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Battache M, Suarez-Fernandez M, Klooster MV, Cambon F, Sánchez-Vallet A, Lebrun MH, Langin T, Saintenac C. Stomatal penetration: the cornerstone of plant resistance to the fungal pathogen Zymoseptoria tritici. BMC PLANT BIOLOGY 2024; 24:736. [PMID: 39095719 PMCID: PMC11295904 DOI: 10.1186/s12870-024-05426-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
BACKGROUND Septoria tritici blotch (STB), caused by the foliar fungus Zymoseptoria tritici, is one of the most damaging disease of wheat in Europe. Genetic resistance against this fungus relies on different types of resistance from non-host resistance (NHR) and host species specific resistance (HSSR) to host resistance mediated by quantitative trait loci (QTLs) or major resistance genes (Stb). Characterizing the diversity of theses resistances is of great importance for breeding wheat cultivars with efficient and durable resistance. While the functional mechanisms underlying these resistance types are not well understood, increasing piece of evidence suggest that fungus stomatal penetration and early establishment in the apoplast are both crucial for the outcome of some interactions between Z. tritici and plants. To validate and extend these previous observations, we conducted quantitative comparative phenotypical and cytological analyses of the infection process corresponding to 22 different interactions between plant species and Z. tritici isolates. These interactions included four major bread wheat Stb genes, four bread wheat accessions with contrasting quantitative resistance, two species resistant to Z. tritici isolates from bread wheat (HSSR) and four plant species resistant to all Z. tritici isolates (NHR). RESULTS Infiltration of Z. tritici spores into plant leaves allowed the partial bypass of all bread wheat resistances and durum wheat resistance, but not resistances from other plants species. Quantitative comparative cytological analysis showed that in the non-grass plant Nicotiana benthamiana, Z. tritici was stopped before stomatal penetration. By contrast, in all resistant grass plants, Z. tritici was stopped, at least partly, during stomatal penetration. The intensity of this early plant control process varied depending on resistance types, quantitative resistances being the least effective. These analyses also demonstrated that Stb-mediated resistances, HSSR and NHR, but not quantitative resistances, relied on the strong growth inhibition of the few Z. tritici penetrating hyphae at their entry point in the sub-stomatal cavity. CONCLUSIONS In addition to furnishing a robust quantitative cytological assessment system, our study uncovered three stopping patterns of Z. tritici by plant resistances. Stomatal resistance was found important for most resistances to Z. tritici, independently of its type (Stb, HSSR, NHR). These results provided a basis for the functional analysis of wheat resistance to Z. tritici and its improvement.
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Affiliation(s)
- Mélissa Battache
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Marta Suarez-Fernandez
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Technología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Madrid, 28223, Spain
| | | | - Florence Cambon
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Andrea Sánchez-Vallet
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Technología Agraria y Alimentaria (INIA), Pozuelo de Alarcón, Madrid, 28223, Spain
| | - Marc-Henri Lebrun
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Thierry Langin
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Cyrille Saintenac
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France.
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Melotto M, Fochs B, Jaramillo Z, Rodrigues O. Fighting for Survival at the Stomatal Gate. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:551-577. [PMID: 39038249 DOI: 10.1146/annurev-arplant-070623-091552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Stomata serve as the battleground between plants and plant pathogens. Plants can perceive pathogens, inducing closure of the stomatal pore, while pathogens can overcome this immune response with their phytotoxins and elicitors. In this review, we summarize new discoveries in stomata-pathogen interactions. Recent studies have shown that stomatal movement continues to occur in a close-open-close-open pattern during bacterium infection, bringing a new understanding of stomatal immunity. Furthermore, the canonical pattern-triggered immunity pathway and ion channel activities seem to be common to plant-pathogen interactions outside of the well-studied Arabidopsis-Pseudomonas pathosystem. These developments can be useful to aid in the goal of crop improvement. New technologies to study intact leaves and advances in available omics data sets provide new methods for understanding the fight at the stomatal gate. Future studies should aim to further investigate the defense-growth trade-off in relation to stomatal immunity, as little is known at this time.
