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Islam T, Haque MA, Barai HR, Istiaq A, Kim JJ. Antibiotic Resistance in Plant Pathogenic Bacteria: Recent Data and Environmental Impact of Unchecked Use and the Potential of Biocontrol Agents as an Eco-Friendly Alternative. PLANTS (BASEL, SWITZERLAND) 2024; 13:1135. [PMID: 38674544 PMCID: PMC11054394 DOI: 10.3390/plants13081135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/15/2024] [Accepted: 04/17/2024] [Indexed: 04/28/2024]
Abstract
The economic impact of phytopathogenic bacteria on agriculture is staggering, costing billions of US dollars globally. Pseudomonas syringae is the top most phytopathogenic bacteria, having more than 60 pathovars, which cause bacteria speck in tomatoes, halo blight in beans, and so on. Although antibiotics or a combination of antibiotics are used to manage infectious diseases in plants, they are employed far less in agriculture compared to human and animal populations. Moreover, the majority of antibiotics used in plants are immediately washed away, leading to environmental damage to ecosystems and food chains. Due to the serious risk of antibiotic resistance (AR) and the potential for environmental contamination with antibiotic residues and resistance genes, the use of unchecked antibiotics against phytopathogenic bacteria is not advisable. Despite the significant concern regarding AR in the world today, there are inadequate and outdated data on the AR of phytopathogenic bacteria. This review presents recent AR data on plant pathogenic bacteria (PPB), along with their environmental impact. In light of these findings, we suggest the use of biocontrol agents as a sustainable, eco-friendly, and effective alternative to controlling phytopathogenic bacteria.
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Affiliation(s)
- Tarequl Islam
- Department of Microbiology, Noakhali Science and Technology University, Sonapur, Noakhali 3814, Bangladesh;
| | - Md Azizul Haque
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Republic of Korea;
| | - Hasi Rani Barai
- School of Mechanical and IT Engineering, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Republic of Korea;
| | - Arif Istiaq
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St Louis, MO 63110-1010, USA
| | - Jong-Joo Kim
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Republic of Korea;
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Miranda de la Torre JO, Peppino Margutti MY, Lescano López I, Cambiagno DA, Alvarez ME, Cecchini NM. The Arabidopsis chromatin regulator MOM1 is a negative component of the defense priming induced by AZA, BABA and PIP. FRONTIERS IN PLANT SCIENCE 2023; 14:1133327. [PMID: 37229135 PMCID: PMC10203520 DOI: 10.3389/fpls.2023.1133327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/20/2023] [Indexed: 05/27/2023]
Abstract
In plants, the establishment of broad and long-lasting immunity is based on programs that control systemic resistance and immunological memory or "priming". Despite not showing activated defenses, a primed plant induces a more efficient response to recurrent infections. Priming might involve chromatin modifications that allow a faster/stronger activation of defense genes. The Arabidopsis chromatin regulator "Morpheus Molecule 1" (MOM1) has been recently suggested as a priming factor affecting the expression of immune receptor genes. Here, we show that mom1 mutants exacerbate the root growth inhibition response triggered by the key defense priming inducers azelaic acid (AZA), β-aminobutyric acid (BABA) and pipecolic acid (PIP). Conversely, mom1 mutants complemented with a minimal version of MOM1 (miniMOM1 plants) are insensitive. Moreover, miniMOM1 is unable to induce systemic resistance against Pseudomonas sp. in response to these inducers. Importantly, AZA, BABA and PIP treatments reduce the MOM1 expression, but not miniMOM1 transcript levels, in systemic tissues. Consistently, several MOM1-regulated immune receptor genes are upregulated during the activation of systemic resistance in WT plants, while this effect is not observed in miniMOM1. Taken together, our results position MOM1 as a chromatin factor that negatively regulates the defense priming induced by AZA, BABA and PIP.
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Affiliation(s)
- Julián O. Miranda de la Torre
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Micaela Y. Peppino Margutti
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ignacio Lescano López
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Damián Alejandro Cambiagno
- Unidad de Estudios Agropecuarios (UDEA), Instituto Nacional de Tecnología Agropecuaria (INTA)- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
- Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - María E. Alvarez
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicolás M. Cecchini
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Química Biológica-Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Yoo SJ, Choi HJ, Noh SW, Cecchini NM, Greenberg JT, Jung HW. Genetic requirements for infection-specific responses in conferring disease resistance in Arabidopsis. FRONTIERS IN PLANT SCIENCE 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] [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).
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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
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Bundalovic-Torma C, Lonjon F, Desveaux D, Guttman DS. Diversity, Evolution, and Function of Pseudomonas syringae Effectoromes. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:211-236. [PMID: 35537470 DOI: 10.1146/annurev-phyto-021621-121935] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Pseudomonas syringae is an evolutionarily diverse bacterial species complex and a preeminent model for the study of plant-pathogen interactions due in part to its remarkably broad host range. A critical feature of P. syringae virulence is the employment of suites of type III secreted effector (T3SE) proteins, which vary widely in composition and function. These effectors act on a variety of plant intracellular targets to promote pathogenesis but can also be avirulence factors when detected by host immune complexes. In this review, we survey the phylogenetic diversity (PD) of the P. syringae effectorome, comprising 70 distinct T3SE families identified to date, and highlight how avoidance of host immune detection has shaped effectorome diversity through functional redundancy, diversification, and horizontal transfer. We present emerging avenues for research and novel insights that can be gained via future investigations of plant-pathogen interactions through the fusion of large-scale interaction screens and phylogenomic approaches.
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Affiliation(s)
| | - Fabien Lonjon
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
| | - Darrell Desveaux
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada; ,
- Centre for the Analysis of Genome Evolution & Function, University of Toronto, Toronto, Ontario, Canada
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5
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Metaeffector interactions modulate the type III effector-triggered immunity load of Pseudomonas syringae. PLoS Pathog 2022; 18:e1010541. [PMID: 35576228 PMCID: PMC9135338 DOI: 10.1371/journal.ppat.1010541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 05/26/2022] [Accepted: 04/21/2022] [Indexed: 11/19/2022] Open
Abstract
The bacterial plant pathogen Pseudomonas syringae requires type III secreted effectors (T3SEs) for pathogenesis. However, a major facet of plant immunity entails the recognition of a subset of P. syringae’s T3SEs by intracellular host receptors in a process called Effector-Triggered Immunity (ETI). Prior work has shown that ETI-eliciting T3SEs are pervasive in the P. syringae species complex raising the question of how P. syringae mitigates its ETI load to become a successful pathogen. While pathogens can evade ETI by T3SE mutation, recombination, or loss, there is increasing evidence that effector-effector (a.k.a., metaeffector) interactions can suppress ETI. To study the ETI-suppression potential of P. syringae T3SE repertoires, we compared the ETI-elicitation profiles of two genetically divergent strains: P. syringae pv. tomato DC3000 (PtoDC3000) and P. syringae pv. maculicola ES4326 (PmaES4326), which are both virulent on Arabidopsis thaliana but harbour largely distinct effector repertoires. Of the 529 T3SE alleles screened on A. thaliana Col-0 from the P. syringae T3SE compendium (PsyTEC), 69 alleles from 21 T3SE families elicited ETI in at least one of the two strain backgrounds, while 50 elicited ETI in both backgrounds, resulting in 19 differential ETI responses including two novel ETI-eliciting families: AvrPto1 and HopT1. Although most of these differences were quantitative, three ETI responses were completely absent in one of the pathogenic backgrounds. We performed ETI suppression screens to test if metaeffector interactions contributed to these ETI differences, and found that HopQ1a suppressed AvrPto1m-mediated ETI, while HopG1c and HopF1g suppressed HopT1b-mediated ETI. Overall, these results show that P. syringae strains leverage metaeffector interactions and ETI suppression to overcome the ETI load associated with their native T3SE repertoires.
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6
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Neale DB, Zimin AV, Zaman S, Scott AD, Shrestha B, Workman RE, Puiu D, Allen BJ, Moore ZJ, Sekhwal MK, De La Torre AR, McGuire PE, Burns E, Timp W, Wegrzyn JL, Salzberg SL. Assembled and annotated 26.5 Gbp coast redwood genome: a resource for estimating evolutionary adaptive potential and investigating hexaploid origin. G3 (BETHESDA, MD.) 2022; 12:6460957. [PMID: 35100403 PMCID: PMC8728005 DOI: 10.1093/g3journal/jkab380] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022]
Abstract
Sequencing, assembly, and annotation of the 26.5 Gbp hexaploid genome of coast redwood (Sequoia sempervirens) was completed leading toward discovery of genes related to climate adaptation and investigation of the origin of the hexaploid genome. Deep-coverage short-read Illumina sequencing data from haploid tissue from a single seed were combined with long-read Oxford Nanopore Technologies sequencing data from diploid needle tissue to create an initial assembly, which was then scaffolded using proximity ligation data to produce a highly contiguous final assembly, SESE 2.1, with a scaffold N50 size of 44.9 Mbp. The assembly included several scaffolds that span entire chromosome arms, confirmed by the presence of telomere and centromere sequences on the ends of the scaffolds. The structural annotation produced 118,906 genes with 113 containing introns that exceed 500 Kbp in length and one reaching 2 Mb. Nearly 19 Gbp of the genome represented repetitive content with the vast majority characterized as long terminal repeats, with a 2.9:1 ratio of Copia to Gypsy elements that may aid in gene expression control. Comparison of coast redwood to other conifers revealed species-specific expansions for a plethora of abiotic and biotic stress response genes, including those involved in fungal disease resistance, detoxification, and physical injury/structural remodeling and others supporting flavonoid biosynthesis. Analysis of multiple genes that exist in triplicate in coast redwood but only once in its diploid relative, giant sequoia, supports a previous hypothesis that the hexaploidy is the result of autopolyploidy rather than any hybridizations with separate but closely related conifer species.
