1
|
Kumar P, Banday ZZ, Riley JL, Greenberg JT. Agrobacterium-Mediated Transient Gene Expression Optimized for the Bioenergy Crop Camelina sativa. Bio Protoc 2024; 14:e4964. [PMID: 38618179 PMCID: PMC11006800 DOI: 10.21769/bioprotoc.4964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 04/16/2024] Open
Abstract
Camelina sativa, a Brassicaceae family crop, is used for fodder, human food, and biofuels. Its relatively high resistance to abiotic and biotic stresses, as well as being a climate-resilient oilseed crop, has contributed to its popularity. Camelina's seed yield and oil contents have been improved using various technologies like RNAi and CRISPR/Cas9 genome editing. A stable transformation system for protein localization and other cell autonomous investigations, on the other hand, is tedious and time consuming. This study describes a transient gene expression protocol for Camelina sativa cultivar DH55 leaves using Agrobacterium strain C58C1. The method is suitable for subcellular protein localization and colocalization studies and can be used with both constitutive and chemically induced genes. We report the subcellular localization of the N-terminal ER membrane signal anchor region (1-32 aa) of the At3G28580 gene-encoded protein from Arabidopsis in intact leaves and the expression and localization of other known organelle markers. This method offers a fast and convenient way to study proteins in the commercially important Camelina crop system. Key features • This method is based on the approach of Zhang et al. [1] and has been optimized for bioenergy crop Camelina species. • A constitutive and inducible transient gene expression in the hexaploid species Camelina sativa cultivar DH55. • Requires only 16-18 days to complete with high efficacy. Graphical overview.
Collapse
Affiliation(s)
- Pawan Kumar
- Department of Molecular Genetics and Cell Biology,
The University of Chicago, Chicago, IL, USA
- Department of Ecology and Evolution, The University
of Chicago, Chicago, IL, USA
| | - Zeeshan Z. Banday
- Department of Molecular Genetics and Cell Biology,
The University of Chicago, Chicago, IL, USA
| | - John L. Riley
- Department of Molecular Genetics and Cell Biology,
The University of Chicago, Chicago, IL, USA
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology,
The University of Chicago, Chicago, IL, USA
| |
Collapse
|
2
|
Roychoudhry S, Greenberg JT, Cecchini NM. Protocol for analyzing the movement and uptake of isotopically labeled signaling molecule azelaic acid in Arabidopsis. STAR Protoc 2024; 5:102944. [PMID: 38470913 PMCID: PMC10945267 DOI: 10.1016/j.xpro.2024.102944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/01/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Understanding the generation, movement, uptake, and perception of mobile defense signals is key for unraveling the systemic resistance programs in flowering plants against pathogens. Here, we present a protocol for analyzing the movement and uptake of isotopically labeled signaling molecule azelaic acid (AZA) in Arabidopsis thaliana. We describe steps to assess 14C-AZA uptake into leaf discs and its movement from local to systemic tissues. We also detail the assay for uptake and movement of 2H-AZA from roots to the shoot. For complete details on the use and execution of this protocol, please refer to Cecchini et al.1,2.
Collapse
Affiliation(s)
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, USA.
| | - Nicolás M Cecchini
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, CONICET, Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, Córdoba X5000HUA, Argentina.
| |
Collapse
|
3
|
Morgan JM, Jelenska J, Hensley DK, Li P, Srijanto BR, Retterer ST, Standaert RF, Morrell-Falvey JL, Greenberg JT. Using Vertically Aligned Carbon Nanofiber Arrays on Rigid or Flexible Substrates for Delivery of Biomolecules and Dyes to Plants. J Vis Exp 2023. [PMID: 37677009 DOI: 10.3791/65602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023] Open
Abstract
The delivery of biomolecules and impermeable dyes to intact plants is a major challenge. Nanomaterials are up-and-coming tools for the delivery of DNA to plants. As exciting as these new tools are, they have yet to be widely applied. Nanomaterials fabricated on rigid substrate (backing) are particularly difficult to successfully apply to curved plant structures. This study describes the process for microfabricating vertically aligned carbon nanofiber arrays and transferring them from a rigid to a flexible substrate. We detail and demonstrate how these fibers (on either rigid or flexible substrates) can be used for transient transformation or dye (e.g., fluorescein) delivery to plants. We show how VACNFs can be transferred from rigid silicon substrate to a flexible SU-8 epoxy substrate to form flexible VACNF arrays. To overcome the hydrophobic nature of SU-8, fibers in the flexible film were coated with a thin silicon oxide layer (2-3 nm). To use these fibers for delivery to curved plant organs, we deposit a 1 µL droplet of dye or DNA solution on the fiber side of VACNF films, wait 10 min, place the films on the plant organ and employ a swab with a rolling motion to drive fibers into plant cells. With this method, we have achieved dye and DNA delivery in plant organs with curved surfaces.
Collapse
Affiliation(s)
| | - Joanna Jelenska
- Molecular Genetics and Cell Biology, The University of Chicago
| | - Dale K Hensley
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
| | - Pengju Li
- Pritzker School of Molecular Engineering, The University of Chicago
| | | | - Scott T Retterer
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory; Biosciences Division, Oak Ridge National Laboratory
| | | | | | | |
Collapse
|
4
|
Hess RA, Erickson OA, Cole RB, Isaacs JM, Alvarez-Clare S, Arnold J, Augustus-Wallace A, Ayoob JC, Berkowitz A, Branchaw J, Burgio KR, Cannon CH, Ceballos RM, Cohen CS, Coller H, Disney J, Doze VA, Eggers MJ, Ferguson EL, Gray JJ, Greenberg JT, Hoffmann A, Jensen-Ryan D, Kao RM, Keene AC, Kowalko JE, Lopez SA, Mathis C, Minkara M, Murren CJ, Ondrechen MJ, Ordoñez P, Osano A, Padilla-Crespo E, Palchoudhury S, Qin H, Ramírez-Lugo J, Reithel J, Shaw CA, Smith A, Smith RJ, Tsien F, Dolan EL. Virtually the Same? Evaluating the Effectiveness of Remote Undergraduate Research Experiences. CBE Life Sci Educ 2023; 22:ar25. [PMID: 37058442 PMCID: PMC10228262 DOI: 10.1187/cbe.22-01-0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/27/2023] [Accepted: 03/17/2023] [Indexed: 06/02/2023]
Abstract
In-person undergraduate research experiences (UREs) promote students' integration into careers in life science research. In 2020, the COVID-19 pandemic prompted institutions hosting summer URE programs to offer them remotely, raising questions about whether undergraduates who participate in remote research can experience scientific integration and whether they might perceive doing research less favorably (i.e., not beneficial or too costly). To address these questions, we examined indicators of scientific integration and perceptions of the benefits and costs of doing research among students who participated in remote life science URE programs in Summer 2020. We found that students experienced gains in scientific self-efficacy pre- to post-URE, similar to results reported for in-person UREs. We also found that students experienced gains in scientific identity, graduate and career intentions, and perceptions of the benefits of doing research only if they started their remote UREs at lower levels on these variables. Collectively, students did not change in their perceptions of the costs of doing research despite the challenges of working remotely. Yet students who started with low cost perceptions increased in these perceptions. These findings indicate that remote UREs can support students' self-efficacy development, but may otherwise be limited in their potential to promote scientific integration.
Collapse
Affiliation(s)
- Riley A. Hess
- Department of Psychology, University of Georgia, Athens, GA 30602
| | - Olivia A. Erickson
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | - Rebecca B. Cole
- Department of Psychology, University of Georgia, Athens, GA 30602
| | - Jared M. Isaacs
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| | | | - Jonathan Arnold
- Department of Genetics, University of Georgia, Athens, GA 30602
| | | | - Joseph C. Ayoob
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260
| | - Alan Berkowitz
- Education Department, Cary Institute for Ecosystem Studies, Millbrook, NY 12545
| | - Janet Branchaw
- WISCIENCE and Department of Kinesiology, University of Wisconsin–Madison, Madison, WI 53706
| | - Kevin R. Burgio
- Education Department, Cary Institute for Ecosystem Studies, Millbrook, NY 12545
| | | | | | - C. Sarah Cohen
- Department of Biology, Estuary and Ocean Science Center, San Francisco State University, San Francisco, CA 94132
| | - Hilary Coller
- Department of Molecular, Cell and Developmental Biology and, University of California Los Angeles, Los Angeles, CA 90095
| | - Jane Disney
- Community Environmental Health Laboratory, Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672
| | - Van A. Doze
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202
| | - Margaret J. Eggers
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717
| | - Edwin L. Ferguson
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 606307
| | - Jeffrey J. Gray
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 606307
| | - Alexander Hoffmann
- Department of Microbiology, Immunology, and Molecular Genetics and Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095
| | - Danielle Jensen-Ryan
- Department of Math and Sciences, Laramie County Community College, Cheyenne, WY 82007
| | - Robert M. Kao
- Science Department, College of Arts and Sciences, Heritage University, Toppenish, WA 98948
| | - Alex C. Keene
- Department of Biology, Texas A&M University, College Station, TX 77840
| | - Johanna E. Kowalko
- Department of Biological Sciences, Lehigh University, Bethlehem, PA 18015
| | - Steven A. Lopez
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115
| | | | - Mona Minkara
- Department of Bioengineering, Northeastern University, Boston, MA 02115
| | | | - Mary Jo Ondrechen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115
| | - Patricia Ordoñez
- Department of Computer Science, University of Puerto Rico–Río Piedras, San Juan, PR 00925
| | - Anne Osano
- Department of Natural Sciences, Bowie State University, Bowie, MD 20715
| | - Elizabeth Padilla-Crespo
- Department of Science and Technology, Inter American University of Puerto Rico–Aguadilla, Aguadilla, PR 00605
| | | | - Hong Qin
- Department of Computer Science and Engineering and Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, Chattanooga, TN 37403
| | - Juan Ramírez-Lugo
- Department of Biology, University of Puerto Rico–Río Piedras, San Juan, PR 00925
| | - Jennifer Reithel
- Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224
| | - Colin A. Shaw
- Undergraduate Scholars Program and Department of Earth Sciences, Montana State University, Bozeman, MT 59717
| | - Amber Smith
- Wisconsin Institute for Science Education and Community Engagement, University of Wisconsin–Madison, Madison, WI 53706
| | - Rosemary J. Smith
- Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209
| | - Fern Tsien
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Erin L. Dolan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602
| |
Collapse
|
5
|
Yoo SJ, Choi HJ, Noh SW, Cecchini NM, Greenberg JT, Jung HW. Genetic requirements for infection-specific responses in conferring disease resistance in Arabidopsis. Front Plant Sci 2022; 13:1068438. [PMID: 36523630 PMCID: PMC9745044 DOI: 10.3389/fpls.2022.1068438] [Citation(s) in RCA: 1] [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: 10/12/2022] [Accepted: 11/09/2022] [Indexed: 06/01/2023]
Abstract
Immunity in plants arises from defense regulatory circuits that can be conceptualized as modules. Both the types (and isolates) of pathogen and the repertoire of plant receptors may cause different modules to be activated and affect the magnitude of activation. Two major defense enzymes of Arabidopsis are ALD1 and ICS1/SID2. ALD1 is an aminotransferase needed for producing the metabolites pipecolic acid, hydroxy-pipecolic acid, and possibly other defense signals. ICS1/SID2 produces isochorismate, an intermediate in the synthesis of salicylic acid (SA) and SA-derivatives. Metabolites resulting from the activation of these enzymes are found in petiole exudates and may serve as priming signals for systemic disease resistance in Arabidopsis. Mutants lacking ALD1 are known to have reduced SA accumulation. To further investigate the role of ALD1 in relation to the SA-related module, immunity phenotypes of double mutants that disrupt ALD1 and ICS1/SID2 or SA perception by NPR1 were compared with each single mutant after infection by different Pseudomonas strains. Exudates collected from these mutants after infection were also evaluated for their ability to confer disease resistance when applied to wild-type plants. During infection with virulent or attenuated strains, the loss of ALD1 does not increase the susceptibility of npr1 or sid2 mutants, suggesting the main role of ALD1 in this context is in amplifying the SA-related module. In contrast, after an infection that leads to strong pathogen recognition via the cytoplasmic immune receptor RPS2, ALD1 acts additively with both NPR1 and ICS1/SID2 to suppress pathogen growth. The additive effects are observed in early basal defense responses as well as SA-related events. Thus, there are specific conditions that dictate whether the modules independently contribute to immunity to provide additive protection during infection. In the exudate experiments, intact NPR1 and ICS1/SID2, but not ALD1 in the donor plants were needed for conferring immunity. Mixing exudates showed that loss of SID2 yields exudates that suppress active exudates from wild-type or ald1 plants. This indicates that ICS1/SID2 may not only lead to positive defense signals, but also prevent a suppressive signal(s).
