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Clarke CR, Hayes BW, Runde BJ, Markel E, Swingle BM, Vinatzer BA. Comparative genomics of Pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity. PeerJ 2016; 4:e2570. [PMID: 27812402 PMCID: PMC5088630 DOI: 10.7717/peerj.2570] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 09/15/2016] [Indexed: 11/20/2022] Open
Abstract
The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, to replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacteria use chemical-directed regulation of flagellar rotation, a process known as chemotaxis, to move towards favorable environmental conditions. Chemotactic sensing of the plant surface is a potential mechanism through which foliar plant pathogens home in on wounds or stomata, but chemotactic systems in foliar plant pathogens are not well characterized. Comparative genomics of the plant pathogen Pseudomonas syringae pathovar tomato (Pto) implicated annotated chemotaxis genes in the recent adaptations of one Pto lineage. We therefore characterized the chemosensory system of Pto. The Pto genome contains two primary chemotaxis gene clusters, che1 and che2. The che2 cluster is flanked by flagellar biosynthesis genes and similar to the canonical chemotaxis gene clusters of other bacteria based on sequence and synteny. Disruption of the primary phosphorelay kinase gene of the che2 cluster, cheA2, eliminated all swimming and surface motility at 21 °C but not 28 °C for Pto. The che1 cluster is located next to Type IV pili biosynthesis genes but disruption of cheA1 has no observable effect on twitching motility for Pto. Disruption of cheA2 also alters in planta fitness of the pathogen with strains lacking functional cheA2 being less fit in host plants but more fit in a non-host interaction.
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Affiliation(s)
- Christopher R Clarke
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Byron W Hayes
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Brendan J Runde
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
| | - Eric Markel
- Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, United States Department of Agriculture , Ithaca , NY , USA
| | - Bryan M Swingle
- Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, United States Department of Agriculture, Ithaca, NY, USA; Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell, Ithaca, NY, USA
| | - Boris A Vinatzer
- Plant Pathology, Physiology and Weed Science, Virginia Tech , Blacksburg , VA , USA
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Kraus CM, Munkvold KR, Martin GB. Natural Variation in Tomato Reveals Differences in the Recognition of Avr Pto and AvrPtoB Effectors from Pseudomonas syringae. Mol Plant 2016; 9:639-649. [PMID: 26993968 DOI: 10.1016/j.molp.2016.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 05/13/2023]
Abstract
The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto and AvrPtoB-Pto complexes revealed that Pto binds each effector through both a shared and a unique interface. Here we use natural variation in wild species of tomato to further investigate Pto recognition of these two effectors. One species, Solanum chmielewskii, was found to have many accessions that recognize only AvrPtoB. The Pto ortholog from one of these accessions was responsible for recognition of AvrPtoB and it differed from Solanum pimpinellifolium Pto by only 14 amino acids, including two in the AvrPto-specific interface, glutamate-49/glycine-51. Converting these two residues to those in Pto (histidine-49/valine-51) did not restore recognition of AvrPto. Subsequent experiments revealed that a single substitution of a histidine-to-aspartate at position 193 in Pto, which is not near the AvrPto-specific interface, was sufficient for conferring recognition of AvrPto in plant cells. The reciprocal substitution of aspartate-to-histidine-193 in Pto abolished AvrPto recognition, confirming the importance of this residue. Our results reveal new aspects about effector recognition by Pto and demonstrate the value of using natural variation to understand the interaction between resistance proteins and pathogen effectors.
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Affiliation(s)
- Christine M Kraus
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA; Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Kathy R Munkvold
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Gregory B Martin
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA; Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
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Wu CH, Belhaj K, Bozkurt TO, Birk MS, Kamoun S. Helper NLR proteins NRC2a/b and NRC3 but not NRC1 are required for Pto-mediated cell death and resistance in Nicotiana benthamiana. New Phytol 2016; 209:1344-52. [PMID: 26592988 DOI: 10.1111/nph.13764] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Affiliation(s)
- Chih-Hang Wu
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Khaoula Belhaj
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Tolga O Bozkurt
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Marlène S Birk
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Sophien Kamoun
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
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Grzeskowiak L, Stephan W, Rose LE. Epistatic selection and coadaptation in the Prf resistance complex of wild tomato. Infect Genet Evol 2014; 27:456-71. [PMID: 24997333 DOI: 10.1016/j.meegid.2014.06.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/26/2022]
Abstract
Natural selection imposed by pathogens is a strong and pervasive evolutionary force structuring genetic diversity within their hosts' genomes and populations. As a model system for understanding the genomic impact of host-parasite coevolution, we have been studying the evolutionary dynamics of disease resistance genes in wild relatives of the cultivated tomato species. In this study, we investigated the sequence variation and evolutionary history of three linked genes involved in pathogen resistance in populations of Solanum peruvianum (Pto, Fen, and Prf). These genes encode proteins, which form a multimeric complex and together activate defense responses. We used standard linkage disequilibrium, as well as partitioning of linkage disequilibrium components across populations and correlated substitution analysis to identify amino acid positions that are candidates for coevolving sites between Pto/Fen and Prf. These candidates were mapped onto known and predicted structures of Pto, Fen and Prf to visualize putative coevolving regions between proteins. We discuss the functional significance of these coevolving pairs in the context of what is known from previous structure-function studies of Pto, Fen and Prf.
