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Kaur J, Fellers J, Adholeya A, Velivelli SLS, El-Mounadi K, Nersesian N, Clemente T, Shah D. Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat. Transgenic Res 2017; 26:37-49. [PMID: 27582300 PMCID: PMC5243879 DOI: 10.1007/s11248-016-9978-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/16/2016] [Indexed: 11/06/2022]
Abstract
Rust fungi of the order Pucciniales are destructive pathogens of wheat worldwide. Leaf rust caused by the obligate, biotrophic basidiomycete fungus Puccinia triticina (Pt) is an economically important disease capable of causing up to 50 % yield losses. Historically, resistant wheat cultivars have been used to control leaf rust, but genetic resistance is ephemeral and breaks down with the emergence of new virulent Pt races. There is a need to develop alternative measures for control of leaf rust in wheat. Development of transgenic wheat expressing an antifungal defensin offers a promising approach to complement the endogenous resistance genes within the wheat germplasm for durable resistance to Pt. To that end, two different wheat genotypes, Bobwhite and Xin Chun 9 were transformed with a chimeric gene encoding an apoplast-targeted antifungal plant defensin MtDEF4.2 from Medicago truncatula. Transgenic lines from four independent events were further characterized. Homozygous transgenic wheat lines expressing MtDEF4.2 displayed resistance to Pt race MCPSS relative to the non-transgenic controls in growth chamber bioassays. Histopathological analysis suggested the presence of both pre- and posthaustorial resistance to leaf rust in these transgenic lines. MtDEF4.2 did not, however, affect the root colonization of a beneficial arbuscular mycorrhizal fungus Rhizophagus irregularis. This study demonstrates that the expression of apoplast-targeted plant defensin MtDEF4.2 can provide substantial resistance to an economically important leaf rust disease in transgenic wheat without negatively impacting its symbiotic relationship with the beneficial mycorrhizal fungus.
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Affiliation(s)
- Jagdeep Kaur
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA.
| | - John Fellers
- USDA-ARS-HWWGRU, Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506, USA
| | - Alok Adholeya
- Mycorrhizal Applications, 1005 North Warson Road, BRDG Park, St. Louis, MO, 63132, USA
| | | | - Kaoutar El-Mounadi
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
- Department of Biology, Kutztown University of Pennsylvania, Kutztown, PA, 19530, USA
| | - Natalya Nersesian
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Thomas Clemente
- Department of Agronomy and Horticulture/Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Dilip Shah
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
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Zhang X, Nguyen N, Breen S, Outram MA, Dodds PN, Kobe B, Solomon PS, Williams SJ. Production of small cysteine-rich effector proteins in Escherichia coli for structural and functional studies. MOLECULAR PLANT PATHOLOGY 2017; 18:141-151. [PMID: 26915457 PMCID: PMC6638209 DOI: 10.1111/mpp.12385] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 02/22/2016] [Accepted: 02/22/2016] [Indexed: 05/22/2023]
Abstract
Although the lifestyles and infection strategies of plant pathogens are diverse, a prevailing feature is the use of an arsenal of secreted proteins, known as effectors, which aid in microbial infection. In the case of eukaryotic filamentous pathogens, such as fungi and oomycetes, effector proteins are typically dissimilar, at the protein sequence level, to known protein families and functional domains. Consequently, we currently have a limited understanding of how fungal and oomycete effectors promote disease. Protein biochemistry and structural biology are two methods that can contribute greatly to the understanding of protein function. Both techniques are dependent on obtaining proteins that are pure and functional, and generally require the use of heterologous recombinant protein expression systems. Here, we present a general scheme and methodology for the production and characterization of small cysteine-rich (SCR) effectors utilizing Escherichia coli expression systems. Using this approach, we successfully produced cysteine-rich effectors derived from the biotrophic fungal pathogen Melampsora lini and the necrotrophic fungal pathogen Parastagonospora nodorum. Access to functional recombinant proteins facilitated crystallization and functional experiments. These results are discussed in the context of a general workflow that may serve as a template for others interested in understanding the function of SCR effector(s) from their plant pathogen(s) of interest.
