151
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Sánchez-Vallet A, McDonald MC, Solomon PS, McDonald BA. Is Zymoseptoria tritici a hemibiotroph? Fungal Genet Biol 2015; 79:29-32. [DOI: 10.1016/j.fgb.2015.04.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 12/21/2022]
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152
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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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153
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Tsuda K, Somssich IE. Transcriptional networks in plant immunity. THE NEW PHYTOLOGIST 2015; 206:932-947. [PMID: 25623163 DOI: 10.1111/nph.13286] [Citation(s) in RCA: 287] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/09/2014] [Indexed: 05/18/2023]
Abstract
Next to numerous abiotic stresses, plants are constantly exposed to a variety of pathogens within their environment. Thus, their ability to survive and prosper during the course of evolution was strongly dependent on adapting efficient strategies to perceive and to respond to such potential threats. It is therefore not surprising that modern plants have a highly sophisticated immune repertoire consisting of diverse signal perception and intracellular signaling pathways. This signaling network is intricate and deeply interconnected, probably reflecting the diverse lifestyles and infection strategies used by the multitude of invading phytopathogens. Moreover it allows signal communication between developmental and defense programs thereby ensuring that plant growth and fitness are not significantly retarded. How plants integrate and prioritize the incoming signals and how this information is transduced to enable appropriate immune responses is currently a major research area. An important finding has been that pathogen-triggered cellular responses involve massive transcriptional reprogramming within the host. Additional key observations emerging from such studies are that transcription factors (TFs) are often sites of signal convergence and that signal-regulated TFs act in concert with other context-specific TFs and transcriptional co-regulators to establish sensory transcription regulatory networks required for plant immunity.
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Affiliation(s)
- Kenichi Tsuda
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, Cologne, 50829, Germany
| | - Imre E Somssich
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-von-Linne Weg 10, Cologne, 50829, Germany
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154
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Kabbage M, Yarden O, Dickman MB. Pathogenic attributes of Sclerotinia sclerotiorum: switching from a biotrophic to necrotrophic lifestyle. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 233:53-60. [PMID: 25711813 DOI: 10.1016/j.plantsci.2014.12.018] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/20/2014] [Accepted: 12/22/2014] [Indexed: 05/02/2023]
Abstract
Plants and fungi have had many years of friendly and not-so friendly competition for resources and quality of life. As a result, diverse pathosystems evolved numerous strategies, coupled with the emergence of multifaceted pathogenic and saprophytic lifestyles. We discuss fungal lifestyle classifications and how the views associated with certain fungal pathogens, particularly necrotophs, are changing as we learn more about the complexities of their interactions with a given host plant. We discuss the physiological events leading to the transition from biotrophy to necrotrophy in hemi-biotrophs, and conclude that both the control of plant immune responses and the need for a more efficient mode of nutrient acquisition are possible triggers for the transition to necrotrophy. Based on recent findings, we focus on the polyphagous plant pathogen Sclerotinia sclerotiorum. Rather than overwhelming plant foes, S. sclerotiorum has evolved clever means to compromise host recognition and establish disease, resulting in a broad and immensely successful pathogenic lifestyle. The tactics used by this fungus to achieve pathogenic success are being clarified. We propose that the hemi-biotrophic lifestyle may be more temporally and spatially complex than currently depicted, and that combining lifestyle attributes with damage response curves that consider the contribution of both the fungus and the host to pathogenesis, may provide a more holistic manner to view plant pathogens.
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Affiliation(s)
- Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7600, Israel
| | - Martin B Dickman
- Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX, USA; Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA.