Collapse
Affiliation(s)
- Sung-Je Yoo
- Department of Molecular Genetics, Dong-A University, Busan, South Korea
| | - Hyo Ju Choi
- Department of Molecular Genetics, Dong-A University, Busan, South Korea
| | - Seong Woo Noh
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| | - Nicolás M. Cecchini
- Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States
| | - Ho Won Jung
- Department of Molecular Genetics, Dong-A University, Busan, South Korea
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| |
Collapse
|
6
|
Morgan JM, Jelenska J, Hensley D, Retterer ST, Morrell-Falvey JL, Standaert RF, Greenberg JT. An efficient and broadly applicable method for transient transformation of plants using vertically aligned carbon nanofiber arrays. Front Plant Sci 2022; 13:1051340. [PMID: 36507425 PMCID: PMC9728956 DOI: 10.3389/fpls.2022.1051340] [Citation(s) in RCA: 1] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
Transient transformation in plants is a useful process for evaluating gene function. However, there is a scarcity of minimally perturbing methods for gene delivery that can be used on multiple organs, plant species, and non-excised tissues. We pioneered and demonstrated the use of vertically aligned carbon nanofiber (VACNF) arrays to efficiently perform transient transformation of different tissues with DNA constructs in multiple plant species. The VACNFs permeabilize plant tissue transiently to allow molecules into cells without causing a detectable stress response. We successfully delivered DNA into leaves, roots and fruit of five plant species (Arabidopsis, poplar, lettuce, Nicotiana benthamiana, and tomato) and confirmed accumulation of the encoded fluorescent proteins by confocal microscopy. Using this system, it is possible to transiently transform plant cells with both small and large plasmids. The method is successful for species recalcitrant to Agrobacterium-mediated transformation. VACNFs provide simple, reliable means of DNA delivery into a variety of plant organs and species.
Collapse
Affiliation(s)
- Jessica M Morgan
- Biophysical Sciences, The University of Chicago, Chicago, IL, United States
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States
| | - Dale Hensley
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Scott T Retterer
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN, United States
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | | | - Robert F Standaert
- Department of Chemistry, East Tennessee State University, Johnson City, TN, United States
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States
| |
Collapse
|
7
|
Banday ZZ, Cecchini NM, Speed DJ, Scott AT, Parent C, Hu CT, Filzen RC, Agbo E, Greenberg JT. Friend or foe: Hybrid proline-rich proteins determine how plants respond to beneficial and pathogenic microbes. Plant Physiol 2022; 190:860-881. [PMID: 35642916 PMCID: PMC9434206 DOI: 10.1093/plphys/kiac263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/08/2022] [Indexed: 05/21/2023]
Abstract
Plant plastids generate signals, including some derived from lipids, that need to be mobilized to effect signaling. We used informatics to discover potential plastid membrane proteins involved in microbial responses in Arabidopsis (Arabidopsis thaliana). Among these are proteins co-regulated with the systemic immunity component AZELAIC ACID INDUCED 1, a hybrid proline-rich protein (HyPRP), and HyPRP superfamily members. HyPRPs have a transmembrane domain, a proline-rich region (PRR), and a lipid transfer protein domain. The precise subcellular location(s) and function(s) are unknown for most HyPRP family members. As predicted by informatics, a subset of HyPRPs has a pool of proteins that target plastid outer envelope membranes via a mechanism that requires the PRR. Additionally, two HyPRPs may be associated with thylakoid membranes. Most of the plastid- and nonplastid-localized family members also have pools that localize to the endoplasmic reticulum, plasma membrane, or plasmodesmata. HyPRPs with plastid pools regulate, positively or negatively, systemic immunity against the pathogen Pseudomonas syringae. HyPRPs also regulate the interaction with the plant growth-promoting rhizobacteria Pseudomonas simiae WCS417 in the roots to influence colonization, root system architecture, and/or biomass. Thus, HyPRPs have broad and distinct roles in immunity, development, and growth responses to microbes and reside at sites that may facilitate signal molecule transport.
Collapse
Affiliation(s)
- Zeeshan Z Banday
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | | | - DeQuantarius J Speed
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | - Allison T Scott
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | | | - Ciara T Hu
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | - Rachael C Filzen
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | - Elinam Agbo
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637, USA
| | | |
Collapse
|
8
|
Erickson OA, Cole RB, Isaacs JM, Alvarez-Clare S, Arnold J, Augustus-Wallace A, Ayoob JC, Berkowitz A, Branchaw J, Burgio KR, Cannon CH, Ceballos RM, Cohen CS, Coller H, Disney J, Doze VA, Eggers MJ, Farina S, Ferguson EL, Gray JJ, Greenberg JT, Hoffmann A, Jensen-Ryan D, Kao RM, Keene AC, Kowalko JE, Lopez SA, Mathis C, Minkara M, Murren CJ, Ondrechen MJ, Ordoñez P, Osano A, Padilla-Crespo E, Palchoudhury S, Qin H, Ramírez-Lugo J, Reithel J, Shaw CA, Smith A, Smith R, Summers AP, Tsien F, Dolan EL. "How Do We Do This at a Distance?!" A Descriptive Study of Remote Undergraduate Research Programs during COVID-19. CBE Life Sci Educ 2022; 21:ar1. [PMID: 34978923 PMCID: PMC9250374 DOI: 10.1187/cbe.21-05-0125] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The COVID-19 pandemic shut down undergraduate research programs across the United States. A group of 23 colleges, universities, and research institutes hosted remote undergraduate research programs in the life sciences during Summer 2020. Given the unprecedented offering of remote programs, we carried out a study to describe and evaluate them. Using structured templates, we documented how programs were designed and implemented, including who participated. Through focus groups and surveys, we identified programmatic strengths and shortcomings as well as recommendations for improvements from students' perspectives. Strengths included the quality of mentorship, opportunities for learning and professional development, and a feeling of connection with a larger community. Weaknesses included limited cohort building, challenges with insufficient structure, and issues with technology. Although all programs had one or more activities related to diversity, equity, inclusion, and justice, these topics were largely absent from student reports even though programs coincided with a peak in national consciousness about racial inequities and structural racism. Our results provide evidence for designing remote Research Experiences for Undergraduates (REUs) that are experienced favorably by students. Our results also indicate that remote REUs are sufficiently positive to further investigate their affordances and constraints, including the potential to scale up offerings, with minimal concern about disenfranchising students.
Collapse
Affiliation(s)
- Olivia A. Erickson
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602
| | - Rebecca B. Cole
- Department of Psychology, University of Georgia, Athens, GA 30602
| | - Jared M. Isaacs
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602
| | | | - Jonathan Arnold
- Department of Genetics, University of Georgia, Athens, GA 30602
| | - Allison Augustus-Wallace
- Department of Medicine & Office of Diversity & Community Engagement, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Joseph C. Ayoob
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260
| | - Alan Berkowitz
- Education Department, Cary Institute for Ecosystem Studies, Millbrook, NY 12545
| | - Janet Branchaw
- WISCIENCE and the Department of Kinesiology, University of Wisconsin–Madison, Madison, WI 53706
| | - Kevin R. Burgio
- Education Department, Cary Institute for Ecosystem Studies, Millbrook, NY 12545
- New York City Audubon Society, New York, NY 10010; and Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269
| | | | | | - C. Sarah Cohen
- Department of Biology, Estuary and Ocean Science Center, San Francisco State University, San Francisco, CA 94132
| | - Hilary Coller
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095
| | - Jane Disney
- Community Environmental Health Laboratory, Mt. Desert Island Biological Laboratory, Salisbury Cove, ME 04672
| | - Van A. Doze
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND 58202
| | - Margaret J. Eggers
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717
| | - Stacy Farina
- Department of Biology, Howard University, Washington, DC 20059
| | - Edwin L. Ferguson
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Jeffrey J. Gray
- Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Alexander Hoffmann
- Department of Microbiology, Immunology, and Molecular Genetics, and Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, 90095
| | - Danielle Jensen-Ryan
- Department of Math and Sciences, Laramie County Community College, Cheyenne, WY 82007
| | - Robert M. Kao
- Science Department, College of Arts and Sciences, Heritage University, Toppenish, WA 98948
| | - Alex C. Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL 33458
| | | | - Steven A. Lopez
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115
| | - Camille Mathis
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD 21218
| | - Mona Minkara
- Department of Bioengineering, Northeastern University, Boston, MA 02115
| | | | - Mary Jo Ondrechen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115
| | - Patricia Ordoñez
- Department of Computer Science, University of Puerto Rico Río Piedras, San Juan, PR 00925
| | - Anne Osano
- Department of Natural Sciences, Bowie State University, Bowie, MD 20715
| | - Elizabeth Padilla-Crespo
- Department of Science and Technology, Inter American University of Puerto Rico–Aguadilla, Aguadilla, PR 00605
| | - Soubantika Palchoudhury
- Civil and Chemical Engineering Department, University of Tennessee at Chattanooga, Chattanooga, TN 37403-2598
| | - Hong Qin
- Department of Computer Science and Engineering, Department of Biology, Geology, and Environmental Science, University of Tennessee at Chattanooga, Chattanooga, TN 37403
| | - Juan Ramírez-Lugo
- Department of Biology, University of Puerto Rico Río Piedras, San Juan, PR 00925
| | - Jennifer Reithel
- Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224
| | - Colin A. Shaw
- Undergraduate Scholars Program and Department of Earth Sciences, Montana State University, Bozeman, MT 59717
| | - Amber Smith
- Wisconsin Institute for Science Education and Community Engagement, University of Wisconsin–Madison, Madison, WI 53706
| | - Rosemary Smith
- Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209
| | - Adam P. Summers
- Friday Harbor Laboratories, Bio/SAFS, University of Washington, Friday Harbor, WA 98250
| | - Fern Tsien
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112
| | - Erin L. Dolan
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602
- *Address correspondence to: Erin L. Dolan, ()
| |
Collapse
|
9
|
Jeleńska J, Lee J, Manning AJ, Wolfgeher DJ, Ahn Y, Walters-Marrah G, Lopez IE, Garcia L, McClerklin SA, Michelmore RW, Kron SJ, Greenberg JT. Pseudomonas syringae effector HopZ3 suppresses the bacterial AvrPto1-tomato PTO immune complex via acetylation. PLoS Pathog 2021; 17:e1010017. [PMID: 34724007 PMCID: PMC8584673 DOI: 10.1371/journal.ppat.1010017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 11/11/2021] [Accepted: 10/07/2021] [Indexed: 11/23/2022] Open
Abstract
The plant pathogen Pseudomonas syringae secretes multiple effectors that modulate plant defenses. Some effectors trigger defenses due to specific recognition by plant immune complexes, whereas others can suppress the resulting immune responses. The HopZ3 effector of P. syringae pv. syringae B728a (PsyB728a) is an acetyltransferase that modifies not only components of plant immune complexes, but also the Psy effectors that activate these complexes. In Arabidopsis, HopZ3 acetylates the host RPM1 complex and the Psy effectors AvrRpm1 and AvrB3. This study focuses on the role of HopZ3 during tomato infection. In Psy-resistant tomato, the main immune complex includes PRF and PTO, a RIPK-family kinase that recognizes the AvrPto effector. HopZ3 acts as a virulence factor on tomato by suppressing AvrPto1Psy-triggered immunity. HopZ3 acetylates AvrPto1Psy and the host proteins PTO, SlRIPK and SlRIN4s. Biochemical reconstruction and site-directed mutagenesis experiments suggest that acetylation acts in multiple ways to suppress immune signaling in tomato. First, acetylation disrupts the critical AvrPto1Psy-PTO interaction needed to initiate the immune response. Unmodified residues at the binding interface of both proteins and at other residues needed for binding are acetylated. Second, acetylation occurs at residues important for AvrPto1Psy function but not for binding to PTO. Finally, acetylation reduces specific phosphorylations needed for promoting the immune-inducing activity of HopZ3’s targets such as AvrPto1Psy and PTO. In some cases, acetylation competes with phosphorylation. HopZ3-mediated acetylation suppresses the kinase activity of SlRIPK and the phosphorylation of its SlRIN4 substrate previously implicated in PTO-signaling. Thus, HopZ3 disrupts the functions of multiple immune components and the effectors that trigger them, leading to increased susceptibility to infection. Finally, mass spectrometry used to map specific acetylated residues confirmed HopZ3’s unusual capacity to modify histidine in addition to serine, threonine and lysine residues. By secreting virulence proteins (effectors) into their hosts, pathogenic bacteria hijack host cellular processes to promote bacterial colonization and disease development. For the plant pathogen Pseudomonas syringae, the coordinated action of effectors often mediates modifications of host defense proteins to inhibit their function. However, plants have evolved the ability to induce innate immunity upon recognition of effector-induced modifications of host proteins. How do pathogens circumvent the immune-inducing activity of certain effectors? They deploy more effectors to suppress these defenses. HopZ3, an acetyltransferase from P. syringae, is unique among plant pathogen effectors characterized so far in its ability to modify not only multiple components of the effector-triggered immune pathway, but also the triggering effector itself. Through the direct acetylation of residues involved in the interaction and activation of the bacterial effector AvrPto1Psy and tomato kinase PTO, HopZ3 modifications disrupt their binding and block phosphorylations necessary for immune induction. Additionally, HopZ3 acetylates other possible components in the PTO signaling pathway, including activation sites in SlRIPK kinase, leading to suppression of its activity and reduced phosphorylation of SlRIN4s. Our study emphasizes the importance of HopZ3-dependent acetylation of immune complexes and bacterial effectors across plant species in the suppression of effector-induced immunity.