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Affiliation(s)
- Xiaoxiao Zhang
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research CentreUniversity of QueenslandBrisbaneQld4072Australia
| | - Neal Nguyen
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research CentreUniversity of QueenslandBrisbaneQld4072Australia
| | - Susan Breen
- Research School of BiologyThe Australian National UniversityCanberraACT 0200Australia
| | - Megan A. Outram
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research CentreUniversity of QueenslandBrisbaneQld4072Australia
| | | | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research CentreUniversity of QueenslandBrisbaneQld4072Australia
| | - Peter S. Solomon
- Research School of BiologyThe Australian National UniversityCanberraACT 0200Australia
| | - Simon J. Williams
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research CentreUniversity of QueenslandBrisbaneQld4072Australia
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Ramachandran SR, Yin C, Kud J, Tanaka K, Mahoney AK, Xiao F, Hulbert SH. Effectors from Wheat Rust Fungi Suppress Multiple Plant Defense Responses. PHYTOPATHOLOGY 2017; 107:75-83. [PMID: 27503371 DOI: 10.1094/phyto-02-16-0083-r] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Fungi that cause cereal rust diseases (genus Puccinia) are important pathogens of wheat globally. Upon infection, the fungus secretes a number of effector proteins. Although a large repository of putative effectors has been predicted using bioinformatic pipelines, the lack of available high-throughput effector screening systems has limited functional studies on these proteins. In this study, we mined the available transcriptomes of Puccinia graminis and P. striiformis to look for potential effectors that suppress host hypersensitive response (HR). Twenty small (<300 amino acids), secreted proteins, with no predicted functions were selected for the HR suppression assay using Nicotiana benthamiana, in which each of the proteins were transiently expressed and evaluated for their ability to suppress HR caused by four cytotoxic effector-R gene combinations (Cp/Rx, ATR13/RPP13, Rpt2/RPS-2, and GPA/RBP-1) and one mutated R gene-Pto(Y207D). Nine out of twenty proteins, designated Shr1 to Shr9 (suppressors of hypersensitive response), were found to suppress HR in N. benthamiana. These effectors varied in the effector-R gene defenses they suppressed, indicating these pathogens can interfere with a variety of host defense pathways. In addition to HR suppression, effector Shr7 also suppressed PAMP-triggered immune response triggered by flg22. Finally, delivery of Shr7 through Pseudomonas fluorescens EtHAn suppressed nonspecific HR induced by Pseudomonas syringae DC3000 in wheat, confirming its activity in a homologous system. Overall, this study provides the first evidence for the presence of effectors in Puccinia species suppressing multiple plant defense responses.
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Affiliation(s)
- Sowmya R Ramachandran
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Chuntao Yin
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Joanna Kud
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Kiwamu Tanaka
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Aaron K Mahoney
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Fangming Xiao
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
| | - Scot H Hulbert
- First, second, fourth, fifth, and seventh authors: Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430; and third and sixth authors: Plant, Soil and Entomological Sciences, University of Idaho, Moscow, ID 83844-2339
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Cesari S, Moore J, Chen C, Webb D, Periyannan S, Mago R, Bernoux M, Lagudah ES, Dodds PN. Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC-NLR proteins. Proc Natl Acad Sci U S A 2016; 113:10204-9. [PMID: 27555587 PMCID: PMC5018743 DOI: 10.1073/pnas.1605483113] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Plants possess intracellular immune receptors designated "nucleotide-binding domain and leucine-rich repeat" (NLR) proteins that translate pathogen-specific recognition into disease-resistance signaling. The wheat immune receptors Sr33 and Sr50 belong to the class of coiled-coil (CC) NLRs. They confer resistance against a broad spectrum of field isolates of Puccinia graminis f. sp. tritici, including the Ug99 lineage, and are homologs of the barley powdery mildew-resistance protein MLA10. Here, we show that, similarly to MLA10, the Sr33 and Sr50 CC domains are sufficient to induce cell death in Nicotiana benthamiana Autoactive CC domains and full-length Sr33 and Sr50 proteins self-associate in planta In contrast, truncated CC domains equivalent in size to an MLA10 fragment for which a crystal structure was previously determined fail to induce cell death and do not self-associate. Mutations in the truncated region also abolish self-association and cell-death signaling. Analysis of Sr33 and Sr50 CC domains fused to YFP and either nuclear localization or nuclear export signals in N benthamiana showed that cell-death induction occurs in the cytosol. In stable transgenic wheat plants, full-length Sr33 proteins targeted to the cytosol provided rust resistance, whereas nuclear-targeted Sr33 was not functional. These data are consistent with CC-mediated induction of both cell-death signaling and stem rust resistance in the cytosolic compartment, whereas previous research had suggested that MLA10-mediated cell-death and disease resistance signaling occur independently, in the cytosol and nucleus, respectively.
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Affiliation(s)
- Stella Cesari
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - John Moore
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Chunhong Chen
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, Australian National University, Canberra, ACT 0200, Australia
| | - Sambasivam Periyannan
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Rohit Mago
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Maud Bernoux
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Evans S Lagudah
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia
| | - Peter N Dodds
- Commonwealth Scientific and Industrial Research Organization Agriculture, Canberra, ACT 2601, Australia;
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Anderson C, Khan MA, Catanzariti AM, Jack CA, Nemri A, Lawrence GJ, Upadhyaya NM, Hardham AR, Ellis JG, Dodds PN, Jones DA. Genome analysis and avirulence gene cloning using a high-density RADseq linkage map of the flax rust fungus, Melampsora lini. BMC Genomics 2016; 17:667. [PMID: 27550217 PMCID: PMC4994203 DOI: 10.1186/s12864-016-3011-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/11/2016] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Rust fungi are an important group of plant pathogens that cause devastating losses in agricultural, silvicultural and natural ecosystems. Plants can be protected from rust disease by resistance genes encoding receptors that trigger a highly effective defence response upon recognition of specific pathogen avirulence proteins. Identifying avirulence genes is crucial for understanding how virulence evolves in the field. RESULTS To facilitate avirulence gene cloning in the flax rust fungus, Melampsora lini, we constructed a high-density genetic linkage map using single nucleotide polymorphisms detected in restriction site-associated DNA sequencing (RADseq) data. The map comprises 13,412 RADseq markers in 27 linkage groups that together span 5860 cM and contain 2756 recombination bins. The marker sequences were used to anchor 68.9 % of the M. lini genome assembly onto the genetic map. The map and anchored assembly were then used to: 1) show that M. lini has a high overall meiotic recombination rate, but recombination distribution is uneven and large coldspots exist; 2) show that substantial genome rearrangements have occurred in spontaneous loss-of-avirulence mutants; and 3) identify the AvrL2 and AvrM14 avirulence genes by map-based cloning. AvrM14 is a dual-specificity avirulence gene that encodes a predicted nudix hydrolase. AvrL2 is located in the region of the M. lini genome with the lowest recombination rate and encodes a small, highly-charged proline-rich protein. CONCLUSIONS The M. lini high-density linkage map has greatly advanced our understanding of virulence mechanisms in this pathogen by providing novel insights into genome variability and enabling identification of two new avirulence genes.
