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Mapuranga J, Chang J, Zhang L, Zhang N, Yang W. Fungal Secondary Metabolites and Small RNAs Enhance Pathogenicity during Plant-Fungal Pathogen Interactions. J Fungi (Basel) 2022; 9:jof9010004. [PMID: 36675825 PMCID: PMC9862911 DOI: 10.3390/jof9010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Fungal plant pathogens use proteinaceous effectors as well as newly identified secondary metabolites (SMs) and small non-coding RNA (sRNA) effectors to manipulate the host plant's defense system via diverse plant cell compartments, distinct organelles, and many host genes. However, most molecular studies of plant-fungal interactions have focused on secreted effector proteins without exploring the possibly equivalent functions performed by fungal (SMs) and sRNAs, which are collectively known as "non-proteinaceous effectors". Fungal SMs have been shown to be generated throughout the plant colonization process, particularly in the early biotrophic stages of infection. The fungal repertoire of non-proteinaceous effectors has been broadened by the discovery of fungal sRNAs that specifically target plant genes involved in resistance and defense responses. Many RNAs, particularly sRNAs involved in gene silencing, have been shown to transmit bidirectionally between fungal pathogens and their hosts. However, there are no clear functional approaches to study the role of these SM and sRNA effectors. Undoubtedly, fungal SM and sRNA effectors are now a treasured land to seek. Therefore, understanding the role of fungal SM and sRNA effectors may provide insights into the infection process and identification of the interacting host genes that are targeted by these effectors. This review discusses the role of fungal SMs and sRNAs during plant-fungal interactions. It will also focus on the translocation of sRNA effectors across kingdoms, the application of cross-kingdom RNA interference in managing plant diseases and the tools that can be used to predict and study these non-proteinaceous effectors.
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Todd JNA, Carreón-Anguiano KG, Islas-Flores I, Canto-Canché B. Microbial Effectors: Key Determinants in Plant Health and Disease. Microorganisms 2022; 10:1980. [PMID: 36296254 PMCID: PMC9610748 DOI: 10.3390/microorganisms10101980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 11/17/2022] Open
Abstract
Effectors are small, secreted molecules that alter host cell structure and function, thereby facilitating infection or triggering a defense response. Effectoromics studies have focused on effectors in plant-pathogen interactions, where their contributions to virulence are determined in the plant host, i.e., whether the effector induces resistance or susceptibility to plant disease. Effector molecules from plant pathogenic microorganisms such as fungi, oomycetes and bacteria are major disease determinants. Interestingly, the effectors of non-pathogenic plant organisms such as endophytes display similar functions but have different outcomes for plant health. Endophyte effectors commonly aid in the establishment of mutualistic interactions with the plant and contribute to plant health through the induction of systemic resistance against pathogens, while pathogenic effectors mainly debilitate the plant's immune response, resulting in the establishment of disease. Effectors of plant pathogens as well as plant endophytes are tools to be considered in effectoromics for the development of novel strategies for disease management. This review aims to present effectors in their roles as promotors of health or disease for the plant host.