Collapse
Affiliation(s)
- Joanna Jeleńska
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jiyoung Lee
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Andrew J. Manning
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Donald J. Wolfgeher
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Youngjoo Ahn
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - George Walters-Marrah
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Ivan E. Lopez
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Lissette Garcia
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Sheri A. McClerklin
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Richard W. Michelmore
- The Genome Center & Department of Plant Sciences, University of California, Davis, California, United States of America
| | - Stephen J. Kron
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
| |
Collapse
|
10
|
Jiang SC, Engle NL, Banday ZZ, Cecchini NM, Jung HW, Tschaplinski TJ, Greenberg JT. ALD1 accumulation in Arabidopsis epidermal plastids confers local and non-autonomous disease resistance. J Exp Bot 2021; 72:2710-2726. [PMID: 33463678 PMCID: PMC8006555 DOI: 10.1093/jxb/eraa609] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/24/2020] [Indexed: 05/10/2023]
Abstract
The Arabidopsis plastid-localized ALD1 protein acts in the lysine catabolic pathway that produces infection-induced pipecolic acid (Pip), Pip derivatives, and basal non-Pip metabolite(s). ALD1 is indispensable for disease resistance associated with Pseudomonas syringae infections of naïve plants as well as those previously immunized by a local infection, a phenomenon called systemic acquired resistance (SAR). Pseudomonas syringae is known to associate with mesophyll as well as epidermal cells. To probe the importance of epidermal cells in conferring bacterial disease resistance, we studied plants in which ALD1 was only detectable in the epidermal cells of specific leaves. Local disease resistance and many features of SAR were restored when ALD1 preferentially accumulated in the epidermal plastids at immunization sites. Interestingly, SAR restoration occurred without appreciable accumulation of Pip or known Pip derivatives in secondary distal leaves. Our findings establish that ALD1 has a non-autonomous effect on pathogen growth and defense activation. We propose that ALD1 is sufficient in the epidermis of the immunized leaves to activate SAR, but basal ALD1 and possibly a non-Pip metabolite(s) are also needed at all infection sites to fully suppress bacterial growth. Thus, epidermal plastids that contain ALD1 play a key role in local and whole-plant immune signaling.
Collapse
Affiliation(s)
- Shang-Chuan Jiang
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, USA
| | | | - Zeeshan Zahoor Banday
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, USA
| | - Nicolás M Cecchini
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, USA
| | - Ho Won Jung
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, USA
| | | | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, USA
| |
Collapse
|
11
|
Cecchini NM, Speed DJ, Roychoudhry S, Greenberg JT. Kinases and protein motifs required for AZI1 plastid localization and trafficking during plant defense induction. Plant J 2021; 105:1615-1629. [PMID: 33342031 PMCID: PMC8048937 DOI: 10.1111/tpj.15137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 05/10/2023]
Abstract
The proper subcellular localization of defense factors is an important part of the plant immune system. A key component for systemic resistance, lipid transfer protein (LTP)-like AZI1, is needed for the systemic movement of the priming signal azelaic acid (AZA) and a pool of AZI1 exists at the site of AZA production, the plastid envelope. Moreover, after systemic defense-triggering infections, the proportion of AZI1 localized to plastids increases. However, AZI1 does not possess a classical plastid transit peptide that can explain its localization. Instead, AZI1 uses a bipartite N-terminal signature that allows for its plastid targeting. Furthermore, the kinases MPK3 and MPK6, associated with systemic immunity, promote the accumulation of AZI1 at plastids during priming induction. Our results indicate the existence of a mode of plastid targeting possibly related to defense responses.
Collapse
Affiliation(s)
- Nicolás M. Cecchini
- Department of Molecular Genetics and Cell BiologyThe University of Chicago929 East 57th Street GCIS 524WChicagoIL60637USA
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC‐CONICET) and Departamento de Química Biológica Ranwel CaputtoFacultad de Ciencias QuímicasUniversidad Nacional de CórdobaHaya de la Torre y Medina Allende – Ciudad UniversitariaCórdobaX5000HUAArgentina
| | - DeQuantarius J. Speed
- Department of Molecular Genetics and Cell BiologyThe University of Chicago929 East 57th Street GCIS 524WChicagoIL60637USA
| | - Suruchi Roychoudhry
- Department of Molecular Genetics and Cell BiologyThe University of Chicago929 East 57th Street GCIS 524WChicagoIL60637USA
- Centre for Plant SciencesUniversity of LeedsLeedsLS2 9JTUK
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell BiologyThe University of Chicago929 East 57th Street GCIS 524WChicagoIL60637USA
| |
Collapse
|
12
|
Speed DJ, Greenberg JT. The Function and Regulation of Chloroplast Targeting of AZI1, a Key Factor in Plant Systemic Immune Signaling. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
13
|
Cecchini NM, Song Y, Roychoudhry S, Greenberg JT, Haney CH. An Improved Bioassay to Study Arabidopsis Induced Systemic Resistance (ISR) Against Bacterial Pathogens and Insect Pests. Bio Protoc 2019; 9:e3236. [PMID: 33654765 DOI: 10.21769/bioprotoc.3236] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [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: 02/07/2019] [Revised: 04/19/2019] [Accepted: 04/22/2019] [Indexed: 11/02/2022] Open
Abstract
The plant immune system is essential for plants to perceive and defend against bacterial, fungal and insect pests and pathogens. Induced systemic resistance (ISR) is a systemic immune response that occurs upon root colonization by beneficial microbes. A well-studied model for ISR is the association of specific beneficial strains of Pseudomonas spp. with the reference plant Arabidopsis thaliana. Here, we describe a robust, increased throughput, bioassay to study ISR against the bacterial pathogen Pseudomonas cannabina pv. alisalensis (formerly called Pseudomonas syringae pv. maculicola) strain ES4326 and the herbivore Trichoplusia ni by inoculating Pseudomonas simiae strain WCS417 (formerly called Pseudomonas fluorescens WCS417) on Arabidopsis plants grown in Jiffy-7® peat pellets. While most commonly used for Pseudomonas-triggered ISR on Arabidopsis, this assay is effective for diverse rhizosphere bacterial strains, plant species, pathogens and herbivores.
Collapse
Affiliation(s)
- Nicolás M Cecchini
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Córdoba X5000HUA, Argentina
| | - Yi Song
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | | | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, USA
| | - Cara H Haney
- Department of Microbiology and Immunology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| |
Collapse
|
14
|
Cecchini NM, Roychoudhry S, Speed DJ, Steffes K, Tambe A, Zodrow K, Konstantinoff K, Jung HW, Engle NL, Tschaplinski TJ, Greenberg JT. Underground Azelaic Acid-Conferred Resistance to Pseudomonas syringae in Arabidopsis. Mol Plant Microbe Interact 2019; 32:86-94. [PMID: 30156481 DOI: 10.1094/mpmi-07-18-0185-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Local interactions between individual plant organs and diverse microorganisms can lead to whole plant immunity via the mobilization of defense signals. One such signal is the plastid lipid-derived oxylipin azelaic acid (AZA). Arabidopsis lacking AZI1 or EARLI1, related lipid transfer family proteins, exhibit reduced AZA transport among leaves and cannot mount systemic immunity. AZA has been detected in roots as well as leaves. Therefore, the present study addresses the effects on plants of AZA application to roots. AZA but not the structurally related suberic acid inhibits root growth when directly in contact with roots. Treatment of roots with AZA also induces resistance to Pseudomonas syringae in aerial tissues. These effects of AZA on root growth and disease resistance depend, at least partially, on AZI1 and EARLI1. AZI1 in roots localizes to plastids, similar to its known location in leaves. Interestingly, kinases previously shown to modify AZI1 in vitro, MPK3 and MPK6, are also needed for AZA-induced root-growth inhibition and aboveground immunity. Finally, deuterium-labeled AZA applied to the roots does not move to aerial tissues. Thus, AZA application to roots triggers systemic immunity through an AZI1/EARLI1/MPK3/MPK6-dependent pathway and AZA effects may involve one or more additional mobile signals.
Collapse
Affiliation(s)
- Nicolás M Cecchini
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Suruchi Roychoudhry
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - DeQuantarius J Speed
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Kevin Steffes
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Arjun Tambe
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Kristin Zodrow
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Katerina Konstantinoff
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| | - Ho Won Jung
- 2 Department of Molecular Genetics, Dong-A University, 37 Nakdong-Daero 550beon-gil, Saha-gu, Busan 49315, Korea; and
| | - Nancy L Engle
- 3 Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, U.S.A
| | | | - Jean T Greenberg
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago, IL 60637, U.S.A
| |
Collapse
|
15
|
Seguel A, Jelenska J, Herrera-Vásquez A, Marr SK, Joyce MB, Gagesch KR, Shakoor N, Jiang SC, Fonseca A, Wildermuth MC, Greenberg JT, Holuigue L. PROHIBITIN3 Forms Complexes with ISOCHORISMATE SYNTHASE1 to Regulate Stress-Induced Salicylic Acid Biosynthesis in Arabidopsis. Plant Physiol 2018; 176:2515-2531. [PMID: 29438088 PMCID: PMC5841719 DOI: 10.1104/pp.17.00941] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/22/2018] [Indexed: 05/19/2023]
Abstract
Salicylic acid (SA) is a major defense signal in plants. In Arabidopsis (Arabidopsis thaliana), the chloroplast-localized isochorismate pathway is the main source of SA biosynthesis during abiotic stress or pathogen infections. In the first step of the pathway, the enzyme ISOCHORISMATE SYNTHASE1 (ICS1) converts chorismate to isochorismate. An unknown enzyme subsequently converts isochorismate to SA. Here, we show that ICS1 protein levels increase during UV-C stress. To identify proteins that may play roles in SA production by regulating ICS1, we analyzed proteins that coimmunoprecipitated with ICS1 via mass spectrometry. The ICS1 complexes contained a large number of peptides from the PROHIBITIN (PHB) protein family, with PHB3 the most abundant. PHB proteins have diverse biological functions that include acting as scaffolds for protein complex formation and stabilization. PHB3 was reported previously to localize to mitochondria. Using fractionation, protease protection, and live imaging, we show that PHB3 also localizes to chloroplasts, where ICS1 resides. Notably, loss of PHB3 function led to decreased ICS1 protein levels in response to UV-C stress. However, ICS1 transcript levels remain unchanged, indicating that ICS1 is regulated posttranscriptionally. The phb3 mutant displayed reduced levels of SA, the SA-regulated protein PR1, and hypersensitive cell death in response to UV-C and avirulent strains of Pseudomonas syringae and, correspondingly, supported increased growth of P. syringae The expression of a PHB3 transgene in the phb3 mutant complemented all of these phenotypes. We suggest a model in which the formation of PHB3-ICS1 complexes stabilizes ICS1 to promote SA production in response to stress.