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Affiliation(s)
- Claire Anderson
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 2601 Australia
| | - Muhammad Adil Khan
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 2601 Australia
- Current address: ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 Australia
| | - Ann-Maree Catanzariti
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 2601 Australia
| | - Cameron A. Jack
- ANU Bioinformatics Consulting Unit, The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Acton, ACT 2601 Australia
| | - Adnane Nemri
- CSIRO Agriculture, GPO Box 1600, Canberra, ACT 2601 Australia
- Current address: KWS SAAT SE, Grimsehlstraße 31, Einbeck, 37574 Germany
| | | | | | - Adrienne R. Hardham
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 2601 Australia
| | | | - Peter N. Dodds
- CSIRO Agriculture, GPO Box 1600, Canberra, ACT 2601 Australia
| | - David A. Jones
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT 2601 Australia
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Cooper B, Campbell KB, Beard HS, Garrett WM, Islam N. Putative Rust Fungal Effector Proteins in Infected Bean and Soybean Leaves. PHYTOPATHOLOGY 2016; 106:491-9. [PMID: 26780434 DOI: 10.1094/phyto-11-15-0310-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The plant-pathogenic fungi Uromyces appendiculatus and Phakopsora pachyrhizi cause debilitating rust diseases on common bean and soybean. These rust fungi secrete effector proteins that allow them to infect plants, but their effector repertoires are not understood. The discovery of rust fungus effectors may eventually help guide decisions and actions that mitigate crop production loss. Therefore, we used mass spectrometry to identify thousands of proteins in infected beans and soybeans and in germinated fungal spores. The comparative analysis between the two helped differentiate a set of 24 U. appendiculatus proteins targeted for secretion that were specifically found in infected beans and a set of 34 U. appendiculatus proteins targeted for secretion that were found in germinated spores and infected beans. The proteins specific to infected beans included family 26 and family 76 glycoside hydrolases that may contribute to degrading plant cell walls. There were also several types of proteins with structural motifs that may aid in stabilizing the specialized fungal haustorium cell that interfaces the plant cell membrane during infection. There were 16 P. pachyrhizi proteins targeted for secretion that were found in infected soybeans, and many of these proteins resembled the U. appendiculatus proteins found in infected beans, which implies that these proteins are important to rust fungal pathology in general. This data set provides insight to the biochemical mechanisms that rust fungi use to overcome plant immune systems and to parasitize cells.
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Affiliation(s)
- Bret Cooper
- First, second, and third authors: Soybean Genomics and Improvement Laboratory, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Beltsville, MD 20705; fourth author: Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD 20705; and fifth author: Department of Nutrition and Food Science, University of Maryland, College Park 20742
| | - Kimberly B Campbell
- First, second, and third authors: Soybean Genomics and Improvement Laboratory, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Beltsville, MD 20705; fourth author: Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD 20705; and fifth author: Department of Nutrition and Food Science, University of Maryland, College Park 20742
| | - Hunter S Beard
- First, second, and third authors: Soybean Genomics and Improvement Laboratory, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Beltsville, MD 20705; fourth author: Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD 20705; and fifth author: Department of Nutrition and Food Science, University of Maryland, College Park 20742
| | - Wesley M Garrett
- First, second, and third authors: Soybean Genomics and Improvement Laboratory, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Beltsville, MD 20705; fourth author: Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD 20705; and fifth author: Department of Nutrition and Food Science, University of Maryland, College Park 20742
| | - Nazrul Islam
- First, second, and third authors: Soybean Genomics and Improvement Laboratory, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), Beltsville, MD 20705; fourth author: Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD 20705; and fifth author: Department of Nutrition and Food Science, University of Maryland, College Park 20742
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Selin C, de Kievit TR, Belmonte MF, Fernando WGD. Elucidating the Role of Effectors in Plant-Fungal Interactions: Progress and Challenges. Front Microbiol 2016; 7:600. [PMID: 27199930 PMCID: PMC4846801 DOI: 10.3389/fmicb.2016.00600] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 04/11/2016] [Indexed: 11/13/2022] Open
Abstract
Pathogenic fungi have diverse growth lifestyles that support fungal colonization on plants. Successful colonization and infection for all lifestyles depends upon the ability to modify living host plants to sequester the necessary nutrients required for growth and reproduction. Secretion of virulence determinants referred to as “effectors” is assumed to be the key governing factor that determines host infection and colonization. Effector proteins are capable of suppressing plant defense responses and alter plant physiology to accommodate fungal invaders. This review focuses on effector molecules of biotrophic and hemibiotrophic plant pathogenic fungi, and the mechanism required for the release and uptake of effector molecules by the fungi and plant cells, respectively. We also place emphasis on the discovery of effectors, difficulties associated with predicting the effector repertoire, and fungal genomic features that have helped promote effector diversity leading to fungal evolution. We discuss the role of specific effectors found in biotrophic and hemibiotrophic fungi and examine how CRISPR/Cas9 technology may provide a new avenue for accelerating our ability in the discovery of fungal effector function.
