induced following molecular recognition events. Moreover, the relative contribution of each component may depend on evolutionary distances between host and nonhost plants of given pathogen species. This mini-review has focused on the current knowledge of plant NHR, especially the recognition of non-adapted pathogens by nonhost plants at the cellular level. Recent gains in understanding the roles of plasma membrane-localized pattern-recognition receptors (PRRs) and the cytoplasmic nucleotide-binding leucine-rich repeat receptors (NLRs) associated with these processes, as well as the genes involved, are summarized. Finally, we provide a theoretical perspective on the durability of receptor-mediated NHR and its practical potential as an innovative strategy for crop protection against pathogens.
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5
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Lan X, Wang X, Tao Q, Zhang H, Li J, Meng Y, Shan W. Activation of the VQ Motif-Containing Protein Gene VQ28 Compromised Nonhost Resistance of Arabidopsis thaliana to Phytophthora Pathogens. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11070858. [PMID: 35406838 PMCID: PMC9002740 DOI: 10.3390/plants11070858] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 06/01/2023]
Abstract
Nonhost resistance refers to resistance of a plant species to all genetic variants of a non-adapted pathogen. Such resistance has the potential to become broad-spectrum and durable crop disease resistance. We previously employed Arabidopsis thaliana and a forward genetics approach to identify plant mutants susceptible to the nonhost pathogen Phytophthora sojae, which resulted in identification of the T-DNA insertion mutant esp1 (enhanced susceptibility to Phytophthora). In this study, we report the identification of VQ motif-containing protein 28 (VQ28), whose expression was highly up-regulated in the mutant esp1. Stable transgenic A. thaliana plants constitutively overexpressing VQ28 compromised nonhost resistance (NHR) against P. sojae and P. infestans, and supported increased infection of P. parasitica. Transcriptomic analysis showed that overexpression of VQ28 resulted in six differentially expressed genes (DEGs) that are involved in the response to abscisic acid (ABA). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that the contents of endogenous ABA, salicylic acid (SA), and jasmonate (JA) were enriched in VQ28 overexpression lines. These findings suggest that overexpression of VQ28 may lead to an imbalance in plant hormone homeostasis. Furthermore, transient overexpression of VQ28 in Nicotiana benthamiana rendered plants more susceptible to Phytophthora pathogens. Deletion mutant analysis showed that the C-terminus and VQ-motif were essential for plant susceptibility. Taken together, our results suggest that VQ28 negatively regulates plant NHR to Phytophthora pathogens.
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Affiliation(s)
- Xingjie Lan
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Xiaoxia Wang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Agronomy, Northwest A&F University, Xianyang 712100, China
| | - Quandan Tao
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Agronomy, Northwest A&F University, Xianyang 712100, China
| | - Haotian Zhang
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Agronomy, Northwest A&F University, Xianyang 712100, China
| | - Jinyang Li
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Plant Protection, Northwest A&F University, Xianyang 712100, China
| | - Yuling Meng
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Agronomy, Northwest A&F University, Xianyang 712100, China
| | - Weixing Shan
- State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest A&F University, Xianyang 712100, China; (X.L.); (X.W.); (Q.T.); (H.Z.); (J.L.); (Y.M.)
- College of Agronomy, Northwest A&F University, Xianyang 712100, China
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6
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Panstruga R, Moscou MJ. What is the Molecular Basis of Nonhost Resistance? MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1253-1264. [PMID: 32808862 DOI: 10.1094/mpmi-06-20-0161-cr] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article is part of the Top 10 Unanswered Questions in MPMI invited review series.Nonhost resistance is typically considered the ability of a plant species to repel all attempts of a pathogen species to colonize it and reproduce on it. Based on this common definition, nonhost resistance is presumed to be very durable and, thus, of great interest for its potential use in agriculture. Despite considerable research efforts, the molecular basis of this type of plant immunity remains nebulous. We here stress the fact that "nonhost resistance" is a phenomenological rather than a mechanistic concept that comprises more facets than typically considered. We further argue that nonhost resistance essentially relies on the very same genes and pathways as other types of plant immunity, of which some may act as bottlenecks for particular pathogens on a given plant species or under certain conditions. Thus, in our view, the frequently used term "nonhost genes" is misleading and should be avoided. Depending on the plant-pathogen combination, nonhost resistance may involve the recognition of pathogen effectors by host immune sensor proteins, which might give rise to host shifts or host range expansions due to evolutionary-conditioned gains and losses in respective armories. Thus, the extent of nonhost resistance also defines pathogen host ranges. In some instances, immune-related genes can be transferred across plant species to boost defense, resulting in augmented disease resistance. We discuss future routes for deepening our understanding of nonhost resistance and argue that the confusing term "nonhost resistance" should be used more cautiously in the light of a holistic view of plant immunity.
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Affiliation(s)
- Ralph Panstruga
- RWTH Aachen University, Institute for Biology I, Unit of Plant Molecular Cell Biology, Worringer Weg 1, 52056 Aachen, Germany
| | - Matthew J Moscou
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UK, United Kingdom
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7
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Li W, Deng Y, Ning Y, He Z, Wang GL. Exploiting Broad-Spectrum Disease Resistance in Crops: From Molecular Dissection to Breeding. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:575-603. [PMID: 32197052 DOI: 10.1146/annurev-arplant-010720-022215] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant diseases reduce crop yields and threaten global food security, making the selection of disease-resistant cultivars a major goal of crop breeding. Broad-spectrum resistance (BSR) is a desirable trait because it confers resistance against more than one pathogen species or against the majority of races or strains of the same pathogen. Many BSR genes have been cloned in plants and have been found to encode pattern recognition receptors, nucleotide-binding and leucine-rich repeat receptors, and defense-signaling and pathogenesis-related proteins. In addition, the BSR genes that underlie quantitative trait loci, loss of susceptibility and nonhost resistance have been characterized. Here, we comprehensively review the advances made in the identification and characterization of BSR genes in various species and examine their application in crop breeding. We also discuss the challenges and their solutions for the use of BSR genes in the breeding of disease-resistant crops.
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Affiliation(s)
- Wei Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, College of Plant Protection, Hunan Agricultural University, Changsha 410128, China
| | - Yiwen Deng
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China;
| | - Yuese Ning
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zuhua He
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China;
| | - Guo-Liang Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio 43210, USA;
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8
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Wagner G, Laperche A, Lariagon C, Marnet N, Renault D, Guitton Y, Bouchereau A, Delourme R, Manzanares-Dauleux MJ, Gravot A. Resolution of quantitative resistance to clubroot into QTL-specific metabolic modules. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5375-5390. [PMID: 31145785 PMCID: PMC6793449 DOI: 10.1093/jxb/erz265] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 05/21/2019] [Indexed: 05/23/2023]
Abstract
Plant disease resistance is often under quantitative genetic control. Thus, in a given interaction, plant cellular responses to infection are influenced by resistance or susceptibility alleles at different loci. In this study, a genetic linkage analysis was used to address the complexity of the metabolic responses of Brassica napus roots to infection by Plasmodiophora brassicae. Metabolome profiling and pathogen quantification in a segregating progeny allowed a comparative mapping of quantitative trait loci (QTLs) involved in resistance and in metabolic adjustments. Distinct metabolic modules were associated with each resistance QTL, suggesting the involvement of different underlying cellular mechanisms. This approach highlighted the possible role of gluconasturtiin and two unknown metabolites in the resistance conferred by two QTLs on chromosomes C03 and C09, respectively. Only two susceptibility biomarkers (glycine and glutathione) were simultaneously linked to the three main resistance QTLs, suggesting the central role of these compounds in the interaction. By contrast, several genotype-specific metabolic responses to infection were genetically unconnected to resistance or susceptibility. Likewise, variations of root sugar profiles, which might have influenced pathogen nutrition, were not found to be related to resistance QTLs. This work illustrates how genetic metabolomics can help to understand plant stress responses and their possible links with disease.
