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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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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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Kovács-Simon A, Fones HN. Use of chitin:DNA ratio to assess growth form in fungal cells. BMC Biol 2024; 22:10. [PMID: 38233847 PMCID: PMC10795418 DOI: 10.1186/s12915-024-01815-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/04/2024] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND Dimorphism, the ability to switch between a 'yeast-like' and a hyphal growth form, is an important feature of certain fungi, including important plant and human pathogens. The switch to hyphal growth is often associated with virulence, pathogenicity, biofilm formation and stress resistance. Thus, the ability to accurately and efficiently measure fungal growth form is key to research into these fungi, especially for discovery of potential drug targets. To date, fungal growth form has been assessed microscopically, a process that is both labour intensive and costly. RESULTS Here, we unite quantification of the chitin in fungal cell walls and the DNA in nuclei to produce a methodology that allows fungal cell shape to be estimated by calculation of the ratio between cell wall quantity and number of nuclei present in a sample of fungus or infected host tissue. Using the wheat pathogen Zymoseptoria tritici as a test case, with confirmation in the distantly related Fusarium oxysporum, we demonstrate a close, linear relationship between the chitin:DNA ratio and the average polarity index (length/width) of fungal cells. We show the utility of the method for estimating growth form in infected wheat leaves, differentiating between the timing of germination in two different Z. tritici isolates using this ratio. We also show that the method is robust to the occurrence of thick-walled chlamydospores, which show a chitin:DNA ratio that is distinct from either 'yeast-like' blastospores or hyphae. CONCLUSIONS The chitin:DNA ratio provides a simple methodology for determining fungal growth form in bulk tissue samples, reducing the need for labour-intensive microscopic studies requiring specific staining or GFP-tags to visualise the fungus within host tissues. It is applicable to a range of dimorphic fungi under various experimental conditions.
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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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5
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Fones HN, Soanes D, Gurr SJ. Epiphytic proliferation of Zymoseptoria tritici isolates on resistant wheat leaves. Fungal Genet Biol 2023; 168:103822. [PMID: 37343618 DOI: 10.1016/j.fgb.2023.103822] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 06/04/2023] [Accepted: 06/15/2023] [Indexed: 06/23/2023]
Abstract
The wheat pathogen Zymoseptoria tritici is capable of a long period of pre-invasive epiphytic growth. Studies have shown that virulent isolates vary in the extent, duration and growth form of this epiphytic growth, and the fungus has been observed to undergo behaviours such as asexual reproduction by budding and vegetative fusion of hyphae on the leaf surface. This epiphytic colonisation has been investigated very little during interactions in which an isolate of Z. tritici is unable to colonise the apoplast, as occurs during avirulence. However, avirulent isolates have been seen to undergo sexual crosses in the absense of leaf penetration, and it is widely accepted that the main point of distinction between virulent and avirulent isolates occurs at the point of attempted leaf penetration or attempted apoplastic growth, which fails in the avirulent case. In this work, we describe extensive epiphytic growth in three isolates which are unable or have very limited ability to invade the leaf, and show that growth form is as variable as for fully virulent isolates. We demonstrate that during certain interactions, Z. tritici isolates rarely invade the leaf and form pycnidia, but induce necrosis. These isolates are able to achieve higher epiphytic biomass than fully virulent isolates during asymptomatic growth, and may undergo very extensive asexual reproduction on the leaf surface. These findings have implications for open questions such as whether and how Z. tritici obtains nutrients on the leaf surface and the nature of its interaction with wheat defences.
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Affiliation(s)
- H N Fones
- Biosciences, University of Exeter, Exeter, UK
| | - D Soanes
- University of Exeter Medical School, Exeter, UK
| | - S J Gurr
- Biosciences, University of Exeter, Exeter, UK; Department of Biosciences, Utrecht University, Utrecht, the Netherlands.