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Affiliation(s)
- Carrie Selin
- Department of Plant Science, University of Manitoba Winnipeg, MB, Canada
| | | | - Mark F Belmonte
- Department of Biological Sciences, University of Manitoba Winnipeg, MB, Canada
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Sperschneider J, Gardiner DM, Dodds PN, Tini F, Covarelli L, Singh KB, Manners JM, Taylor JM. EffectorP: predicting fungal effector proteins from secretomes using machine learning. THE NEW PHYTOLOGIST 2016; 210:743-61. [PMID: 26680733 DOI: 10.1111/nph.13794] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/05/2015] [Indexed: 05/02/2023]
Abstract
Eukaryotic filamentous plant pathogens secrete effector proteins that modulate the host cell to facilitate infection. Computational effector candidate identification and subsequent functional characterization delivers valuable insights into plant-pathogen interactions. However, effector prediction in fungi has been challenging due to a lack of unifying sequence features such as conserved N-terminal sequence motifs. Fungal effectors are commonly predicted from secretomes based on criteria such as small size and cysteine-rich, which suffers from poor accuracy. We present EffectorP which pioneers the application of machine learning to fungal effector prediction. EffectorP improves fungal effector prediction from secretomes based on a robust signal of sequence-derived properties, achieving sensitivity and specificity of over 80%. Features that discriminate fungal effectors from secreted noneffectors are predominantly sequence length, molecular weight and protein net charge, as well as cysteine, serine and tryptophan content. We demonstrate that EffectorP is powerful when combined with in planta expression data for predicting high-priority effector candidates. EffectorP is the first prediction program for fungal effectors based on machine learning. Our findings will facilitate functional fungal effector studies and improve our understanding of effectors in plant-pathogen interactions. EffectorP is available at http://effectorp.csiro.au.
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Affiliation(s)
- Jana Sperschneider
- Centre for Environment and Life Sciences, CSIRO Agriculture, Perth, 6014, WA, Australia
| | - Donald M Gardiner
- Queensland Bioscience Precinct, CSIRO Agriculture, Brisbane, 4067, QLD, Australia
| | - Peter N Dodds
- Black Mountain Laboratories, CSIRO Agriculture, Canberra, 2601, ACT, Australia
| | - Francesco Tini
- Queensland Bioscience Precinct, CSIRO Agriculture, Brisbane, 4067, QLD, Australia
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, 06121, Umbria, Italy
| | - Lorenzo Covarelli
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, 06121, Umbria, Italy
| | - Karam B Singh
- Centre for Environment and Life Sciences, CSIRO Agriculture, Perth, 6014, WA, Australia
| | - John M Manners
- Black Mountain Laboratories, CSIRO Agriculture, Canberra, 2601, ACT, Australia
| | - Jennifer M Taylor
- Black Mountain Laboratories, CSIRO Agriculture, Canberra, 2601, ACT, Australia
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Kunjeti SG, Iyer G, Johnson E, Li E, Broglie KE, Rauscher G, Rairdan GJ. Identification of Phakopsora pachyrhizi Candidate Effectors with Virulence Activity in a Distantly Related Pathosystem. FRONTIERS IN PLANT SCIENCE 2016; 7:269. [PMID: 27014295 PMCID: PMC4781881 DOI: 10.3389/fpls.2016.00269] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 02/21/2016] [Indexed: 05/26/2023]
Abstract
Phakopsora pachyrhizi is the causal agent of Asian Soybean Rust, a disease that causes enormous economic losses, most markedly in South America. P. pachyrhizi is a biotrophic pathogen that utilizes specialized feeding structures called haustoria to colonize its hosts. In rusts and other filamentous plant pathogens, haustoria have been shown to secrete effector proteins into their hosts to permit successful completion of their life cycle. We have constructed a cDNA library from P. pachyrhizi haustoria using paramagnetic bead-based methodology and have identified 35 P. pachyrhizi candidate effector (CE) genes from this library which are described here. In addition, we quantified the transcript expression pattern of six of these genes and show that two of these CEs are able to greatly increase the susceptibility of Nicotiana benthamiana to Phytophthora infestans. This strongly suggests that these genes play an important role in P. pachyrhizi virulence on its hosts.