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Affiliation(s)
- Geoffrey Wagner
- IGEPP, Agrocampus Ouest, INRA, Université de Rennes, Le Rheu, France
| | - Anne Laperche
- IGEPP, Agrocampus Ouest, INRA, Université de Rennes, Le Rheu, France
| | | | - Nathalie Marnet
- Plateau de Profilage Métabolique et Métabolomique (P2M2), Centre de Recherche Angers Nantes BIA, INRA, Le Rheu, France
| | - David Renault
- UMR EcoBio, Université de Rennes, CNRS, Rennes, France
| | - Yann Guitton
- LUNAM Université, Oniris, Laboratoire d’Etude des Résidus et Contaminants dans les Aliments (LABERCA), Nantes, France
| | - Alain Bouchereau
- IGEPP, Agrocampus Ouest, INRA, Université de Rennes, Le Rheu, France
| | - Régine Delourme
- IGEPP, Agrocampus Ouest, INRA, Université de Rennes, Le Rheu, France
| | | | - Antoine Gravot
- IGEPP, Agrocampus Ouest, INRA, Université de Rennes, Le Rheu, France
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9
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Noman A, Aqeel M, Lou Y. PRRs and NB-LRRs: From Signal Perception to Activation of Plant Innate Immunity. Int J Mol Sci 2019; 20:ijms20081882. [PMID: 30995767 PMCID: PMC6514886 DOI: 10.3390/ijms20081882] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/02/2019] [Accepted: 04/10/2019] [Indexed: 12/11/2022] Open
Abstract
To ward off pathogens and pests, plants use a sophisticated immune system. They use pattern-recognition receptors (PRRs), as well as nucleotide-binding and leucine-rich repeat (NB-LRR) domains, for detecting nonindigenous molecular signatures from pathogens. Plant PRRs induce local and systemic immunity. Plasma-membrane-localized PRRs are the main components of multiprotein complexes having additional transmembrane and cytosolic kinases. Topical research involving proteins and their interactive partners, along with transcriptional and posttranscriptional regulation, has extended our understanding of R-gene-mediated plant immunity. The unique LRR domain conformation helps in the best utilization of a surface area and essentially mediates protein–protein interactions. Genome-wide analyses of inter- and intraspecies PRRs and NB-LRRs offer innovative information about their working and evolution. We reviewed plant immune responses with relevance to PRRs and NB-LRRs. This article focuses on the significant functional diversity, pathogen-recognition mechanisms, and subcellular compartmentalization of plant PRRs and NB-LRRs. We highlight the potential biotechnological application of PRRs and NB-LRRs to enhance broad-spectrum disease resistance in crops.
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Affiliation(s)
- Ali Noman
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310027, China.
- Department of Botany, Government College University, Faisalabad 38000, Pakistan.
| | - Muhammad Aqeel
- State Key Laboratory of Grassland Agro-ecosystems, School of Life Science, Lanzhou University, Lanzhou 730000, China.
| | - Yonggen Lou
- Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310027, China.
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10
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Fonseca JP, Mysore KS. Genes involved in nonhost disease resistance as a key to engineer durable resistance in crops. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 279:108-116. [PMID: 30709487 DOI: 10.1016/j.plantsci.2018.07.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/28/2018] [Accepted: 07/06/2018] [Indexed: 05/25/2023]
Abstract
Most potential pathogens fail to establish virulence for a plethora of plants found in nature. This intrinsic property to resist pathogen virulence displayed by organisms without triggering canonical resistance (R) genes has been termed nonhost resistance (NHR). While host resistance involves recognition of pathogen elicitors such as avirulence factors by bona fide R proteins, mechanism of NHR seems less obvious, often involving more than one gene. We can generally describe NHR in two steps: 1) pre-invasive resistance, either passive or active, which can restrict the pathogen from entering the host, and 2) post-invasive resistance, an active defense response that often results in hypersensitive response like programmed cell death and reactive oxygen species accumulation. While PAMP-triggered-immunity (PTI) is generally effective against nonhost pathogens, effector-triggered-immunity (ETI) can be effective against both host and nonhost pathogens. Prolonged interactions between adapted pathogens and their resistant host plants results in co-evolution, which can lead to new pathogen strains that can be virulent and cause disease on supposedly resistant host. In this context, engineering durable resistance by manipulating genes involved in NHR is an attractive approach for sustainable agriculture. Several genes involved in NHR have been characterized for their role in plant defense. In this review, we report genes involved in NHR identified to date and highlight a few examples where genes involved in NHR have been used to confer resistance in crop plants against economically important diseases.
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11
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Romero CCT, Vermeulen JP, Vels A, Himmelbach A, Mascher M, Niks RE. Mapping resistance to powdery mildew in barley reveals a large-effect nonhost resistance QTL. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2018; 131:1031-1045. [PMID: 29372282 PMCID: PMC5895680 DOI: 10.1007/s00122-018-3055-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 01/12/2018] [Indexed: 05/08/2023]
Abstract
Resistance factors against non-adapted powdery mildews were mapped in barley. Some QTLs seem effective only to non-adapted mildews, while others also play a role in defense against the adapted form. The durability and effectiveness of nonhost resistance suggests promising practical applications for crop breeding, relying upon elucidation of key aspects of this type of resistance. We investigated which genetic factors determine the nonhost status of barley (Hordeum vulgare L.) to powdery mildews (Blumeria graminis). We set out to verify whether genes involved in nonhost resistance have a wide effectiveness spectrum, and whether nonhost resistance genes confer resistance to the barley adapted powdery mildew. Two barley lines, SusBgtSC and SusBgtDC, with some susceptibility to the wheat powdery mildew B. graminis f.sp. tritici (Bgt) were crossed with cv Vada to generate two mapping populations. Each population was assessed for level of infection against four B. graminis ff.spp, and QTL mapping analyses were performed. Our results demonstrate polygenic inheritance for nonhost resistance, with some QTLs effective only to non-adapted mildews, while others play a role against adapted and non-adapted forms. Histology analyses of nonhost interaction show that most penetration attempts are stopped in association with papillae, and also suggest independent layers of defence at haustorium establishment and conidiophore formation. Nonhost resistance of barley to powdery mildew relies mostly on non-hypersensitive mechanisms. A large-effect nonhost resistance QTL mapped to a 1.4 cM interval is suitable for map-based cloning.
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Affiliation(s)
- Cynara C T Romero
- Plant Breeding, Wageningen University & Research, PO Box 386, 6700 AJ, Wageningen, The Netherlands
| | - Jasper P Vermeulen
- Plant Breeding, Wageningen University & Research, PO Box 386, 6700 AJ, Wageningen, The Netherlands
| | - Anton Vels
- Plant Breeding, Wageningen University & Research, PO Box 386, 6700 AJ, Wageningen, The Netherlands
| | - Axel Himmelbach
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Martin Mascher
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
| | - Rients E Niks
- Plant Breeding, Wageningen University & Research, PO Box 386, 6700 AJ, Wageningen, The Netherlands.
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12
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SDE5, a putative RNA export protein, participates in plant innate immunity through a flagellin-dependent signaling pathway in Arabidopsis. Sci Rep 2017; 7:9859. [PMID: 28851870 PMCID: PMC5574965 DOI: 10.1038/s41598-017-07918-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/15/2017] [Indexed: 12/02/2022] Open
Abstract
In eukaryotes, RNA silencing, mediated by small interfering RNAs, is an evolutionarily widespread and versatile silencing mechanism that plays an important role in various biological processes. Increasing evidences suggest that various components of RNA silencing pathway are involved in plant defense machinery against microbial pathogens in Arabidopsis thaliana. Here, we show genetic and molecular evidence that Arabidopsis SDE5 is required to generate an effective resistance against the biotrophic bacteria Pseudomonas syringae pv. tomato DC3000 and for susceptibility to the necrotrophic bacteria Erwinia caratovora pv. caratovora. SDE5, encodes a putative mRNA export factor that is indispensable for transgene silencing and the production of trans-acting siRNAs. SDE5 expression is rapidly induced by exogenous application of phytohormone salicylic acid (SA), methyl jasmonate (MeJA), phytopathogenic bacteria, and flagellin. We further report that SDE5 is involved in basal plant defense and mRNA export. Our genetic data suggests that SDE5 and Nonexpressor of PR Gene1 (NPR1) may contribute to the same SA-signaling pathway. However, SDE5 over-expressing transgenic plant exhibits reduced defense responsive phenotype after flagellin treatment. Taken together, these results support the conclusion that SDE5 contributes to plant innate immunity in Arabidopsis.
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13
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Boutrot F, Zipfel C. Function, Discovery, and Exploitation of Plant Pattern Recognition Receptors for Broad-Spectrum Disease Resistance. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:257-286. [PMID: 28617654 DOI: 10.1146/annurev-phyto-080614-120106] [Citation(s) in RCA: 392] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants are constantly exposed to would-be pathogens and pests, and thus have a sophisticated immune system to ward off these threats, which otherwise can have devastating ecological and economic consequences on ecosystems and agriculture. Plants employ receptor kinases (RKs) and receptor-like proteins (RLPs) as pattern recognition receptors (PRRs) to monitor their apoplastic environment and detect non-self and damaged-self patterns as signs of potential danger. Plant PRRs contribute to both basal and non-host resistances, and treatment with pathogen-/microbe-associated molecular patterns (PAMPs/MAMPs) or damage-associated molecular patterns (DAMPs) recognized by plant PRRs induces both local and systemic immunity. Here, we comprehensively review known PAMPs/DAMPs recognized by plants as well as the plant PRRs described to date. In particular, we describe the different methods that can be used to identify PAMPs/DAMPs and PRRs. Finally, we emphasize the emerging biotechnological potential use of PRRs to improve broad-spectrum, and potentially durable, disease resistance in crops.