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Affiliation(s)
- Maeli Melotto
- Department of Plant Sciences, University of California, Davis, California, USA;
| | - Brianna Fochs
- Department of Plant Sciences, University of California, Davis, California, USA;
- Plant Biology Graduate Group, University of California, Davis, California, USA
| | - Zachariah Jaramillo
- Department of Plant Sciences, University of California, Davis, California, USA;
- Plant Biology Graduate Group, University of California, Davis, California, USA
| | - Olivier Rodrigues
- Unité de Recherche Physiologie, Pathologie et Génétique Végétales, Université de Toulouse, INP-PURPAN, Toulouse, France
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3
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Ijaz U, Zhao C, Shabala S, Zhou M. Molecular Basis of Plant-Pathogen Interactions in the Agricultural Context. BIOLOGY 2024; 13:421. [PMID: 38927301 PMCID: PMC11200688 DOI: 10.3390/biology13060421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/03/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024]
Abstract
Biotic stressors pose significant threats to crop yield, jeopardizing food security and resulting in losses of over USD 220 billion per year by the agriculture industry. Plants activate innate defense mechanisms upon pathogen perception and invasion. The plant immune response comprises numerous concerted steps, including the recognition of invading pathogens, signal transduction, and activation of defensive pathways. However, pathogens have evolved various structures to evade plant immunity. Given these facts, genetic improvements to plants are required for sustainable disease management to ensure global food security. Advanced genetic technologies have offered new opportunities to revolutionize and boost plant disease resistance against devastating pathogens. Furthermore, targeting susceptibility (S) genes, such as OsERF922 and BnWRKY70, through CRISPR methodologies offers novel avenues for disrupting the molecular compatibility of pathogens and for introducing durable resistance against them in plants. Here, we provide a critical overview of advances in understanding disease resistance mechanisms. The review also critically examines management strategies under challenging environmental conditions and R-gene-based plant genome-engineering systems intending to enhance plant responses against emerging pathogens. This work underscores the transformative potential of modern genetic engineering practices in revolutionizing plant health and crop disease management while emphasizing the importance of responsible application to ensure sustainable and resilient agricultural systems.
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Affiliation(s)
- Usman Ijaz
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
| | - Chenchen Zhao
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
| | - Sergey Shabala
- School of Biological Science, University of Western Australia, Crawley, WA 6009, Australia;
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
| | - Meixue Zhou
- Tasmanian Institute of Agriculture, University of Tasmania, Launceston, TAS 7250, Australia; (U.I.); (C.Z.)
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Baran B, Ölmez F, Çapa B, Dikilitas M. Defense Pathways of Wheat Plants Inoculated with Zymoseptoria tritici under NaCl Stress Conditions: An Overview. Life (Basel) 2024; 14:648. [PMID: 38792668 PMCID: PMC11122936 DOI: 10.3390/life14050648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/27/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Due to being sessile, plants develop a broad range of defense pathways when they face abiotic or biotic stress factors. Although plants are subjected to more than one type of stress at a time in nature, the combined effects of either multiple stresses of one kind (abiotic or biotic) or more kinds (abiotic and biotic) have now been realized in agricultural lands due to increases in global warming and environmental pollution, along with population increases. Soil-borne pathogens, or pathogens infecting aerial parts, can have devastating effects on plants when combined with other stressors. Obtaining yields or crops from sensitive or moderately resistant plants could be impossible, and it could be very difficult from resistant plants. The mechanisms of combined stress in many plants have previously been studied and elucidated. Recent studies proposed new defense pathways and mechanisms through signaling cascades. In light of these mechanisms, it is now time to develop appropriate strategies for crop protection under multiple stress conditions. This may involve using disease-resistant or stress-tolerant plant varieties, implementing proper irrigation and drainage practices, and improving soil quality. However, generation of both stress-tolerant and disease-resistant crop plants is of crucial importance. The establishment of a database and understanding of the defense mechanisms under combined stress conditions would be meaningful for the development of resistant and tolerant plants. It is clear that leaf pathogens show great tolerance to salinity stress and result in pathogenicity in crop plants. We noticed that regulation of the stomata through biochemical applications and some effort with the upregulation of the minor gene expressions indirectly involved with the defense mechanisms could be a great way to increase the defense metabolites without interfering with quality parameters. In this review, we selected wheat as a model plant and Zymoseptoria tritici as a model leaf pathogen to evaluate the defense mechanisms under saline conditions through physiological, biochemical, and molecular pathways and suggested various ways to generate tolerant and resistant cereal plants.