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Affiliation(s)
- Lukasz Grzeskowiak
- Section of Evolutionary Biology, Ludwig Maximilian University Munich, Grosshadernerstr. 2, 82152 Planegg, Germany; Center for Research and Innovation, Fondazione Edmund Mach, Via E. Mach 1, 38010 San Michele all'Adige, Italy
| | - Wolfgang Stephan
- Section of Evolutionary Biology, Ludwig Maximilian University Munich, Grosshadernerstr. 2, 82152 Planegg, Germany
| | - Laura E Rose
- Section of Evolutionary Biology, Ludwig Maximilian University Munich, Grosshadernerstr. 2, 82152 Planegg, Germany; Institute of Population Genetics, Heinrich Heine University Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany.
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Wu T, Tang D, Chen W, Huang H, Wang R, Chen Y. Expression of antimicrobial peptides thanatin(S) in transgenic Arabidopsis enhanced resistance to phytopathogenic fungi and bacteria. Gene 2013; 527:235-42. [PMID: 23820081 DOI: 10.1016/j.gene.2013.06.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 06/08/2013] [Accepted: 06/19/2013] [Indexed: 11/29/2022]
Abstract
Thanatin(S) is an analog of thanatin, an insect antimicrobial peptide possessing strong and broad spectrum of antimicrobial activity. In order to investigate if the thanatin could be used in engineering transgenic plants for increased resistance against phytopathogens, the synthetic thanatin(S) was introduced into Arabidopsis thaliana plants. To increase the expression level of thanatin(S) in plants, the coding sequence was optimized by plant-preference codon. To avoid cellular protease degradation, signal peptide of rice Cht1 was fused to N terminal of thanatin(S) for secreting the expressed thanatin(S) into intercellular spaces. To evaluate the application value of thanatin(S) in plant disease control, the synthesized coding sequence of Cht1 signal peptide (Cht1SP)-thanatin(S) was ligated to plant gateway destination binary vectors pGWB11 (with FLAG tag). Meanwhile, in order to observe the subcellular localization of Cht1SP-thanatin(S)-GFP and thanatin(S)-GFP, the sequences of Cht1SP-thanatin(S) and thanatin(S) were respectively linked to pGWB5 (with GFP tag). The constructs were transformed into Arabidopsis ecotype Col-0 and mutant pad4-1 via Agrobacterium-mediated transformation. The transformants with Cht1SP-thanatin(S)-FLAG fusion gene were analyzed by genomic PCR, real-time PCR, and western blots and the transgenic Arabidopsis plants introduced respectively Cht1SP-thanatin(S)-GFP and thanatin(S)-GFP were observed by confocal microscopy. Transgenic plants expressing Cht1SP-thanatin(S)-FLAG fusion protein showed antifungal activity against Botrytis cinerea and powdery mildew, as well as antibacterial activity against Pseudomonas syringae pv. tomato. And the results from confocal observation showed that the GFP signal from Cht1SP-thanatin(S)-GFP transgenic Arabidopsis plants occurred mainly in intercellular space, while that from thanatin(S)-GFP transgenic plants was mainly detected in the cytoplasm and that from empty vector transgenic plants was distributed uniformly throughout the cell, demonstrating that Cht1 signal peptide functioned. In addition, thanatin(S) and thanatin(S)-FLAG chemically synthesized have both in vitro antimicrobial activities against P. syringae pv. tomato and B. cinerea. So, thanatin(S) is an ideal candidate AMPs for the construction of transgenic crops endowed with a broad-spectrum resistance to phytopathogens and the strategy is feasible to link a signal peptide to the target gene.
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Affiliation(s)
- Tingquan Wu
- Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
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Singh SP, Vivek S, Bezbaruah RL, Barooah M. Prediction of the three-dimensional structure of serine/threonine protein kinase pto of Solanum lycopersicum by homology modelling. Bioinformation 2012; 8:212-5. [PMID: 22493521 PMCID: PMC3314873 DOI: 10.6026/97320630008212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 01/07/2012] [Indexed: 11/29/2022] Open
Abstract
The resistant gene Pto of Solanum lycopersicum interacts with the avr Pto gene product of the bacterial pathogen Pseudomonas syringae pv tomato to launch a cascade of molecular events that triggers the hypersensitive disease-resistance response in tamato. The paper describes attempts to predict the structure of Pto encoding a serine/threonine protein kinase to understand the mechanism and function. A three-dimensional model based on the crystal structure of effect protein Avr ptob complexed with Kinase Pto and bacterial effector protein Avrpto was generated using Modeller9v7. We adopted different modelling approaches for our study, Intialy, we generated a model based on a single template protein and then a model based on multiple templates. The models generated through these approaches were further assessed with ANOLEA energy assessment, Ram Page server and PROCHECK for stereochemistry and geometry check. Comparative analysis suggested that the model generated was better than the templates. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in studying protein-protein interactions.
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Affiliation(s)
- Salam Pradeep Singh
- Bioinformatics Infrastructure Facility, Biotechnology Division, North-East Institute of Science & Technology (CSIR), Jorhat- 785006,
Assam
| | - Sarangthem Vivek
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam
| | - Rajib Lochan Bezbaruah
- Bioinformatics Infrastructure Facility, Biotechnology Division, North-East Institute of Science & Technology (CSIR), Jorhat- 785006,
Assam
| | - Madhumita Barooah
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat, Assam
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