Collapse
Affiliation(s)
- Aldo Seguel
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Ariel Herrera-Vásquez
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Sharon K Marr
- Department of Plant and Microbial Pathology, University of California, Berkeley, California 94720
| | - Michael B Joyce
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Kelsey R Gagesch
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Nadia Shakoor
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Shang-Chuan Jiang
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Alejandro Fonseca
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Mary C Wildermuth
- Department of Plant and Microbial Pathology, University of California, Berkeley, California 94720
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Loreto Holuigue
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| |
Collapse
|
16
|
Manning AJ, Lee J, Wolfgeher DJ, Kron SJ, Greenberg JT. Simple strategies to enhance discovery of acetylation post-translational modifications by quadrupole-orbitrap LC-MS/MS. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2018; 1866:224-229. [DOI: 10.1016/j.bbapap.2017.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/07/2017] [Accepted: 10/13/2017] [Indexed: 12/26/2022]
|
17
|
Michelmore R, Coaker G, Bart R, Beattie G, Bent A, Bruce T, Cameron D, Dangl J, Dinesh-Kumar S, Edwards R, Eves-van den Akker S, Gassmann W, Greenberg JT, Hanley-Bowdoin L, Harrison RJ, Harvey J, He P, Huffaker A, Hulbert S, Innes R, Jones JDG, Kaloshian I, Kamoun S, Katagiri F, Leach J, Ma W, McDowell J, Medford J, Meyers B, Nelson R, Oliver R, Qi Y, Saunders D, Shaw M, Smart C, Subudhi P, Torrance L, Tyler B, Valent B, Walsh J. Foundational and Translational Research Opportunities to Improve Plant Health. Mol Plant Microbe Interact 2017; 30:515-516. [PMID: 28398839 PMCID: PMC5810936 DOI: 10.1094/mpmi-01-17-0010-cr] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Reader Comments | Submit a Comment The white paper reports the deliberations of a workshop focused on biotic challenges to plant health held in Washington, D.C. in September 2016. Ensuring health of food plants is critical to maintaining the quality and productivity of crops and for sustenance of the rapidly growing human population. There is a close linkage between food security and societal stability; however, global food security is threatened by the vulnerability of our agricultural systems to numerous pests, pathogens, weeds, and environmental stresses. These threats are aggravated by climate change, the globalization of agriculture, and an over-reliance on nonsustainable inputs. New analytical and computational technologies are providing unprecedented resolution at a variety of molecular, cellular, organismal, and population scales for crop plants as well as pathogens, pests, beneficial microbes, and weeds. It is now possible to both characterize useful or deleterious variation as well as precisely manipulate it. Data-driven, informed decisions based on knowledge of the variation of biotic challenges and of natural and synthetic variation in crop plants will enable deployment of durable interventions throughout the world. These should be integral, dynamic components of agricultural strategies for sustainable agriculture.
Collapse
Affiliation(s)
- Richard Michelmore
- 1 The Genome Center and Departments of Plant Sciences, Molecular & Cellular Biology, and Medical Microbiology & Immunology, University of California, Davis, CA, U.S.A
| | - Gitta Coaker
- 2 Department of Plant Pathology, University of California, Davis, CA, U.S.A
| | | | | | - Andrew Bent
- 5 University of Wisconsin, Madison, WI, U.S.A
| | | | | | - Jeffery Dangl
- 8 University of North Carolina, Chapel Hill, NC, U.S.A
| | | | - Rob Edwards
- 10 University of Newcastle, Newcastle upon Tyne, U.K
| | | | | | | | | | | | | | - Ping He
- 17 Texas A&M University, College Station, TX, U.S.A
| | | | - Scot Hulbert
- 19 Washington State University, Pullman, WA, U.S.A
| | - Roger Innes
- 20 Indiana University, Bloomigton, IN, U.S.A
| | | | | | | | | | - Jan Leach
- 24 Colorado State University, Fort Collins, CO, U.S.A
| | - Wenbo Ma
- 22 University of California, Riverside, CA, U.S.A
| | | | | | | | | | | | - Yiping Qi
- 29 East Carolina University, Greenville, NC, U.S.A
| | | | | | | | | | - Lesley Torrance
- 33 University of St. Andrews and James Hutton Institute, Fife, U.K
| | - Bret Tyler
- 34 Oregon State University, Corvallis, OR, U.S.A.; and
| | | | - John Walsh
- 35 University of Warwick, Wellesbourne, U.K
| |
Collapse
|
18
|
Jelenska J, Davern SM, Standaert RF, Mirzadeh S, Greenberg JT. Flagellin peptide flg22 gains access to long-distance trafficking in Arabidopsis via its receptor, FLS2. J Exp Bot 2017; 68:1769-1783. [PMID: 28521013 PMCID: PMC5444442 DOI: 10.1093/jxb/erx060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Diverse pathogen-derived molecules, such as bacterial flagellin and its conserved peptide flg22, are recognized in plants via plasma membrane receptors and induce both local and systemic immune responses. The fate of such ligands was unknown: whether and by what mechanism(s) they enter plant cells and whether they are transported to distal tissues. We used biologically active fluorophore and radiolabeled peptides to establish that flg22 moves to distal organs with the closest vascular connections. Remarkably, entry into the plant cell via endocytosis together with the FLS2 receptor is needed for delivery to vascular tissue and long-distance transport of flg22. This contrasts with known routes of long distance transport of other non-cell-permeant molecules in plants, which require membrane-localized transporters for entry to vascular tissue. Thus, a plasma membrane receptor acts as a transporter to enable access of its ligand to distal trafficking routes.
Collapse
Affiliation(s)
- Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Sandra M Davern
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Nuclear Security and Isotope Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Robert F Standaert
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull Wollan Center - a Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Saed Mirzadeh
- Nuclear Security and Isotope Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
19
|
Zhang Z, Tateda C, Jiang SC, Shrestha J, Jelenska J, Speed DJ, Greenberg JT. A Suite of Receptor-Like Kinases and a Putative Mechano-Sensitive Channel Are Involved in Autoimmunity and Plasma Membrane-Based Defenses in Arabidopsis. Mol Plant Microbe Interact 2017; 30:150-160. [PMID: 28051349 DOI: 10.1094/mpmi-09-16-0184-r] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In plants, cell surface pattern recognition receptors (PRRs) provide a first line of defense against pathogens. Although each PRR recognizes a specific ligand, they share common signaling outputs, such as callose and other cell wall-based defenses. Several PRRs are also important for callose induction in response to the defense signal salicylic acid (SA). The extent to which common components are needed for PRR signaling outputs is not known. The gain-of-function Arabidopsis mutant of ACCELERATED CELL DEATH6 (ACD6) acd6-1 shows constitutive callose production that partially depends on PRRs. ACD6-1 (and ACD6) forms complexes with the PRR FLAGELLIN SENSING2, and ACD6 is needed for responses to several PRR ligands. Thus, ACD6-1 could serve as a probe to identify additional proteins important for PRR-mediated signaling. Candidate signaling proteins (CSPs), identified in our proteomic screen after immunoprecipitation of hemagglutinin (HA)-tagged ACD6-1, include several subfamilies of receptor-like kinase (RLK) proteins and a MECHANO-SENSITIVE CHANNEL OF SMALL CONDUCTANCE-LIKE 4 (MSL4). In acd6-1, CSPs contribute to autoimmunity. In wild type, CSPs are needed for defense against bacteria and callose responses to two or more microbial-derived patterns and an SA agonist. CSPs may function to either i) promote the assembly of signaling complexes, ii) regulate the output of known PRRs, or both.
Collapse
Affiliation(s)
- Zhongqin Zhang
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| | - Chika Tateda
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| | - Shang-Chuan Jiang
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| | - Jay Shrestha
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| | | | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago
| |
Collapse
|
20
|
Davern SM, McKnight TE, Standaert RF, Morrell-Falvey JL, Shpak ED, Kalluri UC, Jelenska J, Greenberg JT, Mirzadeh S. Carbon Nanofiber Arrays: A Novel Tool for Microdelivery of Biomolecules to Plants. PLoS One 2016; 11:e0153621. [PMID: 27119338 PMCID: PMC4847769 DOI: 10.1371/journal.pone.0153621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/31/2016] [Indexed: 11/19/2022] Open
Abstract
Effective methods for delivering bioprobes into the cells of intact plants are essential for investigating diverse biological processes. Increasing research on trees, such as Populus spp., for bioenergy applications is driving the need for techniques that work well with tree species. This report introduces vertically aligned carbon nanofiber (VACNF) arrays as a new tool for microdelivery of labeled molecules to Populus leaf tissue and whole plants. We demonstrated that VACNFs penetrate the leaf surface to deliver sub-microliter quantities of solution containing fluorescent or radiolabeled molecules into Populus leaf cells. Importantly, VACNFs proved to be gentler than abrasion with carborundum, a common way to introduce material into leaves. Unlike carborundum, VACNFs did not disrupt cell or tissue integrity, nor did they induce production of hydrogen peroxide, a typical wound response. We show that femtomole to picomole quantities of labeled molecules (fluorescent dyes, small proteins and dextran), ranging from 0.5-500 kDa, can be introduced by VACNFs, and we demonstrate the use of the approach to track delivered probes from their site of introduction on the leaf to distal plant regions. VACNF arrays thus offer an attractive microdelivery method for the introduction of biomolecules and other probes into trees and potentially other types of plants.
Collapse
Affiliation(s)
- Sandra M. Davern
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Timothy E. McKnight
- Electrical & Electronics Systems Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Robert F. Standaert
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Biology & Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Jennifer L. Morrell-Falvey
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Elena D. Shpak
- Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Udaya C. Kalluri
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Saed Mirzadeh
- Nuclear Security & Isotope Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
| |
Collapse
|
21
|
Affiliation(s)
- Hua Lu
- Department of Biological Sciences, University of Maryland Baltimore CountyBaltimore, MD, USA
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of ChicagoChicago, IL, USA
| | - Loreto Holuigue
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de ChileSantiago, Chile
| |
Collapse
|
22
|
Lee J, Manning AJ, Wolfgeher D, Jelenska J, Cavanaugh KA, Xu H, Fernandez SM, Michelmore RW, Kron SJ, Greenberg JT. Acetylation of an NB-LRR Plant Immune-Effector Complex Suppresses Immunity. Cell Rep 2015; 13:1670-82. [PMID: 26586425 PMCID: PMC4967551 DOI: 10.1016/j.celrep.2015.10.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 09/10/2015] [Accepted: 10/09/2015] [Indexed: 12/21/2022] Open
Abstract
Modifications of plant immune complexes by secreted pathogen effectors can trigger strong immune responses mediated by the action of nucleotide binding-leucine-rich repeat immune receptors. Although some strains of the pathogen Pseudomonas syringae harbor effectors that individually can trigger immunity, the plant’s response may be suppressed by other virulence factors. This work reveals a robust strategy for immune suppression mediated by HopZ3, an effector in the YopJ family of acetyltransferases. The suppressing HopZ3 effector binds to and can acetylate multiple members of the RPM1 immune complex, as well as two P. syringae effectors that together activate the RPM1 complex. These acetylations modify serine, threonine, lysine, and/or histidine residues in the targets. Through HopZ3-mediated acetylation, it is possible that the whole effector-immune complex is inactivated, leading to increased growth of the pathogen.