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Zhu J, Moreno-Pérez A, Coaker G. Understanding plant pathogen interactions using spatial and single-cell technologies. Commun Biol 2023; 6:814. [PMID: 37542114 PMCID: PMC10403533 DOI: 10.1038/s42003-023-05156-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 07/18/2023] [Indexed: 08/06/2023] Open
Abstract
Plants are in contact with diverse pathogens and microorganisms. Intense investigation over the last 30 years has resulted in the identification of multiple immune receptors in model and crop species as well as signaling overlap in surface-localized and intracellular immune receptors. However, scientists still have a limited understanding of how plants respond to diverse pathogens with spatial and cellular resolution. Recent advancements in single-cell, single-nucleus and spatial technologies can now be applied to plant-pathogen interactions. Here, we outline the current state of these technologies and highlight outstanding biological questions that can be addressed in the future.
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Affiliation(s)
- Jie Zhu
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Alba Moreno-Pérez
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA.
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Zhu J, Lolle S, Tang A, Guel B, Kvitko B, Cole B, Coaker G. Single-cell profiling of Arabidopsis leaves to Pseudomonas syringae infection. Cell Rep 2023; 42:112676. [PMID: 37342910 PMCID: PMC10528479 DOI: 10.1016/j.celrep.2023.112676] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 03/07/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
Plant response to pathogen infection varies within a leaf, yet this heterogeneity is not well resolved. We expose Arabidopsis to Pseudomonas syringae or mock treatment and profile >11,000 individual cells using single-cell RNA sequencing. Integrative analysis of cell populations from both treatments identifies distinct pathogen-responsive cell clusters exhibiting transcriptional responses ranging from immunity to susceptibility. Pseudotime analyses through pathogen infection reveals a continuum of disease progression from an immune to a susceptible state. Confocal imaging of promoter-reporter lines for transcripts enriched in immune cell clusters shows expression surrounding substomatal cavities colonized or in close proximity to bacterial colonies, suggesting that cells within immune clusters represent sites of early pathogen invasion. Susceptibility clusters exhibit more general localization and are highly induced at later stages of infection. Overall, our work shows cellular heterogeneity within an infected leaf and provides insight into plant differential response to infection at a single-cell level.
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Affiliation(s)
- Jie Zhu
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA
| | - Signe Lolle
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA
| | - Andrea Tang
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA
| | - Bella Guel
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA
| | - Brian Kvitko
- Department of Plant Pathology, University of Georgia, Athens, GA 30602, USA
| | - Benjamin Cole
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA.
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Cerón-Bustamante M, Tini F, Beccari G, Benincasa P, Covarelli L. Effect of Different Light Wavelengths on Zymoseptoria tritici Development and Leaf Colonization in Bread Wheat. J Fungi (Basel) 2023; 9:670. [PMID: 37367606 DOI: 10.3390/jof9060670] [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: 04/17/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
The wheat pathogen Zymoseptoria tritici can respond to light by modulating its gene expression. Because several virulence-related genes are differentially expressed in response to light, different wavelengths could have a crucial role in the Z. tritici-wheat interaction. To explore this opportunity, the aim of this study was to analyze the effect of blue (470 nm), red (627 nm), blue-red, and white light on the in vitro and in planta development of Z. tritici. The morphology (mycelium appearance, color) and phenotypic (mycelium growth) characteristics of a Z. tritici strain were evaluated after 14 days under the different light conditions in two independent experiments. In addition, bread wheat plants were artificially inoculated with Z. tritici and grown for 35 days under the same light treatments. The disease incidence, severity, and fungal DNA were analyzed in a single experiment. Statistical differences were determined by using an ANOVA. The obtained results showed that the different light wavelengths induced specific morphological changes in mycelial growth. The blue light significantly reduced colony growth, while the dark and red light favored fungal development (p < 0.05). The light quality also influenced host colonization, whereby the white and red light had stimulating and repressing effects, respectively (p < 0.05). This precursory study demonstrated the influence of light on Z. tritici colonization in bread wheat.