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Affiliation(s)
- Jewel Nicole Anna Todd
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Karla Gisel Carreón-Anguiano
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Ignacio Islas-Flores
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
| | - Blondy Canto-Canché
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., Calle 43 No. 130 x 32 y 34, Colonia Chuburná de Hidalgo, Mérida C.P. 97205, Yucatán, Mexico
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Minina EA, Dauphinee AN, Ballhaus F, Gogvadze V, Smertenko AP, Bozhkov PV. Apoptosis is not conserved in plants as revealed by critical examination of a model for plant apoptosis-like cell death. BMC Biol 2021; 19:100. [PMID: 33980238 PMCID: PMC8117276 DOI: 10.1186/s12915-021-01018-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 04/01/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Animals and plants diverged over one billion years ago and evolved unique mechanisms for many cellular processes, including cell death. One of the most well-studied cell death programmes in animals, apoptosis, involves gradual cell dismantling and engulfment of cellular fragments, apoptotic bodies, through phagocytosis. However, rigid cell walls prevent plant cell fragmentation and thus apoptosis is not applicable for executing cell death in plants. Furthermore, plants are devoid of the key components of apoptotic machinery, including phagocytosis as well as caspases and Bcl-2 family proteins. Nevertheless, the concept of plant "apoptosis-like programmed cell death" (AL-PCD) is widespread. This is largely due to superficial morphological resemblances between plant cell death and apoptosis, and in particular between protoplast shrinkage in plant cells killed by various stimuli and animal cell volume decrease preceding fragmentation into apoptotic bodies. RESULTS Here, we provide a comprehensive spatio-temporal analysis of cytological and biochemical events occurring in plant cells subjected to heat shock at 40-55 °C and 85 °C, the experimental conditions typically used to trigger AL-PCD and necrotic cell death, respectively. We show that cell death under both conditions was not accompanied by membrane blebbing or formation of apoptotic bodies, as would be expected during apoptosis. Instead, we observed instant and irreversible permeabilization of the plasma membrane and ATP depletion. These processes did not depend on mitochondrial functionality or the presence of Ca2+ and could not be prevented by an inhibitor of ferroptosis. We further reveal that the lack of protoplast shrinkage at 85 °C, the only striking morphological difference between cell deaths induced by 40-55 °C or 85 °C heat shock, is a consequence of the fixative effect of the high temperature on intracellular contents. CONCLUSIONS We conclude that heat shock-induced cell death is an energy-independent process best matching definition of necrosis. Although the initial steps of this necrotic cell death could be genetically regulated, classifying it as apoptosis or AL-PCD is a terminological misnomer. Our work supports the viewpoint that apoptosis is not conserved across animal and plant kingdoms and demonstrates the importance of focusing on plant-specific aspects of cell death pathways.
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Affiliation(s)
- Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7015, SE-750 07, Uppsala, Sweden.
- COS, Heidelberg University, Im Neuenheimer Feld 230, 69120, Heidelberg, Germany.
| | - Adrian N Dauphinee
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7015, SE-750 07, Uppsala, Sweden
| | - Florentine Ballhaus
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7015, SE-750 07, Uppsala, Sweden
| | - Vladimir Gogvadze
- Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Box 210, SE-171 77, Stockholm, Sweden
- Faculty of Medicine, MV Lomonosov Moscow State University, 119991, Moscow, Russia
| | - Andrei P Smertenko
- Institute of Biological Chemistry, College of Human, Agricultural, and Natural Resource Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, P.O. Box 7015, SE-750 07, Uppsala, Sweden.
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Pontes JGDM, Fernandes LS, Dos Santos RV, Tasic L, Fill TP. Virulence Factors in the Phytopathogen-Host Interactions: An Overview. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:7555-7570. [PMID: 32559375 DOI: 10.1021/acs.jafc.0c02389] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phytopathogens are responsible for great losses in agriculture, once they are able to subvert or elude the host defense mechanisms through virulence factors secretion for their dissemination. Herein, it is reviewed phytotoxins that act as virulence factors and are produced by bacterial phytopathogens (Candidatus Liberibacter spp., Erwinia amylovora, Pseudomonas syringae pvs and Xanthomonas spp.) and fungi (Alternaria alternata, Botrytis cinerea, Cochliobolus spp., Fusarium spp., Magnaporthe spp., and Penicillium spp.), which were selected in accordance to their worldwide importance due to the biochemical and economical aspects. In the current review, it is sought to understand the role of virulence factors in the pathogen-host interactions that result in plant diseases.