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Affiliation(s)
- Freddy Boutrot
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, United Kingdom;
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, United Kingdom;
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Tock AJ, Fourie D, Walley PG, Holub EB, Soler A, Cichy KA, Pastor-Corrales MA, Song Q, Porch TG, Hart JP, Vasconcellos RCC, Vicente JG, Barker GC, Miklas PN. Genome-Wide Linkage and Association Mapping of Halo Blight Resistance in Common Bean to Race 6 of the Globally Important Bacterial Pathogen. FRONTIERS IN PLANT SCIENCE 2017; 8:1170. [PMID: 28736566 PMCID: PMC5500643 DOI: 10.3389/fpls.2017.01170] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/19/2017] [Indexed: 05/11/2023]
Abstract
Pseudomonas syringae pv. phaseolicola (Psph) Race 6 is a globally prevalent and broadly virulent bacterial pathogen with devastating impact causing halo blight of common bean (Phaseolus vulgaris L.). Common bean lines PI 150414 and CAL 143 are known sources of resistance against this pathogen. We constructed high-resolution linkage maps for three recombinant inbred populations to map resistance to Psph Race 6 derived from the two common bean lines. This was complemented with a genome-wide association study (GWAS) of Race 6 resistance in an Andean Diversity Panel of common bean. Race 6 resistance from PI 150414 maps to a single major-effect quantitative trait locus (QTL; HB4.2) on chromosome Pv04 and confers broad-spectrum resistance to eight other races of the pathogen. Resistance segregating in a Rojo × CAL 143 population maps to five chromosome arms and includes HB4.2. GWAS detected one QTL (HB5.1) on chromosome Pv05 for resistance to Race 6 with significant influence on seed yield. The same HB5.1 QTL, found in both Canadian Wonder × PI 150414 and Rojo × CAL 143 populations, was effective against Race 6 but lacks broad resistance. This study provides evidence for marker-assisted breeding for more durable halo blight control in common bean by combining alleles of race-nonspecific resistance (HB4.2 from PI 150414) and race-specific resistance (HB5.1 from cv. Rojo).
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Affiliation(s)
- Andrew J. Tock
- School of Life Sciences, Faculty of Science, University of WarwickWellesbourne, United Kingdom
- Department of Plant Sciences, Faculty of Biology, University of CambridgeCambridge, United Kingdom
| | - Deidré Fourie
- ARC-Grain Crops InstitutePotchefstroom, South Africa
| | - Peter G. Walley
- Functional and Comparative Genomics, Institute of Integrative Biology, University of LiverpoolLiverpool, United Kingdom
| | - Eric B. Holub
- School of Life Sciences, Faculty of Science, University of WarwickWellesbourne, United Kingdom
| | - Alvaro Soler
- Grain Legume Genetics and Physiology Research Unit, Agricultural Research Service, US Department of AgricultureProsser, WA, United States
| | - Karen A. Cichy
- Sugarbeet and Bean Research Unit, Agricultural Research Service, US Department of AgricultureEast Lansing, MI, United States
| | - Marcial A. Pastor-Corrales
- Soybean Genomics and Improvement Laboratory, Agricultural Research Service, US Department of AgricultureBeltsville, MD, United States
| | - Qijian Song
- Soybean Genomics and Improvement Laboratory, Agricultural Research Service, US Department of AgricultureBeltsville, MD, United States
| | - Timothy G. Porch
- Tropical Agriculture Research Station, Agricultural Research Service, US Department of AgricultureMayagüez, Puerto Rico
| | - John P. Hart
- Tropical Agriculture Research Station, Agricultural Research Service, US Department of AgricultureMayagüez, Puerto Rico
| | | | - Joana G. Vicente
- School of Life Sciences, Faculty of Science, University of WarwickWellesbourne, United Kingdom
| | - Guy C. Barker
- School of Life Sciences, Faculty of Science, University of WarwickWellesbourne, United Kingdom
| | - Phillip N. Miklas
- Grain Legume Genetics and Physiology Research Unit, Agricultural Research Service, US Department of AgricultureProsser, WA, United States
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Velásquez AC, Oney M, Huot B, Xu S, He SY. Diverse mechanisms of resistance to Pseudomonas syringae in a thousand natural accessions of Arabidopsis thaliana. THE NEW PHYTOLOGIST 2017; 214:1673-1687. [PMID: 28295393 PMCID: PMC5423860 DOI: 10.1111/nph.14517] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/07/2017] [Indexed: 05/03/2023]
Abstract
Plants are continuously threatened by pathogen attack and, as such, they have evolved mechanisms to evade, escape and defend themselves against pathogens. However, it is not known what types of defense mechanisms a plant would already possess to defend against a potential pathogen that has not co-evolved with the plant. We addressed this important question in a comprehensive manner by studying the responses of 1041 accessions of Arabidopsis thaliana to the foliar pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. We characterized the interaction using a variety of established methods, including different inoculation techniques, bacterial mutant strains, and assays for the hypersensitive response, salicylic acid (SA) accumulation and reactive oxygen species production . Fourteen accessions showed resistance to infection by Pst DC3000. Of these, two accessions had a surface-based mechanism of resistance, six showed a hypersensitive-like response while three had elevated SA levels. Interestingly, A. thaliana was discovered to have a recognition system for the effector AvrPto, and HopAM1 was found to modulate Pst DC3000 resistance in two accessions. Our comprehensive study has significant implications for the understanding of natural disease resistance mechanisms at the species level and for the ecology and evolution of plant-pathogen interactions.
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Affiliation(s)
| | - Matthew Oney
- MSU-DOE Plant Research Laboratory, East Lansing, MI 48824, USA
| | - Bethany Huot
- MSU-DOE Plant Research Laboratory, East Lansing, MI 48824, USA
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI 48824, USA
| | - Shu Xu
- MSU-DOE Plant Research Laboratory, East Lansing, MI 48824, USA
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, P. R. China
| | - Sheng Yang He
- MSU-DOE Plant Research Laboratory, East Lansing, MI 48824, USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
- Howard Hughes Medical Institute, Gordon and Betty Moore Foundation, Michigan State University, East Lansing, MI 48824, USA
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Zhang X, Valdés-López O, Arellano C, Stacey G, Balint-Kurti P. Genetic dissection of the maize (Zea mays L.) MAMP response. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2017; 130:1155-1168. [PMID: 28289802 DOI: 10.1007/s00122-017-2876-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 02/07/2017] [Indexed: 06/06/2023]
Abstract
Loci associated with variation in maize responses to two microbe-associated molecular patterns (MAMPs) were identified. MAMP responses were correlated. No relationship between MAMP responses and quantitative disease resistance was identified. Microbe-associated molecular patterns (MAMPs) are highly conserved molecules commonly found in microbes which can be recognized by plant pattern recognition receptors. Recognition triggers a suite of responses including production of reactive oxygen species (ROS) and nitric oxide (NO) and expression changes of defense-related genes. In this study, we used two well-studied MAMPs (flg22 and chitooctaose) to challenge different maize lines to determine whether there was variation in the level of responses to these MAMPs, to dissect the genetic basis underlying that variation and to understand the relationship between MAMP response and quantitative disease resistance (QDR). Naturally occurring quantitative variation in ROS, NO production, and defense genes expression levels triggered by MAMPs was observed. A major quantitative traits locus (QTL) associated with variation in the ROS production response to both flg22 and chitooctaose was identified on chromosome 2 in a recombinant inbred line (RIL) population derived from the maize inbred lines B73 and CML228. Minor QTL associated with variation in the flg22 ROS response was identified on chromosomes 1 and 4. Comparison of these results with data previously obtained for variation in QDR and the defense response in the same RIL population did not provide any evidence for a common genetic basis controlling variation in these traits.
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Affiliation(s)
- Xinye Zhang
- Maize Research Institute, Sichuan Agricultural University, 211 Huimin Road, Wenjiang District, Chengdu, 611130, Sichuan, China
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Oswaldo Valdés-López
- Division of Plant Science and Biochemistry, University of Missouri, Columbia, MO, 65211, USA
- Laboratorio de Genomica Funcional de Leguminosas, FES Iztacala, UNAM, Tlalnepantla, 54090, Mexico
| | - Consuelo Arellano
- Statistics Department, North Carolina State University, Raleigh, NC, 27695, USA
| | - Gary Stacey
- Division of Plant Science and Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Peter Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA.
- U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS) Plant Science Research Unit, Raleigh, NC, USA.
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An C, Wang C, Mou Z. The Arabidopsis Elongator complex is required for nonhost resistance against the bacterial pathogens Xanthomonas citri subsp. citri and Pseudomonas syringae pv. phaseolicola NPS3121. THE NEW PHYTOLOGIST 2017; 214:1245-1259. [PMID: 28134437 DOI: 10.1111/nph.14442] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/16/2016] [Indexed: 05/17/2023]
Abstract
Although in recent years nonhost resistance has attracted considerable attention for its broad spectrum and durability, the genetic and mechanistic components of nonhost resistance have not been fully understood. We used molecular and histochemical approaches including quantitative PCR, chromatin immunoprecipitation, and 3,3'-diaminobenzidine and aniline blue staining. The evolutionarily conserved histone acetyltransferase complex Elongator was identified as a major component of nonhost resistance against Xanthomonas citri subsp. citri (Xcc) and Pseudomonas syringae pv. phaseolicola (Psp) NPS3121. Mutations in Elongator genes inhibit Xcc-, Psp NPS3121- and/or flg22-induced defense responses including defense gene expression, callose deposition, and reactive oxygen species (ROS) and salicylic acid (SA) accumulation. Mutations in Elongator also attenuate the ROS-SA amplification loop. We show that suppressed ROS and SA accumulation in Elongator mutants is correlated with reduced expression of the Arabidopsis respiratory burst oxidase homologue AtrbohD and the SA biosynthesis gene ISOCHORISMATE SYNTHASE1 (ICS1). Furthermore, we found that the Elongator subunit ELP2 is associated with the chromatin of AtrbohD and ICS1 and is required for maintaining basal histone H3 acetylation levels in these key defense genes. As both AtrbohD and ICS1 contribute to nonhost resistance against Xcc, our results reveal an epigenetic mechanism by which Elongator regulates nonhost resistance in Arabidopsis.