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Affiliation(s)
- David B Neale
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Aleksey V Zimin
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21211, USA
| | - Sumaira Zaman
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.,Department of Computer Science & Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Alison D Scott
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Bikash Shrestha
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Rachael E Workman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Daniela Puiu
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21211, USA
| | - Brian J Allen
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Zane J Moore
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Manoj K Sekhwal
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | | | - Patrick E McGuire
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
| | - Emily Burns
- Save the Redwoods League, San Francisco, CA 94104, USA
| | - Winston Timp
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21211, USA.,Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jill L Wegrzyn
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.,Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Steven L Salzberg
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.,Center for Computational Biology, Johns Hopkins University, Baltimore, MD 21211, USA.,Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA.,Department of Biostatistics, Johns Hopkins University, Baltimore, MD 21205, USA
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7
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Zeng HY, Bao HN, Chen YL, Chen DK, Zhang K, Liu SK, Yang L, Li YK, Yao N. The Two Classes of Ceramide Synthases Play Different Roles in Plant Immunity and Cell Death. FRONTIERS IN PLANT SCIENCE 2022; 13:824585. [PMID: 35463421 PMCID: PMC9021646 DOI: 10.3389/fpls.2022.824585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 03/21/2022] [Indexed: 05/12/2023]
Abstract
Ceramide synthases (CSs) produce ceramides from long-chain bases (LCBs). However, how CSs regulate immunity and cell death in Arabidopsis thaliana remains unclear. Here, we decipher the roles of two classes of CS, CSI (LAG1 HOMOLOG 2, LOH2) and CSII (LOH1/3), in these processes. The loh1-2 and loh1-1 loh3-1 mutants were resistant to the bacterial pathogen Pseudomonas syringae pv maculicola (Psm) DG3 and exhibited programmed cell death (PCD), along with increased LCBs and ceramides, at later stages. In loh1-2, the Psm resistance, PCD, and sphingolipid accumulation were mostly suppressed by inactivation of the lipase-like proteins ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) and PHYTOALEXIN DEFICIENT 4 (PAD4), and partly suppressed by loss of SALICYLIC ACID INDUCTION DEFICIENT 2 (SID2). The LOH1 inhibitor fumonisin B1 (FB1) triggered EDS1/PAD4-independent LCB accumulation, and EDS1/PAD4-dependent cell death, resistance to Psm, and C16 Cer accumulation. Loss of LOH2 enhances FB1-, and sphinganine-induced PCD, indicating that CSI negatively regulates the signaling triggered by CSII inhibition. Like Cer, LCBs mediate cell death and immunity signaling, partly through the EDS1/PAD4 pathway. Our results show that the two classes of ceramide synthases differentially regulate EDS1/PAD4-dependent PCD and immunity via subtle control of LCBs and Cers in Arabidopsis.
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8
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Sharma A, Timilsina S, Abrahamian P, Minsavage GV, Colee J, Ojiambo PS, Goss EM, Vallad GE, Jones JB. Need for speed: bacterial effector XopJ2 is associated with increased dispersal velocity of Xanthomonas perforans. Environ Microbiol 2021; 23:5850-5865. [PMID: 33891376 PMCID: PMC8597037 DOI: 10.1111/1462-2920.15541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/20/2021] [Indexed: 11/28/2022]
Abstract
Bacterial spot caused by Xanthomonas perforans (Xp) is an economically important disease in tomato. Previous studies have shown that the recently isolated Xp strains have acquired and retained the effector gene, xopJ2, which has been reported to increase fitness of the pathogen in the field. To elucidate the fitness benefit of xopJ2, we quantified the effect of xopJ2 on the dispersal and evolution of Xp populations on tomato. We compared movement of two wild-type Xp strains expressing xopJ2 to their respective xopJ2 mutants when co-inoculated in the field. We developed a binary logistic model to predict the presence of Xp over spatial and temporal dimensions with or without xopJ2. Based on the model, wild-type bacteria were dispersed approximately three times faster than the xopJ2 mutants. In a simulation experiment, the selective advantage due to increased dispersal velocity led to an increase in the frequency of xopJ2 gene in the Xp population and its apparent fixation within 10 to 12 cropping seasons of the tomato crop. Our results show that the presence of a single gene can affect the dispersal of a bacterial pathogen and significantly alter its population dynamics.
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Affiliation(s)
- Anuj Sharma
- Department of Plant PathologyUniversity of FloridaGainesvilleFloridaUSA
| | - Sujan Timilsina
- Department of Plant PathologyUniversity of FloridaGainesvilleFloridaUSA
| | - Peter Abrahamian
- Gulf Coast Research and Education CenterUniversity of FloridaWimaumaFloridaUSA
| | | | - James Colee
- Statistics Consulting Unit, Institute of Food and Agricultural SciencesUniversity of FloridaGainesvilleFloridaUSA
| | - Peter S. Ojiambo
- Department of Entomology and Plant PathologyNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Erica M. Goss
- Department of Plant PathologyUniversity of FloridaGainesvilleFloridaUSA
- Emerging Pathogens InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Gary E. Vallad
- Gulf Coast Research and Education CenterUniversity of FloridaWimaumaFloridaUSA
| | - Jeffrey B. Jones
- Department of Plant PathologyUniversity of FloridaGainesvilleFloridaUSA
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9
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Cecchini NM, Speed DJ, Roychoudhry S, Greenberg JT. Kinases and protein motifs required for AZI1 plastid localization and trafficking during plant defense induction. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 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] [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.
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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
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10
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Moon H, Pandey A, Yoon H, Choi S, Jeon H, Prokchorchik M, Jung G, Witek K, Valls M, McCann HC, Kim M, Jones JDG, Segonzac C, Sohn KH. Identification of RipAZ1 as an avirulence determinant of Ralstonia solanacearum in Solanum americanum. MOLECULAR PLANT PATHOLOGY 2021; 22:317-333. [PMID: 33389783 PMCID: PMC7865085 DOI: 10.1111/mpp.13030] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 11/07/2020] [Accepted: 11/23/2020] [Indexed: 05/08/2023]
Abstract
Ralstonia solanacearum causes bacterial wilt disease in many plant species. Type III-secreted effectors (T3Es) play crucial roles in bacterial pathogenesis. However, some T3Es are recognized by corresponding disease resistance proteins and activate plant immunity. In this study, we identified the R. solanacearum T3E protein RipAZ1 (Ralstonia injected protein AZ1) as an avirulence determinant in the black nightshade species Solanum americanum. Based on the S. americanum accession-specific avirulence phenotype of R. solanacearum strain Pe_26, 12 candidate avirulence T3Es were selected for further analysis. Among these candidates, only RipAZ1 induced a cell death response when transiently expressed in a bacterial wilt-resistant S. americanum accession. Furthermore, loss of ripAZ1 in the avirulent R. solanacearum strain Pe_26 resulted in acquired virulence. Our analysis of the natural sequence and functional variation of RipAZ1 demonstrated that the naturally occurring C-terminal truncation results in loss of RipAZ1-triggered cell death. We also show that the 213 amino acid central region of RipAZ1 is sufficient to induce cell death in S. americanum. Finally, we show that RipAZ1 may activate defence in host cell cytoplasm. Taken together, our data indicate that the nucleocytoplasmic T3E RipAZ1 confers R. solanacearum avirulence in S. americanum. Few avirulence genes are known in vascular bacterial phytopathogens and ripAZ1 is the first one in R. solanacearum that is recognized in black nightshades. This work thus opens the way for the identification of disease resistance genes responsible for the specific recognition of RipAZ1, which can be a source of resistance against the devastating bacterial wilt disease.
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Affiliation(s)
- Hayoung Moon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Ankita Pandey
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hayeon Yoon
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Sera Choi
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Hyelim Jeon
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
| | - Maxim Prokchorchik
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Gayoung Jung
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
| | - Kamil Witek
- The Sainsbury LaboratoryUniversity of East AngliaNorwichUK
| | - Marc Valls
- Department of GeneticsUniversity of BarcelonaBarcelonaSpain
- Centre for Research in Agricultural Genomics (CSIC‐IRTA‐UAB‐UB)BellaterraSpain
| | - Honour C. McCann
- New Zealand Institute of Advanced StudiesMassey UniversityAucklandNew Zealand
- Max Planck Institute for Developmental BiologyTübingenGermany
| | - Min‐Sung Kim
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- Division of Integrative Biosciences and BiotechnologyPohang University of Science and TechnologyRepublic of Korea
| | | | - Cécile Segonzac
- Department of Agriculture, Forestry and BioresourcesSeoul National UniversitySeoulRepublic of Korea
- Plant Immunity Research CenterSeoul National UniversitySeoulRepublic of Korea
- Department of Plant Science, Plant Genomics and Breeding InstituteAgricultural Life Science Research InstituteSeoul National UniversitySeoulRepublic of Korea
| | - Kee Hoon Sohn
- Department of Life SciencesPohang University of Science and TechnologyPohangRepublic of Korea
- School of Interdisciplinary Bioscience and BioengineeringPohang University of Science and TechnologyPohangRepublic of Korea
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11
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Noh SW, Seo RR, Park HJ, Jung HW. Two Arabidopsis Homologs of Human Lysine-Specific Demethylase Function in Epigenetic Regulation of Plant Defense Responses. FRONTIERS IN PLANT SCIENCE 2021; 12:688003. [PMID: 34194459 PMCID: PMC8236864 DOI: 10.3389/fpls.2021.688003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/18/2021] [Indexed: 05/02/2023]
Abstract
Epigenetic marks such as covalent histone modification and DNA methylation are crucial for mitotically and meiotically inherited cellular memory-based plant immunity. However, the roles of individual players in the epigenetic regulation of plant immunity are not fully understood. Here we reveal the functions of two Arabidopsis thaliana homologs of human lysine-specific demethylase1-like1, LDL1 and LDL2, in the maintenance of methyl groups at lysine 4 of histone H3 and in plant immunity to Pseudomonas syringae infection. The growth of virulent P. syringae strains was reduced in ldl1 and ldl2 single mutants compared to wild-type plants. Local and systemic disease resistance responses, which coincided with the rapid, robust transcription of defense-related genes, were more stably expressed in ldl1 ldl2 double mutants than in the single mutants. At the nucleosome level, mono-methylated histone H3K4 accumulated in ldl1 ldl2 plants genome-wide and in the mainly promoter regions of the defense-related genes examined in this study. Furthermore, in silico comparative analysis of RNA-sequencing and chromatin immunoprecipitation data suggested that several WRKY transcription factors, e.g., WRKY22/40/70, might be partly responsible for the enhanced immunity of ldl1 ldl2. These findings suggest that LDL1 and LDL2 control the transcriptional sensitivity of a group of defense-related genes to establish a primed defense response in Arabidopsis.