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Affiliation(s)
| | - Laura Soler Fernandes
- Laboratório de Biologia Quı́mica Microbiana (LaBioQuiMi), IQ-UNICAMP, Campinas, SP, Brazil
| | | | - Ljubica Tasic
- Laboratório de Quı́mica Biológica (LQB), IQ-UNICAMP, Campinas, SP, Brazil
| | - Taicia Pacheco Fill
- Laboratório de Biologia Quı́mica Microbiana (LaBioQuiMi), IQ-UNICAMP, Campinas, SP, Brazil
- Institute of Chemistry, Universidade Estadual de Campinas (UNICAMP), P.O. Box 6154, 13083970 Campinas, SP, Brazil
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Ozturk IK, Dupont PY, Chettri P, McDougal R, Böhl OJ, Cox RJ, Bradshaw RE. Evolutionary relics dominate the small number of secondary metabolism genes in the hemibiotrophic fungus Dothistroma septosporum. Fungal Biol 2019; 123:397-407. [PMID: 31053329 DOI: 10.1016/j.funbio.2019.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/12/2019] [Accepted: 02/21/2019] [Indexed: 10/27/2022]
Abstract
Fungal secondary metabolites have important functions for the fungi that produce them, such as roles in virulence and competition. The hemibiotrophic pine needle pathogen Dothistroma septosporum has one of the lowest complements of secondary metabolite (SM) backbone genes of plant pathogenic fungi, indicating that this fungus produces a limited range of SMs. Amongst these SMs is dothistromin, a well-characterised polyketide toxin and virulence factor that is required for expansion of disease lesions in Dothistroma needle blight disease. Dothistromin genes are dispersed across six loci on one chromosome, rather than being clustered as for most SM genes. We explored other D. septosporum SM genes to determine if they are associated with gene clusters, and to predict what their likely products and functions might be. Of nine functional SM backbone genes in the D. septosporum genome, only four were expressed under a range of in planta and in culture conditions, one of which was the dothistromin PKS backbone gene. Of the other three expressed genes, gene knockout studies suggested that DsPks1 and DsPks2 are not required for virulence and attempts to determine a functional squalestatin-like SM product for DsPks2 were not successful. However preliminary evidence suggested that DsNps3, the only SM backbone gene to be most highly expressed in the early stage of disease, appears to be a virulence factor. Thus, despite the small number of SM backbone genes in D. septosporum, most of them appear to be poorly expressed or dispensable for virulence in planta. This work contributes to a growing body of evidence that many fungal secondary metabolite gene clusters might be non-functional and may be evolutionary relics.
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Affiliation(s)
- I Kutay Ozturk
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North, 4410, New Zealand
| | - Pierre-Yves Dupont
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North, 4410, New Zealand; Institute of Environmental Science and Research, Christchurch, 8041, New Zealand
| | - Pranav Chettri
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North, 4410, New Zealand
| | - Rebecca McDougal
- Scion, NZ Forest Research Institute Ltd, Rotorua, 3010, New Zealand
| | - Ole J Böhl
- Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1b, Hannover, 30167, Germany
| | - Russell J Cox
- Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1b, Hannover, 30167, Germany
| | - Rosie E Bradshaw
- Bio-Protection Research Centre, Institute of Fundamental Sciences, Massey University, Palmerston North, 4410, New Zealand.
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Petrov V, Qureshi MK, Hille J, Gechev T. Occurrence, biochemistry and biological effects of host-selective plant mycotoxins. Food Chem Toxicol 2017; 112:251-264. [PMID: 29288760 DOI: 10.1016/j.fct.2017.12.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 12/21/2017] [Accepted: 12/22/2017] [Indexed: 02/08/2023]
Abstract
Host-selective mycotoxins (HSTs) are various secondary metabolites or proteinaceous compounds secreted by pathogenic necrotrophic fungi that feed off on dead tissues of certain plants. Research on the HSTs has not only fundamental but also practical importance. On one hand they are implicated in the onset of devastating crop diseases. On the other hand, they have been studied as a good model for revealing the intricate mechanisms of plant-pathogen interactions. At the cellular level, HSTs target different compartments and in most instances induce programmed cell death (PCD) by a wide range of mechanisms. Often the responses provoked by HSTs resemble the effector-triggered immunity used by plant cells to combat biotrophic pathogens, which suggests that HST-producing fungi exploit the plants' own defensive systems to derive benefits. Although by definition HSTs are active only in tissues of susceptible plant genotypes, it has been demonstrated that some of them are able to influence animal cells as well. The possible effects, like cytotoxicity or cytostasis, can be harmful or beneficial and thus HSTs may either pose a health risk for humans and livestock, or be of prospective use in the fields of pharmacology, medicine and agriculture.