Collapse
Affiliation(s)
- Jiyoung Lee
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Andrew J Manning
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Donald Wolfgeher
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Keri A Cavanaugh
- The Genome Center & Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Huaqin Xu
- The Genome Center & Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Sandra M Fernandez
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Richard W Michelmore
- The Genome Center & Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Stephen J Kron
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
| |
Collapse
|
23
|
Cecchini NM, Jung HW, Engle NL, Tschaplinski TJ, Greenberg JT. ALD1 Regulates Basal Immune Components and Early Inducible Defense Responses in Arabidopsis. Mol Plant Microbe Interact 2015; 28:455-66. [PMID: 25372120 DOI: 10.1094/mpmi-06-14-0187-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Robust immunity requires basal defense machinery to mediate timely responses and feedback cycles to amplify defenses against potentially spreading infections. AGD2-LIKE DEFENSE RESPONSE PROTEIN 1 (ALD1) is needed for the accumulation of the plant defense signal salicylic acid (SA) during the first hours after infection with the pathogen Pseudomonas syringae and is also upregulated by infection and SA. ALD1 is an aminotransferase with multiple substrates and products in vitro. Pipecolic acid (Pip) is an ALD1-dependent bioactive product induced by P. syringae. Here, we addressed roles of ALD1 in mediating defense amplification as well as the levels and responses of basal defense machinery. ALD1 needs immune components PAD4 and ICS1 (an SA synthesis enzyme) to confer disease resistance, possibly through a transcriptional amplification loop between them. Furthermore, ALD1 affects basal defense by controlling microbial-associated molecular pattern (MAMP) receptor levels and responsiveness. Vascular exudates from uninfected ALD1-overexpressing plants confer local immunity to the wild type and ald1 mutants yet are not enriched for Pip. We infer that, in addition to affecting Pip accumulation, ALD1 produces non-Pip metabolites that play roles in immunity. Thus, distinct metabolite signals controlled by the same enzyme affect basal and early defenses versus later defense responses, respectively.
Collapse
Affiliation(s)
- Nicolás M Cecchini
- 1 Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street GCIS 524W, Chicago 60637, U.S.A
| | | | | | | | | |
Collapse
|
24
|
Tateda C, Zhang Z, Greenberg JT. Linking pattern recognition and salicylic acid responses in Arabidopsis through ACCELERATED CELL DEATH6 and receptors. Plant Signal Behav 2015; 10:e1010912. [PMID: 26442718 PMCID: PMC4883847 DOI: 10.1080/15592324.2015.1010912] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/22/2014] [Accepted: 01/05/2015] [Indexed: 05/19/2023]
Abstract
The Arabidopsis membrane protein ACCELERATED CELL DEATH 6 (ACD6) and the defense signal salicylic acid (SA) are part of a positive feedback loop that regulates the levels of at least 2 pathogen-associated molecular patterns (PAMP) receptors, including FLAGELLIN SENSING 2 (FLS2) and CHITIN ELICITOR RECEPTOR (LYSM domain receptor-like kinase 1, CERK1). ACD6- and SA-mediated regulation of these receptors results in potentiation of responses to FLS2 and CERK1 ligands (e.g. flg22 and chitin, respectively). ACD6, FLS2 and CERK1 are also important for callose induction in response to an SA agonist even in the absence of PAMPs. Here, we report that another receptor, EF-Tu RECEPTOR (EFR) is also part of the ACD6/SA signaling network, similar to FLS2 and CERK1.
Collapse
Affiliation(s)
- Chika Tateda
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| | - Zhongqin Zhang
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
- Correspondence to: Jean T Greenberg;
| |
Collapse
|
25
|
Tateda C, Zhang Z, Shrestha J, Jelenska J, Chinchilla D, Greenberg JT. Salicylic acid regulates Arabidopsis microbial pattern receptor kinase levels and signaling. Plant Cell 2014; 26:4171-87. [PMID: 25315322 PMCID: PMC4247590 DOI: 10.1105/tpc.114.131938] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 09/19/2014] [Accepted: 09/27/2014] [Indexed: 05/18/2023]
Abstract
In Arabidopsis thaliana, responses to pathogen-associated molecular patterns (PAMPs) are mediated by cell surface pattern recognition receptors (PRRs) and include the accumulation of reactive oxygen species, callose deposition in the cell wall, and the generation of the signal molecule salicylic acid (SA). SA acts in a positive feedback loop with ACCELERATED CELL DEATH6 (ACD6), a membrane protein that contributes to immunity. This work shows that PRRs associate with and are part of the ACD6/SA feedback loop. ACD6 positively regulates the abundance of several PRRs and affects the responsiveness of plants to two PAMPs. SA accumulation also causes increased levels of PRRs and potentiates the responsiveness of plants to PAMPs. Finally, SA induces PRR- and ACD6-dependent signaling to induce callose deposition independent of the presence of PAMPs. This PAMP-independent effect of SA causes a transient reduction of PRRs and ACD6-dependent reduced responsiveness to PAMPs. Thus, SA has a dynamic effect on the regulation and function of PRRs. Within a few hours, SA signaling promotes defenses and downregulates PRRs, whereas later (within 24 to 48 h) SA signaling upregulates PRRs, and plants are rendered more responsive to PAMPs. These results implicate multiple modes of signaling for PRRs in response to PAMPs and SA.
Collapse
Affiliation(s)
- Chika Tateda
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Zhongqin Zhang
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Jay Shrestha
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| | - Delphine Chinchilla
- Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, 4056 Basel, Switzerland
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
| |
Collapse
|
26
|
Zhang Z, Shrestha J, Tateda C, Greenberg JT. Salicylic acid signaling controls the maturation and localization of the arabidopsis defense protein ACCELERATED CELL DEATH6. Mol Plant 2014; 7:1365-1383. [PMID: 24923602 PMCID: PMC4168298 DOI: 10.1093/mp/ssu072] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
ACCELERATED CELL DEATH6 (ACD6) is a multipass membrane protein with an ankyrin domain that acts in a positive feedback loop with the defense signal salicylic acid (SA). This study implemented biochemical approaches to infer changes in ACD6 complexes and localization. In addition to forming endoplasmic reticulum (ER)- and plasma membrane (PM)-localized complexes, ACD6 forms soluble complexes, where it is bound to cytosolic HSP70, ubiquitinated, and degraded via the proteasome. Thus, ACD6 constitutively undergoes ER-associated degradation. During SA signaling, the soluble ACD6 pool decreases, whereas the PM pool increases. Similarly, ACD6-1, an activated version of ACD6 that induces SA, is present at low levels in the soluble fraction and high levels in the PM. However, ACD6 variants with amino acid substitutions in the ankyrin domain form aberrant, inactive complexes, are induced by a SA agonist, but show no PM localization. SA signaling also increases the PM pools of FLAGELLIN SENSING2 (FLS2) and BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1). FLS2 forms complexes ACD6; both FLS2 and BAK1 require ACD6 for maximal accumulation at the PM in response to SA signaling. A plausible scenario is that SA increases the efficiency of productive folding and/or complex formation in the ER, such that ACD6, together with FLS2 and BAK1, reaches the cell surface to more effectively promote immune responses.
Collapse
Affiliation(s)
- Zhongqin Zhang
- Department of Molecular Genetics and Cell Biology, University of Chicago, 929 East 57 Street, GCIS W524, Chicago, IL 60637, USA
| | - Jay Shrestha
- Department of Molecular Genetics and Cell Biology, University of Chicago, 929 East 57 Street, GCIS W524, Chicago, IL 60637, USA
| | - Chika Tateda
- Department of Molecular Genetics and Cell Biology, University of Chicago, 929 East 57 Street, GCIS W524, Chicago, IL 60637, USA
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, 929 East 57 Street, GCIS W524, Chicago, IL 60637, USA.
| |
Collapse
|
27
|
Bi FC, Liu Z, Wu JX, Liang H, Xi XL, Fang C, Sun TJ, Yin J, Dai GY, Rong C, Greenberg JT, Su WW, Yao N. Loss of ceramide kinase in Arabidopsis impairs defenses and promotes ceramide accumulation and mitochondrial H2O2 bursts. Plant Cell 2014; 26:3449-67. [PMID: 25149397 PMCID: PMC4176443 DOI: 10.1105/tpc.114.127050] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/12/2014] [Accepted: 08/04/2014] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana plants that lack ceramide kinase, encoded by ACCELERATED CELL DEATH5 (ACD5), display spontaneous programmed cell death late in development and accumulate substrates of ACD5. Here, we compared ceramide accumulation kinetics, defense responses, ultrastructural features, and sites of reactive oxygen species (ROS) production in wild-type and acd5 plants during development and/or Botrytis cinerea infection. Quantitative sphingolipid profiling indicated that ceramide accumulation in acd5 paralleled the appearance of spontaneous cell death, and it was accompanied by autophagy and mitochondrial ROS accumulation. Plants lacking ACD5 differed significantly from the wild type in their responses to B. cinerea, showing earlier and higher increases in ceramides, greater disease, smaller cell wall appositions (papillae), reduced callose deposition and apoplastic ROS, and increased mitochondrial ROS. Together, these data show that ceramide kinase greatly affects sphingolipid metabolism and the site of ROS accumulation during development and infection, which likely explains the developmental and infection-related cell death phenotypes. The acd5 plants also showed an early defect in restricting B. cinerea germination and growth, which occurred prior to the onset of cell death. This early defect in B. cinerea restriction in acd5 points to a role for ceramide phosphate and/or the balance of ceramides in mediating early antifungal responses that are independent of cell death.
Collapse
Affiliation(s)
- Fang-Cheng Bi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Zhe Liu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Hua Liang
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
| | - Xue-Li Xi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Ce Fang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Tie-Jun Sun
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jian Yin
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Guang-Yi Dai
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Chan Rong
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois 60637
| | - Wei-Wei Su
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Nan Yao
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P.R. China
| |
Collapse
|
28
|
Kang Y, Jelenska J, Cecchini NM, Li Y, Lee MW, Kovar DR, Greenberg JT. HopW1 from Pseudomonas syringae disrupts the actin cytoskeleton to promote virulence in Arabidopsis. PLoS Pathog 2014; 10:e1004232. [PMID: 24968323 PMCID: PMC4072799 DOI: 10.1371/journal.ppat.1004232] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 05/22/2014] [Indexed: 01/17/2023] Open
Abstract
A central mechanism of virulence of extracellular bacterial pathogens is the injection into host cells of effector proteins that modify host cellular functions. HopW1 is an effector injected by the type III secretion system that increases the growth of the plant pathogen Pseudomonas syringae on the Columbia accession of Arabidopsis. When delivered by P. syringae into plant cells, HopW1 causes a reduction in the filamentous actin (F-actin) network and the inhibition of endocytosis, a known actin-dependent process. When directly produced in plants, HopW1 forms complexes with actin, disrupts the actin cytoskeleton and inhibits endocytosis as well as the trafficking of certain proteins to vacuoles. The C-terminal region of HopW1 can reduce the length of actin filaments and therefore solubilize F-actin in vitro. Thus, HopW1 acts by disrupting the actin cytoskeleton and the cell biological processes that depend on actin, which in turn are needed for restricting P. syringae growth in Arabidopsis.