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Affiliation(s)
- Seong Woo Noh
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| | - Ri-Ra Seo
- Department of Applied Bioscience, Dong-A University, Busan, South Korea
| | - Hee Jin Park
- Institute of Agricultural Life Science, Dong-A University, Busan, South Korea
- *Correspondence: Hee Jin Park,
| | - Ho Won Jung
- Institute of Agricultural Life Science, Dong-A University, Busan, South Korea
- Department of Molecular Genetics, Dong-A University, Busan, South Korea
- Ho Won Jung,
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12
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Gimenez-Ibanez S, Zamarreño AM, García-Mina JM, Solano R. An Evolutionarily Ancient Immune System Governs the Interactions between Pseudomonas syringae and an Early-Diverging Land Plant Lineage. Curr Biol 2019; 29:2270-2281.e4. [PMID: 31303486 DOI: 10.1016/j.cub.2019.05.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 04/15/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
Evolutionary molecular plant-microbe interactions (EvoMPMI) is an emerging field bridging the gap between molecular phytopathology and evolutionary studies. EvoMPMI research is currently challenging due to the scarcity of pathogenic model systems in early-diverging land plants. Liverworts are among the earliest diverging land-plant lineages, and Marchantia polymorpha has emerged as a liverwort model for evolutionary studies. However, bacterial pathogens of Marchantia have not yet been discovered, and the molecular mechanisms controlling plant-pathogen interactions in this early-diverging land plant remain unknown. Here, we describe a robust experimental plant-bacterial pathosystem for EvoMPMI studies and discover that an ancient immune system governs plant-microbe interactions between M. polymorpha and the hemi-biotrophic pathogenic bacteria Pseudomonas syringae. We show that P. syringae pv tomato (Pto) DC3000, causal agent of tomato bacterial speck disease, colonizes M. polymorpha and activates typical hallmarks of plant innate immunity. Virulence of Pto DC3000 on M. polymorpha relies on effector activities inside liverwort cells, including conserved AvrPto and AvrPtoB functions. Host specificity analyses uncovered pathogenic differences among P. syringae strains, suggesting that M. polymorpha-P. syringae interactions are controlled by the genetic backgrounds of both host and pathogen. Finally, we show that ancient phytohormone defensive networks govern M. polymorpha-P. syringae interactions. Altogether, our results demonstrate that the basic structure of the plant immune system of extant angiosperms is evolutionarily ancient and conserved in early-diverging land plants. This basic immune system may have been instrumental for land colonization by the common ancestor of land plants.
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Affiliation(s)
- Selena Gimenez-Ibanez
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC (CNB-CSIC), Madrid 28049, Spain.
| | - Angel M Zamarreño
- Environmental Biology Department, University of Navarra, Navarra 31008, Spain
| | - Jose M García-Mina
- Environmental Biology Department, University of Navarra, Navarra 31008, Spain
| | - Roberto Solano
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC (CNB-CSIC), Madrid 28049, Spain.
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13
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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] [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.
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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
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14
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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. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 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] [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.
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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
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15
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Medina CA, Reyes PA, Trujillo CA, Gonzalez JL, Bejarano DA, Montenegro NA, Jacobs JM, Joe A, Restrepo S, Alfano JR, Bernal A. The role of type III effectors from Xanthomonas axonopodis pv. manihotis in virulence and suppression of plant immunity. MOLECULAR PLANT PATHOLOGY 2018; 19:593-606. [PMID: 28218447 PMCID: PMC6638086 DOI: 10.1111/mpp.12545] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 01/25/2017] [Accepted: 02/15/2017] [Indexed: 05/29/2023]
Abstract
Xanthomonas axonopodis pv. manihotis (Xam) causes cassava bacterial blight, the most important bacterial disease of cassava. Xam, like other Xanthomonas species, requires type III effectors (T3Es) for maximal virulence. Xam strain CIO151 possesses 17 predicted T3Es belonging to the Xanthomonas outer protein (Xop) class. This work aimed to characterize nine Xop effectors present in Xam CIO151 for their role in virulence and modulation of plant immunity. Our findings demonstrate the importance of XopZ, XopX, XopAO1 and AvrBs2 for full virulence, as well as a redundant function in virulence between XopN and XopQ in susceptible cassava plants. We tested their role in pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) using heterologous systems. AvrBs2, XopR and XopAO1 are capable of suppressing PTI. ETI suppression activity was only detected for XopE4 and XopAO1. These results demonstrate the overall importance and diversity in functions of major virulence effectors AvrBs2 and XopAO1 in Xam during cassava infection.
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Affiliation(s)
- Cesar Augusto Medina
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Paola Andrea Reyes
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Cesar Augusto Trujillo
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Juan Luis Gonzalez
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - David Alejandro Bejarano
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Nathaly Andrea Montenegro
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - Jonathan M. Jacobs
- Institut de Recherche pour le De´veloppement (IRD), CiradUniversite´ Montpellier, Interactions Plantes Microorganismes Environnement (IPME), 34394MontpellierFrance
| | - Anna Joe
- Center for Plant Science InnovationUniversity of NebraskaLincolnNE68588‐0660USA
- Department of Plant PathologyUniversity of NebraskaLincolnNE68588‐0722USA
- Present address:
Department of Plant Pathology and the Genome CenterUniversity of California, Davis, CA 95616, USA, and Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Silvia Restrepo
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
| | - James R. Alfano
- Center for Plant Science InnovationUniversity of NebraskaLincolnNE68588‐0660USA
- Department of Plant PathologyUniversity of NebraskaLincolnNE68588‐0722USA
| | - Adriana Bernal
- Universidad de los Andes, Laboratorio de Micología y Fitopatología de la Universidad de los Andes111711 BogotáColombia
- Present address:
Novozymes, Inc., DavisCA95618USA
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16
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Zhang ZM, Ma KW, Gao L, Hu Z, Schwizer S, Ma W, Song J. Mechanism of host substrate acetylation by a YopJ family effector. NATURE PLANTS 2017; 3:17115. [PMID: 28737762 PMCID: PMC5546152 DOI: 10.1038/nplants.2017.115] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 06/26/2017] [Indexed: 05/22/2023]
Abstract
The Yersinia outer protein J (YopJ) family of bacterial effectors depends on a novel acetyltransferase domain to acetylate signalling proteins from plant and animal hosts. However, the underlying mechanism is unclear. Here, we report the crystal structures of PopP2, a YopJ effector produced by the plant pathogen Ralstonia solanacearum, in complex with inositol hexaphosphate (InsP6), acetyl-coenzyme A (AcCoA) and/or substrate Resistance to Ralstonia solanacearum 1 (RRS1-R)WRKY. PopP2 recognizes the WRKYGQK motif of RRS1-RWRKY to position a targeted lysine in the active site for acetylation. Importantly, the PopP2-RRS1-RWRKY association is allosterically regulated by InsP6 binding, suggesting a previously unidentified role of the eukaryote-specific cofactor in substrate interaction. Furthermore, we provide evidence for the reaction intermediate of PopP2-mediated acetylation, an acetyl-cysteine covalent adduct, lending direct support to the 'ping-pong'-like catalytic mechanism proposed for YopJ effectors. Our study provides critical mechanistic insights into the virulence activity of YopJ class of acetyltransferases.
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Affiliation(s)
- Zhi-Min Zhang
- Department of Biochemistry, University of California, Riverside, California 92521, USA
| | - Ka-Wai Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
| | - Linfeng Gao
- Environmental Toxicology Program, University of California, Riverside, California 92521, USA
| | - Zhenquan Hu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Anhui 230031, China
| | - Simon Schwizer
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
| | - Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521, USA
- Center for Plant Cell Biology, University of California, Riverside, California 92521, USA
- Institute of Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - Jikui Song
- Department of Biochemistry, University of California, Riverside, California 92521, USA
- Environmental Toxicology Program, University of California, Riverside, California 92521, USA
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17
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ALTERED MERISTEM PROGRAM1 has conflicting effects on the tolerance to heat shock and symptom development after Pseudomonas syringae infection. Biochem Biophys Res Commun 2016; 480:296-301. [PMID: 27743891 DOI: 10.1016/j.bbrc.2016.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 10/11/2016] [Indexed: 11/23/2022]
Abstract
An Arabidopsis thaliana ALTERED MERISTEM PROGRAM1 (AtAMP1), which encodes a putative glutamate carboxypeptidase, not only controls shoot apical meristem development, but also is involved in tolerance response to abiotic stresses. Here, we introduce a novel mutant; named amp1-32 that is a phenocopier to previously isolated different amp1 mutant alleles. Interestingly, tiny leaves were continuously developed at the bottom of pre-emerged leaves in the amp1-32. The amp1-32 mutant was less sensitive to heat shock treatment lasting for 3 h, whereas disease symptoms were severely developed in the mutant after Pseudomonas syringae infection. The mRNA levels of 171 genes were significantly altered in the mutant, as compared to wild-type plants. The transcription of genes involved in hormone signaling, post-embryonic development, and shoot development were up-regulated in the amp1-32 mutant, whereas expression of genes related to responsiveness to pathogens and (in)organic matters, were decreased in the mutant. Taken together, perturbation of CK- and ABA-related events by AMP1 mutation caused aberrant development phenotype and conflicting responses against abiotic and biotic stresses in Arabidopsis.