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Affiliation(s)
- Veselin Petrov
- Center of Plant Systems Biology and Biotechnology, 139 Ruski blvd., Plovdiv 4000, Bulgaria; Department of Plant Physiology and Biochemistry, Agricultural University, 12 Mendeleev str., Plovdiv 4000, Bulgaria.
| | - Muhammad Kamran Qureshi
- Department of Plant Breeding & Genetics, Faculty of Agricultural Sciences & Technology, Bahauddin Zakariya University, Bosan Road, 60800, Multan, Punjab, Pakistan.
| | - Jacques Hille
- Department of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Tsanko Gechev
- Center of Plant Systems Biology and Biotechnology, 139 Ruski blvd., Plovdiv 4000, Bulgaria; Institute of Molecular Biology and Biotechnology, 105 Ruski blvd., Plovdiv 4000, Bulgaria; Department of Plant Physiology and Molecular Biology, Plovdiv University, 24 Tsar Assen str., Plovdiv 4000, Bulgaria.
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Mukhtar M, McCormack M, Argueso C, Pajerowska-Mukhtar K. Pathogen Tactics to Manipulate Plant Cell Death. Curr Biol 2016; 26:R608-R619. [DOI: 10.1016/j.cub.2016.02.051] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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8
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Van Bockhaven J, Steppe K, Bauweraerts I, Kikuchi S, Asano T, Höfte M, De Vleesschauwer D. Primary metabolism plays a central role in moulding silicon-inducible brown spot resistance in rice. MOLECULAR PLANT PATHOLOGY 2015; 16:811-24. [PMID: 25583155 PMCID: PMC6638399 DOI: 10.1111/mpp.12236] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Over recent decades, a multitude of studies have shown the ability of silicon (Si) to protect various plants against a range of microbial pathogens exhibiting different lifestyles and infection strategies. Despite this relative wealth of knowledge, an understanding of the action mechanism of Si is still in its infancy, which hinders its widespread application for agricultural purposes. In an attempt to further elucidate the molecular underpinnings of Si-induced disease resistance, we studied the transcriptome of control and Si-treated rice plants infected with the necrotrophic brown spot fungus Cochliobolus miyabeanus. Analysis of brown spot-infected control plants suggested that C. miyabeanus represses plant photosynthetic processes and nitrate reduction in order to trigger premature senescence and cause disease. In Si-treated plants, however, these pathogen-induced metabolic alterations are strongly impaired, suggesting that Si alleviates stress imposed by the pathogen. Interestingly, Si also significantly increased photorespiration rates in brown spot-infected plants. Although photorespiration is often considered as a wasteful process, recent studies have indicated that this metabolic bypass also enhances resistance during abiotic stress and pathogen attack by protecting the plant's photosynthetic machinery. In view of these findings, our results favour a scenario in which Si enhances brown spot resistance by counteracting C. miyabeanus-induced senescence and cell death via increased photorespiration. Moreover, our results shed light onto the mechanistic basis of Si-induced disease control and support the view that, in addition to activating plant immune responses, Si can also reduce disease severity by interfering with pathogen virulence strategies.
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Affiliation(s)
- Jonas Van Bockhaven
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - Ingvar Bauweraerts
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - Shoshi Kikuchi
- Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, 305-8602, Ibaraki, Japan
| | - Takayuki Asano
- Plant Genome Research Unit, Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, 305-8602, Ibaraki, Japan
| | - Monica Höfte
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
| | - David De Vleesschauwer
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, B-9000, Ghent, Belgium
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9
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Pusztahelyi T, Holb IJ, Pócsi I. Secondary metabolites in fungus-plant interactions. FRONTIERS IN PLANT SCIENCE 2015; 6:573. [PMID: 26300892 PMCID: PMC4527079 DOI: 10.3389/fpls.2015.00573] [Citation(s) in RCA: 254] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 07/13/2015] [Indexed: 05/18/2023]
Abstract
Fungi and plants are rich sources of thousands of secondary metabolites. The genetically coded possibilities for secondary metabolite production, the stimuli of the production, and the special phytotoxins basically determine the microscopic fungi-host plant interactions and the pathogenic lifestyle of fungi. The review introduces plant secondary metabolites usually with antifungal effect as well as the importance of signaling molecules in induced systemic resistance and systemic acquired resistance processes. The review also concerns the mimicking of plant effector molecules like auxins, gibberellins and abscisic acid by fungal secondary metabolites that modulate plant growth or even can subvert the plant defense responses such as programmed cell death to gain nutrients for fungal growth and colonization. It also looks through the special secondary metabolite production and host selective toxins of some significant fungal pathogens and the plant response in form of phytoalexin production. New results coming from genome and transcriptional analyses in context of selected fungal pathogens and their hosts are also discussed.