Collapse
Affiliation(s)
- Yongsung Kang
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Nicolas M. Cecchini
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Yujie Li
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Min Woo Lee
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - David R. Kovar
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| |
Collapse
|
29
|
Jelenska J, Kang Y, Greenberg JT. Plant pathogenic bacteria target the actin microfilament network involved in the trafficking of disease defense components. Bioarchitecture 2014; 4:149-53. [PMID: 25551177 PMCID: PMC4914032 DOI: 10.4161/19490992.2014.980662] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 02/06/2023]
Abstract
Cells of infected organisms transport disease defense-related molecules along actin filaments to deliver them to their sites of action to combat the pathogen. To accommodate higher demand for intracellular traffic, plant F-actin density increases transiently during infection or treatment of Arabidopsis with pathogen-associated molecules. Many animal and plant pathogens interfere with actin polymerization and depolymerization to avoid immune responses. Pseudomonas syringae, a plant extracellular pathogen, injects HopW1 effector into host cells to disrupt the actin cytoskeleton and reduce vesicle movement in order to elude defense responses. In some Arabidopsis accessions, however, HopW1 is recognized and causes resistance via an actin-independent mechanism. HopW1 targets isoform 7 of vegetative actin (ACT7) that is regulated by phytohormones and environmental factors. We hypothesize that dynamic changes of ACT7 filaments are involved in plant immunity.
Collapse
Affiliation(s)
- Joanna Jelenska
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| | - Yongsung Kang
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
- Current address: Department of Agricultural Biotechnology; Seoul National University; Seoul, South Korea
| | - Jean T Greenberg
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| |
Collapse
|
30
|
Lee J, Teitzel GM, Greenberg JT. SGT1b is required for HopZ3-mediated suppression of the epiphytic growth of Pseudomonas syringae on N. benthamiana. Plant Signal Behav 2012; 7:1129-31. [PMID: 22899059 PMCID: PMC3489644 DOI: 10.4161/psb.21319] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Type III secreted effectors shape the potential of bacterial pathogens to cause disease on plants. Some effectors affect pathogen growth only in specific niches. For example, HopZ3 causes reduced epiphytic growth of Pseudomonas syringae strain B728a on Nicotiana benthamiana. This raises the question of whether genes important for effector-triggered disease resistance are needed for responses to effectors whose major effect is in the epiphytic niche. We report that SGT1b, a protein known to be important for defense activation, is essential for HopZ3-mediated suppression of PsyB728a epiphytic growth. SGT1b is required for HopZ3- and AvrB3-induced cell death in N. benthamiana plants that express the Pto resistance gene from tomato. We suggest that HopZ3 activates R gene mediated responses in N. benthamiana.
Collapse
Affiliation(s)
- Jiyoung Lee
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| | - Gail M. Teitzel
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology; The University of Chicago; Chicago, IL USA
| |
Collapse
|
31
|
Lee J, Teitzel GM, Munkvold K, del Pozo O, Martin GB, Michelmore RW, Greenberg JT. Type III secretion and effectors shape the survival and growth pattern of Pseudomonas syringae on leaf surfaces. Plant Physiol 2012; 158:1803-18. [PMID: 22319072 PMCID: PMC3320187 DOI: 10.1104/pp.111.190686] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/07/2012] [Indexed: 05/19/2023]
Abstract
The bacterium Pseudomonas syringae pv syringae B728a (PsyB728a) uses a type III secretion system (T3SS) to inject effector proteins into plant cells, a process that modulates the susceptibility of different plants to infection. Analysis of GREEN FLUORESCENT PROTEIN-expressing PsyB728a after spray inoculation without additives under moderate relative humidity conditions permitted (1) a detailed analysis of this strain's survival and growth pattern on host (Nicotiana benthamiana) and nonhost (tomato [Solanum lycopersicum]) leaf surfaces, (2) an assessment of the role of plant defenses in affecting PsyB728a leaf surface (epiphytic) growth, and (3) the contribution of the T3SS and specific effectors to PsyB728a epiphytic survival and growth. On host leaf surfaces, PsyB728a cells initially persist without growing, and show an increased population only after 48 h, unless plants are pretreated with the defense-inducing chemical benzothiazole. During the persistence period, some PsyB728a cells induce a T3SS reporter, whereas a T3SS-deficient mutant shows reduced survival. By 72 h, rare invasion by PsyB728a to the mesophyll region of host leaves occurs, but endophytic and epiphytic bacterial growths are not correlated. The effectors HopZ3 and HopAA1 delay the onset of epiphytic growth of PsyB728a on N. benthamiana, whereas they promote epiphytic survival/growth on tomato. These effectors localize to distinct sites in plant cells and likely have different mechanisms of action. HopZ3 may enzymatically modify host targets, as it requires residues important for the catalytic activity of other proteins in its family of proteases. Thus, the T3SS, HopAA1, HopZ3, and plant defenses strongly influence epiphytic survival and/or growth of PsyB728a.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637 (J.L., G.M.T., J.T.G.); Boyce Thompson Institute for Plant Research, Ithaca, New York 14853 (K.M., O.d.P., G.B.M.); Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853 (G.B.M.); The Genome Center, University of California, Davis, California 95616 (R.W.M.)
| |
Collapse
|
32
|
Pattanayak GK, Venkataramani S, Hortensteiner S, Kunz L, Christ B, Moulin M, Smith AG, Okamoto Y, Tamiaki H, Sugishima M, Greenberg JT. Accelerated cell death 2 suppresses mitochondrial oxidative bursts and modulates cell death in Arabidopsis. Plant J 2012; 69:589-600. [PMID: 21988537 PMCID: PMC3274588 DOI: 10.1111/j.1365-313x.2011.04814.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The Arabidopsis ACCELERATED CELL DEATH 2 (ACD2) protein protects cells from programmed cell death (PCD) caused by endogenous porphyrin-related molecules like red chlorophyll catabolite or exogenous protoporphyrin IX. We previously found that during bacterial infection, ACD2, a chlorophyll breakdown enzyme, localizes to both chloroplasts and mitochondria in leaves. Additionally, acd2 cells show mitochondrial dysfunction. In plants with acd2 and ACD2 (+) sectors, ACD2 functions cell autonomously, implicating a pro-death ACD2 substrate as being cell non-autonomous in promoting the spread of PCD. ACD2 targeted solely to mitochondria can reduce the accumulation of an ACD2 substrate that originates in chloroplasts, indicating that ACD2 substrate molecules are likely to be mobile within cells. Two different light-dependent reactive oxygen bursts in mitochondria play prominent and causal roles in the acd2 PCD phenotype. Finally, ACD2 can complement acd2 when targeted to mitochondria or chloroplasts, respectively, as long as it is catalytically active: the ability to bind substrate is not sufficient for ACD2 to function in vitro or in vivo. Together, the data suggest that ACD2 localizes dynamically during infection to protect cells from pro-death mobile substrate molecules, some of which may originate in chloroplasts, but have major effects on mitochondria.
Collapse
Affiliation(s)
- Gopal K. Pattanayak
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
| | - Sujatha Venkataramani
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
| | | | - Lukas Kunz
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland
| | - Bastien Christ
- Institute of Plant Biology, University of Zurich, CH-8008 Zurich, Switzerland
| | - Michael Moulin
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB23EA, United Kingdom
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB23EA, United Kingdom
| | - Yukihiro Okamoto
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
| |
Collapse
|
33
|
Bi FC, Zhang QF, Liu Z, Fang C, Li J, Su JB, Greenberg JT, Wang HB, Yao N. A conserved cysteine motif is critical for rice ceramide kinase activity and function. PLoS One 2011; 6:e18079. [PMID: 21483860 PMCID: PMC3069040 DOI: 10.1371/journal.pone.0018079] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 02/22/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Ceramide kinase (CERK) is a key regulator of cell survival in dicotyledonous plants and animals. Much less is known about the roles of CERK and ceramides in mediating cellular processes in monocot plants. Here, we report the characterization of a ceramide kinase, OsCERK, from rice (Oryza sativa spp. Japonica cv. Nipponbare) and investigate the effects of ceramides on rice cell viability. PRINCIPAL FINDINGS OsCERK can complement the Arabidopsis CERK mutant acd5. Recombinant OsCERK has ceramide kinase activity with Michaelis-Menten kinetics and optimal activity at 7.0 pH and 40°C. Mg2+ activates OsCERK in a concentration-dependent manner. Importantly, a CXXXCXXC motif, conserved in all ceramide kinases and important for the activity of the human enzyme, is critical for OsCERK enzyme activity and in planta function. In a rice protoplast system, inhibition of CERK leads to cell death and the ratio of added ceramide and ceramide-1-phosphate, CERK's substrate and product, respectively, influences cell survival. Ceramide-induced rice cell death has apoptotic features and is an active process that requires both de novo protein synthesis and phosphorylation, respectively. Finally, mitochondria membrane potential loss previously associated with ceramide-induced cell death in Arabidopsis was also found in rice, but it occurred with different timing. CONCLUSIONS OsCERK is a bona fide ceramide kinase with a functionally and evolutionarily conserved Cys-rich motif that plays an important role in modulating cell fate in plants. The vital function of the conserved motif in both human and rice CERKs suggests that the biochemical mechanism of CERKs is similar in animals and plants. Furthermore, ceramides induce cell death with similar features in monocot and dicot plants.
Collapse
Affiliation(s)
- Fang-Cheng Bi
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Quan-Fang Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhe Liu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ce Fang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Bin Su
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Hong-Bin Wang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Nan Yao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
34
|
Abstract
Plant heat shock protein Hsp70 is the major target of HopI1, a virulence effector of pathogenic Pseudomonas syringae. Hsp70 is essential for the virulence function of HopI1. HopI1 directly binds Hsp70 through its C-terminal J domain and stimulates Hsp70 ATP hydrolysis activity in vitro. In plants, HopI1 forms large complexes in association with Hsp70 and induces and recruits cytosolic Hsp70 to chloroplasts, the site of HopI1 localization. Deletion of a central P/Q-rich repeat region disrupts HopI1 virulence but not Hsp70 interactions or association with chloroplasts. Thus, HopI1 must not only bind Hsp70 through its J domain, but likely actively affects Hsp70 activity and/or specificity. At high temperature, HopI1 is dispensable for P. syringae pathogenicity, unless excess Hsp70 is provided. A working hypothesis is that Hsp70 has a defense-promoting activity(s) that HopI1 or high temperature can subvert. Enhanced susceptibility of Hsp70-depleted plants to nonpathogenic strains of P. syringae supports a defense-promoting role for Hsp70.
Collapse
Affiliation(s)
- Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Jodocus A. van Hal
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637
| |
Collapse
|
35
|
Wroblewski T, Caldwell KS, Piskurewicz U, Cavanaugh KA, Xu H, Kozik A, Ochoa O, McHale LK, Lahre K, Jelenska J, Castillo JA, Blumenthal D, Vinatzer BA, Greenberg JT, Michelmore RW. Comparative large-scale analysis of interactions between several crop species and the effector repertoires from multiple pathovars of Pseudomonas and Ralstonia. Plant Physiol 2009; 150:1733-49. [PMID: 19571308 PMCID: PMC2719141 DOI: 10.1104/pp.109.140251] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Accepted: 06/23/2009] [Indexed: 05/18/2023]
Abstract
Bacterial plant pathogens manipulate their hosts by injection of numerous effector proteins into host cells via type III secretion systems. Recognition of these effectors by the host plant leads to the induction of a defense reaction that often culminates in a hypersensitive response manifested as cell death. Genes encoding effector proteins can be exchanged between different strains of bacteria via horizontal transfer, and often individual strains are capable of infecting multiple hosts. Host plant species express diverse repertoires of resistance proteins that mediate direct or indirect recognition of bacterial effectors. As a result, plants and their bacterial pathogens should be considered as two extensive coevolving groups rather than as individual host species coevolving with single pathovars. To dissect the complexity of this coevolution, we cloned 171 effector-encoding genes from several pathovars of Pseudomonas and Ralstonia. We used Agrobacterium tumefaciens-mediated transient assays to test the ability of each effector to induce a necrotic phenotype on 59 plant genotypes belonging to four plant families, including numerous diverse accessions of lettuce (Lactuca sativa) and tomato (Solanum lycopersicum). Known defense-inducing effectors (avirulence factors) and their homologs commonly induced extensive necrosis in many different plant species. Nonhost species reacted to multiple effector proteins from an individual pathovar more frequently and more intensely than host species. Both homologous and sequence-unrelated effectors could elicit necrosis in a similar spectrum of plants, suggesting common effector targets or targeting of the same pathways in the plant cell.