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18
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MacQueen A, Sun X, Bergelson J. Genetic architecture and pleiotropy shape costs of Rps2-mediated resistance in Arabidopsis thaliana. NATURE PLANTS 2016; 2:16110. [PMID: 27428524 PMCID: PMC4968571 DOI: 10.1038/nplants.2016.110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/20/2016] [Indexed: 05/03/2023]
Abstract
The mounting evidence that R genes incur large fitness costs raises a question: how can there be a 5-10% fitness reduction for all 149 R genes in the Arabidopsis thaliana genome? The R genes tested to date segregate for insertion-deletion (indel) polymorphisms where susceptible alleles are complete deletions. Since costs of resistance are measured as the differential fitness of isolines carrying resistant and susceptible alleles, indels reveal costs that may be masked when susceptible alleles are expressed. Rps2 segregates for two expressed clades of alleles, one resistant and one susceptible. Plants with resistant Rps2 are not less fit than those with a susceptible Rps2 allele in the absence of disease. Instead, all alleles provide a fitness benefit relative to an artificial deletion because of the role of RPS2 as a negative regulator of defence. Our results highlight the interplay between genomic architecture and the magnitude of costs of resistance.
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Affiliation(s)
- Alice MacQueen
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA
| | - Xiaoqin Sun
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA
| | - Joy Bergelson
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA
- To whom correspondence should be addressed.
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19
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MacQueen A, Bergelson J. Modulation of R-gene expression across environments. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2093-105. [PMID: 26983577 PMCID: PMC4793800 DOI: 10.1093/jxb/erv530] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Some environments are more conducive to pathogen growth than others, and, as a consequence, plants might be expected to invest more in resistance when pathogen growth is favored. Resistance (R-) genes in Arabidopsis thaliana have unusually extensive variation in basal expression when comparing the same R-gene among accessions collected from different environments. R-gene expression variation was characterized to explore whether R-gene expression is up-regulated in environments favoring pathogen proliferation and down-regulated when risks of infection are low; down-regulation would follow if costs of R-gene expression negatively impact plant fitness in the absence of disease. Quantitative reverse transcription-PCR was used to quantify the expression of 13 R-gene loci in plants grown in eight environmental conditions for each of 12 A. thaliana accessions, and large effects of the environment on R-gene expression were found. Surprisingly, almost every change in the environment--be it a change in biotic or abiotic conditions--led to an increase in R-gene expression, a response that was distinct from the average transcriptome response and from that of other stress response genes. These changes in expression are functional in that environmental change prior to infection affected levels of specific disease resistance to isolates of Pseudomonas syringae. In addition, there are strong latitudinal clines in basal R-gene expression and clines in R-gene expression plasticity correlated with drought and high temperatures. These results suggest that variation in R-gene expression across environments may be shaped by natural selection to reduce fitness costs of R-gene expression in permissive or predictable environments.
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Affiliation(s)
- Alice MacQueen
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA
| | - Joy Bergelson
- Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA.
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20
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Arabidopsis AZI1 family proteins mediate signal mobilization for systemic defence priming. Nat Commun 2015. [PMID: 26203923 DOI: 10.1038/ncomms8658] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Priming is a major mechanism behind the immunological 'memory' observed during two key plant systemic defences: systemic acquired resistance (SAR) and induced systemic resistance (ISR). Lipid-derived azelaic acid (AZA) is a mobile priming signal. Here, we show that the lipid transfer protein (LTP)-like AZI1 and its closest paralog EARLI1 are necessary for SAR, ISR and the systemic movement and uptake of AZA in Arabidopsis. Imaging and fractionation studies indicate that AZI1 and EARLI1 localize to expected places for lipid exchange/movement to occur. These are the ER/plasmodesmata, chloroplast outer envelopes and membrane contact sites between them. Furthermore, these LTP-like proteins form complexes and act at the site of SAR establishment. The plastid targeting of AZI1 and AZI1 paralogs occurs through a mechanism that may enable/facilitate their roles in signal mobilization.
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21
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Cecchini NM, Jung HW, Engle NL, Tschaplinski TJ, Greenberg JT. ALD1 Regulates Basal Immune Components and Early Inducible Defense Responses in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 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] [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.
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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
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22
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Zhang C, Xie Q, Anderson RG, Ng G, Seitz NC, Peterson T, McClung CR, McDowell JM, Kong D, Kwak JM, Lu H. Crosstalk between the circadian clock and innate immunity in Arabidopsis. PLoS Pathog 2013; 9:e1003370. [PMID: 23754942 PMCID: PMC3675028 DOI: 10.1371/journal.ppat.1003370] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 04/04/2013] [Indexed: 12/17/2022] Open
Abstract
The circadian clock integrates temporal information with environmental cues in regulating plant development and physiology. Recently, the circadian clock has been shown to affect plant responses to biotic cues. To further examine this role of the circadian clock, we tested disease resistance in mutants disrupted in CCA1 and LHY, which act synergistically to regulate clock activity. We found that cca1 and lhy mutants also synergistically affect basal and resistance gene-mediated defense against Pseudomonas syringae and Hyaloperonospora arabidopsidis. Disrupting the circadian clock caused by overexpression of CCA1 or LHY also resulted in severe susceptibility to P. syringae. We identified a downstream target of CCA1 and LHY, GRP7, a key constituent of a slave oscillator regulated by the circadian clock and previously shown to influence plant defense and stomatal activity. We show that the defense role of CCA1 and LHY against P. syringae is at least partially through circadian control of stomatal aperture but is independent of defense mediated by salicylic acid. Furthermore, we found defense activation by P. syringae infection and treatment with the elicitor flg22 can feedback-regulate clock activity. Together this data strongly supports a direct role of the circadian clock in defense control and reveal for the first time crosstalk between the circadian clock and plant innate immunity.
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Affiliation(s)
- Chong Zhang
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Qiguang Xie
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Ryan G. Anderson
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Gina Ng
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Nicholas C. Seitz
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Thomas Peterson
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - C. Robertson McClung
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America
| | - John M. McDowell
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Dongdong Kong
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - June M. Kwak
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
- Department of Cell Biology and Molecular Genetics, Department of Plant Science and Landscape Architecture, University of Maryland, College Park, Maryland, United States of America
- Department of Plant Molecular Systems Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, Republic of Korea
| | - Hua Lu
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
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Atamian HS, Chaudhary R, Cin VD, Bao E, Girke T, Kaloshian I. In planta expression or delivery of potato aphid Macrosiphum euphorbiae effectors Me10 and Me23 enhances aphid fecundity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:67-74. [PMID: 23194342 DOI: 10.1094/mpmi-06-12-0144-fi] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The interactions between aphids and their host plants seem to be analogous to those of plant-microbial pathogens. Unlike microbial pathogen effectors, little is known about aphid effectors and their ability to interfere with host immunity. To date, only three functional aphid effectors have been reported. To identify potato aphid (Macrosiphum euphorbiae) effectors, we developed a salivary gland transcriptome using Illumina technology. We generated 85 million Illumina reads from salivary glands and assembled them into 646 contigs. Ab initio sequence analysis predicted secretion signal peptides in 24% of these sequences, suggesting that they might be secreted into the plant during aphid feeding. Eight of these candidate effectors with secretion signal peptides were functionally characterized using Agrobacterium tumefaciens-mediated transient overexpression in Nicotiana benthamiana. Two candidate effectors, Me10 and Me23, increased aphid fecundity, suggesting their ability to suppress N. benthamiana defenses. Five of these candidate effectors, including Me10 and Me23, were also analyzed in tomato by delivering them through the Pseudomonas syringae type three secretion system. In tomato, only Me10 increased aphid fecundity. This work identified two additional aphid effectors with ability to manipulate the host for their advantage.
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24
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Bever JD, Platt TG, Morton ER. Microbial population and community dynamics on plant roots and their feedbacks on plant communities. Annu Rev Microbiol 2012; 66:265-83. [PMID: 22726216 PMCID: PMC3525954 DOI: 10.1146/annurev-micro-092611-150107] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The composition of the soil microbial community can be altered dramatically due to association with individual plant species, and these effects on the microbial community can have important feedbacks on plant ecology. Negative plant-soil feedback plays primary roles in maintaining plant community diversity, whereas positive plant-soil feedback may cause community conversion. Host-specific differentiation of the microbial community results from the trade-offs associated with overcoming plant defense and the specific benefits associated with plant rewards. Accumulation of host-specific pathogens likely generates negative feedback on the plant, while changes in the density of microbial mutualists likely generate positive feedback. However, the competitive dynamics among microbes depends on the multidimensional costs of virulence and mutualism, the fine-scale spatial structure within plant roots, and active plant allocation and localized defense. Because of this, incorporating a full view of microbial dynamics is essential to explaining the dynamics of plant-soil feedbacks and therefore plant community ecology.
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Affiliation(s)
- James D. Bever
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Thomas G. Platt
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Elise R. Morton
- Department of Biology, Indiana University, Bloomington, Indiana 47405
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25
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Üstün Ş, Müller P, Palmisano R, Hensel M, Börnke F. SseF, a type III effector protein from the mammalian pathogen Salmonella enterica, requires resistance-gene-mediated signalling to activate cell death in the model plant Nicotiana benthamiana. THE NEW PHYTOLOGIST 2012; 194:1046-1060. [PMID: 22471508 DOI: 10.1111/j.1469-8137.2012.04124.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Type III effector proteins (T3Es) of many Gram-negative pathogenic bacteria manipulate highly conserved cellular processes, indicating conservation in virulence mechanisms during the infection of hosts of divergent evolutionary origin. In order to identify conserved effector functions, we used a cross-kingdom approach in which we expressed selected T3Es from the mammalian pathogen Salmonella enterica in leaves of Nicotiana benthamiana and searched for possible virulence or avirulence phenotypes. We show that the T3E SseF of S. enterica triggers hypersensitive response (HR)-like symptoms, a hallmark of effector-triggered immunity in plants, either when transiently expressed in leaves of N. benthamiana by Agrobacterium tumefaciens infiltration or when delivered by Xanthomonas campestris pv vesicatoria (Xcv) through the type III secretion system. The ability of SseF to elicit HR-like symptoms was lost upon silencing of suppressor of G2 allele of skp1 (SGT1), indicating that the S. enterica T3E is probably recognized by an R protein in N. benthamiana. Xcv translocating an AvrRpt2-SseF fusion protein was restricted in multiplication within leaves of N. benthamiana. Bacterial growth was not impaired but symptom development was rather accelerated in a compatible interaction with susceptible pepper (Capsicum annuum) plants. We conclude that the S. enterica T3E SseF is probably recognized by the plant immune system in N. benthamiana, resulting in effector-triggered immunity.