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Affiliation(s)
- Tünde Pusztahelyi
- Central Laboratory, Faculty of Agricultural and Food Sciences and Environmental Management, University of DebrecenDebrecen, Hungary
| | - Imre J. Holb
- Faculty of Agricultural and Food Sciences and Environmental Management, Institute of Horticulture, University of DebrecenDebrecen, Hungary
- Department of Plant Pathology, Centre for Agricultural Research, Plant Protection Institute, Hungarian Academy of SciencesDebrecen, Hungary
| | - István Pócsi
- Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of DebrecenDebrecen, Hungary
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10
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Stotz HU, Mitrousia GK, de Wit PJGM, Fitt BDL. Effector-triggered defence against apoplastic fungal pathogens. TRENDS IN PLANT SCIENCE 2014; 19:491-500. [PMID: 24856287 PMCID: PMC4123193 DOI: 10.1016/j.tplants.2014.04.009] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 04/07/2014] [Accepted: 04/23/2014] [Indexed: 05/18/2023]
Abstract
R gene-mediated host resistance against apoplastic fungal pathogens is not adequately explained by the terms pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) or effector-triggered immunity (ETI). Therefore, it is proposed that this type of resistance is termed 'effector-triggered defence' (ETD). Unlike PTI and ETI, ETD is mediated by R genes encoding cell surface-localised receptor-like proteins (RLPs) that engage the receptor-like kinase SOBIR1. In contrast to this extracellular recognition, ETI is initiated by intracellular detection of pathogen effectors. ETI is usually associated with fast, hypersensitive host cell death, whereas ETD often triggers host cell death only after an elapsed period of endophytic pathogen growth. In this opinion, we focus on ETD responses against foliar fungal pathogens of crops.
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Affiliation(s)
- Henrik U Stotz
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
| | - Georgia K Mitrousia
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
| | - Pierre J G M de Wit
- Wageningen University and Research Centre, Laboratory of Phytopathology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Bruce D L Fitt
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK.
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11
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Srivastava A, Cho IK, Cho Y. The Bdtf1 gene in Alternaria brassicicola is important in detoxifying brassinin and maintaining virulence on Brassica species. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1429-1440. [PMID: 23945003 DOI: 10.1094/mpmi-07-13-0186-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Brassinin is an antifungal compound induced in Brassica plants after microbial infection. Molecular evidence is incomplete, however, in supporting the importance of brassinin in plant resistance to pathogens. To test the importance of brassinin in plant defense, we studied the functions of the gene Bdtf1 in the necrotrophic fungus Alternaria brassicicola. Several strains of mutants of this gene were weakly virulent on Brassica species, causing lesions 70% smaller in diameter than the wild type on three Brassica species. These mutants, however, were as virulent as the wild type on Arabidopsis thaliana. They were similar to the wild type in spore germination, colony morphology, and mycelial growth in nutrient-rich media, both with and without stress-inducing chemicals. Unlike wild-type A. brassicicola, however, the mutants failed to germinate and their hyphal growth was arrested in the presence of 200 μM brassinin. When grown in a medium containing 100 μM brassinin, wild-type mycelium entirely converted the brassinin into a nontoxic derivative, of which the precise chemical nature was not established. Mutants of the Bdtf1 gene were unable to perform this conversion. Our results support the hypothesis that the ability of A. brassicicola to detoxify brassinin is necessary for successful infection of Brassica species.
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12
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Stergiopoulos I, Collemare J, Mehrabi R, De Wit PJGM. Phytotoxic secondary metabolites and peptides produced by plant pathogenic Dothideomycete fungi. FEMS Microbiol Rev 2012; 37:67-93. [PMID: 22931103 DOI: 10.1111/j.1574-6976.2012.00349.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/01/2012] [Accepted: 07/19/2012] [Indexed: 01/25/2023] Open
Abstract
Many necrotrophic plant pathogenic fungi belonging to the class of Dothideomycetes produce phytotoxic metabolites and peptides that are usually required for pathogenicity. Phytotoxins that affect a broad range of plant species are known as non-host-specific toxins (non-HSTs), whereas HSTs affect only a particular plant species or more often genotypes of that species. For pathogens producing HSTs, pathogenicity and host specificity are largely defined by the ability to produce the toxin, while plant susceptibility is dependent on the presence of the toxin target. Non-HSTs are not the main determinants of pathogenicity but contribute to virulence of the producing pathogen. Dothideomycetes are remarkable for the production of toxins, particularly HSTs because they are the only fungal species known so far to produce them. The synthesis, regulation, and mechanisms of action of the most important HSTs and non-HSTs will be discussed. Studies on the mode of action of HSTs have highlighted the induction of programed cell death (PCD) as an important mechanism. We discuss HST-induced PCD and the plant hypersensitive response upon recognition of avirulence factors that share common pathways. In this respect, although nucleotide-binding-site-leucine-rich repeat types of resistance proteins mediate resistance against biotrophs, they can also contribute to susceptibility toward necrotrophs.