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Affiliation(s)
- Behzat Baran
- Plant Protection Research Institute, Sur, Diyarbakır 21110, Türkiye;
| | - Fatih Ölmez
- Department of Plant Protection, Faculty of Agriculture, Sivas University of Science and Technology, Sivas 58010, Türkiye;
| | - Beritan Çapa
- Department of Plant Protection Şanliurfa, Faculty of Agriculture, Harran University, Sanliurfa 63000, Türkiye;
| | - Murat Dikilitas
- Department of Plant Protection Şanliurfa, Faculty of Agriculture, Harran University, Sanliurfa 63000, Türkiye;
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Alassimone J, Praz C, Lorrain C, De Francesco A, Carrasco-López C, Faino L, Shen Z, Meile L, Sánchez-Vallet A. The Zymoseptoria tritici Avirulence Factor AvrStb6 Accumulates in Hyphae Close to Stomata and Triggers a Wheat Defense Response Hindering Fungal Penetration. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:432-444. [PMID: 38265007 DOI: 10.1094/mpmi-11-23-0181-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Zymoseptoria tritici, the causal agent of Septoria tritici blotch, is one of Europe's most damaging wheat pathogens, causing significant economic losses. Genetic resistance is a common strategy to control the disease, Stb6 being a resistance gene used for more than 100 years in Europe. This study investigates the molecular mechanisms underlying Stb6-mediated resistance. Utilizing confocal microscopy imaging, we determined that Z. tritici epiphytic hyphae mainly accumulate the corresponding avirulence factor AvrStb6 in close proximity to stomata. Consequently, the progression of AvrStb6-expressing avirulent strains is hampered during penetration. The fungal growth inhibition co-occurs with a transcriptional reprogramming in wheat characterized by an induction of immune responses, genes involved in stomatal regulation, and cell wall-related genes. Overall, we shed light on the gene-for-gene resistance mechanisms in the wheat-Z. tritici pathosystem at the cytological and transcriptomic level, and our results highlight that stomatal penetration is a critical process for pathogenicity and resistance. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Coraline Praz
- Centro de Biotecnología y Genómica de Plantas (CBGP)/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid), Spain
| | - Cécile Lorrain
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Agustina De Francesco
- Centro de Biotecnología y Genómica de Plantas (CBGP)/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid), Spain
| | - Cristian Carrasco-López
- Centro de Biotecnología y Genómica de Plantas (CBGP)/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid), Spain
| | - Luigi Faino
- Environmental Biology, Sapienza University of Rome, Roma, Italy
| | - Ziqi Shen
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Lukas Meile
- Centro de Biotecnología y Genómica de Plantas (CBGP)/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid), Spain
| | - Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Centro de Biotecnología y Genómica de Plantas (CBGP)/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid), Spain
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6
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Qutb AM, Cambon F, McDonald MC, Saintenac C, Kettles GJ. The Egyptian wheat cultivar Gemmeiza-12 is a source of resistance against the fungus Zymoseptoria tritici. BMC PLANT BIOLOGY 2024; 24:248. [PMID: 38580955 PMCID: PMC10996218 DOI: 10.1186/s12870-024-04930-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/19/2024] [Indexed: 04/07/2024]
Abstract
BACKGROUND Wheat is one of the world's most important cereal crops. However, the fungal pathogen Zymoseptoria tritici can cause disease epidemics, leading to reduced yields. With climate change and development of new agricultural areas with suitable environments, Z. tritici may advance into geographical areas previously unaffected by this pathogen. It is currently unknown how Egyptian wheat will perform in the face of this incoming threat. This project aimed to assess the resistance of Egyptian wheat germplasm to Z. tritici, to identify cultivars with high levels of resistance and characterise the mechanism(s) of resistance present in these cultivars. RESULTS Eighteen Egyptian wheat cultivars were screened against two Z. tritici model isolates and exhibited a wide spectrum of responses. This ranged from resistance to complete susceptibility to one or both isolates tested. The most highly resistant cultivars from the initial screen were then tested under two environmental conditions against modern UK field isolates. Disease levels under UK-like conditions were higher, however, symptom development on the cultivar Gemmeiza-12 was noticeably slower than on other Egyptian wheats. The robustness of the resistance shown by Gemmeiza-12 was confirmed in experiments mimicking Egyptian environmental conditions, where degree of Z. tritici infection was lower. The Kompetitive allele-specific PCR (KASP) diagnostic assay suggested the presence of an Stb6 resistant allele in several Egyptian wheats including Gemmeiza-12. Infection assays using the IPO323 WT and IPO323ΔAvrStb6 mutant confirmed the presence of Stb6 in several Egyptian cultivars including Gemmeiza-12. Confocal fluorescence microscopy demonstrated that growth of the IPO323 strain is blocked at the point of stomatal penetration on Gemmeiza-12, consistent with previous reports of Stb gene mediated resistance. In addition to this R-gene mediated resistance, IPO323 spores showed lower adherence to leaves of Gemmeiza-12 compared to UK wheat varieties, suggesting other aspects of leaf physiology may also contribute to the resistance phenotype of this cultivar. CONCLUSION These results indicate that Gemmeiza-12 will be useful in future breeding programs where improved resistance to Z. tritici is a priority.