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Affiliation(s)
- Şuayib Üstün
- Department Biologie, Lehrstuhl für Biochemie, Friedrich Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Petra Müller
- Infektionsbiologische Abteilung im Mikrobiologischen Institut, Universitätsklinikum Erlangen, Wasserturmstr. 3-5, 91054 Erlangen, Germany
| | - Ralf Palmisano
- Department Biologie, Lehrstuhl für Biochemie, Friedrich Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Michael Hensel
- Infektionsbiologische Abteilung im Mikrobiologischen Institut, Universitätsklinikum Erlangen, Wasserturmstr. 3-5, 91054 Erlangen, Germany
| | - Frederik Börnke
- Department Biologie, Lehrstuhl für Biochemie, Friedrich Alexander Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
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26
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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 PHYSIOLOGY 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] [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.
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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.)
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27
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Abstract
Miniature inverted terminal repeat elements (MITEs) are nonautonomous mobile elements that have a significant impact on bacterial evolution. Here we characterize E622, a 611-bp virulence-associated MITE from Pseudomonas syringae, which contains no coding region but has almost perfect 168-bp inverted repeats. Using an antibiotic coupling assay, we show that E622 is transposable and can mobilize an antibiotic resistance gene contained between its borders. Its predicted parent element, designated TnE622, has a typical transposon structure with a three-gene operon, consisting of resolvase, integrase, and exeA-like genes, which is bounded by the same terminal inverted repeats as E622. A broader genome level survey of the E622/TnE622 inverted repeats identified homologs in Pseudomonas, Salmonella, Shewanella, Erwinia, Pantoea, and the cyanobacteria Nostoc and Cyanothece, many of which appear to encompass known virulence genes, including genes encoding toxins, enzymes, and type III secreted effectors. Its association with niche-specific genetic determinants, along with its persistence and evolutionary diversification, indicates that this mobile element family has played a prominent role in the evolution of many agriculturally and clinically relevant pathogenic bacteria.
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28
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Champigny MJ, Shearer H, Mohammad A, Haines K, Neumann M, Thilmony R, He SY, Fobert P, Dengler N, Cameron RK. Localization of DIR1 at the tissue, cellular and subcellular levels during Systemic Acquired Resistance in Arabidopsis using DIR1:GUS and DIR1:EGFP reporters. BMC PLANT BIOLOGY 2011; 11:125. [PMID: 21896186 PMCID: PMC3180652 DOI: 10.1186/1471-2229-11-125] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/06/2011] [Indexed: 05/05/2023]
Abstract
BACKGROUND Systemic Acquired Resistance (SAR) is an induced resistance response to pathogens, characterized by the translocation of a long-distance signal from induced leaves to distant tissues to prime them for increased resistance to future infection. DEFECTIVE in INDUCED RESISTANCE 1 (DIR1) has been hypothesized to chaperone a small signaling molecule to distant tissues during SAR in Arabidopsis. RESULTS DIR1 promoter:DIR1-GUS/dir1-1 lines were constructed to examine DIR1 expression. DIR1 is expressed in seedlings, flowers and ubiquitously in untreated or mock-inoculated mature leaf cells, including phloem sieve elements and companion cells. Inoculation of leaves with SAR-inducing avirulent or virulent Pseudomonas syringae pv tomato (Pst) resulted in Type III Secretion System-dependent suppression of DIR1 expression in leaf cells. Transient expression of fluorescent fusion proteins in tobacco and intercellular washing fluid experiments indicated that DIR1's ER signal sequence targets it for secretion to the cell wall. However, DIR1 expressed without a signal sequence rescued the dir1-1 SAR defect, suggesting that a cytosolic pool of DIR1 is important for the SAR response. CONCLUSIONS Although expression of DIR1 decreases during SAR induction, the protein localizes to all living cell types of the vasculature, including companion cells and sieve elements, and therefore DIR1 is well situated to participate in long-distance signaling during SAR.
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Affiliation(s)
- Marc J Champigny
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1 Canada
- Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Heather Shearer
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1 Canada
- Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Asif Mohammad
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1 Canada
| | - Karen Haines
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1 Canada
| | - Melody Neumann
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Roger Thilmony
- Department of Plant Biology, Michigan State University, East Lansing MI, 48824 USA
- USDA-ARS, Western Regional Research Center, Crop Improvement and Utilization Research Unit, 800 Buchanan St., Albany, CA, 94710 USA
| | - Sheng Yang He
- Department of Plant Biology, Michigan State University, East Lansing MI, 48824 USA
| | - Pierre Fobert
- Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Nancy Dengler
- Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada
| | - Robin K Cameron
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1 Canada
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29
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Lee JY, Wang X, Cui W, Sager R, Modla S, Czymmek K, Zybaliov B, van Wijk K, Zhang C, Lu H, Lakshmanan V. A plasmodesmata-localized protein mediates crosstalk between cell-to-cell communication and innate immunity in Arabidopsis. THE PLANT CELL 2011; 23:3353-73. [PMID: 21934146 PMCID: PMC3203451 DOI: 10.1105/tpc.111.087742] [Citation(s) in RCA: 187] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Plasmodesmata (PD) are thought to play a fundamental role in almost every aspect of plant life, including normal growth, physiology, and developmental responses. However, how specific signaling pathways integrate PD-mediated cell-to-cell communication is not well understood. Here, we present experimental evidence showing that the Arabidopsis thaliana plasmodesmata-located protein 5 (PDLP5; also known as HOPW1-1-INDUCED GENE1) mediates crosstalk between PD regulation and salicylic acid-dependent defense responses. PDLP5 was found to localize at the central region of PD channels and associate with PD pit fields, acting as an inhibitor to PD trafficking, potentially through its capacity to modulate PD callose deposition. As a regulator of PD, PDLP5 was also essential for conferring enhanced innate immunity against bacterial pathogens in a salicylic acid-dependent manner. Based on these findings, a model is proposed illustrating that the regulation of PD closure mediated by PDLP5 constitutes a crucial part of coordinated control of cell-to-cell communication and defense signaling.
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Affiliation(s)
- Jung-Youn Lee
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19711, USA.
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30
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Park BS, Song JT, Seo HS. Arabidopsis nitrate reductase activity is stimulated by the E3 SUMO ligase AtSIZ1. Nat Commun 2011; 2:400. [PMID: 21772271 PMCID: PMC3160146 DOI: 10.1038/ncomms1408] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 06/21/2011] [Indexed: 11/09/2022] Open
Abstract
Small ubiquitin-related modifier (SUMO) is a small polypeptide that modulates protein activity and regulates hormone signalling, abiotic and biotic responses in plants. Here we show that AtSIZ regulates nitrogen assimilation in Arabidopsis through its E3 SUMO ligase function. Dwarf plants of siz1-2 flower early, show abnormal seed development and have high salicylic acid content and enhanced resistance to bacterial pathogens. These mutant phenotypes are reverted to wild-type phenotypes by exogenous ammonium but not by nitrate, phosphate or potassium. Decreased nitrate reductase activity in siz1-2 plants resulted in low nitrogen concentrations, low nitric oxide production and high nitrate content in comparison with wild-type plants. The nitrate reductases, NIA1 and NIA2, are sumoylated by AtSIZ1, which dramatically increases their activity. Both sumoylated and non-sumoylated NIA1 and NIA2 can form dimers. Our results indicate that AtSIZ1 positively controls nitrogen assimilation by promoting sumoylation of NRs in Arabidopsis.
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Affiliation(s)
- Bong Soo Park
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
| | - Jong Tae Song
- School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Korea
| | - Hak Soo Seo
- Department of Plant Science, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
- Bio-MAX Institute, Seoul National University, Seoul 151-818, Korea
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31
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Wang GF, Seabolt S, Hamdoun S, Ng G, Park J, Lu H. Multiple roles of WIN3 in regulating disease resistance, cell death, and flowering time in Arabidopsis. PLANT PHYSIOLOGY 2011; 156:1508-19. [PMID: 21543726 PMCID: PMC3135961 DOI: 10.1104/pp.111.176776] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 04/26/2011] [Indexed: 05/18/2023]
Abstract
The salicylic acid (SA) regulatory gene HOPW1-1-INTERACTING3 (WIN3) was previously shown to confer resistance to the biotrophic pathogen Pseudomonas syringae. Here, we report that WIN3 controls broad-spectrum disease resistance to the necrotrophic pathogen Botrytis cinerea and contributes to basal defense induced by flg22, a 22-amino acid peptide derived from the conserved region of bacterial flagellin proteins. Genetic analysis indicates that WIN3 acts additively with several known SA regulators, including PHYTOALEXIN DEFICIENT4, NONEXPRESSOR OF PR GENES1 (NPR1), and SA INDUCTION-DEFICIENT2, in regulating SA accumulation, cell death, and/or disease resistance in the Arabidopsis (Arabidopsis thaliana) mutant acd6-1. Interestingly, expression of WIN3 is also dependent on these SA regulators and can be activated by cell death, suggesting that WIN3-mediated signaling is interconnected with those derived from other SA regulators and cell death. Surprisingly, we found that WIN3 and NPR1 synergistically affect flowering time via influencing the expression of flowering regulatory genes FLOWERING LOCUS C and FLOWERING LOCUS T. Taken together, our data reveal that WIN3 represents a novel node in the SA signaling networks to regulate plant defense and flowering time. They also highlight that plant innate immunity and development are closely connected processes, precise regulation of which should be important for the fitness of plants.