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Ahuja I, Kissen R, Bones AM. Phytoalexins in defense against pathogens. TRENDS IN PLANT SCIENCE 2012; 17:73-90. [PMID: 22209038 DOI: 10.1016/j.tplants.2011.11.002] [Citation(s) in RCA: 565] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 11/04/2011] [Accepted: 11/14/2011] [Indexed: 05/18/2023]
Abstract
Plants use an intricate defense system against pests and pathogens, including the production of low molecular mass secondary metabolites with antimicrobial activity, which are synthesized de novo after stress and are collectively known as phytoalexins. In this review, we focus on the biosynthesis and regulation of camalexin, and its role in plant defense. In addition, we detail some of the phytoalexins produced by a range of crop plants from Brassicaceae, Fabaceae, Solanaceae, Vitaceae and Poaceae. This includes the very recently identified kauralexins and zealexins produced by maize, and the biosynthesis and regulation of phytoalexins produced by rice. Molecular approaches are helping to unravel some of the mechanisms and reveal the complexity of these bioactive compounds, including phytoalexin action and metabolism.
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Affiliation(s)
- Ishita Ahuja
- Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway.
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14
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Affiliation(s)
- Martin B. Dickman
- Borlaug Advanced Research Center, Texas A&M University, College Station, Texas, United States of America
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, Texas, United States of America
| | - Paul de Figueiredo
- Borlaug Advanced Research Center, Texas A&M University, College Station, Texas, United States of America
- Department of Plant Pathology & Microbiology, Texas A&M University, College Station, Texas, United States of America
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, United States of America
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, Texas, United States of America
- * E-mail:
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Duke SO, Dayan FE. Modes of action of microbially-produced phytotoxins. Toxins (Basel) 2011; 3:1038-1064. [PMID: 22069756 PMCID: PMC3202864 DOI: 10.3390/toxins3081038] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/15/2011] [Accepted: 08/17/2011] [Indexed: 01/17/2023] Open
Abstract
Some of the most potent phytotoxins are synthesized by microbes. A few of these share molecular target sites with some synthetic herbicides, but many microbial toxins have unique target sites with potential for exploitation by the herbicide industry. Compounds from both non-pathogenic and pathogenic microbes are discussed. Microbial phytotoxins with modes of action the same as those of commercial herbicides and those with novel modes of action of action are covered. Examples of the compounds discussed are tentoxin, AAL-toxin, auscaulitoxin aglycone, hydantocidin, thaxtomin, and tabtoxin.
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Affiliation(s)
- Stephen O. Duke
- United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit, P. O. Box 8048, MS 38677, USA;
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16
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Horbach R, Navarro-Quesada AR, Knogge W, Deising HB. When and how to kill a plant cell: infection strategies of plant pathogenic fungi. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:51-62. [PMID: 20674079 DOI: 10.1016/j.jplph.2010.06.014] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 06/16/2010] [Accepted: 06/18/2010] [Indexed: 05/23/2023]
Abstract
Fungi cause severe diseases on a broad range of crop and ornamental plants, leading to significant economical losses. Plant pathogenic fungi exhibit a huge variability in their mode of infection, differentiation and function of infection structures and nutritional strategy. In this review, advances in understanding mechanisms of biotrophy, necrotrophy and hemibiotrophic lifestyles are described. Special emphasis is given to the biotrophy-necrotrophy switch of hemibiotrophic pathogens, and to biosynthesis, chemical diversity and mode of action of various fungal toxins produced during the infection process.