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Affiliation(s)
- Abdelrahman M Qutb
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Agricultural Botany, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt
| | - Florence Cambon
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, 63000, France
| | - Megan C McDonald
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Cyrille Saintenac
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, 63000, France
| | - Graeme J Kettles
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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7
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Ballot A, Dore J, Rey M, Meiffren G, Langin T, Joly P, Dreux-Zigha A, Taibi A, Prigent-Combaret C. Dimethylpolysulfides production as the major mechanism behind wheat fungal pathogen biocontrol, by Arthrobacter and Microbacterium actinomycetes. Microbiol Spectr 2023; 11:e0529222. [PMID: 37800942 PMCID: PMC10715130 DOI: 10.1128/spectrum.05292-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 08/07/2023] [Indexed: 10/07/2023] Open
Abstract
IMPORTANCE As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat phytopathogens, Fusarium graminearum and Zymoseptoria tritici, may prove to be an interesting alternative to conventional pest management. Here, we have shown that dimethylpolysulfide volatiles are ubiquitously and predominantly produced by wheat-associated Microbacterium and Arthrobacter actinomycetes, displaying antifungal activity against both pathogens. By limiting pathogen growth and DON virulence factor production, the use of such DMPS-producing strains as soil biocontrol inoculants could limit the supply of pathogen inocula in soil and plant residues, providing an attractive alternative to dimethyldisulfide fumigant, which has many non-targeted toxicities. Notably, this study demonstrates the importance of bacterial volatile organic compound uptake by inhibited F. graminearum, providing new insights for the study of volatiles-mediated toxicity mechanisms within bacteria-fungus signaling crosstalk.
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Affiliation(s)
- Aline Ballot
- Laboratoire Ecologie Microbienne UMR 5557, Université Lyon 1, Villeurbanne, France
| | - Jeanne Dore
- Laboratoire Ecologie Microbienne UMR 5557, Université Lyon 1, Villeurbanne, France
| | - Marjolaine Rey
- Laboratoire Ecologie Microbienne UMR 5557, Université Lyon 1, Villeurbanne, France
| | - Guillaume Meiffren
- Laboratoire Ecologie Microbienne UMR 5557, Université Lyon 1, Villeurbanne, France
| | - Thierry Langin
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
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8
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Bernasconi A, Lorrain C, Flury P, Alassimone J, McDonald BA, Sánchez-Vallet A. Virulent strains of Zymoseptoria tritici suppress the host immune response and facilitate the success of avirulent strains in mixed infections. PLoS Pathog 2023; 19:e1011767. [PMID: 37972205 PMCID: PMC10721197 DOI: 10.1371/journal.ppat.1011767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 12/14/2023] [Accepted: 10/19/2023] [Indexed: 11/19/2023] Open
Abstract
Plants interact with a plethora of pathogenic microorganisms in nature. Pathogen-plant interaction experiments focus mainly on single-strain infections, typically ignoring the complexity of multi-strain infections even though mixed infections are common and critical for the infection outcome. The wheat pathogen Zymoseptoria tritici forms highly diverse fungal populations in which several pathogen strains often colonize the same leaf. Despite the importance of mixed infections, the mechanisms governing interactions between a mixture of pathogen strains within a plant host remain largely unexplored. Here we demonstrate that avirulent pathogen strains benefit from being in mixed infections with virulent strains. We show that virulent strains suppress the wheat immune response, allowing avirulent strains to colonize the apoplast and to reproduce. Our experiments indicate that virulent strains in mixed infections can suppress the plant immune system, probably facilitating the persistence of avirulent pathogen strains in fields planted with resistant host plants.