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Affiliation(s)
| | | | | | | | | | - Hua Lu
- Corresponding author; e-mail
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32
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Wang GY, Shi JL, Ng G, Battle SL, Zhang C, Lu H. Circadian clock-regulated phosphate transporter PHT4;1 plays an important role in Arabidopsis defense. MOLECULAR PLANT 2011; 4:516-26. [PMID: 21447757 PMCID: PMC3988428 DOI: 10.1093/mp/ssr016] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 02/10/2011] [Indexed: 05/18/2023]
Abstract
The Arabidopsis accelerated cell death 6-1 (acd6-1) mutant shows constitutive defense, cell death, and extreme dwarf phenotypes. In a screen for acd6-1 suppressors, we identified a mutant that was disrupted by a T-DNA in the PHOSPHATE TRANSPORTER 4;1 (PHT4;1) gene. The suppressor mutant pht4;1-1 is dominant, expresses truncated PHT4;1 transcripts, and is more susceptible to virulent Pseudomonas syringae strains but not to several avirulent strains. Treatment with a salicylic acid (SA) agonist induced a similar level of resistance in Col-0 and pht4;1-1, suggesting that PHT4;1 acts upstream of the SA pathway. Genetic analysis further indicates that PHT4;1 contributes to SID2-dependent and -independent pathways. Transgenic expression of the DNA fragment containing the PHT4;1-1 region or the full-length PHT4;1 gene in wild-type conferred enhanced susceptibility to Pseudomonas infection. Interestingly, expression of PHT4;1 is regulated by the circadian clock. Together, these data suggest that the phosphate transporter PHT4;1 is critical for basal defense and also implicate a potential role of the circadian clock in regulating innate immunity of Arabidopsis.
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Affiliation(s)
| | | | | | | | | | - Hua Lu
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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33
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O'Brien HE, Thakur S, Guttman DS. Evolution of plant pathogenesis in Pseudomonas syringae: a genomics perspective. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:269-89. [PMID: 21568703 DOI: 10.1146/annurev-phyto-072910-095242] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The phytopathogenic bacterium Pseudomonas syringae causes serious diseases in a wide range of important crop plants, with recent severe outbreaks on the New Zealand kiwifruit crop and among British horse chestnut trees. Next-generation genome sequencing of over 25 new strains has greatly broadened our understanding of how this species adapts to a diverse range of plant hosts. Not unexpectedly, the genomes were found to be highly dynamic, and extensive polymorphism was found in the distribution of type III secreted effectors (T3SEs) and other virulence-associated genes, even among strains within the same pathovar. An underexplored area brought to light by these data is the specific metabolic adaptations required for growth on woody hosts. These studies provide a tremendous wealth of candidates for more refined functional characterization, which is greatly enhancing our ability to disentangle the web of host-pathogen interactions that determine disease outcomes.
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Affiliation(s)
- Heath E O'Brien
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2 Canada
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34
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Selote D, Kachroo A. RPG1-B-derived resistance to AvrB-expressing Pseudomonas syringae requires RIN4-like proteins in soybean. PLANT PHYSIOLOGY 2010; 153:1199-211. [PMID: 20484023 PMCID: PMC2899914 DOI: 10.1104/pp.110.158147] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 05/17/2010] [Indexed: 05/20/2023]
Abstract
Soybean (Glycine max) RPG1-B (for resistance to Pseudomonas syringae pv glycinea) mediates species-specific resistance to P. syringae expressing the avirulence protein AvrB, similar to the nonorthologous RPM1 in Arabidopsis (Arabidopsis thaliana). RPM1-derived signaling is presumably induced upon AvrB-derived modification of the RPM1-interacting protein, RIN4 (for RPM1-interacting 4). We show that, similar to RPM1, RPG1-B does not directly interact with AvrB but associates with RIN4-like proteins from soybean. Unlike Arabidopsis, soybean contains at least four RIN4-like proteins (GmRIN4a to GmRIN4d). GmRIN4b, but not GmRIN4a, complements the Arabidopsis rin4 mutation. Both GmRIN4a and GmRIN4b bind AvrB, but only GmRIN4b binds RPG1-B. Silencing either GmRIN4a or GmRIN4b abrogates RPG1-B-derived resistance to P. syringae expressing AvrB. Binding studies show that GmRIN4b interacts with GmRIN4a as well as with two other AvrB/RPG1-B-interacting isoforms, GmRIN4c and GmRIN4d. The lack of functional redundancy among GmRIN4a and GmRIN4b and their abilities to interact with each other suggest that the two proteins might function as a heteromeric complex in mediating RPG1-B-derived resistance. Silencing GmRIN4a or GmRIN4b in rpg1-b plants enhances basal resistance to virulent strains of P. syringae and the oomycete Phytophthora sojae. Interestingly, GmRIN4a- or GmRIN4b-silenced rpg1-b plants respond differently to AvrB-expressing bacteria. Although both GmRIN4a and GmRIN4b function to monitor AvrB in the presence of RPG1-B, GmRIN4a, but not GmRIN4b, negatively regulates AvrB virulence activity in the absence of RPG1-B.
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Affiliation(s)
| | - Aardra Kachroo
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky 40546
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35
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Oh HS, Park DH, Collmer A. Components of the Pseudomonas syringae type III secretion system can suppress and may elicit plant innate immunity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:727-39. [PMID: 20459312 DOI: 10.1094/mpmi-23-6-0727] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The type III secretion system (T3SS) of Pseudomonas syringae translocates into plant cells multiple effectors that suppress pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). P. syringae pv. tomato DC3000 no longer delivers the T3SS translocation reporter AvrPto-Cya in Nicotiana benthamiana leaf tissue in which PTI was induced by prior inoculation with P. fluorescens(pLN18). Cosmid pLN18 expresses the T3SS system of P. syringae pv. syringae 61 but lacks the hopA1(Psy61) effector gene. P. fluorescens(pLN18) expressing HrpH(PtoDC3000) or HopP1(PtoDC3000), two T3SS-associated putative lytic transglycosylases, suppresses PTI, based on multiple assays involving DC3000 challenge inoculum (AvrPto-Cya translocation, hypersensitive response elicitation, and colony development in planta) or on plant responses (vascular dye uptake or callose deposition). Analysis of additional mutations in pHIR11 derivatives revealed that the pLN18-encoded T3SS elicits a higher level of reactive oxygen species (ROS) than does P. fluorescens without a T3SS, that enhanced ROS production is dependent on the HrpK1 translocator, and that HopA1(Psy61) suppresses ROS elicitation attributable to both the P. fluorescens PAMPs and the presence of a functional T3SS.
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Affiliation(s)
- Hye-Sook Oh
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
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36
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Lewis JD, Wu R, Guttman DS, Desveaux D. Allele-specific virulence attenuation of the Pseudomonas syringae HopZ1a type III effector via the Arabidopsis ZAR1 resistance protein. PLoS Genet 2010; 6:e1000894. [PMID: 20368970 PMCID: PMC2848558 DOI: 10.1371/journal.pgen.1000894] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 03/03/2010] [Indexed: 11/19/2022] Open
Abstract
Plant resistance (R) proteins provide a robust surveillance system to defend against potential pathogens. Despite their importance in plant innate immunity, relatively few of the ∼170 R proteins in Arabidopsis have well-characterized resistance specificity. In order to identify the R protein responsible for recognition of the Pseudomonas syringae type III secreted effector (T3SE) HopZ1a, we assembled an Arabidopsis R gene T–DNA Insertion Collection (ARTIC) from publicly available Arabidopsis thaliana insertion lines and screened it for plants lacking HopZ1a-induced immunity. This reverse genetic screen revealed that the Arabidopsis R protein HOPZ-ACTIVATED RESISTANCE 1 (ZAR1; At3g50950) is required for recognition of HopZ1a in Arabidopsis. ZAR1 belongs to the coiled-coil (CC) class of nucleotide binding site and leucine-rich repeat (NBS–LRR) containing R proteins; however, the ZAR1 CC domain phylogenetically clusters in a clade distinct from other related Arabidopsis R proteins. ZAR1–mediated immunity is independent of several genes required by other R protein signaling pathways, including NDR1 and RAR1, suggesting that ZAR1 possesses distinct signaling requirements. The closely-related T3SE protein, HopZ1b, is still recognized by zar1 Arabidopsis plants indicating that Arabidopsis has evolved at least two independent R proteins to recognize the HopZ T3SE family. Also, in Arabidopsis zar1 plants HopZ1a promotes P. syringae growth indicative of an ancestral virulence function for this T3SE prior to the evolution of recognition by the host resistance protein ZAR1. Our results demonstrate that the Arabidopsis resistance protein ZAR1 confers allele-specific recognition and virulence attenuation of the Pseudomonas syringae T3SE protein HopZ1a. Pseudomonas syringae is a model bacterial pathogen that can infect a broad range of plant species, including important crop plants, as well as the model plant Arabidopsis thaliana. P. syringae employs a specialized syringe-like structure called the type III secretion system to inject virulence proteins termed “effectors” directly into the cells of its plant host. In response, plants have evolved a surveillance system to recognize the presence of type III secreted effector (T3SE) proteins as a trigger for immunity. The sentinels of this surveillance system are termed resistance (R) proteins. Here we identify a new resistance protein, ZAR1, which recognizes the T3SE HopZ1a from P. syringae. HopZ1a is part of the important YopJ superfamily of T3SEs whose archetypical member, YopJ, is found in the causal agent of the bubonic plague, Yersinia pestis. We show that ZAR1–mediated immunity is independent of known Arabidopsis resistance-related genes suggesting that ZAR1 possesses novel signaling requirements. Interestingly, in Arabidopsis plants lacking ZAR1, HopZ1a enhances the virulence of P. syringae indicating that ZAR1 has evolved to recognize and attenuate an ancestral HopZ1a virulence function.