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Affiliation(s)
- Chuanfu An
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - Chenggang Wang
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
| | - Zhonglin Mou
- Department of Microbiology and Cell Science, University of Florida, PO Box 110700, Gainesville, FL, 32611, USA
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Luo Q, Liu WW, Pan KD, Peng YL, Fan J. Genetic Interaction between Arabidopsis Qpm3.1 Locus and Bacterial Effector Gene hopW1-1 Underlies Natural Variation in Quantitative Disease Resistance to Pseudomonas Infection. FRONTIERS IN PLANT SCIENCE 2017; 8:695. [PMID: 28523008 PMCID: PMC5415610 DOI: 10.3389/fpls.2017.00695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/18/2017] [Indexed: 05/10/2023]
Abstract
Wide quantitative variation in plant disease resistance across Arabidopsis wild populations has been documented and the underlying mechanisms remain largely unknown. To investigate the genetic and molecular basis of this variation, Arabidopsis recombinant inbred lines (RILs) derived from Aa-0 × Col-0 and Gie-0 × Col-0 crosses were constructed and used for inoculation with Pseudomonas syringae pathovars maculicola ES4326 (ES4326) and tomato DC3000 (DC3000). Bacterial growth assays revealed continuous distribution across the large differences between the most and the least susceptible lines in the RILs. Quantitative trait locus (QTL) mapping analyses identified a number of QTLs underpinning the variance in disease resistance, among which Qpm3.1, a major QTL on chromosome III from both Aa-0 and Gie-0 accessions, preferentially restricted the growth of ES4326. A genetic screen for the ES4326 gene selectively leading to bacterial growth inhibition on accession Aa-0 uncovered the effector gene hopW1-1. Further QTL analysis of disease in RILs inoculated with DC3000 carrying hopW1-1 showed that the genetic interaction between Qpm3.1 and hopW1-1 determined Arabidopsis resistance to bacterial infection. These findings illustrate the complexity of Arabidopsis-Pseudomonas interaction and highlight the importance of pathogen effectors in delineating genetic architectures of quantitative variation in plant disease resistance.
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Affiliation(s)
- Qi Luo
- Ministry of Agriculture Key Laboratory of Plant Pathology, College of Plant Protection, China Agricultural UniversityBeijing, China
- State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
| | - Wei-Wei Liu
- Ministry of Agriculture Key Laboratory of Plant Pathology, College of Plant Protection, China Agricultural UniversityBeijing, China
| | - Ke-Di Pan
- Ministry of Agriculture Key Laboratory of Plant Pathology, College of Plant Protection, China Agricultural UniversityBeijing, China
| | - You-Liang Peng
- Ministry of Agriculture Key Laboratory of Plant Pathology, College of Plant Protection, China Agricultural UniversityBeijing, China
- State Key Laboratory of Agrobiotechnology, China Agricultural UniversityBeijing, China
| | - Jun Fan
- Ministry of Agriculture Key Laboratory of Plant Pathology, College of Plant Protection, China Agricultural UniversityBeijing, China
- *Correspondence: Jun Fan,
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Lee HA, Lee HY, Seo E, Lee J, Kim SB, Oh S, Choi E, Choi E, Lee SE, Choi D. Current Understandings of Plant Nonhost Resistance. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:5-15. [PMID: 27925500 DOI: 10.1094/mpmi-10-16-0213-cr] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nonhost resistance, a resistance of plant species against all nonadapted pathogens, is considered the most durable and efficient immune system of plants but yet remains elusive. The underlying mechanism of nonhost resistance has been investigated at multiple levels of plant defense for several decades. In this review, we have comprehensively surveyed the latest literature on nonhost resistance in terms of preinvasion, metabolic defense, pattern-triggered immunity, effector-triggered immunity, defense signaling, and possible application in crop protection. Overall, we summarize the current understanding of nonhost resistance mechanisms. Pre- and postinvasion is not much deviated from the knowledge on host resistance, except for a few specific cases. Further insights on the roles of the pattern recognition receptor gene family, multiple interactions between effectors from nonadapted pathogen and plant factors, and plant secondary metabolites in host range determination could expand our knowledge on nonhost resistance and provide efficient tools for future crop protection using combinational biotechnology approaches. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- Hyun-Ah Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Hye-Young Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Eunyoung Seo
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Joohyun Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Saet-Byul Kim
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Soohyun Oh
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Eunbi Choi
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Eunhye Choi
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - So Eui Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Doil Choi
- Department of Plant Science, Plant Genomics and Breeding Institute, College of Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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Helft L, Thompson M, Bent AF. Directed Evolution of FLS2 towards Novel Flagellin Peptide Recognition. PLoS One 2016; 11:e0157155. [PMID: 27270917 PMCID: PMC4894583 DOI: 10.1371/journal.pone.0157155] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 05/25/2016] [Indexed: 12/20/2022] Open
Abstract
Microbe-associated molecular patterns (MAMPs) are molecules, or domains within molecules, that are conserved across microbial taxa and can be recognized by a plant or animal immune system. Although MAMP receptors have evolved to recognize conserved epitopes, the MAMPs in some microbial species or strains have diverged sufficiently to render them unrecognizable by some host immune systems. In this study, we carried out in vitro evolution of the Arabidopsis thaliana flagellin receptor FLAGELLIN-SENSING 2 (FLS2) to isolate derivatives that recognize one or more flagellin peptides from bacteria for which the wild-type Arabidopsis FLS2 confers little or no response. A targeted approach generated amino acid variation at FLS2 residues in a region previously implicated in flagellin recognition. The primary screen tested for elevated response to the canonical flagellin peptide from Pseudomonas aeruginosa, flg22. From this pool, we then identified five alleles of FLS2 that confer modest (quantitatively partial) recognition of an Erwinia amylovora flagellin peptide. Use of this Erwinia-based flagellin peptide to stimulate Arabidopsis plants expressing the resulting FLS2 alleles did not lead to a detectable reduction of virulent P. syringae pv. tomato growth. However, combination of two identified mutations into a single allele further increased FLS2-mediated responses to the E. amylovora flagellin peptide. These studies demonstrate the potential to raise the sensitivity of MAMP receptors toward particular targets.
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Affiliation(s)
- Laura Helft
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Cellular and Molecular Biology Program, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Mikayla Thompson
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Andrew F. Bent
- Department of Plant Pathology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- * E-mail:
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French E, Kim BS, Iyer-Pascuzzi AS. Mechanisms of quantitative disease resistance in plants. Semin Cell Dev Biol 2016; 56:201-208. [PMID: 27212254 DOI: 10.1016/j.semcdb.2016.05.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/14/2016] [Accepted: 05/18/2016] [Indexed: 11/29/2022]
Abstract
Quantitative disease resistance (QDR) causes the reduction, but not absence, of disease, and is a major type of disease resistance for many crop species. QDR results in a continuous distribution of disease scores across a segregating population, and is typically due to many genes with small effects. It may also be a source of durable resistance. The past decade has seen significant progress in cloning genes underlying QDR. In this review, we focus on these recently cloned genes and identify new themes of QDR emerging from these studies.
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Affiliation(s)
- Elizabeth French
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, United States
| | - Bong-Suk Kim
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, United States
| | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, United States.
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Pfeilmeier S, Saur IML, Rathjen JP, Zipfel C, Malone JG. High levels of cyclic-di-GMP in plant-associated Pseudomonas correlate with evasion of plant immunity. MOLECULAR PLANT PATHOLOGY 2016; 17:521-31. [PMID: 26202381 PMCID: PMC4982027 DOI: 10.1111/mpp.12297] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The plant innate immune system employs plasma membrane-localized receptors that specifically perceive pathogen/microbe-associated molecular patterns (PAMPs/MAMPs). This induces a defence response called pattern-triggered immunity (PTI) to fend off pathogen attack. Commensal bacteria are also exposed to potential immune recognition and must employ strategies to evade and/or suppress PTI to successfully colonize the plant. During plant infection, the flagellum has an ambiguous role, acting as both a virulence factor and also as a potent immunogen as a result of the recognition of its main building block, flagellin, by the plant pattern recognition receptors (PRRs), including FLAGELLIN SENSING2 (FLS2). Therefore, strict control of flagella synthesis is especially important for plant-associated bacteria. Here, we show that cyclic-di-GMP [bis-(3'-5')-cyclic di-guanosine monophosphate], a central regulator of bacterial lifestyle, is involved in the evasion of PTI. Elevated cyclic-di-GMP levels in the pathogen Pseudomonas syringae pv. tomato (Pto) DC3000, the opportunist P. aeruginosa PAO1 and the commensal P. protegens Pf-5 inhibit flagellin synthesis and help the bacteria to evade FLS2-mediated signalling in Nicotiana benthamiana and Arabidopsis thaliana. Despite this, high cellular cyclic-di-GMP concentrations were shown to drastically reduce the virulence of Pto DC3000 during plant infection. We propose that this is a result of reduced flagellar motility and/or additional pleiotropic effects of cyclic-di-GMP signalling on bacterial behaviour.