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Affiliation(s)
- Alessio Bernasconi
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Cécile Lorrain
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Priska Flury
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Bruce A. McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Centro de Biotecnología y Genómica de Plantas (CBGP/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid) Spain
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9
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Amezrou R, Audéon C, Compain J, Gélisse S, Ducasse A, Saintenac C, Lapalu N, Louet C, Orford S, Croll D, Amselem J, Fillinger S, Marcel TC. A secreted protease-like protein in Zymoseptoria tritici is responsible for avirulence on Stb9 resistance gene in wheat. PLoS Pathog 2023; 19:e1011376. [PMID: 37172036 DOI: 10.1371/journal.ppat.1011376] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 05/24/2023] [Accepted: 04/19/2023] [Indexed: 05/14/2023] Open
Abstract
Zymoseptoria tritici is the fungal pathogen responsible for Septoria tritici blotch on wheat. Disease outcome in this pathosystem is partly determined by isolate-specific resistance, where wheat resistance genes recognize specific fungal factors triggering an immune response. Despite the large number of known wheat resistance genes, fungal molecular determinants involved in such cultivar-specific resistance remain largely unknown. We identified the avirulence factor AvrStb9 using association mapping and functional validation approaches. Pathotyping AvrStb9 transgenic strains on Stb9 cultivars, near isogenic lines and wheat mapping populations, showed that AvrStb9 interacts with Stb9 resistance gene, triggering an immune response. AvrStb9 encodes an unusually large avirulence gene with a predicted secretion signal and a protease domain. It belongs to a S41 protease family conserved across different filamentous fungi in the Ascomycota class and may constitute a core effector. AvrStb9 is also conserved among a global Z. tritici population and carries multiple amino acid substitutions caused by strong positive diversifying selection. These results demonstrate the contribution of an 'atypical' conserved effector protein to fungal avirulence and the role of sequence diversification in the escape of host recognition, adding to our understanding of host-pathogen interactions and the evolutionary processes underlying pathogen adaptation.
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Affiliation(s)
- Reda Amezrou
- Université Paris-Saclay, INRAE, UR BIOGER, Palaiseau, France
| | - Colette Audéon
- Université Paris-Saclay, INRAE, UR BIOGER, Palaiseau, France
| | - Jérôme Compain
- Université Paris-Saclay, INRAE, UR URGI, Versailles, France
| | | | - Aurélie Ducasse
- Université Paris-Saclay, INRAE, UR BIOGER, Palaiseau, France
| | | | - Nicolas Lapalu
- Université Paris-Saclay, INRAE, UR BIOGER, Palaiseau, France
- Université Paris-Saclay, INRAE, UR URGI, Versailles, France
| | | | - Simon Orford
- Crop Genetics, John Innes Centre, Norwich, United Kingdom
| | - Daniel Croll
- University of Neuchâtel, Laboratory of Evolutionary Genetics, Neuchâtel, Switzerland
| | - Joëlle Amselem
- Université Paris-Saclay, INRAE, UR URGI, Versailles, France
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10
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Rudd JJ. Effector-mediated partial and nonhost disease resistance in wheat. THE NEW PHYTOLOGIST 2023; 238:1340-1342. [PMID: 36999944 DOI: 10.1111/nph.18872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Affiliation(s)
- Jason J Rudd
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden, AL5 2JQ, UK
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11
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Orellana-Torrejon C, Vidal T, Gazeau G, Boixel AL, Gélisse S, Lageyre J, Saint-Jean S, Suffert F. Multiple scenarios for sexual crosses in the fungal pathogen Zymoseptoria tritici on wheat residues: Potential consequences for virulence gene transmission. Fungal Genet Biol 2022; 163:103744. [PMID: 36209959 DOI: 10.1016/j.fgb.2022.103744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/31/2022] [Accepted: 09/30/2022] [Indexed: 01/06/2023]
Abstract
Little is known about the impact of host immunity on sexual reproduction in fungal pathogens. In particular, it is unclear whether crossing requires both sexual partners to infect living plant tissues. We addressed this issue in a three-year experiment investigating different scenarios of Zymoseptoria tritici crosses according to the virulence ('vir') or avirulence ('avr') of the parents against a qualitative resistance gene. Co-inoculations ('vir × vir', 'avr × vir', 'avr × avr') and single inoculations were performed on a wheat cultivar carrying the Stb16q resistance gene (Cellule) and a susceptible cultivar (Apache), in the greenhouse. We assessed the intensity of asexual reproduction by scoring disease severity, and the intensity of sexual reproduction by counting the ascospores discharged from wheat residues. As expected, disease severity was more intense on Cellule for 'vir × vir' co-inoculations than for 'avr × vir' co-inoculations, with no disease for 'avr × avr'. However, all types of co-inoculation yielded sexual offspring, whether or not the parental strains caused plant symptoms. Parenthood was confirmed by genotyping (SSR markers), and the occurrence of crosses between (co-)inoculated and exogenous strains (other strains from the experiment, or from far away) was determined. We showed that symptomatic asexual infection was not required for a strain to participate in sexual reproduction, and deduced from this result that avirulent strains could be maintained asymptomatically "on" or "in" leaf tissues of plants carrying the corresponding resistant gene for long enough to reproduce sexually. In two of the three years, the intensity of sexual reproduction did not differ between the three types of co-inoculation in Cellule, suggesting that crosses involving avirulent strains are not anecdotal. We discuss the possible mechanisms explaining the maintenance of avirulence in Z. tritici populations and the potential impact of particular resistance deployments such as cultivar mixtures for limiting resistance breakdown.