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Affiliation(s)
- Minely Cerón-Bustamante
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Francesco Tini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Giovanni Beccari
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Paolo Benincasa
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
| | - Lorenzo Covarelli
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
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Bhatt K, Suyal DC, Kumar S, Singh K, Goswami P. New insights into engineered plant-microbe interactions for pesticide removal. CHEMOSPHERE 2022; 309:136635. [PMID: 36183882 DOI: 10.1016/j.chemosphere.2022.136635] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/21/2022] [Accepted: 09/25/2022] [Indexed: 06/16/2023]
Abstract
Over the past decades, rapid industrialization along with the overutilization of organic pollutants/pesticides has altered the environmental circumstances. Moreover, various anthropogenic, xenobiotics and natural activities also affected plants, soil, and human health, in both direct and indirect ways. To counter this, several conventional methods are currently practiced, but are uneconomical, noxious, and is yet inefficient for large-scale application. Plant-microbe interactions are mediated naturally in an ecosystem and are practiced in several areas. Plant growth promoting rhizobacteria (PGPR) possess certain attributes affecting plant and soil consequently performing decontamination activity via a direct and indirect mechanism. PGPR also harbors indispensable genes stimulating the mineralization of several organic and inorganic compounds. This makes microbes potential candidates for contributing to sustainably remediating the harmful pesticide contaminants. There is a limited piece of information about the plant-microbe interaction pertaining predict and understand the overall interaction concerning a sustainable environment. Therefore, this review focuses on the plant-microbe interaction in the rhizosphere and inside the plant's tissues, along with the utilization augmenting the crop productivity, reduction in plant stress along with decontamination of pesticides/organic pollutants in soil for sustainable environmental management.
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Affiliation(s)
- Kalpana Bhatt
- Department of Food Science, Purdue University, West Lafayette, IN, 47907, USA.
| | - Deep Chandra Suyal
- Department of Microbiology, Akal College of Basic Sciences, Eternal University, Baru Sahib, Sirmour, Himachal Pradesh, India.
| | - Saurabh Kumar
- ICAR-Research Complex for Eastern Region, Patna, 800014, Bihar, India
| | - Kuldeep Singh
- Department of Microbiology, Chaudhary Charan Singh Haryana Agricultural University, Hisar, 125004, India
| | - Priya Goswami
- Department of Biotechnology, Mangalayatan University, Uttar Pradesh, India
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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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11
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Distinct roles for different autophagy-associated genes in the virulence of the fungal wheat pathogen Zymoseptoria tritici. Fungal Genet Biol 2022; 163:103748. [PMID: 36309095 DOI: 10.1016/j.fgb.2022.103748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 09/16/2022] [Accepted: 10/13/2022] [Indexed: 01/06/2023]
Abstract
The fungal wheat pathogen Zymoseptoria tritici causes major crop losses as the causal agent of the disease Septoria tritici blotch. The infection cycle of Z. tritici displays two distinct phases, beginning with an extended symptomless phase of 1-2 weeks, before the fungus induces host cell death and tissue collapse in the leaf. Recent evidence suggests that the fungus uses little host-derived nutrition during asymptomatic colonisation, raising questions as to the sources of energy required for this initial growth phase. Autophagy is crucial for the pathogenicity of other fungal plant pathogens through its roles in supporting cellular differentiation and growth under starvation. Here we characterised the contributions of the autophagy genes ZtATG1 and ZtATG8 to the development and virulence of Z. tritici. Deletion of ZtATG1 led to inhibition of autophagy but had no impact on starvation-induced hyphal differentiation or virulence, suggesting that autophagy is not required for Z. tritici pathogenicity. Contrastingly, ZtATG8 deletion delayed the transition to necrotrophic growth, despite having no influence on filamentous growth under starvation, pointing to an autophagy-independent role of ZtATG8 during Z. tritici infection. To our knowledge, this study represents the first to find autophagy not to contribute to the virulence of a fungal plant pathogen, and reveals novel roles for different autophagy-associated proteins in Z. tritici.