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155
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Seidl MF, Faino L, Shi-Kunne X, van den Berg GCM, Bolton MD, Thomma BPHJ. The Genome of the Saprophytic Fungus Verticillium tricorpus Reveals a Complex Effector Repertoire Resembling That of Its Pathogenic Relatives. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:362-373. [PMID: 25208342 DOI: 10.1094/mpmi-06-14-0173-r] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Vascular wilts caused by Verticillium spp. are destructive plant diseases affecting hundreds of hosts. Only a few Verticillium spp. are causal agents of vascular wilt diseases, of which V. dahliae is the most notorious pathogen, and several V. dahliae genomes are available. In contrast, V. tricorpus is mainly known as a saprophyte and causal agent of opportunistic infections. Based on a hybrid approach that combines second and third generation sequencing, a near-gapless V. tricorpus genome assembly was obtained. With comparative genomics, we sought to identify genomic features in V. dahliae that confer the ability to cause vascular wilt disease. Unexpectedly, both species encode similar effector repertoires and share a genomic structure with genes encoding secreted proteins clustered in genomic islands. Intriguingly, V. tricorpus contains significantly fewer repetitive elements and an extended spectrum of secreted carbohydrate- active enzymes when compared with V. dahliae. In conclusion, we highlight the technical advances of a hybrid sequencing and assembly approach and show that the saprophyte V. tricorpus shares many hallmark features with the pathogen V. dahliae.
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156
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Sánchez-Vallet A, Mesters JR, Thomma BP. The battle for chitin recognition in plant-microbe interactions. FEMS Microbiol Rev 2015; 39:171-83. [DOI: 10.1093/femsre/fuu003] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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157
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De Coninck B, Timmermans P, Vos C, Cammue BPA, Kazan K. What lies beneath: belowground defense strategies in plants. TRENDS IN PLANT SCIENCE 2015; 20:91-101. [PMID: 25307784 DOI: 10.1016/j.tplants.2014.09.007] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 05/17/2023]
Abstract
Diseases caused by soil-borne pathogens result worldwide in significant yield losses in economically important crops. In contrast to foliar diseases, relatively little is known about the nature of root defenses against these pathogens. This review summarizes the current knowledge on root infection strategies, root-specific preformed barriers, pathogen recognition, and defense signaling. Studies reviewed here suggest that many commonalities as well as differences exist in defense strategies employed by roots and foliar tissues during pathogen attack. Importantly, in addition to pathogens, plant roots interact with a plethora of non-pathogenic and symbiotic microorganisms. Therefore, a good understanding of how plant roots interact with the microbiome would be particularly important to engineer resistance to root pathogens without negatively altering root-beneficial microbe interactions.
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Affiliation(s)
- Barbara De Coninck
- Centre of Microbial and Plant Genetics, Katholieke Universiteit (KU) Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium; Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), Technologiepark 927, 9052 Gent, Belgium
| | - Pieter Timmermans
- Centre of Microbial and Plant Genetics, Katholieke Universiteit (KU) Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Christine Vos
- Centre of Microbial and Plant Genetics, Katholieke Universiteit (KU) Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium; Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), Technologiepark 927, 9052 Gent, Belgium
| | - Bruno P A Cammue
- Centre of Microbial and Plant Genetics, Katholieke Universiteit (KU) Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium; Department of Plant Systems Biology, Vlaams Instituut voor Biotechnologie (VIB), Technologiepark 927, 9052 Gent, Belgium.