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Figueroa M, Upadhyaya NM, Sperschneider J, Park RF, Szabo LJ, Steffenson B, Ellis JG, Dodds PN. Changing the Game: Using Integrative Genomics to Probe Virulence Mechanisms of the Stem Rust Pathogen Puccinia graminis f. sp. tritici. FRONTIERS IN PLANT SCIENCE 2016; 7:205. [PMID: 26941766 PMCID: PMC4764693 DOI: 10.3389/fpls.2016.00205] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/06/2016] [Indexed: 05/03/2023]
Abstract
The recent resurgence of wheat stem rust caused by new virulent races of Puccinia graminis f. sp. tritici (Pgt) poses a threat to food security. These concerns have catalyzed an extensive global effort toward controlling this disease. Substantial research and breeding programs target the identification and introduction of new stem rust resistance (Sr) genes in cultivars for genetic protection against the disease. Such resistance genes typically encode immune receptor proteins that recognize specific components of the pathogen, known as avirulence (Avr) proteins. A significant drawback to deploying cultivars with single Sr genes is that they are often overcome by evolution of the pathogen to escape recognition through alterations in Avr genes. Thus, a key element in achieving durable rust control is the deployment of multiple effective Sr genes in combination, either through conventional breeding or transgenic approaches, to minimize the risk of resistance breakdown. In this situation, evolution of pathogen virulence would require changes in multiple Avr genes in order to bypass recognition. However, choosing the optimal Sr gene combinations to deploy is a challenge that requires detailed knowledge of the pathogen Avr genes with which they interact and the virulence phenotypes of Pgt existing in nature. Identifying specific Avr genes from Pgt will provide screening tools to enhance pathogen virulence monitoring, assess heterozygosity and propensity for mutation in pathogen populations, and confirm individual Sr gene functions in crop varieties carrying multiple effective resistance genes. Toward this goal, much progress has been made in assembling a high quality reference genome sequence for Pgt, as well as a Pan-genome encompassing variation between multiple field isolates with diverse virulence spectra. In turn this has allowed prediction of Pgt effector gene candidates based on known features of Avr genes in other plant pathogens, including the related flax rust fungus. Upregulation of gene expression in haustoria and evidence for diversifying selection are two useful parameters to identify candidate Avr genes. Recently, we have also applied machine learning approaches to agnostically predict candidate effectors. Here, we review progress in stem rust pathogenomics and approaches currently underway to identify Avr genes recognized by wheat Sr genes.
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Affiliation(s)
- Melania Figueroa
- Department of Plant Pathology and the Stakman-Borlaug Center for Sustainable Plant Health, University of MinnesotaSt. Paul, MN, USA
| | - Narayana M. Upadhyaya
- Agriculture, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - Jana Sperschneider
- Agriculture, Centre for Environment and Life Sciences, Commonwealth Scientific and Industrial Research OrganisationPerth, WA, Australia
| | - Robert F. Park
- Faculty of Agriculture and Environment, Plant Breeding Institute, The University of SydneyNarellan, NSW, Australia
| | - Les J. Szabo
- Department of Plant Pathology and the Stakman-Borlaug Center for Sustainable Plant Health, University of MinnesotaSt. Paul, MN, USA
- Cereal Disease Laboratory, United States Department of Agriculture-Agricultural Research ServiceSt. Paul, MN, USA
| | - Brian Steffenson
- Department of Plant Pathology and the Stakman-Borlaug Center for Sustainable Plant Health, University of MinnesotaSt. Paul, MN, USA
| | - Jeff G. Ellis
- Agriculture, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
| | - Peter N. Dodds
- Agriculture, Commonwealth Scientific and Industrial Research OrganisationCanberra, ACT, Australia
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Martin T, Rönnberg-Wästljung AC, Stenlid J, Samils B. Identification of a Differentially Expressed TIR-NBS-LRR Gene in a Major QTL Associated to Leaf Rust Resistance in Salix. PLoS One 2016; 11:e0168776. [PMID: 28002449 PMCID: PMC5176316 DOI: 10.1371/journal.pone.0168776] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 12/06/2016] [Indexed: 11/25/2022] Open
Abstract
An earlier identified major quantitative trait locus for resistance towards the willow leaf rust fungus Melampsora larici-epitea in a Salix viminalis x (S. viminalis × S. schwerinii) population was used to identify potential resistance genes to the rust pathogen. Screening a genomic bacterial artificial chromosome library with markers from the peak position of the QTL region revealed one gene with TIR-NBS-LRR (Toll Interleukin1 Receptor-Nucleotide Binding Site-Leucine-Rich Repeat) domain structure indicative of a resistance gene. The resistance gene analog was denoted RGA1 and further analysis revealed a number of non-synonymous single nucleotide polymorphisms in the LRR domain between the resistant and susceptible Salix genotypes. Gene expression levels under controlled conditions showed a significantly lower constitutive expression of RGA1 in the susceptible genotype. In addition, the susceptible genotype showed a significantly reduced expression level of the RGA1 gene at 24 hours post inoculation with M. larici-epitea. This indicates that the pathogen may actively suppress RGA1 gene expression allowing a compatible plant-pathogen interaction and causing infection.
