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Mason KN, Ekanayake G, Heese A. Staining and automated image quantification of callose in Arabidopsis cotyledons and leaves. Methods Cell Biol 2021; 160:181-199. [PMID: 32896315 DOI: 10.1016/bs.mcb.2020.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Callose is a β-1,3-glucan polysaccharide that is deposited at discrete sites in the plant cell wall in response to microbial pathogens, likely contributing to protection against pathogen infection. Increased callose deposition also occurs in response to the 22-amino acid peptide flg22, a pathogen-associated molecular pattern (PAMP) derived from bacterial flagellin protein. Here, we provide protocols for callose staining using aniline blue in cotyledon and leaf tissue of the model plant Arabidopsis thaliana. Aniline blue stain utilizes a fluorochrome that complexes with callose for its visualization by microscopy using an ultraviolet (UV) filter. For robust quantification of callose deposits, we outline an automated image analysis workflow utilizing the freely available Fiji (Fiji Is Just ImageJ; NIH) software and a Trainable Weka Segmentation (TWS) plugin. Our methodology for automated analysis of large batches of images can be easily adapted to quantify callose in other tissues and plant species, as well as to quantify fluorescent structures other than callose.
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Affiliation(s)
- Kelly N Mason
- Division of Biochemistry, Interdisciplinary Plant Group (IPG), University of Missouri, Columbia, MO, United States
| | - Gayani Ekanayake
- Division of Biochemistry, Interdisciplinary Plant Group (IPG), University of Missouri, Columbia, MO, United States
| | - Antje Heese
- Division of Biochemistry, Interdisciplinary Plant Group (IPG), University of Missouri, Columbia, MO, United States.
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2
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Naseem M, Osmanoğlu Ö, Kaltdorf M, Alblooshi AAMA, Iqbal J, Howari FM, Srivastava M, Dandekar T. Integrated Framework of the Immune-Defense Transcriptional Signatures in the Arabidopsis Shoot Apical Meristem. Int J Mol Sci 2020; 21:ijms21165745. [PMID: 32796535 PMCID: PMC7460820 DOI: 10.3390/ijms21165745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 11/16/2022] Open
Abstract
The growing tips of plants grow sterile; therefore, disease-free plants can be generated from them. How plants safeguard growing apices from pathogen infection is still a mystery. The shoot apical meristem (SAM) is one of the three stem cells niches that give rise to the above ground plant organs. This is very well explored; however, how signaling networks orchestrate immune responses against pathogen infections in the SAM remains unclear. To reconstruct a transcriptional framework of the differentially expressed genes (DEGs) pertaining to various SAM cellular populations, we acquired large-scale transcriptome datasets from the public repository Gene Expression Omnibus (GEO). We identify here distinct sets of genes for various SAM cellular populations that are enriched in immune functions, such as immune defense, pathogen infection, biotic stress, and response to salicylic acid and jasmonic acid and their biosynthetic pathways in the SAM. We further linked those immune genes to their respective proteins and identify interactions among them by mapping a transcriptome-guided SAM-interactome. Furthermore, we compared stem-cells regulated transcriptome with innate immune responses in plants showing transcriptional separation among their DEGs in Arabidopsis. Besides unleashing a repertoire of immune-related genes in the SAM, our analysis provides a SAM-interactome that will help the community in designing functional experiments to study the specific defense dynamics of the SAM-cellular populations. Moreover, our study promotes the essence of large-scale omics data re-analysis, allowing a fresh look at the SAM-cellular transcriptome repurposing data-sets for new questions.
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Affiliation(s)
- Muhammad Naseem
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, PO Box 144534-D, Abu Dhabi 4783, UAE; (A.A.M.A.A.); (J.I.); (F.M.H.)
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany; (Ö.O.); (M.K.); (M.S.)
- Correspondence: (M.N.); (T.D.)
| | - Özge Osmanoğlu
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany; (Ö.O.); (M.K.); (M.S.)
| | - Martin Kaltdorf
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany; (Ö.O.); (M.K.); (M.S.)
| | - Afnan Ali M. A. Alblooshi
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, PO Box 144534-D, Abu Dhabi 4783, UAE; (A.A.M.A.A.); (J.I.); (F.M.H.)
| | - Jibran Iqbal
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, PO Box 144534-D, Abu Dhabi 4783, UAE; (A.A.M.A.A.); (J.I.); (F.M.H.)
| | - Fares M. Howari
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, PO Box 144534-D, Abu Dhabi 4783, UAE; (A.A.M.A.A.); (J.I.); (F.M.H.)
| | - Mugdha Srivastava
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany; (Ö.O.); (M.K.); (M.S.)
| | - Thomas Dandekar
- Department of Bioinformatics, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany; (Ö.O.); (M.K.); (M.S.)
- Correspondence: (M.N.); (T.D.)
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3
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Naseem M, Srivastava M, Osmanoglu O, Iqbal J, Howari FM, AlRemeithi FA, Dandekar T. Molecular Modeling of the Interaction Between Stem Cell Peptide and Immune Receptor in Plants. Methods Mol Biol 2020; 2094:67-77. [PMID: 31797292 DOI: 10.1007/978-1-0716-0183-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Molecular docking enables comprehensive exploration of interactions between chemical moieties and proteins. Modeling and docking approaches are useful to determine the three-dimensional (3D) structure of experimentally uncrystallized proteins and subsequently their interactions with various inhibitors and activators or peptides. Here, we describe a protocol for carrying out molecular modeling and docking of stem cell peptide CLV3p on plant innate immune receptor FLS2.