Collapse
Affiliation(s)
- Tadeusz Wroblewski
- Genome Center and Department of Plant Sciences, University of California, Davis, California 95616, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Lu H, Salimian S, Gamelin E, Wang G, Fedorowski J, LaCourse W, Greenberg JT. Genetic analysis of acd6-1 reveals complex defense networks and leads to identification of novel defense genes in Arabidopsis. Plant J 2009; 58:401-12. [PMID: 19144005 PMCID: PMC2727925 DOI: 10.1111/j.1365-313x.2009.03791.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Pathogen infection leads to the activation of defense signaling networks in plants. To study these networks and the relationships between their components, we introduced various defense mutations into acd6-1, a constitutive gain-of-function Arabidopsis mutant that is highly disease resistant. acd6-1 plants show spontaneous cell death, reduced stature, and accumulate high levels of camalexin (an anti-fungal compound) and salicylic acid (SA; a signaling molecule). Disruption of several defense genes revealed that in acd6-1, SA levels/signaling were positively correlated with the degree of disease resistance and defense gene expression. Salicylic acid also modulates the severity of cell death. However, accumulation of camalexin in acd6-1 is largely unaffected by reducing the level of SA. In addition, acd6-1 shows ethylene- and jasmonic acid-mediated signaling that is antagonized and therefore masked by the presence of SA. Mutant analysis revealed a new relationship between the signaling components NPR1 and PAD4 and also indicated that multiple defense pathways were required for phenotypes conferred by acd6-1. In addition, our data confirmed that the size of acd6-1 was inversely correlated with SA levels/signaling. We exploited this unique feature of acd6-1 to identify two genes disrupted in acd6-1 suppressor (sup) mutants: one encodes a known SA biosynthetic component (SID2) and the other encodes an uncharacterized putative metalloprotease (At5g20660). Taken together, acd6-1 is a powerful tool not only for dissecting defense regulatory networks but also for discovering novel defense genes.
Collapse
Affiliation(s)
- Hua Lu
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
- To whom correspondence should be addressed: , 410-455-5972 (phone); 410-455-3875 (fax)
| | - Sasan Salimian
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
| | - Emily Gamelin
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 E. 57 street, Chicago, IL 60637
| | - Guoying Wang
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
| | - Jennifer Fedorowski
- Department of Biochemistry and Chemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
| | - William LaCourse
- Department of Biochemistry and Chemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 E. 57 street, Chicago, IL 60637
| |
Collapse
|
37
|
|
38
|
Genger RK, Jurkowski GI, McDowell JM, Lu H, Jung HW, Greenberg JT, Bent AF. Signaling pathways that regulate the enhanced disease resistance of Arabidopsis "defense, no death" mutants. Mol Plant Microbe Interact 2008; 21:1285-96. [PMID: 18785824 PMCID: PMC2923831 DOI: 10.1094/mpmi-21-10-1285] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Arabidopsis dnd1 and dnd2 mutants lack cyclic nucleotide-gated ion channel proteins and carry out avirulence or resistance gene-mediated defense with a greatly reduced hypersensitive response (HR). They also exhibit elevated broad-spectrum disease resistance and constitutively elevated salicylic acid (SA) levels. We examined the contributions of NPR1, SID2 (EDS16), NDR1, and EIN2 to dnd phenotypes. Mutations that affect SA accumulation or signaling (sid2, npr1, and ndr1) abolished the enhanced resistance of dnd mutants against Pseudomonas syringae pv. tomato and Hyaloperonospora parasitica but not Botrytis cinerea. When SA-associated pathways were disrupted, the constitutive activation of NPR1-dependent and NPR1-independent and SA-dependent pathways was redirected toward PDF1.2-associated pathways. This PDF1.2 overexpression was downregulated after infection by P. syringae. Disruption of ethylene signaling abolished the enhanced resistance to B. cinerea but not P. syringae or H. parasitica. However, loss of NPR1, SID2, NDR1, or EIN2 did not detectably alter the reduced HR in dnd mutants. The susceptibility of dnd ein2 plants to B. cinerea despite their reduced-HR phenotype suggests that cell death repression is not the primary cause of dnd resistance to necrotrophic pathogens. The partial restoration of resistance to B. cinerea in dnd1 npr1 ein2 triple mutants indicated that this resistance is not entirely EIN2 dependent. The above findings indicate that the broad-spectrum resistance of dnd mutants occurs due to activation or sensitization of multiple defense pathways, yet none of the investigated pathways are required for the reduced-HR phenotype.
Collapse
Affiliation(s)
- Ruth K Genger
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
Plant infection responses result from the interaction of pathogen-derived molecules with host components. For the bacterial pathogen Pseudomonas syringae, these molecules are often effector proteins (Hops) that are injected into plant cells. P. syringae carrying hopW1-1 have restricted host range on some Arabidopsis thaliana accessions. At least two Arabidopsis genomic regions are important for the natural variation that conditions resistance to P. syringae/hopW1-1. HopW1-1 elicits a resistance response, and consequently the accumulation of the signal molecule salicylic acid (SA) and transcripts of HWI1 (HopW1-1-Induced Gene1). This work identified three HopW1-1-interacting (WIN) plant proteins: a putative acetylornithine transaminase (WIN1), a protein phosphatase (WIN2) and a firefly luciferase superfamily protein (WIN3). Importantly, WIN2 and WIN3 are partially required for HopW1-1-induced disease resistance, SA production and HWI1 expression. The requirement for WIN2 is specific for HopW1-1-induced resistance, whereas WIN3 is important for responses to several effectors. Overexpression of WIN2 or WIN3 confers resistance to virulent P. syringae, which is consistent with these proteins being defense components. Several known genes important for SA production or signaling are also partially (EDS1, NIM1/NPR1, ACD6 and ALD1) or strongly (PAD4) required for the robust resistance induced by HopW1-1, suggesting a key role for SA in the HopW1-1-induced resistance response. Finally, WIN1 is an essential protein, the overexpression of which over-rides the resistance response to HopW1-1 (and several other defense-inducing effectors), and delays SA and HWI1 induction. Thus, the WIN proteins have different roles in modulating plant defense.
Collapse
Affiliation(s)
- Min Woo Lee
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57th Street EBC410, Chicago, IL 60637, USA
| | | | | |
Collapse
|
40
|
Lee MW, Lu H, Jung HW, Greenberg JT. A key role for the Arabidopsis WIN3 protein in disease resistance triggered by Pseudomonas syringae that secrete AvrRpt2. Mol Plant Microbe Interact 2007; 20:1192-200. [PMID: 17918621 DOI: 10.1094/mpmi-20-10-1192] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Effector proteins injected by the pathogenic bacteria Pseudomonas syringae into plants can have profound effects on the pathogen-host interaction due to their efficient recognition by plants and the subsequent triggering of defenses. The AvrRpt2 effector triggers strong local and systemic defense (called systemic acquired resistance [SAR]) responses in Arabidopsis thaliana plants that harbor a functional RPS2 gene that encodes an R protein in the coiled-coil, nucleotide-binding domain, leucine-rich repeat class. The newly identified win3-T mutant shows greatly reduced resistance to P syringae carrying avrRpt2. In win3-T plants, RIN4 cleavage, an early AvrRpt2-induced event, is normal. However, salicylic acid accumulation is compromised, as is SAR induction and the local hypersensitive cell death response after infection by P syringae carrying avrRpt2. WIN3 encodes a member of the firefly luciferase protein superfamily. Expression of WIN3 at an infection site partially requires PAD4, a protein known to play a quantitative role in RPS2-mediated signaling. WIN3 expression in tissue distal to an infection site requires multiple salicylic acid regulatory genes. Finally, win3-T plants show modestly increased susceptibility to virulent P syringae and modestly reduced SAR in response to P. syringae carrying avrRpm1. Thus, WIN3 is a key element of the RPS2 defense response pathway and a basal and systemic defense component.
Collapse
Affiliation(s)
- Min Woo Lee
- Molecular Genetics and Cell Biology Department, The University of Chicago, 1103 East 57th Street, Chicago, IL 60637, USA
| | | | | | | |
Collapse
|
41
|
Jelenska J, Yao N, Vinatzer BA, Wright CM, Brodsky JL, Greenberg JT. A J domain virulence effector of Pseudomonas syringae remodels host chloroplasts and suppresses defenses. Curr Biol 2007; 17:499-508. [PMID: 17350264 PMCID: PMC1857343 DOI: 10.1016/j.cub.2007.02.028] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 02/09/2007] [Accepted: 02/12/2007] [Indexed: 11/15/2022]
Abstract
BACKGROUND The plant pathogen Pseudomonas syringae injects 20-40 different proteins called effectors into host plant cells, yet the functions and sites of action of these effectors in promoting pathogenesis are largely unknown. Plants in turn defend themselves against P. syringae by activating the salicylic acid (SA)-mediated signaling pathway. The P. syringae-specific HopI1 effector has a putative chloroplast-targeting sequence and a J domain. J domains function by activating 70 kDa heat-shock proteins (Hsp70). RESULTS HopI1 is a ubiquitous P. syringae virulence effector that acts inside plant cells. When expressed in plants, HopI1 localizes to chloroplasts, the site of SA synthesis. HopI1 causes chloroplast thylakoid structure remodeling and suppresses SA accumulation. HopI1's C terminus has bona fide J domain activity that is necessary for HopI1-mediated virulence and thylakoid remodeling. Furthermore, HopI1-expressing plants have increased heat tolerance, establishing that HopI1 can engage the plant stress-response machinery. CONCLUSIONS These results strongly suggest that chloroplast Hsp70 is targeted by the P. syringae HopI1 effector to promote bacterial virulence by suppressing plant defenses. The targeting of Hsp70 function through J domain proteins is known to occur in a mammalian virus, SV40. However, this is the first example of a bacterial pathogen exploiting a J domain protein to promote pathogenesis through alterations of chloroplast structure and function.
Collapse
Affiliation(s)
- Joanna Jelenska
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57 Street, EBC409, Chicago IL 60637, USA
| | - Nan Yao
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57 Street, EBC409, Chicago IL 60637, USA
- State Key Laboratory of Biocontrol, College of Life Science, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Boris A. Vinatzer
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57 Street, EBC409, Chicago IL 60637, USA
- Current Address: Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Latham Hall, Blacksburg, VA 24061, USA
| | - Christine M. Wright
- Department of Biological Sciences, University of Pittsburgh, 274 Crawford Hall, Pittsburgh PA 15260, USA
| | - Jeffrey L. Brodsky
- Department of Biological Sciences, University of Pittsburgh, 274 Crawford Hall, Pittsburgh PA 15260, USA
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57 Street, EBC409, Chicago IL 60637, USA
| |
Collapse
|
42
|
Abstract
We investigated the genetic diversity, extent of recombination, natural selection, and population divergence of Ralstonia solanacearum samples obtained from sources worldwide. This plant pathogen causes bacterial wilt in many crops and constitutes a serious threat to agricultural production due to its very wide host range and aggressiveness. Five housekeeping genes, dispersed around the chromosome, and three virulence-related genes, located on the megaplasmid, were sequenced from 58 strains belonging to the four major phylogenetic clusters (phylotypes). Whereas genetic variation is high and consistent for all housekeeping loci studied, virulence-related gene sequences are more diverse. Phylogenetic and statistical analyses suggest that this organism is a highly diverse bacterial species containing four major, deeply separated evolutionary lineages (phylotypes I to IV) and a weaker subdivision of phylotype II into two subgroups. Analysis of molecular variations showed that the geographic isolation and spatial distance have been the significant determinants of genetic variation between phylotypes. R. solanacearum displays high clonality for housekeeping genes in all phylotypes (except phylotype III) and significant levels of recombination for the virulence-related egl and hrpB genes, which are limited mainly to phylotype strains III and IV. Finally, genes essential for species survival are under purifying selection, and those directly involved in pathogenesis might be under diversifying selection.