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Affiliation(s)
- Tom Martin
- Department of Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Jan Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Berit Samils
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
- * E-mail:
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62
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Liu JJ, Sturrock RN, Sniezko RA, Williams H, Benton R, Zamany A. Transcriptome analysis of the white pine blister rust pathogen Cronartium ribicola: de novo assembly, expression profiling, and identification of candidate effectors. BMC Genomics 2015; 16:678. [PMID: 26338692 PMCID: PMC4559923 DOI: 10.1186/s12864-015-1861-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/18/2015] [Indexed: 12/21/2022] Open
Abstract
Background The fungus Cronartium ribicola (Cri) is an economically and ecologically important forest pathogen that causes white pine blister rust (WPBR) disease on five-needle pines. To cause stem cankers and kill white pine trees the fungus elaborates a life cycle with five stages of spore development on five-needle pines and the alternate host Ribes plants. To increase our understanding of molecular WP-BR interactions, here we report genome-wide transcriptional profile analysis of C. ribicola using RNA-seq. Results cDNA libraries were constructed from aeciospore, urediniospore, and western white pine (Pinus monticola) tissues post Cri infection. Over 200 million RNA-seq 100-bp paired-end (PE) reads from rust fungal spores were de novo assembled and a reference transcriptome was generated with 17,880 transcripts that were expressed from 13,629 unigenes. A total of 734 unique proteins were predicted as a part of the Cri secretome from complete open reading frames (ORFs), and 41 % of them were Cronartium-specific. This study further identified a repertoire of candidate effectors and other pathogenicity determinants. Differentially expressed genes (DEGs) were identified to gain an understanding of molecular events important during the WPBR fungus life cycle by comparing Cri transcriptomes at different infection stages. Large-scale changes of in planta gene expression profiles were observed, revealing that multiple fungal biosynthetic pathways were enhanced during mycelium growth inside infected pine stem tissues. Conversely, many fungal genes that were up-regulated at the urediniospore stage appeared to be signalling components and transporters. The secreted fungal protein genes that were up-regulated in pine needle tissues during early infection were primarily associated with cell wall modifications, possibly to mask the rust pathogen from plant defenses. Conclusion This comprehensive transcriptome profiling substantially improves our current understanding of molecular WP-BR interactions. The repertoire of candidate effectors and other putative pathogenicity determinants identified here are valuable for future functional analysis of Cri virulence and pathogenicity. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1861-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jun-Jun Liu
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC, V8Z 1M5, Canada.
| | - Rona N Sturrock
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC, V8Z 1M5, Canada.
| | - Richard A Sniezko
- USDA Forest Service, Dorena Genetic Resource Center, 34963 Shoreview Road, Cottage Grove, OR, 97424, USA.
| | - Holly Williams
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC, V8Z 1M5, Canada.
| | - Ross Benton
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC, V8Z 1M5, Canada.
| | - Arezoo Zamany
- Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC, V8Z 1M5, Canada.
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63
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Figueroa M, Castell-Miller CV, Li F, Hulbert SH, Bradeen JM. Pushing the boundaries of resistance: insights from Brachypodium-rust interactions. FRONTIERS IN PLANT SCIENCE 2015; 6:558. [PMID: 26284085 PMCID: PMC4519692 DOI: 10.3389/fpls.2015.00558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 07/07/2015] [Indexed: 05/20/2023]
Abstract
The implications of global population growth urge transformation of current food and bioenergy production systems to sustainability. Members of the family Poaceae are of particular importance both in food security and for their applications as biofuel substrates. For centuries, rust fungi have threatened the production of valuable crops such as wheat, barley, oat, and other small grains; similarly, biofuel crops can also be susceptible to these pathogens. Emerging rust pathogenic races with increased virulence and recurrent rust epidemics around the world point out the vulnerability of monocultures. Basic research in plant immunity, especially in model plants, can make contributions to understanding plant resistance mechanisms and improve disease management strategies. The development of the grass Brachypodium distachyon as a genetically tractable model for monocots, especially temperate cereals and grasses, offers the possibility to overcome the experimental challenges presented by the genetic and genomic complexities of economically valuable crop plants. The numerous resources and tools available in Brachypodium have opened new doors to investigate the underlying molecular and genetic bases of plant-microbe interactions in grasses and evidence demonstrating the applicability and advantages of working with B. distachyon is increasing. Importantly, several interactions between B. distachyon and devastating plant pathogens, such rust fungi, have been examined in the context of non-host resistance. Here, we discuss the use of B. distachyon in these various pathosystems. Exploiting B. distachyon to understand the mechanisms underpinning disease resistance to non-adapted rust fungi may provide effective and durable approaches to fend off these pathogens. The close phylogenetic relationship among Brachypodium spp. and grasses with industrial and agronomic value support harnessing this model plant to improve cropping systems and encourage its use in translational research.