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Affiliation(s)
- Sebastian Pfeilmeier
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Isabel Marie-Luise Saur
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - John Paul Rathjen
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Jacob George Malone
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
- University of East Anglia, Norwich, NR4 7TJ, UK
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Dessaux Y, Grandclément C, Faure D. Engineering the Rhizosphere. TRENDS IN PLANT SCIENCE 2016; 21:266-278. [PMID: 26818718 DOI: 10.1016/j.tplants.2016.01.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/14/2015] [Accepted: 01/04/2016] [Indexed: 05/25/2023]
Abstract
All components of the rhizosphere can be engineered to promote plant health and growth, two features that strongly depend upon the interactions of living organisms with their environment. This review describes the progress in plant and microbial molecular genetics and ecology that has led to a wealth of potential applications. Recent efforts especially deal with the plant defense machinery that is instrumental in engineering plant resistance to biotic stresses. Another approach involves microbial population engineering rather than single strain engineering. More generally, the plants (and the associated microbes) are no longer seen as 'individual' but rather as a holobiont, in other words a unit of selection in evolution, a concept that holds great promise for future plant breeding programs.
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Affiliation(s)
- Yves Dessaux
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
| | - Catherine Grandclément
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France
| | - Denis Faure
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l'Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France
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Shi Q, Febres VJ, Jones JB, Moore GA. A survey of FLS2 genes from multiple citrus species identifies candidates for enhancing disease resistance to Xanthomonas citri ssp. citri. HORTICULTURE RESEARCH 2016; 3:16022. [PMID: 27222722 PMCID: PMC4863249 DOI: 10.1038/hortres.2016.22] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/03/2016] [Accepted: 04/05/2016] [Indexed: 05/20/2023]
Abstract
Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from 'Duncan' grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2-2) and 'Sun Chu Sha' mandarin (C. reticulata, CrFLS2-1 and CrFLS2-2). We were able to isolate only one FLS2 from 'Nagami' kumquat (Fortunella margarita, FmFLS2-1) and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome. Phylogenetic analysis, gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus. FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1, with induced expression levels higher in canker-resistant citrus than in susceptible ones. Interestingly, 'Nagami' kumquat showed the highest FLS2-1 steady-state expression levels, although it was not induced by Xflg22. We selected FmFLS2-1, CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays. Both FmFLS2-1 and CrFLS2-2, the two proteins from canker-resistant species, conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype. These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types.
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Affiliation(s)
- Qingchun Shi
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Vicente J Febres
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA
| | - Jeffrey B Jones
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA
| | - Gloria A Moore
- Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32611, USA
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Shi Q, Febres VJ, Jones JB, Moore GA. Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker. MOLECULAR PLANT PATHOLOGY 2015; 16:507-20. [PMID: 25231217 PMCID: PMC6638359 DOI: 10.1111/mpp.12206] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker.
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Affiliation(s)
- Qingchun Shi
- Horticultural Sciences Department, University of Florida, P.O. Box 110690, Gainesville, FL, 32611, USA
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Kadota Y, Sklenar J, Derbyshire P, Stransfeld L, Asai S, Ntoukakis V, Jones JD, Shirasu K, Menke F, Jones A, Zipfel C. Direct regulation of the NADPH oxidase RBOHD by the PRR-associated kinase BIK1 during plant immunity. Mol Cell 2014; 54:43-55. [PMID: 24630626 DOI: 10.1016/j.molcel.2014.02.021] [Citation(s) in RCA: 566] [Impact Index Per Article: 56.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 01/15/2014] [Accepted: 02/20/2014] [Indexed: 01/09/2023]
Abstract
The rapid production of reactive oxygen species (ROS) burst is a conserved signaling output in immunity across kingdoms. In plants, perception of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern recognition receptors (PRRs) activates the NADPH oxidase RBOHD by hitherto unknown mechanisms. Here, we show that RBOHD exists in complex with the receptor kinases EFR and FLS2, which are the PRRs for bacterial EF-Tu and flagellin, respectively. The plasma-membrane-associated kinase BIK1, which is a direct substrate of the PRR complex, directly interacts with and phosphorylates RBOHD upon PAMP perception. BIK1 phosphorylates different residues than calcium-dependent protein kinases, and both PAMP-induced BIK1 activation and BIK1-mediated phosphorylation of RBOHD are calcium independent. Importantly, phosphorylation of these residues is critical for the PAMP-induced ROS burst and antibacterial immunity. Our study reveals a rapid regulatory mechanism of a plant RBOH, which occurs in parallel with and is essential for its paradigmatic calcium-based regulation.
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Affiliation(s)
- Yasuhiro Kadota
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK; RIKEN Center for Sustainable Resource Science, Plant Immunity Research Group, Suehiro-cho 1-7-22 Tsurumi-ku, Yokohama 230-0045, Japan
| | - Jan Sklenar
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Paul Derbyshire
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Lena Stransfeld
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Shuta Asai
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK; RIKEN Center for Sustainable Resource Science, Plant Immunity Research Group, Suehiro-cho 1-7-22 Tsurumi-ku, Yokohama 230-0045, Japan
| | - Vardis Ntoukakis
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Jonathan Dg Jones
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, Plant Immunity Research Group, Suehiro-cho 1-7-22 Tsurumi-ku, Yokohama 230-0045, Japan
| | - Frank Menke
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Alexandra Jones
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK.
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Trdá L, Fernandez O, Boutrot F, Héloir MC, Kelloniemi J, Daire X, Adrian M, Clément C, Zipfel C, Dorey S, Poinssot B. The grapevine flagellin receptor VvFLS2 differentially recognizes flagellin-derived epitopes from the endophytic growth-promoting bacterium Burkholderia phytofirmans and plant pathogenic bacteria. THE NEW PHYTOLOGIST 2014; 201:1371-1384. [PMID: 24491115 DOI: 10.1111/nph.12592] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 10/06/2013] [Indexed: 05/21/2023]
Abstract
• The role of flagellin perception in the context of plant beneficial bacteria still remains unclear. Here, we characterized the flagellin sensing system flg22-FLAGELLIN SENSING 2 (FLS2) in grapevine, and analyzed the flagellin perception in the interaction with the endophytic plant growth-promoting rhizobacterium (PGPR) Burkholderia phytofirmans. • The functionality of the grapevine FLS2 receptor, VvFLS2, was demonstrated by complementation assays in the Arabidopsis thaliana fls2 mutant, which restored flg22-induced H₂O₂ production and growth inhibition. Using synthetic flg22 peptides from different bacterial origins, we compared recognition specificities between VvFLS2 and AtFLS2. • In grapevine, flg22-triggered immune responses are conserved and led to partial resistance against Botrytis cinerea. Unlike flg22 peptides derived from Pseudomonas aeruginosa or Xanthomonas campestris, flg22 peptide derived from B. phytofirmans triggered only a small oxidative burst, weak and transient defense gene induction and no growth inhibition in grapevine. Although, in Arabidopsis, all the flg22 epitopes exhibited similar biological activities, the expression of VvFLS2 into the fls2 background conferred differential flg22 responses characteristic for grapevine. • These results demonstrate that VvFLS2 differentially recognizes flg22 from different bacteria, and suggest that flagellin from the beneficial PGPR B. phytofirmans has evolved to evade this grapevine immune recognition system.