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Affiliation(s)
- Jennifer D. Lewis
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Ronald Wu
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - David S. Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada
| | - Darrell Desveaux
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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37
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Clarke CR, Cai R, Studholme DJ, Guttman DS, Vinatzer BA. Pseudomonas syringae strains naturally lacking the classical P. syringae hrp/hrc Locus are common leaf colonizers equipped with an atypical type III secretion system. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:198-210. [PMID: 20064063 DOI: 10.1094/mpmi-23-2-0198] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Pseudomonas syringae is best known as a plant pathogen that causes disease by translocating immune-suppressing effector proteins into plant cells through a type III secretion system (T3SS). However, P. syringae strains belonging to a newly described phylogenetic subgroup (group 2c) are missing the canonical P. syringae hrp/hrc cluster coding for a T3SS, flanking effector loci, and any close orthologue of known P. syringae effectors. Nonetheless, P. syringae group 2c strains are common leaf colonizers and grow on some tested plant species to population densities higher than those obtained by other P. syringae strains on nonhost species. Moreover, group 2c strains have genes necessary for the production of phytotoxins, have an ice nucleation gene, and, most interestingly, contain a novel hrp/hrc cluster, which is only distantly related to the canonical P. syringae hrp/hrc cluster. This hrp/hrc cluster appears to encode a functional T3SS although the genes hrpK and hrpS, present in the classical P. syringae hrp/hrc cluster, are missing. The genome sequence of a representative group 2c strain also revealed distant orthologues of the P. syringae effector genes avrE1 and hopM1 and the P. aeruginosa effector genes exoU and exoY. A putative life cycle for group 2c P. syringae is discussed.
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Affiliation(s)
- Christopher R Clarke
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Latham Hall, Ag Quad Lane, Blacksburg 24061, USA
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38
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Munkvold KR, Martin GB. Advances in experimental methods for the elucidation of Pseudomonas syringae effector function with a focus on AvrPtoB. MOLECULAR PLANT PATHOLOGY 2009; 10:777-93. [PMID: 19849784 PMCID: PMC2835503 DOI: 10.1111/j.1364-3703.2009.00586.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pseudomonas syringae infects a wide range of plant species through the use of a type III secretion system. The effector proteins injected into the plant cell through this molecular syringe serve as promoters of disease by subverting the plant immune response to the benefit of the bacteria in the intercellular space. The targets and activities of a subset of effectors have been elucidated recently. In this article, we focus on the experimental approaches that have proved most successful in probing the molecular basis of effectors, ranging from loss-of-function to gain-of-function analyses utilizing several techniques for effector delivery into plants. In particular, we highlight how these diverse approaches have been applied to the study of one effector--AvrPtoB--a multifunctional protein with the ability to suppress both effector-triggered immunity and pathogen (or microbe)-associated molecular pattern-triggered immunity. Taken together, advances in this field illustrate the need for multiple experimental approaches when elucidating the function of a single effector.
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Affiliation(s)
- Kathy R Munkvold
- Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA
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39
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Ferrante P, Clarke CR, Cavanaugh KA, Michelmore RW, Buonaurio R, Vinatzer BA. Contributions of the effector gene hopQ1-1 to differences in host range between Pseudomonas syringae pv. phaseolicola and P. syringae pv. tabaci. MOLECULAR PLANT PATHOLOGY 2009; 10:837-42. [PMID: 19849789 PMCID: PMC6640246 DOI: 10.1111/j.1364-3703.2009.00577.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
To study the role of type III-secreted effectors in the host adaptation of the tobacco (Nicotiana sp.) pathogen Pseudomonas syringae pv. tabaci, a selection of seven strains was first characterized by multilocus sequence typing (MLST) to determine their phylogenetic affinity. MLST revealed that all strains represented a tight phylogenetic group and that the most closely related strain with a completely sequenced genome was the bean (Phaseolus vulgaris) pathogen P. syringae pv. phaseolicola 1448A. Using primers designed to 21 P. syringae pv. phaseolicola 1448A effector genes, it was determined that P. syringae pv. phaseolicola 1448A shared at least 10 effectors with all tested P. syringae pv. tabaci strains. Six of the 11 effectors that failed to amplify from P. syringae pv. tabaci strains were individually expressed in one P. syringae pv. tabaci strain. Although five effectors had no effect on phenotype, growth in planta and disease severity of the transgenic P. syringae pv. tabaci expressing hopQ1-1(Pph1448A) were significantly increased in bean, but reduced in tobacco. We conclude that hopQ1-1 has been retained in P. syringae pv. phaseolicola 1448A, as this effector suppresses immunity in bean, whereas hopQ1-1 is missing from P. syringae pv. tabaci strains because it triggers defences in Nicotiana spp. This provides evidence that fine-tuning effector repertoires during host adaptation lead to a concomitant reduction in virulence in non-host species.
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Affiliation(s)
- Patrizia Ferrante
- Dipartimento di Scienze Agrarie e Ambientali, Università degli Studi di Perugia, Via Borgo XX Giugno 74, 06121 Perugia, Italy
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40
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Jiang W, Jiang BL, Xu RQ, Huang JD, Wei HY, Jiang GF, Cen WJ, Liu J, Ge YY, Li GH, Su LL, Hang XH, Tang DJ, Lu GT, Feng JX, He YQ, Tang JL. Identification of six type III effector genes with the PIP box in Xanthomonas campestris pv. campestris and five of them contribute individually to full pathogenicity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:1401-1411. [PMID: 19810809 DOI: 10.1094/mpmi-22-11-1401] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Xanthomonas campestris pv. campestris is the pathogen of black rot of cruciferous plants. The pathogenicity of the pathogen depends on the type III secretion system (T3SS) that translocates directly effector proteins into plant cells, where they play important roles in the molecular interaction between the pathogen and its hosts. The T3SS of Xanthomonas spp. is encoded by a cluster of hypersensitive response and pathogenicity (hrp) genes. It has been demonstrated that the expression of hrp genes and some type III secreted (T3S)-effector genes is coactivated by the key hrp regulatory protein HrpX. The regulation by HrpX can be mediated by the binding of HrpX protein to a cis-regulatory element named the plant-inducible promoter (PIP) box present in the promoter region of HrpX-regulated genes. A genome screen revealed that X. campestris pv. campestris 8004 possesses 56 predicted genes with the PIP box. Nine of these genes have been shown to encode T3S effectors, Hrp, and Hrp-associated proteins. In this study, we employed an established T3S effector translocation assay with the hypersensitive-reaction-inducing domain of X. campestris pv. campestris AvrBs1 as a reporter to characterize the remaining 47 genes with the PIP box and showed that 6 of them, designated as XopXccE1, XopXccP, XopXccQ, XopXccR1, XopXccLR, and AvrXccB, harbor a functional translocation signal in their N-terminal regions, indicating that they are T3S effectors of X. campestris pv. campestris. We provided evidence to demonstrate that all these effectors are expressed in an HrpX-dependent manner and their translocation into plant cells relies on the translocon protein HrpF and the chaperone HpaB. Mutational analyses demonstrated that all these effectors, except AvrXccB, are individually required for full virulence and growth of X. campestris pv. campestris in the host plant Chinese radish.
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Affiliation(s)
- Wei Jiang
- Guangxi Key Laboratory of Subtropical Bioresources Conservation and Utilization, The Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, and College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, Guangxi 530004, China
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41
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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. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 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] [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.
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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
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42
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Ma W, Guttman DS. Evolution of prokaryotic and eukaryotic virulence effectors. CURRENT OPINION IN PLANT BIOLOGY 2008; 11:412-419. [PMID: 18585954 DOI: 10.1016/j.pbi.2008.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 05/13/2008] [Accepted: 05/16/2008] [Indexed: 05/26/2023]
Abstract
Coevolutionary interactions between plants and their bacterial and eukaryotic pathogens are mediated by virulence effectors. These effectors face the daunting challenge of carrying out virulence functions, while also potentially exposing the pathogen to host defense systems. Very strong selective pressures are imposed by these competing roles, and the subsequent genetic changes leave their footprints in the extant allelic variation. This review examines the evolutionary processes that drive pathogen-host interactions as revealed by the genetic signatures left in virulence effectors, and speculate on the different pressures imposed on bacterial versus eukaryotic pathogens. We find numerous instances of positive selection for new allelic forms, and diversifying selection for genetic variability, which results in altered host-pathogen interactions. We also describe how the genetic structure of both bacterial and eukaryotic virulence effectors may contribute to their rapid generation and turnover.
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Affiliation(s)
- Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, USA
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43
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Lee MW, Jelenska J, Greenberg JT. Arabidopsis proteins important for modulating defense responses to Pseudomonas syringae that secrete HopW1-1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:452-65. [PMID: 18266921 DOI: 10.1111/j.1365-313x.2008.03439.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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.
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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
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44
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Mohr TJ, Liu H, Yan S, Morris CE, Castillo JA, Jelenska J, Vinatzer BA. Naturally occurring nonpathogenic isolates of the plant pathogen Pseudomonas syringae lack a type III secretion system and effector gene orthologues. J Bacteriol 2008; 190:2858-70. [PMID: 18263729 PMCID: PMC2293242 DOI: 10.1128/jb.01757-07] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 01/28/2008] [Indexed: 12/28/2022] Open
Abstract
Pseudomonas syringae causes plant diseases, and the main virulence mechanism is a type III secretion system (T3SS) that translocates dozens of effector proteins into plant cells. Here we report the existence of a subgroup of P. syringae isolates that do not cause disease on any plant species tested. This group is monophyletic and most likely evolved from a pathogenic P. syringae ancestor through loss of the T3SS. In the nonpathogenic isolate P. syringae 508 the genomic region that in pathogenic P. syringae strains contains the hrp-hrc cluster coding for the T3SS and flanking effector genes is absent. P. syringae 508 was also surveyed for the presence of effector orthologues from the closely related pathogenic strain P. syringae pv. syringae B728a, but none were detected. The absence of the hrp-hrc cluster and effector orthologues was confirmed for other nonpathogenic isolates. Using the AvrRpt2 effector as reporter revealed the inability of P. syringae 508 to translocate effectors into plant cells. Adding a plasmid-encoded T3SS and the P. syringae pv. syringae 61 effector gene hopA1 increased in planta growth almost 10-fold. This suggests that P. syringae 508 supplemented with a T3SS could be used to determine functions of individual effectors in the context of a plant infection, avoiding the confounding effect of other effectors with similar functions present in effector mutants of pathogenic isolates.