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Affiliation(s)
- Muhammad Naseem
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, UAE
- Department of Bioinformatics, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Mugdha Srivastava
- Department of Bioinformatics, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Ozge Osmanoglu
- Department of Bioinformatics, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Jibran Iqbal
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, UAE
| | - Fares M Howari
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, UAE
| | - Fatima A AlRemeithi
- Department of Life and Environmental Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi, UAE
| | - Thomas Dandekar
- Department of Bioinformatics, Biocenter, University of Wuerzburg, Wuerzburg, Germany.
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A Novel Method for Sampling and Long-Term Monitoring of Microbes That Uses Stickers of Plain Paper. Appl Environ Microbiol 2019; 85:AEM.00766-19. [PMID: 31126944 DOI: 10.1128/aem.00766-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 04/24/2019] [Indexed: 11/20/2022] Open
Abstract
Detection of pathogens is crucial in food production areas. While it is well established, swabbing as a state-of-the-art sampling method offers several drawbacks with respect to yield, standardization, overall handling, and long-term monitoring. This led us to develop and evaluate a method that is easier to use at a lower cost and that should be at least as sensitive. After evaluating sundry promising materials, we tested text-marking paper stickers for their suitability to take up and release Listeria monocytogenes with their nonsticky paper side over a 14-day time period using quantitative PCR. The recovery rate was similar to that in previous studies using conventional swabs, and we also confirmed the feasibility of pooling besides resilience to cleansing and disinfection. In a proof-of-concept experiment that sampled several locations, such as door handles, the occurrences of L. monocytogenes and Escherichia coli were determined. The results suggest that the presented sticker system might offer a promising cost-effective alternative sampling system with improved handling characteristics.IMPORTANCE As a ubiquitous bacterium, Listeria monocytogenes has a propensity to enter food production areas inadvertently via fomites such as door handles and switches. While the bacterium might not be in direct contact with the food products, knowing the microbial status of the surroundings is essential for risk assessment. Our investigation into a novel quantitative PCR (qPCR)-based sampling system with the highest sensitivity and ability to monitor over long periods of time, yet based on paper, proved to be cost-effective and reasonably convenient to handle.
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5
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Wei Y, Caceres‐Moreno C, Jimenez‐Gongora T, Wang K, Sang Y, Lozano‐Duran R, Macho AP. The Ralstonia solanacearum csp22 peptide, but not flagellin-derived peptides, is perceived by plants from the Solanaceae family. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1349-1362. [PMID: 29265643 PMCID: PMC5999195 DOI: 10.1111/pbi.12874] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/10/2017] [Accepted: 12/12/2017] [Indexed: 05/20/2023]
Abstract
Ralstonia solanacearum, the causal agent of bacterial wilt disease, is considered one of the most destructive bacterial pathogens due to its lethality, unusually wide host range, persistence and broad geographical distribution. In spite of the extensive research on plant immunity over the last years, the perception of molecular patterns from R. solanacearum that activate immunity in plants is still poorly understood, which hinders the development of strategies to generate resistance against bacterial wilt disease. The perception of a conserved peptide of bacterial flagellin, flg22, is regarded as paradigm of plant perception of invading bacteria; however, no elicitor activity has been detected for R. solanacearum flg22. Recent reports have shown that other epitopes from flagellin are able to elicit immune responses in specific species from the Solanaceae family, yet our results show that these plants do not perceive any epitope from R. solanacearum flagellin. Searching for elicitor peptides from R. solanacearum, we found several protein sequences similar to the consensus of the elicitor peptide csp22, reported to elicit immunity in specific Solanaceae plants. A R. solanacearum csp22 peptide (csp22Rsol ) was indeed able to trigger immune responses in Nicotiana benthamiana and tomato, but not in Arabidopsis thaliana. Additionally, csp22Rsol treatment conferred increased resistance to R. solanacearum in tomato. Transgenic A. thaliana plants expressing the tomato csp22 receptor (SlCORE) gained the ability to respond to csp22Rsol and became more resistant to R. solanacearum infection. Our results shed light on the mechanisms for perception of R. solanacearum by plants, paving the way for improving current approaches to generate resistance against R. solanacearum.