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Affiliation(s)
- Lucie Trdá
- Université de Bourgogne, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
| | - Olivier Fernandez
- Laboratoire Stress, Défenses et Reproduction des Plantes, URVVC EA 4707, Université de Reims Champagne-Ardenne, Campus Moulin de la Housse Chemin des Rouliers, 51687, Reims, France
| | - Freddy Boutrot
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Marie-Claire Héloir
- Université de Bourgogne, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
| | - Jani Kelloniemi
- Université de Bourgogne, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
| | - Xavier Daire
- INRA, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
| | - Marielle Adrian
- Université de Bourgogne, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
| | - Christophe Clément
- Laboratoire Stress, Défenses et Reproduction des Plantes, URVVC EA 4707, Université de Reims Champagne-Ardenne, Campus Moulin de la Housse Chemin des Rouliers, 51687, Reims, France
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Stéphan Dorey
- Laboratoire Stress, Défenses et Reproduction des Plantes, URVVC EA 4707, Université de Reims Champagne-Ardenne, Campus Moulin de la Housse Chemin des Rouliers, 51687, Reims, France
| | - Benoit Poinssot
- Université de Bourgogne, UMR 1347 Agroécologie, Pôle Interactions Plantes Micro-organismes - ERL CNRS 6300, 17 rue Sully, 21000, Dijon, France
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Rant JC, Arraiano LS, Chabannes M, Brown JKM. Quantitative trait loci for partial resistance to Pseudomonas syringae pv. maculicola in Arabidopsis thaliana. MOLECULAR PLANT PATHOLOGY 2013; 14:828-37. [PMID: 23724899 PMCID: PMC3902988 DOI: 10.1111/mpp.12043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Segregation of partial resistance to Pseudomonas syringae pv. maculicola (Psm) ES4326 was studied in the recombinant inbred population created from accessions (ecotypes) Columbia (Col-4), the more susceptible parent, and Landsberg (Ler-0). Plants were spray inoculated with lux-transformed bacteria in experiments to measure susceptibility. The amount of disease produced on a range of Col × Ler lines by spray inoculation was highly correlated with that produced by pressure infiltration of bacteria into the apoplast. Quantitative trait locus (QTL) analysis identified four loci that contributed to partial resistance: QRpsJIC-1.1, QRpsJIC-2.1, QRpsJIC-3.1 and QRpsJIC-5.1 on chromosomes 1, 2, 3 and 5, respectively. QRpsJIC-3.1, located 8.45 cM from the top of the consensus genetic map of chromosome 3, had a large, approximately additive effect on partial resistance, explaining 50% of the genetic variation in this population. Fine mapping narrowed the region within which this QTL was located to 62 genes. A list of candidate genes included several major classes of resistance gene.
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Wang L, Fobert PR. Arabidopsis clade I TGA factors regulate apoplastic defences against the bacterial pathogen Pseudomonas syringae through endoplasmic reticulum-based processes. PLoS One 2013; 8:e77378. [PMID: 24086773 PMCID: PMC3785447 DOI: 10.1371/journal.pone.0077378] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 09/10/2013] [Indexed: 11/26/2022] Open
Abstract
During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae. Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), following elicitation with salicylic acid (SA), clade I function was shown to be largely independent of NPR1. Unlike mutants in NPR1, tga1-1 tga4-1 plants do not display reductions in steady-state levels of SA-pathway marker genes following treatment with this phenolic signaling metabolite or after challenge with virulent or avirulent P. syringae. By exploiting bacterial strains that have limited capacity to suppress Arabidopsis defence responses, the present study demonstrates that tga1-1 tga4-1 plants are compromised in basal resistance and defective in several apoplastic defence responses, including the oxidative burst of reactive oxygen species, callose deposition, as well as total and apoplastic PATHOGENESIS-RELATED 1 (PR-1) protein accumulation. Furthermore, analysis of npr1-1 and the tga1-1 tga4-1 npr1-1 triple mutant indicates that clade I TGA factors act substantially independent of NPR1 in mediating disease resistance against these strains of P. syringae. Increased sensitivity to the N-glycosylation inhibitor tunicamycin and elevated levels of endoplasmic reticulum (ER) stress marker genes encoding ER-resident chaperones in mutant seedlings suggest that loss of apoplastic defence responses is associated with aberrant protein secretion and implicate clade I TGA factors as positive regulators of one or more ER-related secretion pathways.
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Affiliation(s)
- Lipu Wang
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada ; National Research Council Canada, Saskatoon, Saskatchewan, Canada
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Wei HL, Chakravarthy S, Worley JN, Collmer A. Consequences of flagellin export through the type III secretion system of Pseudomonas syringae reveal a major difference in the innate immune systems of mammals and the model plant Nicotiana benthamiana. Cell Microbiol 2013; 15:601-18. [PMID: 23107228 DOI: 10.1111/cmi.12059] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/28/2012] [Accepted: 10/16/2012] [Indexed: 02/02/2023]
Abstract
Bacterial flagellin is perceived as a microbe (or pathogen)-associated molecular pattern (MAMP or PAMP) by the extracellular pattern recognition receptors, FLS2 and TLR5, of plants and mammals respectively. Flagellin accidently translocated into mammalian cells by pathogen type III secretion systems (T3SSs) is recognized by nucleotide-binding leucine-rich repeat receptor NLRC4 as a pattern of pathogenesis and induces a death-associated immune response. The non-pathogen Pseudomonas fluorescens Pf0-1, expressing a Pseudomonas syringae T3SS, and the plant pathogen P. syringae pv. tomato DC3000 were used to seek evidence of an analogous cytoplasmic recognition system for flagellin in the model plant Nicotiana benthamiana. Flagellin (FliC) was secreted in culture and translocated into plant cells by the T3SS expressed in Pf0-1 and DC3000 and in their ΔflgGHI flagellar pathway mutants. ΔfliC and ΔflgGHI mutants of Pf0-1 and DC3000 were strongly reduced in elicitation of reactive oxygen species production and in immunity induction as indicated by the ability of challenge bacteria inoculated 6 h later to translocate a type III effector-reporter and to elicit effector-triggered cell death. Agrobacterium-mediated transient expression in N. benthamiana of FliC with or without a eukaryotic export signal peptide, coupled with virus-induced gene silencing of FLS2, revealed no immune response that was not FLS2 dependent. Transiently expressed FliC from DC3000 and Pectobacterium carotovorum did notinduce cell death in N. benthamiana, tobacco or tomato leaves. Flagellin is the major Pseudomonas MAMP perceived by N. benthamiana, and although flagellin secretion through the plant cell wall by the T3SS may partially contribute to FLS2-dependent immunity, flagellin in the cytosol does not elicit immune-associated cell death. We postulate that a death response to translocated MAMPs would produce vulnerability to the many necrotrophic pathogens of plants, such as P. carotovorum, which differ from P. syringae and other (hemi)biotrophic pathogens in benefitting from death-associated immune responses.
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Affiliation(s)
- Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, 14853, USA
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Senthil-Kumar M, Mysore KS. Nonhost resistance against bacterial pathogens: retrospectives and prospects. ANNUAL REVIEW OF PHYTOPATHOLOGY 2013; 51:407-27. [PMID: 23725473 DOI: 10.1146/annurev-phyto-082712-102319] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Nonhost resistance is a broad-spectrum plant defense that provides immunity to all members of a plant species against all isolates of a microorganism that is pathogenic to other plant species. Upon landing on the surface of a nonhost plant species, a potential bacterial pathogen initially encounters preformed and, later, induced plant defenses. One of the initial defense responses from the plant is pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). Nonhost plants also have mechanisms to detect nonhost-pathogen effectors and can trigger a defense response referred to as effector-triggered immunity (ETI). This nonhost resistance response often results in a hypersensitive response (HR) at the infection site. This review provides an overview of these plant defense strategies. We enumerate plant genes that impart nonhost resistance and the bacterial counter-defense strategies. In addition, prospects for application of nonhost resistance to achieve broad-spectrum and durable resistance in crop plants are also discussed.
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Affiliation(s)
- Muthappa Senthil-Kumar
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73402, USA.
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Leba LJ, Cheval C, Ortiz-Martín I, Ranty B, Beuzón CR, Galaud JP, Aldon D. CML9, an Arabidopsis calmodulin-like protein, contributes to plant innate immunity through a flagellin-dependent signalling pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 71:976-89. [PMID: 22563930 DOI: 10.1111/j.1365-313x.2012.05045.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Many stimuli such as hormones and elicitors induce changes in intracellular calcium levels to integrate information and activate appropriate responses. The Ca(2+) signals are perceived by various Ca(2+) sensors, and calmodulin (CaM) is one of the best characterized in eukaryotes. Calmodulin-like (CML) proteins extend the Ca(2+) toolkit in plants; they share sequence similarity with the ubiquitous and highly conserved CaM but their roles at physiological and molecular levels are largely unknown. Knowledge of the contribution of Ca(2+) decoding proteins to plant immunity is emerging, and we report here data on Arabidopsis thaliana CML9, whose expression is rapidly induced by phytopathogenic bacteria, flagellin and salicylic acid. Using a reverse genetic approach, we present evidence that CML9 is involved in plant defence by modulating responses to bacterial strains of Pseudomonas syringae. Compared to wild-type plants, the later responses normally observed upon flagellin application are altered in knockout mutants and over-expressing transgenic lines. Collectively, using PAMP treatment and P. syringae strains, we have established that CML9 participates in plant innate immunity.
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Affiliation(s)
- Louis-Jérôme Leba
- Université de Toulouse, Université de Toulouse, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan Cedex, France
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Fan J, Doerner P. Genetic and molecular basis of nonhost disease resistance: complex, yes; silver bullet, no. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:400-6. [PMID: 22445191 DOI: 10.1016/j.pbi.2012.03.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 02/24/2012] [Accepted: 03/01/2012] [Indexed: 05/20/2023]
Abstract
Nonhost resistance (NHR), in which a successful pathogen on some plants fails to overcome host barriers on others, has attracted much attention owing to its potential for robust crop improvement. Recent advances reveal that a multitude of underlying mechanisms contribute to NHR, ranging from components shared with recognition-based defenses up to recessive susceptibility factors involved in plant primary metabolism. Most NHR appears multi-factorial and quantitative. This implies that there is no single, 'silver bullet' NHR mechanism that can be used to broadly restrict pathogens in many or all crops.