| | - Kemal Kazan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture Flagship, Queensland Bioscience Precinct, Brisbane, Queensland, 4067, Australia; Queensland Alliance for Agriculture & Food Innovation (QAAFI), The University of Queensland, St Lucia, Brisbane, Queensland 4067, Australia
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158
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Tan KC, Phan HTT, Rybak K, John E, Chooi YH, Solomon PS, Oliver RP. Functional redundancy of necrotrophic effectors - consequences for exploitation for breeding. FRONTIERS IN PLANT SCIENCE 2015; 6:501. [PMID: 26217355 PMCID: PMC4495316 DOI: 10.3389/fpls.2015.00501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Necrotrophic diseases of wheat cause major losses in most wheat growing areas of world. Tan spot (caused by Pyrenophora tritici-repentis) and septoria nodorum blotch (SNB; Parastagonospora nodorum) have been shown to reduce yields by 10-20% across entire agri-ecological zones despite the application of fungicides and a heavy focus over the last 30 years on resistance breeding. Efforts by breeders to improve the resistance of cultivars has been compromised by the universal finding that resistance was quantitative and governed by multiple quantitative trait loci (QTL). Most QTL had a limited effect that was hard to measure precisely and varied significantly from site to site and season to season. The discovery of necrotrophic effectors has given breeding for disease resistance new methods and tools. In the case of tan spot in West Australia, a single effector, PtrToxA and its recogniser gene Tsn1, has a dominating impact in disease resistance. The delivery of ToxA to breeders has had a major impact on cultivar choice and breeding strategies. For P. nodorum, three effectors - SnToxA, SnTox1, and SnTox3 - have been well characterized. Unlike tan spot, no one effector has a dominating role. Genetic analysis of various mapping populations and pathogen isolates has shown that different effectors have varying impact and that epistatic interactions also occur. As a result of these factors the deployment of these effectors for SNB resistance breeding is more complex. We have deleted the three effectors in a strain of P. nodorum and measured effector activity and disease potential of the triple knockout mutant. The culture filtrate causes necrosis in several cultivars and the strain causes disease, albeit the overall levels are less than in the wild type. Modeling of the field disease resistance scores of cultivars from their reactions to the microbially expressed effectors SnToxA, SnTox1, and SnTox3 is significantly improved by including the response to the triple knockout mutant culture filtrate. This indicates that one or more further effectors are secreted into the culture filtrate. We conclude that the in vitro-secreted necrotrophic effectors explain a very large part of the disease response of wheat germplasm and that this method of resistance breeding promises to further reduce the impact of these globally significant diseases.
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Affiliation(s)
- Kar-Chun Tan
- Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, BentleyWA, Australia
- *Correspondence: Richard P. Oliver and Kar-Chun Tan, Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, Bentley, WA 6102, Australia, ;
| | - Huyen T. T. Phan
- Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, BentleyWA, Australia
| | - Kasia Rybak
- Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, BentleyWA, Australia
| | - Evan John
- Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, BentleyWA, Australia
| | - Yit H. Chooi
- Plant Sciences Division, Research School of Biology, Australian National University, CanberraACT, Australia
- School of Chemistry and Biochemistry, University of Western Australia, PerthWA, Australia
| | - Peter S. Solomon
- Plant Sciences Division, Research School of Biology, Australian National University, CanberraACT, Australia
| | - Richard P. Oliver
- Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, BentleyWA, Australia
- *Correspondence: Richard P. Oliver and Kar-Chun Tan, Centre for Crop Disease Management, Department of Environment and Agriculture, Curtin University, Bentley, WA 6102, Australia, ;
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159
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Cook DE, Mesarich CH, Thomma BPHJ. Understanding plant immunity as a surveillance system to detect invasion. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:541-63. [PMID: 26047564 DOI: 10.1146/annurev-phyto-080614-120114] [Citation(s) in RCA: 302] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Various conceptual models to describe the plant immune system have been presented. The most recent paradigm to gain wide acceptance in the field is often referred to as the zigzag model, which reconciles the previously formulated gene-for-gene hypothesis with the recognition of general elicitors in a single model. This review focuses on the limitations of the current paradigm of molecular plant-microbe interactions and how it too narrowly defines the plant immune system. As such, we discuss an alternative view of plant innate immunity as a system that evolves to detect invasion. This view accommodates the range from mutualistic to parasitic symbioses that plants form with diverse organisms, as well as the spectrum of ligands that the plant immune system perceives. Finally, how this view can contribute to the current practice of resistance breeding is discussed.