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Affiliation(s)
- Yali Wei
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Carlos Caceres‐Moreno
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Tamara Jimenez‐Gongora
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesBeijingChina
| | - Keke Wang
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Yuying Sang
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Rosa Lozano‐Duran
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
| | - Alberto P. Macho
- Shanghai Center for Plant Stress BiologyCAS Center for Excellence in Molecular Plant SciencesShanghai Institutes of Biological SciencesChinese Academy of SciencesShanghaiChina
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6
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AtPep3 is a hormone-like peptide that plays a role in the salinity stress tolerance of plants. Proc Natl Acad Sci U S A 2018; 115:5810-5815. [PMID: 29760074 DOI: 10.1073/pnas.1719491115] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Peptides encoded by small coding genes play an important role in plant development, acting in a similar manner as phytohormones. Few hormone-like peptides, however, have been shown to play a role in abiotic stress tolerance. In the current study, 17 Arabidopsis genes coding for small peptides were found to be up-regulated in response to salinity stress. To identify peptides leading salinity stress tolerance, we generated transgenic Arabidopsis plants overexpressing these small coding genes and assessed survivability and root growth under salinity stress conditions. Results indicated that 4 of the 17 overexpressed genes increased salinity stress tolerance. Further studies focused on AtPROPEP3, which was the most highly up-regulated gene under salinity stress. Treatment of plants with synthetic peptides encoded by AtPROPEP3 revealed that a C-terminal peptide fragment (AtPep3) inhibited the salt-induced bleaching of chlorophyll in seedlings. Conversely, knockdown AtPROPEP3 transgenic plants exhibited a hypersensitive phenotype under salinity stress, which was complemented by the AtPep3 peptide. This functional AtPep3 peptide region overlaps with an AtPep3 elicitor peptide that is related to the immune response of plants. Functional analyses with a receptor mutant of AtPep3 revealed that AtPep3 was recognized by the PEPR1 receptor and that it functions to increase salinity stress tolerance in plants. Collectively, these data indicate that AtPep3 plays a significant role in both salinity stress tolerance and immune response in Arabidopsis.
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7
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Hind SR, Hoki JS, Baccile JA, Boyle PC, Schroeder FC, Martin GB. Detecting the interaction of peptide ligands with plant membrane receptors. ACTA ACUST UNITED AC 2017; 2:240-269. [PMID: 29098191 DOI: 10.1002/cppb.20053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The field of plant receptor biology has rapidly expanded in recent years, however the demonstration of direct interaction between receptor-ligand pairs remains a challenge. Click chemistry has revolutionized small molecule research but lacks popularity in plant research. Here we describe a method that tests for the direct physical interaction of a candidate receptor protein and a peptide ligand. This protocol describes the generation of the ligand probe, transient expression of a receptor protein, enrichment of membrane-bound receptors, photo-crosslinking and click chemistry-mediated reporter addition, and detection of the receptor-ligand complex. Copper-based click chemistry confers several advantages, including the versatility to use almost any azide-containing reporter molecule for detection or visualization of the complex and addition of the reporter molecule after receptor-ligand binding which reduces the need for bulky ligand modifications that could interfere with the interaction.
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Affiliation(s)
| | - Jason S Hoki
- Boyce Thompson Institute, Ithaca, New York.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York
| | - Joshua A Baccile
- Boyce Thompson Institute, Ithaca, New York.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York
| | | | - Frank C Schroeder
- Boyce Thompson Institute, Ithaca, New York.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York
| | - Gregory B Martin
- Boyce Thompson Institute, Ithaca, New York.,School of Integrative Plant Science, Cornell University, Ithaca, New York
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8
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Abstract
Shoot meristems are maintained by pluripotent stem cells that are controlled by CLAVATA-WUSCHEL feedback signaling. This pathway, which coordinates stem cell proliferation with differentiation, was first identified in Arabidopsis, but appears to be conserved in diverse higher plant species. In this Review, we highlight the commonalities and differences between CLAVATA-WUSCHEL pathways in different species, with an emphasis on Arabidopsis, maize, rice and tomato. We focus on stem cell control in shoot meristems, but also briefly discuss the role of these signaling components in root meristems.
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Affiliation(s)
- Marc Somssich
- Heinrich-Heine-University, Düsseldorf D-40225, Germany
| | - Byoung Il Je
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Rüdiger Simon
- Heinrich-Heine-University, Düsseldorf D-40225, Germany
| | - David Jackson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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9
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Gust AA, Pruitt R, Nürnberger T. Sensing Danger: Key to Activating Plant Immunity. TRENDS IN PLANT SCIENCE 2017; 22:779-791. [PMID: 28779900 DOI: 10.1016/j.tplants.2017.07.005] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/06/2017] [Accepted: 07/11/2017] [Indexed: 05/20/2023]
Abstract
In both plants and animals, defense against pathogens relies on a complex surveillance system for signs of danger. Danger signals may originate from the infectious agent or from the host itself. Immunogenic plant host factors can be roughly divided into two categories: molecules which are passively released upon cell damage ('classical' damage-associated molecular patterns, DAMPs), and peptides which are processed and/or secreted upon infection to modulate the immune response (phytocytokines). We highlight the ongoing challenge to understand how plants sense various danger signals and integrate this information to produce an appropriate immune response to diverse challenges.
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Affiliation(s)
- Andrea A Gust
- Department of Plant Biochemistry, Center of Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany.
| | - Rory Pruitt
- Department of Plant Biochemistry, Center of Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Thorsten Nürnberger
- Department of Plant Biochemistry, Center of Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany.