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Affiliation(s)
- Ralf Horbach
- Martin-Luther-University Halle-Wittenberg, Faculty of Natural Sciences III, Institute for Agricultural and Nutritional Sciences, Phytopathology and Plant Protection, Betty-Heimann-Strasse 3, Halle (Saale), Germany
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17
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Asai S, Mase K, Yoshioka H. Role of nitric oxide and reactive oxygen [corrected] species in disease resistance to necrotrophic pathogens. PLANT SIGNALING & BEHAVIOR 2010; 5:872-4. [PMID: 20448455 PMCID: PMC3014541 DOI: 10.4161/psb.5.7.11899] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nitric oxide (NO) and reactive oxygen species (ROS) are important signaling molecules in plant immunity. However, roles of NO and ROS in disease resistance to necrotrophic pathogens are not fully understood. We have recently demonstrated that NO plays a pivotal role in basal defense against Botrytis cinerea and the expression of the salicylic acid (SA) -responsive gene PR-1in Nicotiana benthamiana. By contrast, ROS function negatively in resistance or positively in expansion of disease lesions during B. cinerea-N. benthamiana interaction. Here, analysis in NahG-transgenic N. benthamiana showed that SA signaling is not involved in resistance to B. cinerea in N. benthamiana. We discuss how NO and ROS participate in disease resistance to necrotrophic pathogens on the basis of recent reports.
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Affiliation(s)
- Shuta Asai
- Laboratory of Defense in Plant-Pathogen Interactions, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
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18
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Chen S, Yin C, Qiang S, Zhou F, Dai X. Chloroplastic oxidative burst induced by tenuazonic acid, a natural photosynthesis inhibitor, triggers cell necrosis in Eupatorium adenophorum Spreng. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:391-405. [PMID: 20026008 DOI: 10.1016/j.bbabio.2009.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 12/08/2009] [Accepted: 12/14/2009] [Indexed: 01/15/2023]
Abstract
Tenuazonic acid (TeA), a nonhost-specific phytotoxin produced by Alternaria alternata, was determined to be a novel natural photosynthesis inhibitor owning several action sites in chloroplasts. To further elucidate the mode of its action, studies were conducted to assess the production and involvement of reactive oxygen species (ROS) in the toxic activity of TeA. A series of experiments indicated that TeA treatment can induce chloroplast-derived ROS generation including not only (1)O(2) but also superoxide radical, H(2)O(2) and hydroxyl radicals in Eupatorium adenophorum mesophyll cells, resulting from electron leakage and charge recombination in PSII as well as thylakoid overenergization due to inhibition of the PSII electron transport beyond Q(A) and the reduction of end acceptors on the PSI acceptor side and chloroplast ATPase activity. The initial production of TeA-induced ROS was restricted to chloroplasts and accompanied with a certain degree of chloroplast damage. Subsequently, abundant ROS were quickly dispersed throughout whole cell and cellular compartments, causing a series of irreversible cellular harm such as chlorophyll breakdown, lipid peroxidation, plasma membrane rupture, chromatin condensation, DNA cleavage, and organelle disintegration, and finally resulting in rapid cell destruction and leaf necrosis. These results show that TeA causing cell necrosis of host-plants is a result of direct oxidative damage from chloroplast-mediated ROS eruption.
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Affiliation(s)
- Shiguo Chen
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
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19
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Lerat S, Babana AH, El Oirdi M, El Hadrami A, Daayf F, Beaudoin N, Bouarab K, Beaulieu C. Streptomyces scabiei and its toxin thaxtomin A induce scopoletin biosynthesis in tobacco and Arabidopsis thaliana. PLANT CELL REPORTS 2009; 28:1895-903. [PMID: 19859716 DOI: 10.1007/s00299-009-0792-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 09/24/2009] [Accepted: 10/06/2009] [Indexed: 05/28/2023]
Abstract
Streptomyces scabiei is the predominant causal agent of common scab of potato in North America. The virulence of common scab-causing streptomycetes relies on their capacity to synthesize thaxtomins. In this study, the effects of S. scabiei infection and of thaxtomin A, the main toxin produced by S. scabiei, were tested for the elicitation of plant defense molecules in the model plants tobacco (Nicotiana tabacum) and Arabidopsis thaliana. Tobacco leaves infected with spores of S. scabiei strain EF-35 or infiltrated with purified thaxtomin A produced a blue fluorescent compound that was not detected in leaves infiltrated with spores of a S. scabiei mutant deficient in thaxtomin A biosynthesis. Thin layer chromatography and high performance liquid chromatography identified this fluorescent compound as scopoletin, a plant defense phytoalexin. Arabidopsis seedlings grown in liquid medium also excreted scopoletin as a reaction to S. scabiei and thaxtomin A. The effects of the presence of scopoletin on S. scabiei were also investigated. The phytoalexin scopoletin caused a slight reduction of bacterial growth and a severe decrease of thaxtomin A production. Scopoletin was shown to inhibit thaxtomin A production by repression of a gene involved in the toxin biosynthesis.