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Affiliation(s)
- David E Cook
- Laboratory of Phytopathology, Wageningen University, 6708 PB Wageningen, The Netherlands; ,
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160
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Lo Presti L, Lanver D, Schweizer G, Tanaka S, Liang L, Tollot M, Zuccaro A, Reissmann S, Kahmann R. Fungal effectors and plant susceptibility. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:513-45. [PMID: 25923844 DOI: 10.1146/annurev-arplant-043014-114623] [Citation(s) in RCA: 649] [Impact Index Per Article: 72.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants can be colonized by fungi that have adopted highly diverse lifestyles, ranging from symbiotic to necrotrophic. Colonization is governed in all systems by hundreds of secreted fungal effector molecules. These effectors suppress plant defense responses and modulate plant physiology to accommodate fungal invaders and provide them with nutrients. Fungal effectors either function in the interaction zone between the fungal hyphae and host or are transferred to plant cells. This review describes the effector repertoires of 84 plant-colonizing fungi. We focus on the mechanisms that allow these fungal effectors to promote virulence or compatibility, discuss common plant nodes that are targeted by effectors, and provide recent insights into effector evolution. In addition, we address the issue of effector uptake in plant cells and highlight open questions and future challenges.
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Affiliation(s)
- Libera Lo Presti
- Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany; , , , , , , , ,
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161
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Klimes A, Dobinson KF, Thomma BPHJ, Klosterman SJ. Genomics spurs rapid advances in our understanding of the biology of vascular wilt pathogens in the genus Verticillium. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:181-98. [PMID: 26047557 DOI: 10.1146/annurev-phyto-080614-120224] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The availability of genomic sequences of several Verticillium species triggered an explosion of genome-scale investigations of mechanisms fundamental to the Verticillium life cycle and disease process. Comparative genomics studies have revealed evolutionary mechanisms, such as hybridization and interchromosomal rearrangements, that have shaped these genomes. Functional analyses of a diverse group of genes encoding virulence factors indicate that successful host xylem colonization relies on specific Verticillium responses to various stresses, including nutrient deficiency and host defense-derived oxidative stress. Regulatory pathways that control responses to changes in nutrient availability also appear to positively control resting structure development. Conversely, resting structure development seems to be repressed by pathways, such as those involving effector secretion, which promote responses to host defenses. The genomics-enabled functional characterization of responses to the challenges presented by the xylem environment, accompanied by identification of novel virulence factors, has rapidly expanded our understanding of niche adaptation in Verticillium species.
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Affiliation(s)
- Anna Klimes
- Department of Physical and Biological Sciences, Western New England University, Springfield, Massachusetts 01119;
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162
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Gijzen M, Ishmael C, Shrestha SD. Epigenetic control of effectors in plant pathogens. FRONTIERS IN PLANT SCIENCE 2014; 5:638. [PMID: 25429296 PMCID: PMC4228847 DOI: 10.3389/fpls.2014.00638] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 10/27/2014] [Indexed: 05/07/2023]
Abstract
Plant pathogens display impressive versatility in adapting to host immune systems. Pathogen effector proteins facilitate disease but can become avirulence (Avr) factors when the host acquires discrete recognition capabilities that trigger immunity. The mechanisms that lead to changes to pathogen Avr factors that enable escape from host immunity are diverse, and include epigenetic switches that allow for reuse or recycling of effectors. This perspective outlines possibilities of how epigenetic control of Avr effector gene expression may have arisen and persisted in filamentous plant pathogens, and how it presents special problems for diagnosis and detection of specific pathogen strains or pathotypes.
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Affiliation(s)
- Mark Gijzen
- Agriculture and Agri-Food CanadaLondon, ON, Canada
- Department of Biology, University of Western OntarioLondon, ON, Canada
- *Correspondence: Mark Gijzen, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON N5V 4T3, Canada e-mail:
| | - Chelsea Ishmael
- Agriculture and Agri-Food CanadaLondon, ON, Canada
- Department of Biology, University of Western OntarioLondon, ON, Canada
| | - Sirjana D. Shrestha
- Agriculture and Agri-Food CanadaLondon, ON, Canada
- Department of Biology, University of Western OntarioLondon, ON, Canada
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