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Affiliation(s)
- Melania Figueroa
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, MN, USA
| | - Claudia V. Castell-Miller
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, MN, USA
| | - Feng Li
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, MN, USA
| | - Scot H. Hulbert
- Department of Plant Pathology, Washington State University, Pullman, WA, USA
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA
| | - James M. Bradeen
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, USA
- Stakman-Borlaug Center for Sustainable Plant Health, University of Minnesota, St. Paul, MN, USA
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64
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How eukaryotic filamentous pathogens evade plant recognition. Curr Opin Microbiol 2015; 26:92-101. [PMID: 26162502 DOI: 10.1016/j.mib.2015.06.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 12/29/2022]
Abstract
Plant pathogenic fungi and oomycetes employ sophisticated mechanisms for evading host recognition. After host penetration, many fungi and oomycetes establish a biotrophic interaction. It is assumed that different strategies employed by these pathogens to avoid triggering host defence responses, including establishment of biotrophic interfacial layers between the pathogen and host, masking of invading hyphae and active suppression of host defence mechanisms, are essential for a biotrophic parasitic lifestyle. During the infection process, filamentous plant pathogens secrete various effectors, which are hypothesized to be involved in facilitating effective host infection. Live-cell imaging of fungi and oomycetes secreting fluorescently labeled effector proteins as well as functional characterization of the components of biotrophic interfaces have led to the recent progress in understanding how eukaryotic filamentous pathogens evade plant recognition.
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65
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Petre B, Saunders DGO, Sklenar J, Lorrain C, Win J, Duplessis S, Kamoun S. Candidate Effector Proteins of the Rust Pathogen Melampsora larici-populina Target Diverse Plant Cell Compartments. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:689-700. [PMID: 25650830 DOI: 10.1094/mpmi-01-15-0003-r] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Rust fungi are devastating crop pathogens that deliver effector proteins into infected tissues to modulate plant functions and promote parasitic growth. The genome of the poplar leaf rust fungus Melampsora larici-populina revealed a large catalog of secreted proteins, some of which have been considered candidate effectors. Unraveling how these proteins function in host cells is a key to understanding pathogenicity mechanisms and developing resistant plants. In this study, we used an effectoromics pipeline to select, clone, and express 20 candidate effectors in Nicotiana benthamiana leaf cells to determine their subcellular localization and identify the plant proteins they interact with. Confocal microscopy revealed that six candidate effectors target the nucleus, nucleoli, chloroplasts, mitochondria, and discrete cellular bodies. We also used coimmunoprecipitation (coIP) and mass spectrometry to identify 606 N. benthamiana proteins that associate with the candidate effectors. Five candidate effectors specifically associated with a small set of plant proteins that may represent biologically relevant interactors. We confirmed the interaction between the candidate effector MLP124017 and TOPLESS-related protein 4 from poplar by in planta coIP. Altogether, our data enable us to validate effector proteins from M. larici-populina and reveal that these proteins may target multiple compartments and processes in plant cells. It also shows that N. benthamiana can be a powerful heterologous system to study effectors of obligate biotrophic pathogens.
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Affiliation(s)
- Benjamin Petre
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
- 2 INRA, UMR 1136 Interactions Arbres/Microorganismes, Centre INRA Nancy Lorraine, 54280 Champenoux, France
- 3 Université de Lorraine, UMR 1136 Interactions Arbres/Microorganismes, Faculté des Sciences et Technologies, 54506 Vandoeuvre-lès-Nancy, France
| | - Diane G O Saunders
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
- 4 The Genome Analysis Centre, Norwich Research Park, NR4 7UH Norwich, U.K
- 5 The John Innes Centre, Norwich Research Park, NR4 7UH Norwich, U.K
| | - Jan Sklenar
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
| | - Cécile Lorrain
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
- 2 INRA, UMR 1136 Interactions Arbres/Microorganismes, Centre INRA Nancy Lorraine, 54280 Champenoux, France
- 3 Université de Lorraine, UMR 1136 Interactions Arbres/Microorganismes, Faculté des Sciences et Technologies, 54506 Vandoeuvre-lès-Nancy, France
| | - Joe Win
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
| | - Sébastien Duplessis
- 2 INRA, UMR 1136 Interactions Arbres/Microorganismes, Centre INRA Nancy Lorraine, 54280 Champenoux, France
- 3 Université de Lorraine, UMR 1136 Interactions Arbres/Microorganismes, Faculté des Sciences et Technologies, 54506 Vandoeuvre-lès-Nancy, France
| | - Sophien Kamoun
- 1 The Sainsbury Laboratory, Norwich Research Park, NR4 7UH Norwich, U.K
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Wang X, McCallum BD, Fetch T, Bakkeren G, Saville BJ. Sr36- and Sr5-Mediated Resistance Response to Puccinia graminis f. sp. tritici Is Associated with Callose Deposition in Wheat Guard Cells. PHYTOPATHOLOGY 2015; 105:728-737. [PMID: 26056723 DOI: 10.1094/phyto-08-14-0213-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Race-specific resistance of wheat to Puccinia graminis f. sp. tritici is primarily posthaustorial and often involves the induction of a hypersensitive response (HR). The aim of this study was to investigate host defense responses induced in interactions between P. graminis f. sp. tritici races and wheat lines carrying different race-specific stem rust resistance (Sr) genes. In incompatible interactions between wheat lines carrying Sr36 in three genetic backgrounds (LMPG, Prelude, or W2691) and avirulent P. graminis f. sp. tritici races MCCFC or RCCDM, callose accumulated within 24 h in wheat guard cells contacted by a P. graminis f. sp. tritici appressorium, and P. graminis f. sp. tritici ingress was inhibited following appressorium formation. Accordingly, the expression of transcripts encoding a callose synthase increased in the incompatible interaction between LMPG-Sr36 and avirulent P. graminis f. sp. tritici race MCCFC. Furthermore, the inhibition of callose synthesis through the infiltration of 2-deoxy-D-glucose (DDG) increased the ability of P. graminis f. sp. tritici race MCCFC to infect LMPG-Sr36. A similar induction of callose deposition in wheat guard cells was also observed within 24 h after inoculation (hai) with avirulent P. graminis f. sp. tritici race HKCJC on LMPG-Sr5 plants. In contrast, this defense response was not induced in incompatible interactions involving Sr6, Sr24, or Sr30. Instead, the induction of an HR and cellular lignification were noted. The manifestation of the HR and cellular lignification was induced earlier (24 hai) and was more extensive in the resistance response mediated by Sr6 compared with those mediated by Sr24 or Sr30. These results indicate that the resistance mediated by Sr36 is similar to that mediated by Sr5 but different from those triggered by Sr6, Sr24, or Sr30. Resistance responses mediated by Sr5 and Sr36 are prehaustorial, and are a result of very rapid recognition of molecules derived from avirulent isolates of P. graminis f. sp. tritici, in contrast to the responses triggered in lines with Sr6, Sr24, and Sr30.