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Affiliation(s)
- Jun Fan
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China.
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Vetter MM, Kronholm I, He F, Häweker H, Reymond M, Bergelson J, Robatzek S, de Meaux J. Flagellin perception varies quantitatively in Arabidopsis thaliana and its relatives. Mol Biol Evol 2012; 29:1655-67. [PMID: 22319159 DOI: 10.1093/molbev/mss011] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Much is known about the evolution of plant immunity components directed against specific pathogen strains: They show pervasive functional variation and have the potential to coevolve with pathogen populations. However, plants are effectively protected against most microbes by generalist immunity components that detect conserved pathogen-associated molecular patterns (PAMPs) and control the onset of PAMP-triggered immunity. In Arabidopsis thaliana, the receptor kinase flagellin sensing 2 (FLS2) confers recognition of bacterial flagellin (flg22) and activates a manifold defense response. To decipher the evolution of this system, we performed functional assays across a large set of A. thaliana genotypes and Brassicaceae relatives. We reveal extensive variation in flg22 perception, most of which results from changes in protein abundance. The observed variation correlates with both the severity of elicited defense responses and bacterial proliferation. We analyzed nucleotide variation segregating at FLS2 in A. thaliana and detected a pattern of variation suggestive of the rapid fixation of a novel adaptive allele. However, our study also shows that evolution at the receptor locus alone does not explain the evolution of flagellin perception; instead, components common to pathways downstream of PAMP perception likely contribute to the observed quantitative variation. Within and among close relatives, PAMP perception evolves quantitatively, which contrasts with the changes in recognition typically associated with the evolution of R genes.
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Affiliation(s)
- M Madlen Vetter
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
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Valdés-López O, Thibivilliers S, Qiu J, Xu WW, Nguyen TH, Libault M, Le BH, Goldberg RB, Hill CB, Hartman GL, Diers B, Stacey G. Identification of quantitative trait loci controlling gene expression during the innate immunity response of soybean. PLANT PHYSIOLOGY 2011; 157:1975-86. [PMID: 21963820 PMCID: PMC3327182 DOI: 10.1104/pp.111.183327] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/29/2011] [Indexed: 05/21/2023]
Abstract
Microbe-associated molecular pattern-triggered immunity (MTI) is an important component of the plant innate immunity response to invading pathogens. However, most of our knowledge of MTI comes from studies of model systems with relatively little work done with crop plants. In this work, we report on variation in both the microbe-associated molecular pattern-triggered oxidative burst and gene expression across four soybean (Glycine max) genotypes. Variation in MTI correlated with the level of pathogen resistance for each genotype. A quantitative trait locus analysis on these traits identified four loci that appeared to regulate gene expression during MTI in soybean. Likewise, we observed that both MTI variation and pathogen resistance were quantitatively inherited. The approach utilized in this study may have utility for identifying key resistance loci useful for developing improved soybean cultivars.
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Affiliation(s)
- Oswaldo Valdés-López
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Sandra Thibivilliers
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Jing Qiu
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Wayne Wenzhong Xu
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Tran H.N. Nguyen
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | | | - Brandon H. Le
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Robert B. Goldberg
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Curtis B. Hill
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Glen L. Hartman
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Brian Diers
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
| | - Gary Stacey
- Department of Statistics (J.Q.) and Divisions of Biochemistry and Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center (O.V.-L., S.T., T.H.N.N., M.L., G.S.), University of Missouri, Columbia, Missouri 65211; Minnesota Supercomputing Institute for Advanced Computational Research, University of Minnesota, Minneapolis, Minnesota 55455 (W.W.X.); Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (B.H.L., R.B.G.); United States Department of Agriculture-Agricultural Research Service (G.L.H.) and Department of Crop Sciences (C.B.H., G.L.H., B.D.), University of Illinois, Urbana, Illinois 61801
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Sun W, Liu L, Bent AF. Type III secretion-dependent host defence elicitation and type III secretion-independent growth within leaves by Xanthomonas campestris pv. campestris. MOLECULAR PLANT PATHOLOGY 2011; 12:731-45. [PMID: 21726374 PMCID: PMC6640278 DOI: 10.1111/j.1364-3703.2011.00707.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In many plant-bacterial interactions, loss of the type III secretion system (T3SS) severely reduces bacterial growth, symptom causation and suppression of defences in host plants. In the present study of Xanthomonas campestris pv. campestris (Xcc), Xcc strain B305 grew better than strain B186 in Arabidopsis thaliana after hydathode inoculation, and B305 strains mutated to the loss of T3SS (ΔhrcC and/or ΔhrpE; also ΔhrcCΔflgBC) grew similarly to wild-type B305 in Arabidopsis leaves. Unlike Xcc strain B186, wild-type B305 was relatively inefficient in secreting the exogenous T3S effector AvrBsT, but ΔhrcC and/or ΔhrpE attenuated the disease symptoms caused by Xcc B305, showing that the partially compromised T3SS of this strain still promotes necrotic leaf symptoms. In contrast with the T3SS-dependent defence suppression that has been observed for some other plant pathogenic bacteria, the Xcc B186 and B305 wild-type strains (which are virulent on Arabidopsis) caused greater elicitation of host PR-1 and PR-5 expression and callose deposition in comparison with their respective T3SS mutants. A defence-suppressing/virulence-enhancing activity of the Xcc T3SS effector suite was detectable when co-inoculation with wild-type Xcc B186 increased the growth of ΔhrcC Xcc, but this activity did not prevent the above defence elicitation. Experiments using T3SS mutants and Arabidopsis fls2 mutants suggested that FLS2 does not play a prominent role in restriction of the examined Xcc strains. However, ectopic overexpression of the Pseudomonas syringae effector AvrPto promoted in planta growth of wild-type and ΔhrcC Xcc. In summary, the T3SS components or effector suite from virulent Xcc strains elicit some host defence responses, but suppress other defences and stimulate more severe disease symptoms, AvrPto-disruptable elements other than FLS2 apparently contribute to the host restriction of Xcc, and in some virulent Xcc strains the T3SS is not absolutely required for wild-type levels of bacterial growth within the plant.
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Affiliation(s)
- Wenxian Sun
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
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Arnold DL, Lovell HC, Jackson RW, Mansfield JW. Pseudomonas syringae pv. phaseolicola: from 'has bean' to supermodel. MOLECULAR PLANT PATHOLOGY 2011; 12:617-27. [PMID: 21726364 PMCID: PMC6640400 DOI: 10.1111/j.1364-3703.2010.00697.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
UNLABELLED Pseudomonas syringae pv. phaseolicola causes halo blight of the common bean, Phaseolus vulgaris, worldwide and remains difficult to control. Races of the pathogen cause either disease symptoms or a resistant hypersensitive response on a series of differentially reacting bean cultivars. The molecular genetics of the interaction between P. syringae pv. phaseolicola and bean, and the evolution of bacterial virulence, have been investigated in depth and this research has led to important discoveries in the field of plant-microbe interactions. In this review, we discuss several of the areas of study that chart the rise of P. syringae pv. phaseolicola from a common pathogen of bean plants to a molecular plant-pathogen supermodel bacterium. TAXONOMY Bacteria; Proteobacteria, gamma subdivision; order Pseudomonadales; family Pseudomonadaceae; genus Pseudomonas; species Pseudomonas syringae; Genomospecies 2; pathogenic variety phaseolicola. MICROBIOLOGICAL PROPERTIES Gram-negative, aerobic, motile, rod-shaped, 1.5 µm long, 0.7-1.2 µm in diameter, at least one polar flagellum, optimal temperatures for growth of 25-30°C, oxidase negative, arginine dihydrolase negative, levan positive and elicits the hypersensitive response on tobacco. HOST RANGE Major bacterial disease of common bean (Phaseolus vulgaris) in temperate regions and above medium altitudes in the tropics. Natural infections have been recorded on several other legume species, including all members of the tribe Phaseoleae with the exception of Desmodium spp. and Pisum sativum. DISEASE SYMPTOMS Water-soaked lesions on leaves, pods, stems or petioles, that quickly develop greenish-yellow haloes on leaves at temperatures of less than 23°C. Infected seeds may be symptomless, or have wrinkled or buttery-yellow patches on the seed coat. Seedling infection is recognized by general chlorosis, stunting and distortion of growth. EPIDEMIOLOGY Seed borne and disseminated from exudation by water-splash and wind occurring during rainfall. Bacteria invade through wounds and natural openings (notably stomata). Weedy and cultivated alternative hosts may also harbour the bacterium. DISEASE CONTROL Some measure of control is achieved with copper formulations and streptomycin. Pathogen-free seed and resistant cultivars are recommended. USEFUL WEBSITES Pseudomonas-plant interaction http://www.pseudomonas-syringae.org/; PseudoDB http://xbase.bham.ac.uk/pseudodb/; Plant Associated and Environmental Microbes Database (PAMDB) http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; PseudoMLSA Database http://www.uib.es/microbiologiaBD/Welcome.html.