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Affiliation(s)
- Toni J Mohr
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Latham Hall, Ag Quad Lane, Blacksburg, VA 24061, USA
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45
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Lewis JD, Abada W, Ma W, Guttman DS, Desveaux D. The HopZ family of Pseudomonas syringae type III effectors require myristoylation for virulence and avirulence functions in Arabidopsis thaliana. J Bacteriol 2008; 190:2880-91. [PMID: 18263728 PMCID: PMC2293245 DOI: 10.1128/jb.01702-07] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 01/28/2008] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas syringae utilizes the type III secretion system to translocate effector proteins into plant cells, where they can contribute to the pathogen's ability to infect and cause disease. Recognition of these effectors by resistance proteins induces defense responses that typically include a programmed cell death reaction called the hypersensitive response. The YopJ/HopZ family of type III effector proteins is a common family of effector proteins found in animal- and plant-pathogenic bacteria. The HopZ family in P. syringae includes HopZ1a(PsyA2), HopZ1b(PgyUnB647), HopZ1c(PmaE54326), HopZ2(Ppi895A) and HopZ3(PsyB728a). HopZ1a is predicted to be most similar to the ancestral hopZ allele and causes a hypersensitive response in multiple plant species, including Arabidopsis thaliana. Therefore, it has been proposed that host defense responses have driven the diversification of this effector family. In this study, we further characterized the hypersensitive response induced by HopZ1a and demonstrated that it is not dependent on known resistance genes. Further, we identified a novel virulence function for HopZ2 that requires the catalytic cysteine demonstrated to be required for protease activity. Sequence analysis of the HopZ family revealed the presence of a predicted myristoylation sequence in all members except HopZ3. We demonstrated that the myristoylation site is required for membrane localization of this effector family and contributes to the virulence and avirulence activities of HopZ2 and HopZ1a, respectively. This paper provides insight into the selective pressures driving virulence protein evolution by describing a detailed functional characterization of the diverse HopZ family of type III effectors with the model plant Arabidopsis.
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Affiliation(s)
- Jennifer D Lewis
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, Ontario M5S 3B2, Canada
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46
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Song JT, Koo YJ, Seo HS, Kim MC, Choi YD, Kim JH. Overexpression of AtSGT1, an Arabidopsis salicylic acid glucosyltransferase, leads to increased susceptibility to Pseudomonas syringae. PHYTOCHEMISTRY 2008; 69:1128-34. [PMID: 18226820 DOI: 10.1016/j.phytochem.2007.12.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 12/07/2007] [Accepted: 12/10/2007] [Indexed: 05/08/2023]
Abstract
We reported previously that a recombinant salicylic acid (SA) glucosyltransferase1 (AtSGT1) from Arabidopsis thaliana catalyzes the formation of both SA 2-O-beta-D-glucoside (SAG) and the glucose ester of SA (SGE). Here, transgenic Arabidopsis plants overexpressing AtSGT1 have been constructed, and their phenotypes analyzed. Compared to wild-type plants, transgenic plants showed an increased susceptibility to Pseudomonas syringae and reduced the accumulation levels of both free SA and its glucosylated forms (SAG and SGE). On the other hand, the overexpression increased the levels of methyl salicylate (MeSA) and methyl salicylate 2-O-beta-D-glucoside (MeSAG), and also induced SA carboxyl methyltransferase1 (AtBSMT1) expression, whose products catalyze the conversion of SA to MeSA. Our data indicate that reduced resistance by AtSGT1 overexpression results from a reduction in SA content, which is at least in part caused by increases in MeSAG and MeSA levels at the expense of SA. Our study also suggests that genetic manipulation of AtSGT1 can be utilized as an important regulatory tool for pathogen control.
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Affiliation(s)
- Jong Tae Song
- School of Applied Biosciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
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47
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Rentel MC, Leonelli L, Dahlbeck D, Zhao B, Staskawicz BJ. Recognition of the Hyaloperonospora parasitica effector ATR13 triggers resistance against oomycete, bacterial, and viral pathogens. Proc Natl Acad Sci U S A 2008; 105:1091-6. [PMID: 18198274 PMCID: PMC2242713 DOI: 10.1073/pnas.0711215105] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Indexed: 01/01/2023] Open
Abstract
Phytopathogenic oomycetes cause some of the most devastating diseases affecting agricultural crops. Hyaloperonospora parasitica is a native oomycete pathogen of Arabidopsis and is related to other oomycete phytopathogens that include several species of Phytophthora, including the causal agent of potato late blight. Recently, four oomycete effector genes have been isolated, and several oomycete genomes have been sequenced. We have developed an efficient and genetically amenable system to test putative effector genes using the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. The H. parasitica effector protein ATR13 was delivered via P. syringae by fusing the ATR13 gene with the avrRpm1 type three secretion signal peptide, a bacterial sequence that allows transfer of proteins into the host cell through the bacterial type III secretion system. We also inserted ATR13 into the genome of the turnip mosaic virus, a single-stranded RNA virus. Our results show that delivery of ATR13 via the bacterial or viral pathogen triggers defense responses in plants containing the cognate resistance protein RPP13(Nd), which restricts proliferation of both pathogens. Hence, recognition of ATR13 by RPP13 initiates defense responses that are effective against oomycete, bacterial and viral pathogens, pointing to a common defense mechanism. We have characterized regions of the RPP13(Nd) resistance protein that are essential for effector recognition and/or downstream signaling, using transient coexpression in Nicotiana benthamiana.
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Affiliation(s)
- Maike C. Rentel
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Lauriebeth Leonelli
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Douglas Dahlbeck
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Bingyu Zhao
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
| | - Brian J. Staskawicz
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3120
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48
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Vinatzer BA, Yan S. Mining the genomes of plant pathogenic bacteria: how not to drown in gigabases of sequence. MOLECULAR PLANT PATHOLOGY 2008; 9:105-118. [PMID: 18705888 PMCID: PMC6640517 DOI: 10.1111/j.1364-3703.2007.00438.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hundreds of bacterial genomes including the genomes of dozens of plant pathogenic bacteria have been sequenced. These genomes represent an invaluable resource for molecular plant pathologists. In this review, we describe different approaches that can be used for mining bacterial genome sequences and examples of how some of these approaches have been used to analyse plant pathogen genomes so far. We review how genomes can be mined one by one and how comparative genomics of closely related genomes releases the true power of genomics. Databases and tools useful for genome mining that are publicly accessible on the Internet are also described. Finally, the need for new databases and tools to efficiently mine today's plant pathogen genomes and hundreds more in the near future is discussed.
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Affiliation(s)
- Boris A Vinatzer
- Department of Plant Pathology, Physiology, and Weed Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
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McCann HC, Guttman DS. Evolution of the type III secretion system and its effectors in plant-microbe interactions. THE NEW PHYTOLOGIST 2008; 177:33-47. [PMID: 18078471 DOI: 10.1111/j.1469-8137.2007.02293.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Many bacterial plant pathogens require the type III secretion system (T3SS) and its effector proteins (T3SEs) to invade and extract nutrients from their hosts successfully. While the molecular function of this system is being studied intensively, we know comparatively little about the evolutionary and ecological pressures governing its fate over time, and even less about the detailed mechanisms underlying and driving complex T3SS-mediated coevolutionary dynamics. In this review we summarize our current understanding of how host-pathogen interactions evolve, with a particular focus on the T3SS of bacterial plant pathogens. We explore the evolutionary origins of the T3SS relative to the closely related flagellar system, and investigate the evolutionary pressures on this secretion and translocation apparatus. We examine the evolutionary forces acting on T3SEs, and compare the support for vertical descent with modification of these virulence-associated systems (pathoadaptation) vs horizontal gene transfer. We address the evolutionary origins of T3SEs from the perspective of both the evolutionary mechanisms that generate new effectors, and the mobile elements that may be the source of novel genetic material. Finally, we propose a number of questions raised by these studies, which may serve to guide our thinking about these complex processes.
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Affiliation(s)
- Honour C McCann
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S3B2, Canada
| | - David S Guttman
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S3B2, Canada
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Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis thaliana auxin physiology. Proc Natl Acad Sci U S A 2007; 104:20131-6. [PMID: 18056646 DOI: 10.1073/pnas.0704901104] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Pseudomonas syringae type III effector AvrRpt2 promotes bacterial virulence on Arabidopsis thaliana plants lacking a functional RPS2 gene (rps2 mutant plants). To investigate the mechanisms underlying the virulence activity of AvrRpt2, we examined the phenotypes of transgenic A. thaliana rps2 seedlings constitutively expressing AvrRpt2. These seedlings exhibited phenotypes reminiscent of A. thaliana mutants with altered auxin physiology, including longer primary roots, increased number of lateral roots, and increased sensitivity to exogenous auxin. They also had increased levels of free indole acetic acid (IAA). The presence of AvrRpt2 also was correlated with a further increase in free IAA levels during infection with P. syringae pv. tomato strain DC3000 (PstDC3000). These results indicate that AvrRpt2 alters A. thaliana auxin physiology. Application of the auxin analog 1-naphthaleneacetic acid promoted disease symptom development in PstDC3000-infected plants, suggesting that elevated auxin levels within host tissue promote PstDC3000 virulence. Thus, AvrRpt2 may be among the virulence factors of P. syringae that modulate host auxin physiology to promote disease.
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