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Affiliation(s)
- X Wang
- First, second, and third authors: Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada; fourth author: Pacific Agri-Food Research Centre, Agriculture and Agri Food Canada, Summerland, BC, VOH 1ZO, Canada; and fifth author: Forensic Science Program, and Environmental and Life Sciences Graduate Program Trent University, Peterborough, ON, K9J 7B8, Canada
| | - B D McCallum
- First, second, and third authors: Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada; fourth author: Pacific Agri-Food Research Centre, Agriculture and Agri Food Canada, Summerland, BC, VOH 1ZO, Canada; and fifth author: Forensic Science Program, and Environmental and Life Sciences Graduate Program Trent University, Peterborough, ON, K9J 7B8, Canada
| | - T Fetch
- First, second, and third authors: Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada; fourth author: Pacific Agri-Food Research Centre, Agriculture and Agri Food Canada, Summerland, BC, VOH 1ZO, Canada; and fifth author: Forensic Science Program, and Environmental and Life Sciences Graduate Program Trent University, Peterborough, ON, K9J 7B8, Canada
| | - G Bakkeren
- First, second, and third authors: Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada; fourth author: Pacific Agri-Food Research Centre, Agriculture and Agri Food Canada, Summerland, BC, VOH 1ZO, Canada; and fifth author: Forensic Science Program, and Environmental and Life Sciences Graduate Program Trent University, Peterborough, ON, K9J 7B8, Canada
| | - B J Saville
- First, second, and third authors: Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada; fourth author: Pacific Agri-Food Research Centre, Agriculture and Agri Food Canada, Summerland, BC, VOH 1ZO, Canada; and fifth author: Forensic Science Program, and Environmental and Life Sciences Graduate Program Trent University, Peterborough, ON, K9J 7B8, Canada
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Sperschneider J, Dodds PN, Gardiner DM, Manners JM, Singh KB, Taylor JM. Advances and challenges in computational prediction of effectors from plant pathogenic fungi. PLoS Pathog 2015; 11:e1004806. [PMID: 26020524 PMCID: PMC4447458 DOI: 10.1371/journal.ppat.1004806] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Jana Sperschneider
- CSIRO Agriculture Flagship, Centre for Environment and Life Sciences, Perth, Western Australia, Australia
- * E-mail:
| | - Peter N. Dodds
- CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, Australian Capital Territory, Australia
| | - Donald M. Gardiner
- CSIRO Agriculture Flagship, Queensland Bioscience Precinct, Brisbane, Queensland, Australia
| | - John M. Manners
- CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, Australian Capital Territory, Australia
| | - Karam B. Singh
- CSIRO Agriculture Flagship, Centre for Environment and Life Sciences, Perth, Western Australia, Australia
- University of Western Australia Institute of Agriculture, University of Western Australia, Crawley, Western Australia, Australia
| | - Jennifer M. Taylor
- CSIRO Agriculture Flagship, Black Mountain Laboratories, Canberra, Australian Capital Territory, Australia
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68
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Bettgenhaeuser J, Gilbert B, Ayliffe M, Moscou MJ. Nonhost resistance to rust pathogens - a continuation of continua. FRONTIERS IN PLANT SCIENCE 2014; 5:664. [PMID: 25566270 PMCID: PMC4263244 DOI: 10.3389/fpls.2014.00664] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 11/07/2014] [Indexed: 05/25/2023]
Abstract
The rust fungi (order: Pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina), which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi) is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant-pathogen interactions in this intermediate state are characterized either by (1) the majority of accessions of a species being resistant to the rust or (2) the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host) to complete immunity within a species (nonhost). In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens.
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Affiliation(s)
| | - Brian Gilbert
- Commonwealth Scientific and Industrial Research Organisation, Agriculture FlagshipCanberra, ACT, Australia
| | - Michael Ayliffe
- Commonwealth Scientific and Industrial Research Organisation, Agriculture FlagshipCanberra, ACT, Australia
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