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10
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Characterizing the Immune-Eliciting Activity of Putative Microbe-Associated Molecular Patterns in Tomato. Methods Mol Biol 2017; 1578:249-261. [PMID: 28220431 DOI: 10.1007/978-1-4939-6859-6_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Detection of conserved microbe-associated molecular patterns (MAMPs), such as bacterial flagellin, is the first line of active defense in plants against pathogenic invaders. Successful pathogens must subvert this immune response to grow to high population density and cause disease. Flagellin from the bacterial pathogen Pseudomonas was the first identified bacterial MAMP and many species across the plant kingdom have sensitive perception systems for detecting the 22-amino acid epitope known as flg22. Tomato and several other solanaceous plants are also able to independently detect a second epitope of flagellin known as flgII-28. This chapter details four experimental protocols to identify and confirm the immune response-eliciting activity of flagellin and putative MAMPs with focus on the Pseudomonas-tomato pathosystem.
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11
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Abstract
The plant perception of pathogen-associated molecular patterns triggers a plethora of cellular immune responses. One of these responses is a rapid and transient burst of reactive oxygen species (ROS) mediated by plasma membrane-localized NADPH oxidases. The ROS burst requires a functional receptor complex and the contribution of several additional regulatory components. In laboratory conditions, the ROS burst can be detected a few minutes after the treatment with an immunogenic microbial elicitor. For these reasons, the elicitor-triggered ROS burst has been often exploited as readout to probe the contribution of plant components to early immune responses. Here, we describe a detailed protocol for the measurement of elicitor-triggered ROS burst in a simple, fast, and easy manner.
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Affiliation(s)
- Yuying Sang
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Alberto P Macho
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, 201602, China.
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12
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Ranf S, Scheel D, Lee J. Challenges in the identification of microbe-associated molecular patterns in plant and animal innate immunity: a case study with bacterial lipopolysaccharide. MOLECULAR PLANT PATHOLOGY 2016; 17:1165-9. [PMID: 27604847 PMCID: PMC6638395 DOI: 10.1111/mpp.12452] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Stefanie Ranf
- Phytopathology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Emil-Ramann-Str. 2, D-85354, Freising-Weihenstephan, Germany.
- Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle, Germany.
| | - Dierk Scheel
- Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle, Germany
| | - Justin Lee
- Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle, Germany
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13
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Hind SR, Strickler SR, Boyle PC, Dunham DM, Bao Z, O'Doherty IM, Baccile JA, Hoki JS, Viox EG, Clarke CR, Vinatzer BA, Schroeder FC, Martin GB. Tomato receptor FLAGELLIN-SENSING 3 binds flgII-28 and activates the plant immune system. NATURE PLANTS 2016; 2:16128. [PMID: 27548463 DOI: 10.1038/nplants.2016.128] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 07/22/2016] [Indexed: 05/13/2023]
Abstract
Plants and animals detect the presence of potential pathogens through the perception of conserved microbial patterns by cell surface receptors. Certain solanaceous plants, including tomato, potato and pepper, detect flgII-28, a region of bacterial flagellin that is distinct from that perceived by the well-characterized FLAGELLIN-SENSING 2 receptor. Here we identify and characterize the receptor responsible for this recognition in tomato, called FLAGELLIN-SENSING 3. This receptor binds flgII-28 and enhances immune responses leading to a reduction in bacterial colonization of leaf tissues. Further characterization of FLS3 and its signalling pathway could provide new insights into the plant immune system and transfer of the receptor to other crop plants offers the potential of enhancing resistance to bacterial pathogens that have evolved to evade FLS2-mediated immunity.
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Affiliation(s)
- Sarah R Hind
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Susan R Strickler
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Patrick C Boyle
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Diane M Dunham
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Zhilong Bao
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Inish M O'Doherty
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Joshua A Baccile
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Jason S Hoki
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Elise G Viox
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
| | - Christopher R Clarke
- Department of Plant Pathology, Physiology and Weed Sciences, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Boris A Vinatzer
- Department of Plant Pathology, Physiology and Weed Sciences, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Frank C Schroeder
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Gregory B Martin
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA
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14
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Kraus CM, Munkvold KR, Martin GB. Natural Variation in Tomato Reveals Differences in the Recognition of AvrPto and AvrPtoB Effectors from Pseudomonas syringae. MOLECULAR 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] [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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15
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Shcherbakova LA, Odintsova TI, Stakheev AA, Fravel DR, Zavriev SK. Identification of a Novel Small Cysteine-Rich Protein in the Fraction from the Biocontrol Fusarium oxysporum Strain CS-20 that Mitigates Fusarium Wilt Symptoms and Triggers Defense Responses in Tomato. FRONTIERS IN PLANT SCIENCE 2016; 6:1207. [PMID: 26779237 PMCID: PMC4703993 DOI: 10.3389/fpls.2015.01207] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/15/2015] [Indexed: 05/06/2023]
Abstract
The biocontrol effect of the non-pathogenic Fusarium oxysporum strain CS-20 against the tomato wilt pathogen F. oxysporum f. sp. lycopersici (FOL) has been previously reported to be primarily plant-mediated. This study shows that CS-20 produces proteins, which elicit defense responses in tomato plants. Three protein-containing fractions were isolated from CS-20 biomass using size exclusion chromatography. Exposure of seedling roots to one of these fractions prior to inoculation with pathogenic FOL strains significantly reduced wilt severity. This fraction initiated an ion exchange response in cultured tomato cells resulting in a reversible alteration of extracellular pH; increased tomato chitinase activity, and induced systemic resistance by enhancing PR-1 expression in tomato leaves. Two other protein fractions were inactive in seedling protection. The main polypeptide (designated CS20EP), which was specifically present in the defense-inducing fraction and was not detected in inactive protein fractions, was identified. The nucleotide sequence encoding this protein was determined, and its complete amino acid sequence was deduced from direct Edman degradation (25 N-terminal amino acid residues) and DNA sequencing. The CS20EP was found to be a small basic cysteine-rich protein with a pI of 9.87 and 23.43% of hydrophobic amino acid residues. BLAST search in the NCBI database showed that the protein is new; however, it displays 48% sequence similarity with a hypothetical protein FGSG_10784 from F. graminearum strain PH-1. The contribution of CS20EP to elicitation of tomato defense responses resulting in wilt mitigating is discussed.