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Affiliation(s)
- Carolina Orellana-Torrejon
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France; Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120 Palaiseau, France
| | - Tiphaine Vidal
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Gwilherm Gazeau
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Anne-Lise Boixel
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Sandrine Gélisse
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Jérôme Lageyre
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120 Palaiseau, France
| | - Sébastien Saint-Jean
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120 Palaiseau, France
| | - Frédéric Suffert
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France.
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Ghiasi Noei F, Imami M, Didaran F, Ghanbari MA, Zamani E, Ebrahimi A, Aliniaeifard S, Farzaneh M, Javan-Nikkhah M, Feechan A, Mirzadi Gohari A. Stb6 mediates stomatal immunity, photosynthetic functionality, and the antioxidant system during the Zymoseptoria tritici-wheat interaction. FRONTIERS IN PLANT SCIENCE 2022; 13:1004691. [PMID: 36388590 PMCID: PMC9645118 DOI: 10.3389/fpls.2022.1004691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
This study offers new perspectives on the biochemical and physiological changes that occur in wheat following a gene-for-gene interaction with the fungal pathogen Zymoseptoria tritici. The Z. tritici isolate IPO323, carries AvrStb6, while ΔAvrStb6#33, lacks AvrStb6. The wheat cultivar (cv.) Shafir, bears the corresponding resistance gene Stb6. Inoculation of cv. Shafir with these isolates results in two contrasted phenotypes, offering a unique opportunity to study the immune response caused by the recognition of AvrStb6 by Stb6. We employed a variety of methodologies to dissect the physiological and biochemical events altered in cv. Shafir, as a result of the AvrStb6-Stb6 interaction. Comparative analysis of stomatal conductance demonstrated that AvrStb6-Stb6 mediates transient stomatal closures to restrict the penetration of Zymoseptoria tritici. Tracking photosynthetic functionality through chlorophyll fluorescence imaging analysis demonstrated that AvrStb6-Stb6 retains the functionality of photosynthesis apparatus by promoting Non-Photochemical Quenching (NPQ). Furthermore, the PlantCV image analysis tool was used to compare the H2O2 accumulation and incidence of cell death (2, 4, 8, 12, 16, and 21 dpi), over Z. tritici infection. Finally, our research shows that the AvrStb6-Stb6 interaction coordinates the expression and activity of antioxidant enzymes, both enzymatic and non-enzymatic, to counteract oxidative stress. In conclusion, the Stb6-AvrStb6 interaction in the Z. tritici-wheat pathosystem triggers transient stomatal closure and maintains photosynthesis while regulating oxidative stress.
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Affiliation(s)
- Fateme Ghiasi Noei
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Mojtaba Imami
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Fardad Didaran
- Photosynthesis Laboratory, Department of Horticulture, Aburaihan Campus, University of Tehran, Tehran, Iran
| | - Mohammad Amin Ghanbari
- Department of Horticultural Science, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Elham Zamani
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Amin Ebrahimi
- Agronomy and Plant Breeding Department, Faculty of Agriculture, Shahrood University of Technology, Semnan, Iran
| | - Sasan Aliniaeifard
- Photosynthesis Laboratory, Department of Horticulture, Aburaihan Campus, University of Tehran, Tehran, Iran
| | - Mohsen Farzaneh
- Department of Agriculture, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Mohammad Javan-Nikkhah
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Angela Feechan
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Amir Mirzadi Gohari
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
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