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Abstract
Animal and plant pathogenic bacteria use type III secretion systems to translocate proteinaceous effectors to subvert innate immunity of their host organisms. Type III secretion/effector systems are a crucial pathogenicity factor in many bacterial pathogens of plants and animals. Pseudomonas syringae pv. tomato (Pst) DC3000 injects a total of 36 protein effectors that target a variety of host proteins. Studies of a subset of Pst DC3000 effectors demonstrated that bacterial effectors, once inside the host cell, are localized to different subcellular compartments, including plasma membrane, cytoplasm, mitochondria, chloroplast, and Trans-Golgi network, to carry out their virulence functions. Identifying the subcellular localization of bacterial effector proteins in host cells could provide substantial clues to understanding the molecular and cellular basis of the virulence activities of effector proteins. In this chapter, we present methods for transient or stable expression of bacterial effector proteins in tobacco and/or Arabidopsis thaliana for live cell imaging as well as confirming the subcellular localization in plants using fluorescent organelle markers or chemical treatment.
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Affiliation(s)
- Kyaw Aung
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
- Howard Hughes Medical Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Xiufang Xin
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Christy Mecey
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA
| | - Sheng Yang He
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA.
- Howard Hughes Medical Institute, Michigan State University, East Lansing, MI, 48824, USA.
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Mecey C, Hauck P, Trapp M, Pumplin N, Plovanich A, Yao J, He SY. A critical role of STAYGREEN/Mendel's I locus in controlling disease symptom development during Pseudomonas syringae pv tomato infection of Arabidopsis. Plant Physiol 2011; 157:1965-74. [PMID: 21994350 PMCID: PMC3327183 DOI: 10.1104/pp.111.181826] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 09/29/2011] [Indexed: 05/18/2023]
Abstract
Production of disease symptoms represents the final phase of infectious diseases and is a main cause of crop loss and/or marketability. However, little is known about the molecular basis of disease symptom development. In this study, a genetic screening was conducted to identify Arabidopsis (Arabidopsis thaliana) mutants that are impaired specifically in the development of disease symptoms (leaf chlorosis and/or necrosis) after infection with the bacterial pathogen Pseudomonas syringae pv tomato (Pst) DC3000. An ethyl methanesulfonate-induced Arabidopsis mutant (no chlorosis1 [noc1]) was identified. In wild-type plants, the abundance of chlorophylls decreased markedly after Pst DC3000 infection, whereas the total amount of chlorophylls remained relatively unchanged in the noc1 mutant. Interestingly, noc1 mutant plants also exhibited reduced disease symptoms in response to the fungal pathogen Alternaria brassicicola. Genetic and molecular analyses showed that the nuclear gene STAYGREEN (SGR; or Mendel's I locus) is mutated (resulting in the aspartic acid to tyrosine substitution at amino acid position 88) in noc1 plants. Transforming wild-type SGR cDNA into the noc1 mutant rescued the chlorosis phenotype in response to Pst DC3000 infection. The SGR transcript was highly induced by Pst DC3000, A. brassicicola, or coronatine (COR), a bacterial phytotoxin that promotes chlorosis. The induction of SGR expression by COR is dependent on COI1, a principal component of the jasmonate receptor complex. These results suggest that pathogen/COR-induced expression of SGR is a critical step underlying the development of plant disease chlorosis.