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Affiliation(s)
- Larisa A. Shcherbakova
- Laboratory of Physiological Plant Pathology, All-Russian Research Institute of PhytopathologyMoscow, Russia
| | - Tatyana I. Odintsova
- Laboratory of Molecular-Genetic Bases of Plant Immunity, Vavilov Institute of General GeneticsMoscow, Russia
| | - Alexander A. Stakheev
- Laboratory of Molecular Diagnostic, M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of SciencesMoscow, Russia
| | - Deborah R. Fravel
- Crop Production and Protection, United States Department of Agriculture, Agricultural Research ServiceBeltsville, MD, USA
| | - Sergey K. Zavriev
- Laboratory of Molecular Diagnostic, M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of SciencesMoscow, Russia
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Leslie ME, Heese A. A re-elicitation assay to correlate flg22-signaling competency with ligand-induced endocytic degradation of the FLS2 receptor. Methods Mol Biol 2015; 1209:149-62. [PMID: 25117282 DOI: 10.1007/978-1-4939-1420-3_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
In the model plant Arabidopsis, the best studied Pattern-triggered immunity (PTI) system is perception of the bacterial pathogen-associated molecular pattern (PAMP) flagellin, or its active peptide-derivative flg22, by the plasma membrane-localized receptor FLAGELLIN SENSING 2 (FLS2). Flg22 perception initiates an array of immune responses including the fast and transient production of reactive oxygen species (ROS). In addition, FLS2 undergoes ligand-induced endocytosis and subsequent degradation within 60 min of flg22-treatment. Luminol-based assays are routinely used to measure extracellular ROS production within minutes after flg22 treatment. Many mutants in flg22-response pathways display defects in flg22-induced ROS production. Here, we describe a luminol-based ROS Re-elicitation Assay that can be utilized to quantitatively assess flg22-signaling competency of FLS2 at times during which FLS2 is internalized, trafficked through endosomal compartments, and degraded in response to flg22. This assay may also be employed to correlate FLS2 signaling competency with receptor accumulation in vesicular trafficking mutants that either affect FLS2 endocytosis or replenishment of FLS2 through the secretory pathway. In addition, this assay can be extended to studies of other PAMP (ligand)-receptor pairs.
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Affiliation(s)
- Michelle E Leslie
- Division of Biochemistry, Interdisciplinary Plant Group (IPG), University of Missouri-Columbia, 117 Schweitzer Hall, Columbia, MO, 65211, USA
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Böhm H, Albert I, Oome S, Raaymakers TM, Van den Ackerveken G, Nürnberger T. A conserved peptide pattern from a widespread microbial virulence factor triggers pattern-induced immunity in Arabidopsis. PLoS Pathog 2014; 10:e1004491. [PMID: 25375108 PMCID: PMC4223075 DOI: 10.1371/journal.ppat.1004491] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 09/27/2014] [Indexed: 11/18/2022] Open
Abstract
Microbe- or host damage-derived patterns mediate activation of pattern-triggered immunity (PTI) in plants. Microbial virulence factor (effector)-triggered immunity (ETI) constitutes a second layer of plant protection against microbial attack. Various necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) produced by bacterial, oomycete and fungal microbes are phytotoxic virulence factors that exert immunogenic activities through phytotoxin-induced host cell damage. We here show that multiple cytotoxic NLPs also carry a pattern of 20 amino acid residues (nlp20) that triggers immunity-associated plant defenses and immunity to microbial infection in Arabidopsis thaliana and related plant species with similar characteristics as the prototype pattern, bacterial flagellin. Characteristic differences in flagellin and nlp20 plant responses exist however, as nlp20s fail to trigger extracellular alkalinization in Arabidopsis cell suspensions and seedling growth inhibition. Immunogenic nlp20 peptide motifs are frequently found in bacterial, oomycete and fungal NLPs. Such an unusually broad taxonomic distribution within three phylogenetic kingdoms is unprecedented among microbe-derived triggers of immune responses in either metazoans or plants. Our findings suggest that cytotoxic NLPs carrying immunogenic nlp20 motifs trigger PTI in two ways as typical patterns and by inflicting host cell damage. We further propose that conserved structures within a microbial virulence factor might have driven the emergence of a plant pattern recognition system mediating PTI. As this is reminiscent of the evolution of immune receptors mediating ETI, our findings support the idea that there is a continuum between PTI and ETI.