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Affiliation(s)
- Sylvain Lerat
- Centre SEVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada
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20
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Williams B, Dickman M. Plant programmed cell death: can't live with it; can't live without it. MOLECULAR PLANT PATHOLOGY 2008; 9:531-44. [PMID: 18705866 PMCID: PMC6640338 DOI: 10.1111/j.1364-3703.2008.00473.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The decision of whether a cell should live or die is fundamental for the wellbeing of all organisms. Despite intense investigation into cell growth and proliferation, only recently has the essential and equally important idea that cells control/programme their own demise for proper maintenance of cellular homeostasis gained recognition. Furthermore, even though research into programmed cell death (PCD) has been an extremely active area of research there are significant gaps in our understanding of the process in plants. In this review, we discuss PCD during plant development and pathogenesis, and compare/contrast this with mammalian apoptosis.
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Affiliation(s)
- Brett Williams
- Institute for Plant Genomics and Biotechnology, Texas A&M University, Department of Plant Pathology and Microbiology, College Station, TX 77843, USA
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21
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Amirsadeghi S, Robson CA, Vanlerberghe GC. The role of the mitochondrion in plant responses to biotic stress. PHYSIOLOGIA PLANTARUM 2007; 129:253-266. [PMID: 0 DOI: 10.1111/j.1399-3054.2006.00775.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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22
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Qutob D, Kemmerling B, Brunner F, Küfner I, Engelhardt S, Gust AA, Luberacki B, Seitz HU, Stahl D, Rauhut T, Glawischnig E, Schween G, Lacombe B, Watanabe N, Lam E, Schlichting R, Scheel D, Nau K, Dodt G, Hubert D, Gijzen M, Nürnberger T. Phytotoxicity and innate immune responses induced by Nep1-like proteins. THE PLANT CELL 2006; 18:3721-44. [PMID: 17194768 PMCID: PMC1785393 DOI: 10.1105/tpc.106.044180] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 10/09/2006] [Accepted: 11/10/2006] [Indexed: 05/13/2023]
Abstract
We show that oomycete-derived Nep1 (for necrosis and ethylene-inducing peptide1)-like proteins (NLPs) trigger a comprehensive immune response in Arabidopsis thaliana, comprising posttranslational activation of mitogen-activated protein kinase activity, deposition of callose, production of nitric oxide, reactive oxygen intermediates, ethylene, and the phytoalexin camalexin, as well as cell death. Transcript profiling experiments revealed that NLPs trigger extensive reprogramming of the Arabidopsis transcriptome closely resembling that evoked by bacteria-derived flagellin. NLP-induced cell death is an active, light-dependent process requiring HSP90 but not caspase activity, salicylic acid, jasmonic acid, ethylene, or functional SGT1a/SGT1b. Studies on animal, yeast, moss, and plant cells revealed that sensitivity to NLPs is not a general characteristic of phospholipid bilayer systems but appears to be restricted to dicot plants. NLP-induced cell death does not require an intact plant cell wall, and ectopic expression of NLP in dicot plants resulted in cell death only when the protein was delivered to the apoplast. Our findings strongly suggest that NLP-induced necrosis requires interaction with a target site that is unique to the extracytoplasmic side of dicot plant plasma membranes. We propose that NLPs play dual roles in plant pathogen interactions as toxin-like virulence factors and as triggers of plant innate immune responses.
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Affiliation(s)
- Dinah Qutob
- Agriculture and Agri-Food Canada, London ON N5V 4T3, Canada
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