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Ham JH, Majerczak DR, Nomura K, Mecey C, Uribe F, He SY, Mackey D, Coplin DL. Multiple activities of the plant pathogen type III effector proteins WtsE and AvrE require WxxxE motifs. Mol Plant Microbe Interact 2009; 22:703-12. [PMID: 19445595 PMCID: PMC2748107 DOI: 10.1094/mpmi-22-6-0703] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [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] [Indexed: 05/20/2023]
Abstract
The broadly conserved AvrE-family of type III effectors from gram-negative plant-pathogenic bacteria includes important virulence factors, yet little is known about the mechanisms by which these effectors function inside plant cells to promote disease. We have identified two conserved motifs in AvrE-family effectors: a WxxxE motif and a putative C-terminal endoplasmic reticulum membrane retention/retrieval signal (ERMRS). The WxxxE and ERMRS motifs are both required for the virulence activities of WtsE and AvrE, which are major virulence factors of the corn pathogen Pantoea stewartii subsp. stewartii and the tomato or Arabidopsis pathogen Pseudomonas syringae pv. tomato, respectively. The WxxxE and the predicted ERMRS motifs are also required for other biological activities of WtsE, including elicitation of the hypersensitive response in nonhost plants and suppression of defense responses in Arabidopsis. A family of type III effectors from mammalian bacterial pathogens requires WxxxE and subcellular targeting motifs for virulence functions that involve their ability to mimic activated G-proteins. The conservation of related motifs and their necessity for the function of type III effectors from plant pathogens indicates that disturbing host pathways by mimicking activated host G-proteins may be a virulence mechanism employed by plant pathogens as well.
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Affiliation(s)
- Jong Hyun Ham
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
| | - Doris R. Majerczak
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
| | - Kinya Nomura
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Christy Mecey
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Francisco Uribe
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - Sheng-Yang He
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, 43210
| | - David L. Coplin
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210
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Melotto M, Mecey C, Niu Y, Chung HS, Katsir L, Yao J, Zeng W, Thines B, Staswick P, Browse J, Howe G, He SY. A critical role of two positively charged amino acids in the Jas motif of Arabidopsis JAZ proteins in mediating coronatine- and jasmonoyl isoleucine-dependent interactions with the COI1 F-box protein. Plant J 2008; 55:979-88. [PMID: 18547396 PMCID: PMC2653208 DOI: 10.1111/j.1365-313x.2008.03566.x] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [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: 05/17/2023]
Abstract
SUMMARY Coronatine is an important virulence factor produced by several pathovars of the bacterial pathogen Pseudomonas syringae. The structure of coronatine is similar to that of a class of plant hormones called jasmonates (JAs). An important step in JA signaling is the SCF(COI1) E3 ubiquitin ligase-dependent degradation of JAZ repressor proteins. We have recently shown that jasmonoyl isoleucine (JA-Ile) promotes physical interaction between Arabidopsis JAZ1 and COI1 (the F-box component of SCF(COI1)) proteins, and that the JA-Ile-dependent COI1-JAZ1 interaction could be reconstituted in yeast cells (i.e. in the absence of other plant proteins). Here we show that coronatine, but not its two biosynthetic precursors, also promotes interaction between Arabidopsis COI1 and multiple JAZ proteins. The C-terminal Jas motif, but not the N-terminal (NT) domain or central ZIM domain of JAZ proteins, is critical for JA-Ile/coronatine-dependent interaction with COI1. Two positively charged amino acid residues in the Jas domain were identified as essential for coronatine-dependent COI1-JAZ interactions. Mutations of these two residues did not affect the ability of JAZ1 and JAZ9 to interact with the transcription factor AtMYC2. Importantly, transgenic Arabidopsis plants expressing JAZ1 carrying these two mutations exhibited JA-insensitive phenotypes, including male sterility and enhanced resistance to P. syringae infection. These results not only suggest that coronatine and JA-Ile target the physical interaction between COI1 and the Jas domain of JAZ repressors, but also illustrate the critical role of positively charged amino acids in the Jas domain in mediating the JA-Ile/coronatine-dependent JAZ interaction with COI1.
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Affiliation(s)
- Maeli Melotto
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Christy Mecey
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Yajie Niu
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Hoo Sun Chung
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Leron Katsir
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Yao
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Weiqing Zeng
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Bryan Thines
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Paul Staswick
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA
| | - John Browse
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Gregg Howe
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
| | - Sheng Yang He
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
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