Collapse
Affiliation(s)
- José A Castillo
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637, USA
| | | |
Collapse
|
43
|
Abstract
Many Gram-negative plant and animal pathogens share a common virulence strategy that relies on the specialized type III secretion system. This apparatus is used to secrete virulence factors, called effectors, into the extracellular host environment and directly into the cytoplasm of host cells. Effectors interfere with host signaling and host metabolism to create an optimal environment for pathogen replication. The identification of effectors in plant pathogens was limited for many years to those effectors that elicit strong plant defenses on some hosts. The members of this subset, called avirulence proteins, can be readily identified because they dominantly confer strong defense-inducing properties to a heterologous virulent strain. This chapter describes two methods to identify type III-secreted effectors in plant pathogens independently of their phenotype. The first method consists of an in vivo molecular genetic screen that uses the activity of an avirulence protein to identify effectors without avirulence activity. It should be possible to apply this method to most Gram-negative plant pathogens. The second method consists of a bioinformatic approach applicable to those pathogens for which at least a draft genome sequence is available.
Collapse
Affiliation(s)
- Boris A Vinatzer
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, USA
| | | |
Collapse
|
44
|
Vinatzer BA, Teitzel GM, Lee MW, Jelenska J, Hotton S, Fairfax K, Jenrette J, Greenberg JT. The type III effector repertoire of Pseudomonas syringae pv. syringae B728a and its role in survival and disease on host and non-host plants. Mol Microbiol 2006; 62:26-44. [PMID: 16942603 DOI: 10.1111/j.1365-2958.2006.05350.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The bacterial plant pathogen Pseudomonas syringae injects a large repertoire of effector proteins into plant cells using a type III secretion apparatus. Effectors can trigger or suppress defences in a host-dependent fashion. Host defences are often accompanied by programmed cell death, while interference with defences is sometimes associated with cell death suppression. We previously predicted the effector repertoire of the sequenced bean pathogen P. syringae pv. syringae (Psy) B728a using bioinformatics. Here we show that PsyB728a is also pathogenic on the model plant species Nicotiana benthamiana (tobacco). We confirm our effector predictions and clone the nearly complete PsyB728a effector repertoire. We find effectors to have different cell death-modulating activities and distinct roles during the infection of the susceptible bean and tobacco hosts. Unexpectedly, we do not find a strict correlation between cell death-eliciting and defence-eliciting activity and between cell death-suppressing activity and defence-interfering activity. Furthermore, we find several effectors with quantitative avirulence activities on their susceptible hosts, but with growth-promoting effects on Arabidopsis thaliana, a species on which PsyB728a does not cause disease. We conclude that P. syringae strains may have evolved large effector repertoires to extend their host ranges or increase their survival on various unrelated plant species.
Collapse
Affiliation(s)
- Boris A Vinatzer
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Polytechnic Institute and State University, Fralin Biotechnology Center, West Campus Drive, Blacksburg, VA 24061-0346, USA
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
The Arabidopsis thaliana chloroplast protein ACCELERATED CELL DEATH2 (ACD2) modulates the amount of programmed cell death (PCD) triggered by Pseudomonas syringae and protoporphyrin IX (PPIX) treatment. In vitro, ACD2 can reduce red chlorophyll catabolite, a chlorophyll derivative. We find that ACD2 shields root protoplasts that lack chlorophyll from light- and PPIX-induced PCD. Thus, chlorophyll catabolism is not obligatory for ACD2 anti-PCD function. Upon P. syringae infection, ACD2 levels and localization change in cells undergoing PCD and in their close neighbors. Thus, ACD2 shifts from being largely in chloroplasts to partitioning to chloroplasts, mitochondria, and, to a small extent, cytosol. ACD2 protects cells from PCD that requires the early mitochondrial oxidative burst. Later, the chloroplasts of dying cells generate NO, which only slightly affects cell viability. Finally, the mitochondria in dying cells have dramatically altered movements and cellular distribution. Overproduction of both ACD2 (localized to mitochondria and chloroplasts) and ascorbate peroxidase (localized to chloroplasts) greatly reduces P. syringae-induced PCD, suggesting a pro-PCD role for mitochondrial and chloroplast events. During infection, ACD2 may bind to and/or reduce PCD-inducing porphyrin-related molecules in mitochondria and possibly chloroplasts that generate reactive oxygen species, cause altered organelle behavior, and activate a cascade of PCD-inducing events.
Collapse
Affiliation(s)
- Nan Yao
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637, USA
| | | |
Collapse
|
46
|
Gabriel DW, Allen C, Schell M, Denny TP, Greenberg JT, Duan YP, Flores-Cruz Z, Huang Q, Clifford JM, Presting G, González ET, Reddy J, Elphinstone J, Swanson J, Yao J, Mulholland V, Liu L, Farmerie W, Patnaikuni M, Balogh B, Norman D, Alvarez A, Castillo JA, Jones J, Saddler G, Walunas T, Zhukov A, Mikhailova N. Identification of open reading frames unique to a select agent: Ralstonia solanacearum race 3 biovar 2. Mol Plant Microbe Interact 2006; 19:69-79. [PMID: 16404955 DOI: 10.1094/mpmi-19-0069] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An 8x draft genome was obtained and annotated for Ralstonia solanacearum race 3 biovar 2 (R3B2) strain UW551, a United States Department of Agriculture Select Agent isolated from geranium. The draft UW551 genome consisted of 80,169 reads resulting in 582 contigs containing 5,925,491 base pairs, with an average 64.5% GC content. Annotation revealed a predicted 4,454 protein coding open reading frames (ORFs), 43 tRNAs, and 5 rRNAs; 2,793 (or 62%) of the ORFs had a functional assignment. The UW551 genome was compared with the published genome of R. solanacearum race 1 biovar 3 tropical tomato strain GMI1000. The two phylogenetically distinct strains were at least 71% syntenic in gene organization. Most genes encoding known pathogenicity determinants, including predicted type III secreted effectors, appeared to be common to both strains. A total of 402 unique UW551 ORFs were identified, none of which had a best hit or >45% amino acid sequence identity with any R. solanacearum predicted protein; 16 had strong (E < 10(-13)) best hits to ORFs found in other bacterial plant pathogens. Many of the 402 unique genes were clustered, including 5 found in the hrp region and 38 contiguous, potential prophage genes. Conservation of some UW551 unique genes among R3B2 strains was examined by polymerase chain reaction among a group of 58 strains from different races and biovars, resulting in the identification of genes that may be potentially useful for diagnostic detection and identification of R3B2 strains. One 22-kb region that appears to be present in GMI1000 as a result of horizontal gene transfer is absent from UW551 and encodes enzymes that likely are essential for utilization of the three sugar alcohols that distinguish biovars 3 and 4 from biovars 1 and 2.
Collapse
Affiliation(s)
- Dean W Gabriel
- Plant Pathology Department, University of Florida, Gainesville, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
The ACCELERATED CELL DEATH 6 (ACD6) protein, composed of an ankyrin-repeat domain and a predicted transmembrane region, is a necessary positive regulator of Arabidopsis defenses. ACD6 overexpression confers enhanced disease resistance by priming stronger and quicker defense responses during pathogen infection, plant development or treatment with an agonist of the key defense regulator salicylic acid (SA). Modulation of ACD6 affects both SA-dependent and SA-independent defenses. ACD6 localizes to the plasma membrane and is an integral membrane protein with a cytoplasmic ankyrin domain. An activated version of ACD6 with a predicted transmembrane helix mutation called ACD6-1 has the same localization and overall topology as the wild-type protein. A genetic screen for mutants that suppress acd6-1-conferred phenotypes identified 17 intragenic mutations of ACD6. The majority of these mutations reside in the ankyrin domain and in predicted transmembrane helices, suggesting that both ankyrin and transmembrane domains are important for ACD6 function. One mutation (S638F) also identified a key residue in a putative loop between two transmembrane helices. This mutation did not alter the stability or localization of ACD6, suggesting that S635 is a critical residue for ACD6 function. Based on structural modeling, two ankyrin domain mutations are predicted to be in surface-accessible residues. As ankyrin repeats are protein interaction modules, these mutations may disrupt protein-protein interactions. A plausible scenario is that information exchange between the ankyrin and transmembrane domains is involved in activating defense signaling.
Collapse
Affiliation(s)
- Hua Lu
- Department of Molecular Genetics and Cell Biology, The University of Chicago, IL 60637, USA
| | | | | |
Collapse
|
48
|
Vinatzer BA, Jelenska J, Greenberg JT. Bioinformatics correctly identifies many type III secretion substrates in the plant pathogen Pseudomonas syringae and the biocontrol isolate P. fluorescens SBW25. Mol Plant Microbe Interact 2005; 18:877-88. [PMID: 16134900 DOI: 10.1094/mpmi-18-0877] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The plant pathogen Pseudomonas syringae causes disease by secreting a potentially large set of virulence proteins called effectors directly into host cells, their environment, or both, using a type III secretion system (T3SS). Most P. syringae effectors have a common upstream element called the hrp box, and their N-terminal regions have amino acids biases, features that permit their bioinformatic prediction. One of the most prominent biases is a positive serine bias. We previously used the truncated AvrRpt2(81-255) effector containing a serine-rich stretch from amino acids 81 to 100 as a T3SS reporter. Region 81 to 100 of this reporter does not contribute to the secretion or translocation of AvrRpt2 or to putative effector protein chimeras. Rather, the serine-rich region from the N-terminus of AvrRpt2 is important for protein accumulation in bacteria. Most of the N-terminal region (amino acids 15 to 100) is not essential for secretion in culture or delivery to plants. However, portions of this sequence may increase the efficiency of AvrRpt2 secretion, delivery to plants, or both. Two effectors previously identified with the AvrRpt2(81-255) reporter were secreted in culture independently of AvrRpt2, validating the use of the C terminus of AvrRpt2 as a T3SS reporter. Finally, using the reduced AvrRpt2(101-255) reporter, we confirmed seven predicted effectors from P. syringae pv. tomato DC3000, four from P. syringae pv. syringae B728a, and two from P. fluorescens SBW25.
Collapse
Affiliation(s)
- Boris A Vinatzer
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57th Street, EBC410, Chicago, IL 60637, USA.
| | | | | |
Collapse
|
49
|
Abstract
Localized programmed cell death (PCD) is part of a widespread defense mechanism in plants. A recent paper in Cell () shows that autophagy, a process in which cytoplasm and sometimes organelles are engulfed by double membrane vesicles and degraded, is essential for preventing uncontrolled local and systemic PCD during infection and for limiting viral replication.
Collapse
Affiliation(s)
- Jean T Greenberg
- The Department of Developmental Genetics and Cell Biology, The University of Chicago, 1103 East 57th Street, Chicago, Illinois 60637, USA
| |
Collapse
|
50
|
Lindeberg M, Stavrinides J, Chang JH, Alfano JR, Collmer A, Dangl JL, Greenberg JT, Mansfield JW, Guttman DS. Proposed guidelines for a unified nomenclature and phylogenetic analysis of type III Hop effector proteins in the plant pathogen Pseudomonas syringae. Mol Plant Microbe Interact 2005; 18:275-82. [PMID: 15828679 DOI: 10.1094/mpmi-18-0275] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pathovars of Pseudomonas syringae interact with their plant hosts via the action of Hrp outer protein (Hop) effector proteins, injected into plant cells by the type III secretion system (TTSS). Recent availability of complete genome sequences for a number of P. syringae pathovars has led to a significant increase in the rate of effector discovery. However, lack of a systematic nomenclature has resulted in multiple names being assigned to the same Hop, unrelated Hops designated by the same alphabetic character, and failure of name choices to reflect consistent standards of experimental confirmation or phylogenetic relatedness. Therefore, specific experimental and bioinformatic criteria are proposed for proteins to be designated as Hops. A generic Hop name structure, HopXY#pv strain, also is proposed, wherein family membership is indicated by the alphabetic characters, subgroup membership numerically, and source pathovar and strain in subscript. Guidelines are provided for phylogenetic characterization and name selection for Hops that are novel, related to previously characterized Hops, chimeras, pseudogenes, truncations, or nonexpressed alleles. Phylogenetic analyses of previously characterized Hops are described, the results of which have been used to guide their integration into the proposed nomenclature.
Collapse
Affiliation(s)
- Magdalen Lindeberg
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA
| | | | | | | | | | | | | | | | | |
Collapse
|