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Affiliation(s)
- Dawn L Arnold
- Centre for Research in Plant Science, University of the West of England, Bristol BS16 1QY, UK.
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LRR conservation mapping to predict functional sites within protein leucine-rich repeat domains. PLoS One 2011; 6:e21614. [PMID: 21789174 PMCID: PMC3138743 DOI: 10.1371/journal.pone.0021614] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 06/03/2011] [Indexed: 11/19/2022] Open
Abstract
Computational prediction of protein functional sites can be a critical first step for analysis of large or complex proteins. Contemporary methods often require several homologous sequences and/or a known protein structure, but these resources are not available for many proteins. Leucine-rich repeats (LRRs) are ligand interaction domains found in numerous proteins across all taxonomic kingdoms, including immune system receptors in plants and animals. We devised Repeat Conservation Mapping (RCM), a computational method that predicts functional sites of LRR domains. RCM utilizes two or more homologous sequences and a generic representation of the LRR structure to identify conserved or diversified patches of amino acids on the predicted surface of the LRR. RCM was validated using solved LRR+ligand structures from multiple taxa, identifying ligand interaction sites. RCM was then used for de novo dissection of two plant microbe-associated molecular pattern (MAMP) receptors, EF-TU RECEPTOR (EFR) and FLAGELLIN-SENSING 2 (FLS2). In vivo testing of Arabidopsis thaliana EFR and FLS2 receptors mutagenized at sites identified by RCM demonstrated previously unknown functional sites. The RCM predictions for EFR, FLS2 and a third plant LRR protein, PGIP, compared favorably to predictions from ODA (optimal docking area), Consurf, and PAML (positive selection) analyses, but RCM also made valid functional site predictions not available from these other bioinformatic approaches. RCM analyses can be conducted with any LRR-containing proteins at www.plantpath.wisc.edu/RCM, and the approach should be modifiable for use with other types of repeat protein domains.
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Ahmad S, Van Hulten M, Martin J, Pieterse CMJ, Van Wees SCM, Ton J. Genetic dissection of basal defence responsiveness in accessions of Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2011; 34:1191-206. [PMID: 21414016 DOI: 10.1111/j.1365-3040.2011.02317.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Basal resistance involves a multitude of pathogen- and herbivore-inducible defence mechanisms, ranging from localized callose deposition to systemic defence gene induction by salicylic acid (SA) and jasmonic acid (JA). In this study, we have explored and dissected genetic variation in the responsiveness of basal defence mechanisms within a selection of Arabidopsis accessions. Responsiveness of JA-induced PDF1.2 gene expression was associated with enhanced basal resistance against the necrotrophic fungus Plectosphaerella cucumerina and the herbivore Spodoptera littoralis. Conversely, accessions showing augmented PR-1 induction upon SA treatment were more resistant to the hemi-biotrophic pathogen Pseudomonas syringae, and constitutively expressed defence-related transcription factor (TF) genes. Unexpectedly, accessions with primed responsiveness to SA deposited comparatively little callose after treatment with microbe-associated molecular patterns. A quantitative trait locus (QTL) analysis identified two loci regulating flagellin-induced callose and one locus regulating SA-induced PR-1 expression. The latter QTL was found to contribute to basal resistance against P. syringae. None of the defence regulatory QTLs influenced plant growth, suggesting that the constitutive defence priming conferred by these loci is not associated with major costs on plant growth. Our study demonstrates that natural variation in basal resistance can be exploited to identify genetic loci that prime the plant's basal defence arsenal.
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Affiliation(s)
- Shakoor Ahmad
- Rothamsted Research, Centre of Sustainable Pest and Disease Management, West Common, Harpenden, Herts, UK
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Hirai H, Takai R, Iwano M, Nakai M, Kondo M, Takayama S, Isogai A, Che FS. Glycosylation regulates specific induction of rice immune responses by Acidovorax avenae flagellin. J Biol Chem 2011; 286:25519-30. [PMID: 21628471 DOI: 10.1074/jbc.m111.254029] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Plants have a sensitive system that detects various pathogen-derived molecules to protect against infection. Flagellin, a main component of the bacterial flagellum, from the rice avirulent N1141 strain of the Gram-negative phytopathogenic bacterium Acidovorax avenae induces plant immune responses including H₂O generation, whereas flagellin from the rice virulent K1 strain of A. avenae does not induce these immune responses. To clarify the molecular mechanism that leads to these differing responses between the K1 and N1141 flagellins, recombinant K1 and N1141 flagellins were generated using an Escherichia coli expression system. When cultured rice cells were treated with recombinant K1 or N1141 flagellin, both flagellins equally induced H₂O₂ generation, suggesting that post-translational modifications of the flagellins are involved in the specific induction of immune responses. Mass spectrometry analyses using glycosyltransferase-deficient mutants showed that 1,600- and 2,150-Da glycans were present on the flagellins from N1141 and K1, respectively. A deglycosylated K1 flagellin induced immune responses in the same manner as N1141 flagellin. Site-directed mutagenesis revealed that glycans were attached to four amino acid residues (Ser¹⁷⁸, Ser¹⁸³, Ser²¹², and Thr³⁵¹) in K1 flagellin. Among mutant K1 flagellins in which each glycan-attached amino acid residue was changed to alanine, S178A and S183A, K1 flagellin induced a strong immune response in cultured rice cells, indicating that the glycans at Ser¹⁷⁸ and Ser¹⁸³ in K1 flagellin prevent epitope recognition in rice.
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Affiliation(s)
- Hiroyuki Hirai
- Graduate School of Bio-Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
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Lipscomb L, Schell MA. Elucidation of the regulon and cis-acting regulatory element of HrpB, the AraC-type regulator of a plant pathogen-like type III secretion system in Burkholderia pseudomallei. J Bacteriol 2011; 193:1991-2001. [PMID: 21335458 PMCID: PMC3133045 DOI: 10.1128/jb.01379-10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 02/04/2011] [Indexed: 12/17/2022] Open
Abstract
The human pathogen Burkholderia pseudomallei possesses multiple type III secretion system (T3SS) gene clusters. One of these, the B. pseudomallei T3SS2 (T3SS2(bp)) gene cluster, which apparently plays no role in animal virulence, is also found in six additional Burkholderia spp. and is very similar to T3SSs found in phytopathogenic Xanthomonas spp. and Ralstonia solanacearum. The T3SS2(bp) gene cluster also encodes an AraC-type regulatory protein (HrpB(bp)) that is an ortholog of HrpB, the master regulator of the R. solanacearum T3SS (T3SS(rso)) and its secreted effectors. Transcriptome analysis showed that HrpB(bp) activates the expression of T3SS2(bp) genes, as well as their orthologs in R. solanacearum. In addition to activating T3SS2(bp), HrpB(bp) also upregulates the expression of ~30 additional B. pseudomallei genes, including some that may confer production of adhesive pili, a polyketide toxin, several putative T3SS2(bp)-secreted effectors, and components of a regulatory cascade. T3SS2(bp) promoter regions were found to contain a conserved DNA motif (p2(bp) box) identical in sequence and position to the hrp(II) box required for HrpB-dependent T3SS(rso) transcription activation. The p2(bp) box is also present in the promoter regions of the essentially identical T3SS found in the very closely related species Burkholderia thailandensis (T3SS2(bt)). Analysis of p2(bp) box mutants showed that it is essential for HrpB(bp)-mediated transcription activation in both species. Although it has been suggested that T3SS2(bp) and T3SS2(bt) may function in phytopathogenicity, we were unable to demonstrate a phytopathogenic phenotype for B. thailandensis in three different plant hosts.
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Affiliation(s)
- Lyla Lipscomb
- Department of Microbiology, University of Georgia, Athens, Georgia 30602
| | - Mark A. Schell
- Department of Microbiology, University of Georgia, Athens, Georgia 30602
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Activation of plant pattern-recognition receptors by bacteria. Curr Opin Microbiol 2011; 14:54-61. [PMID: 21215683 DOI: 10.1016/j.mib.2010.12.005] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/13/2010] [Accepted: 12/14/2010] [Indexed: 12/22/2022]
Abstract
The first active layer of plant innate immunity relies on the recognition by surface receptors of molecules indicative of non-self or modified-self. The activation of pattern-recognition receptors (PRRs) by pathogen-associated molecular patterns (PAMPs) is in essence sufficient to stop pathogen invasion through transcriptional reprogramming and production of anti-microbials. The few PRR/PAMP pairs that are characterised provide useful models to study the specificity of ligand-binding and likely activation mechanisms. Both classical and new approaches are still required to identify new bacterial PAMPs. Current genetic screens, functional genomics and biochemical analyses have identified the regulation mechanisms of PRR transcription and biogenesis, provided insights into the composition of PRR complexes at the plasma membrane and highlighted the roles of long-known signalling components in PAMP-triggered immunity (PTI).
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