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Affiliation(s)
- Hannah Böhm
- Center of Plant Molecular Biology (ZMBP)-Plant Biochemistry, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Isabell Albert
- Center of Plant Molecular Biology (ZMBP)-Plant Biochemistry, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Stan Oome
- Plant-Microbe Interactions, Department of Biology, Utrecht University, Utrecht, The Netherlands
- Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands
| | - Tom M. Raaymakers
- Plant-Microbe Interactions, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Guido Van den Ackerveken
- Plant-Microbe Interactions, Department of Biology, Utrecht University, Utrecht, The Netherlands
- Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands
| | - Thorsten Nürnberger
- Center of Plant Molecular Biology (ZMBP)-Plant Biochemistry, Eberhard-Karls-University Tübingen, Tübingen, Germany
- * E-mail:
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Naseem M, Srivastava M, Dandekar T. Stem-cell-triggered immunity safeguards cytokinin enriched plant shoot apexes from pathogen infection. FRONTIERS IN PLANT SCIENCE 2014; 5:588. [PMID: 25400652 PMCID: PMC4214217 DOI: 10.3389/fpls.2014.00588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/10/2014] [Indexed: 06/04/2023]
Abstract
Intricate mechanisms discriminate between friends and foes in plants. Plant organs deploy overlapping and distinct protection strategies. Despite vulnerability to a plethora of pathogens, the growing tips of plants grow bacteria free. The shoot apical meristem (SAM) is among three stem cells niches, a self-renewable reservoir for the future organogenesis of leaf, stem, and flowers. How plants safeguard this high value growth target from infections was not known until now. Recent reports find the stem cell secreted 12-amino acid peptide CLV3p (CLAVATA3 peptide) is perceived by FLS2 (FLAGELLIN SENSING 2) receptor and activates the transcription of immunity and defense marker genes. No infection in the SAM of wild type plants and bacterial infection in clv3 and fls2 mutants illustrate this natural protection against infections. Cytokinins (CKs) are enriched in the SAM and regulate meristem activities by their involvement in stem cell signaling networks. Auxin mediates plant susceptibility to pathogen infections while CKs boost plant immunity. Here, in addition to the stem-cell-triggered immunity we also highlight a potential link between CK signaling and CLV3p mediated immune response in the SAM.
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Affiliation(s)
| | | | - Thomas Dandekar
- *Correspondence: Thomas Dandekar, Functional Genomics and Systems Biology Group, Department of Bioinformatics, Biocenter, University of Wuerzburg, Am Hubland, D-97074 Wuerzburg, Germany e-mail:
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Vinatzer BA, Monteil CL, Clarke CR. Harnessing population genomics to understand how bacterial pathogens emerge, adapt to crop hosts, and disseminate. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:19-43. [PMID: 24820995 DOI: 10.1146/annurev-phyto-102313-045907] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Crop diseases emerge without warning. In many cases, diseases cross borders, or even oceans, before plant pathologists have time to identify and characterize the causative agents. Genome sequencing, in combination with intensive sampling of pathogen populations and application of population genetic tools, is now providing the means to unravel how bacterial crop pathogens emerge from environmental reservoirs, how they evolve and adapt to crops, and what international and intercontinental routes they follow during dissemination. Here, we introduce the field of population genomics and review the population genomics research of bacterial plant pathogens over the past 10 years. We highlight the potential of population genomics for investigating plant pathogens, using examples of population genomics studies of human pathogens. We also describe the complementary nature of the fields of population genomics and molecular plant-microbe interactions and propose how to translate new insights into improved disease prevention and control.
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Affiliation(s)
- Boris A Vinatzer
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, Virginia 24061; ,
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21
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Clarke CR, Chinchilla D, Hind SR, Taguchi F, Miki R, Ichinose Y, Martin GB, Leman S, Felix G, Vinatzer BA. Allelic variation in two distinct Pseudomonas syringae flagellin epitopes modulates the strength of plant immune responses but not bacterial motility. THE NEW PHYTOLOGIST 2013; 200:847-860. [PMID: 23865782 PMCID: PMC3797164 DOI: 10.1111/nph.12408] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/07/2013] [Indexed: 05/18/2023]
Abstract
The bacterial flagellin (FliC) epitopes flg22 and flgII-28 are microbe-associated molecular patterns (MAMPs). Although flg22 is recognized by many plant species via the pattern recognition receptor FLS2, neither the flgII-28 receptor nor the extent of flgII-28 recognition by different plant families is known. Here, we tested the significance of flgII-28 as a MAMP and the importance of allelic diversity in flg22 and flgII-28 in plant-pathogen interactions using purified peptides and a Pseudomonas syringae ∆fliC mutant complemented with different fliC alleles. The plant genotype and allelic diversity in flg22 and flgII-28 were found to significantly affect the plant immune response, but not bacterial motility. The recognition of flgII-28 is restricted to a number of solanaceous species. Although the flgII-28 peptide does not trigger any immune response in Arabidopsis, mutations in both flg22 and flgII-28 have FLS2-dependent effects on virulence. However, the expression of a tomato allele of FLS2 does not confer to Nicotiana benthamiana the ability to detect flgII-28, and tomato plants silenced for FLS2 are not altered in flgII-28 recognition. Therefore, MAMP diversification is an effective pathogen virulence strategy, and flgII-28 appears to be perceived by an as yet unidentified receptor in the Solanaceae, although it has an FLS2-dependent virulence effect in Arabidopsis.
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Affiliation(s)
- Christopher R. Clarke
- Department of Plant Pathology, Physiology and Weed Sciences Latham Hall, Ag Quad Lane, Virginia Tech, Blacksburg, VA 24061, USA
| | - Delphine Chinchilla
- Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | - Sarah R. Hind
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
| | - Fumiko Taguchi
- Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan
| | - Ryuji Miki
- Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan
| | - Yuki Ichinose
- Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan
| | - Gregory B. Martin
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; and Genomics and Biotechnology Section, Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Scotland Leman
- Department of Statistics, Virginia Tech, Blacksburg, VA 24061, USA
| | - Georg Felix
- Zentrum für Molekularbiologie der Pflanzen, University Tübingen, 72076, Germany
| | - Boris A. Vinatzer
- Department of Plant Pathology, Physiology and Weed Sciences Latham Hall, Ag Quad Lane, Virginia Tech, Blacksburg, VA 24061, USA
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Henry E, Yadeta KA, Coaker G. Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity. THE NEW PHYTOLOGIST 2013; 199:908-15. [PMID: 23909802 PMCID: PMC3740753 DOI: 10.1111/nph.12214] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/05/2013] [Indexed: 05/19/2023]
Abstract
Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance.
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Affiliation(s)
- Elizabeth Henry
- Department of Plant Pathology, University of California at Davis, Davis, CA, USA
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Newman MA, Sundelin T, Nielsen JT, Erbs G. MAMP (microbe-associated molecular pattern) triggered immunity in plants. FRONTIERS IN PLANT SCIENCE 2013; 4:139. [PMID: 23720666 PMCID: PMC3655273 DOI: 10.3389/fpls.2013.00139] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/23/2013] [Indexed: 05/18/2023]
Abstract
Plants are sessile organisms that are under constant attack from microbes. They rely on both preformed defenses, and their innate immune system to ward of the microbial pathogens. Preformed defences include for example the cell wall and cuticle, which act as physical barriers to microbial colonization. The plant immune system is composed of surveillance systems that perceive several general microbe elicitors, which allow plants to switch from growth and development into a defense mode, rejecting most potentially harmful microbes. The elicitors are essential structures for pathogen survival and are conserved among pathogens. The conserved microbe-specific molecules, referred to as microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs), are recognized by the plant innate immune systems pattern recognition receptors (PRRs). General elicitors like flagellin (Flg), elongation factor Tu (EF-Tu), peptidoglycan (PGN), lipopolysaccharides (LPS), Ax21 (Activator of XA21-mediated immunity in rice), fungal chitin, and β-glucans from oomycetes are recognized by plant surface localized PRRs. Several of the MAMPs and their corresponding PRRs have, in recent years, been identified. This review focuses on the current knowledge regarding important MAMPs from bacteria, fungi, and oomycetes, their structure, the plant PRRs that recognizes them, and how they induce MAMP-triggered immunity (MTI) in plants.
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Affiliation(s)
- Mari-Anne Newman
- *Correspondence: Mari-Anne Newman, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark. e-mail:
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Segonzac C, Nimchuk ZL, Beck M, Tarr PT, Robatzek S, Meyerowitz EM, Zipfel C. The shoot apical meristem regulatory peptide CLV3 does not activate innate immunity. THE PLANT CELL 2012; 24:3186-92. [PMID: 22923673 PMCID: PMC3462624 DOI: 10.1105/tpc.111.091264] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 01/24/2012] [Accepted: 08/01/2012] [Indexed: 05/20/2023]
Abstract
The Arabidopsis thaliana leucine-rich repeat receptor kinase FLAGELLIN SENSING2 (FLS2) is required for the recognition of bacterial flagellin in innate immunity. Recently, FLS2 was proposed to act as a multispecific receptor recognizing unrelated exogenous and endogenous peptide ligands, including CLAVATA3 (CLV3), a key regulator of shoot meristem stem cell production. Here, we report experimental evidence demonstrating that FLS2 does not recognize CLV3 and that the shoot apical meristem is immune to bacteria independently of CLV3 perception.
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Affiliation(s)
- Cécile Segonzac
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Zachary L. Nimchuk
- Division of Biology, California Institute of Technology, Pasadena, California 91125
| | - Martina Beck
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Paul T. Tarr
- Division of Biology, California Institute of Technology, Pasadena, California 91125
| | - Silke Robatzek
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Elliot M. Meyerowitz
- Division of Biology, California Institute of Technology, Pasadena, California 91125
- The Sainsbury Laboratory–University of Cambridge, Cambridge CB2 1LR, United Kingdom
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, United Kingdom
- Address correspondence to
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Murphy E, Smith S, De Smet I. Small signaling peptides in Arabidopsis development: how cells communicate over a short distance. THE PLANT CELL 2012; 24:3198-217. [PMID: 22932676 PMCID: PMC3462626 DOI: 10.1105/tpc.112.099010] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To sustain plants' postembryonic growth and development in a structure of cells fixed in cell walls, a tightly controlled short distance cell-cell communication is required. The focus on phytohormones, such as auxin, has historically overshadowed the importance of small peptide signals, but it is becoming clear that secreted peptide signals are important in cell-cell communication to coordinate and integrate cellular functions. However, of the more than 1000 potential secreted peptides, so far only very few have been functionally characterized or matched to a receptor. Here, we will describe our current knowledge on how small peptide signals can be identified, how they are modified and processed, which roles they play in Arabidopsis thaliana development, and through which receptors they act.
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Affiliation(s)
- Evan Murphy
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Stephanie Smith
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Ive De Smet
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, Leicestershire LE12 5RD, United Kingdom
- Centre for Plant Integrative Biology, University of Nottingham, Nottingham LE12 5RD, United Kingdom
- Address correspondence to
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Monaghan J, Zipfel C. Plant pattern recognition receptor complexes at the plasma membrane. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:349-57. [PMID: 22705024 DOI: 10.1016/j.pbi.2012.05.006] [Citation(s) in RCA: 406] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 05/15/2012] [Accepted: 05/23/2012] [Indexed: 05/18/2023]
Abstract
A key feature of innate immunity is the ability to recognize and respond to potential pathogens in a highly sensitive and specific manner. In plants, the activation of pattern recognition receptors (PRRs) by pathogen-associated molecular patterns (PAMPs) elicits a defense programme known as PAMP-triggered immunity (PTI). Although only a handful of PAMP-PRR pairs have been defined, all known PRRs are modular transmembrane proteins containing ligand-binding ectodomains. It is becoming clear that PRRs do not act alone but rather function as part of multi-protein complexes at the plasma membrane. Recent studies describing the molecular interactions and protein modifications that occur between PRRs and their regulatory proteins have provided important mechanistic insight into how plants avoid infection and achieve immunity.
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Lee H, Khatri A, Plotnikov JM, Zhang XC, Sheen J. Complexity in differential peptide-receptor signaling: response to Segonzac et Al. and Mueller et Al. commentaries. THE PLANT CELL 2012; 24:3177-85. [PMID: 22923676 PMCID: PMC3462623 DOI: 10.1105/tpc.112.099259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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Martin C. Commentaries and letters to the editor of the plant cell. THE PLANT CELL 2012; 24:3172-3173. [PMID: 22923672 PMCID: PMC3462621 DOI: 10.1105/tpc.112.240880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Mueller K, Bittel P, Chinchilla D, Jehle AK, Albert M, Boller T, Felix G. Chimeric FLS2 receptors reveal the basis for differential flagellin perception in Arabidopsis and tomato. THE PLANT CELL 2012; 24:2213-24. [PMID: 22634763 PMCID: PMC3442597 DOI: 10.1105/tpc.112.096073] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 03/15/2012] [Accepted: 05/02/2012] [Indexed: 05/18/2023]
Abstract
The flagellin receptor of Arabidopsis thaliana, At-FLAGELLIN SENSING2 (FLS2), has become a model for mechanistic and functional studies on plant immune receptors. Here, we started out with a comparison of At-FLS2 and the orthologous tomato (Solanum lycopersicum) receptor Sl-FLS2. Both receptors specifically responded to picomolar concentrations of the genuine flg22 ligand but proved insensitive to >10(6)-fold higher concentrations of CLV3 peptides that have recently been reported as a second type of ligand for At-FLS2. At-FLS2 and Sl-FLS2 exhibit species-specific differences in the recognition of shortened or sequence-modified flg22 ligands. To map the sites responsible for these species-specific traits on the FLS2 receptors, we performed domain swaps, substituting subsets of the 28 leucine-rich repeats (LRRs) in At-FLS2 with the corresponding LRRs from Sl-FLS2. We found that the LRRs 7 to 10 of Sl-FLS2 determine the high affinity of Sl-FLS2 for the core part RINSAKDD of flg22. In addition, we discovered importance of the LRRs 19 to 24 for the responsiveness to C-terminally modified flagellin peptides. These results indicate that ligand perception in FLS2 is a complex molecular process that involves LRRs from both the outermost and innermost LRRs of the FLS2 ectodomain.
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Affiliation(s)
- Katharina Mueller
- Zentrum für Molekularbiologie der Pflanzen, University Tübingen, 72076 Tuebingen, Germany
| | - Pascal Bittel
- Zurich-Basel Plant Science Center, Botanisches Institut, Universität Basel, 4056 Basel, Switzerland
| | - Delphine Chinchilla
- Zurich-Basel Plant Science Center, Botanisches Institut, Universität Basel, 4056 Basel, Switzerland
| | - Anna K. Jehle
- Zentrum für Molekularbiologie der Pflanzen, University Tübingen, 72076 Tuebingen, Germany
| | - Markus Albert
- Zentrum für Molekularbiologie der Pflanzen, University Tübingen, 72076 Tuebingen, Germany
| | - Thomas Boller
- Zurich-Basel Plant Science Center, Botanisches Institut, Universität Basel, 4056 Basel, Switzerland
| | - Georg Felix
- Zentrum für Molekularbiologie der Pflanzen, University Tübingen, 72076 Tuebingen, Germany
- Address correspondence to
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