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Pilo P, Lawless C, Tiley AMM, Karki SJ, Burke JI, Feechan A. Comparison of microscopic and metagenomic approaches to identify cereal pathogens and track fungal spore release in the field. FRONTIERS IN PLANT SCIENCE 2022; 13:1039090. [PMID: 36340419 PMCID: PMC9630935 DOI: 10.3389/fpls.2022.1039090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Wheat is one of the main staple food crops, and 775 million tonnes of wheat were produced worldwide in 2022. Fungal diseases such as Fusarium head blight, Septoria tritici blotch, spot blotch, tan spot, stripe rust, leaf rust, and powdery mildew cause serious yield losses in wheat and can impact quality. We aimed to investigate the incidence of spores from major fungal pathogens of cereals in the field by comparing microscopic and metagenomic based approaches for spore identification. Spore traps were set up in four geographically distinct UK wheat fields (Carnoustie, Angus; Bishop Burton, Yorkshire; Swindon, Wiltshire; and Lenham, Kent). Six major cereal fungal pathogen genera (Alternaria spp., Blumeria graminis, Cladosporium spp., Fusarium spp., Puccinia spp., and Zymoseptoria spp.) were found using these techniques at all sites. Using metagenomic and BLAST analysis, 150 cereal pathogen species (33 different genera) were recorded on the spore trap tapes. The metagenomic BLAST analysis showed a higher accuracy in terms of species-specific identification than the taxonomic tool software Kraken2 or microscopic analysis. Microscopic data from the spore traps was subsequently correlated with weather data to examine the conditions which promote ascospore release of Fusarium spp. and Zymoseptoria spp. This revealed that Zymoseptoria spp. and Fusarium spp. ascospore release show a positive correlation with relative humidity (%RH). Whereas air temperature (°C) negatively affects Zymoseptoria spp. ascospore release.
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Affiliation(s)
- Paola Pilo
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Ireland
| | - Colleen Lawless
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Ireland
| | - Anna M. M. Tiley
- Department of Agriculture, Food and the Marine, Celbridge, Ireland
| | - Sujit J. Karki
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Ireland
| | - James I. Burke
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Ireland
| | - Angela Feechan
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Ireland
- Institute for Life and Earth Sciences, School of Energy, Geosciences, Infrastructure and Society, Heriot-Watt University, Edinburgh, United Kingdom
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13
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Zymoseptoria tritici white-collar complex integrates light, temperature and plant cues to initiate dimorphism and pathogenesis. Nat Commun 2022; 13:5625. [PMID: 36163135 PMCID: PMC9512790 DOI: 10.1038/s41467-022-33183-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/07/2022] [Indexed: 11/08/2022] Open
Abstract
Transitioning from spores to hyphae is pivotal to host invasion by the plant pathogenic fungus Zymoseptoria tritici. This dimorphic switch can be initiated by high temperature in vitro (~27 °C); however, such a condition may induce cellular heat stress, questioning its relevance to field infections. Here, we study the regulation of the dimorphic switch by temperature and other factors. Climate data from wheat-growing areas indicate that the pathogen sporadically experiences high temperatures such as 27 °C during summer months. However, using a fluorescent dimorphic switch reporter (FDR1) in four wild-type strains, we show that dimorphic switching already initiates at 15-18 °C, and is enhanced by wheat leaf surface compounds. Transcriptomics reveals 1261 genes that are up- or down-regulated in hyphae of all strains. These pan-strain core dimorphism genes (PCDGs) encode known effectors, dimorphism and transcription factors, and light-responsive proteins (velvet factors, opsins, putative blue light receptors). An FDR1-based genetic screen reveals a crucial role for the white-collar complex (WCC) in dimorphism and virulence, mediated by control of PCDG expression. Thus, WCC integrates light with biotic and abiotic cues to orchestrate Z. tritici infection.
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14
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Tiley AMM, Lawless C, Pilo P, Karki SJ, Lu J, Long Z, Gibriel H, Bailey AM, Feechan A. The Zymoseptoria tritici white collar-1 gene, ZtWco-1, is required for development and virulence on wheat. Fungal Genet Biol 2022; 161:103715. [PMID: 35709910 DOI: 10.1016/j.fgb.2022.103715] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 06/02/2022] [Accepted: 06/06/2022] [Indexed: 11/04/2022]
Abstract
The fungus Zymoseptoria tritici causes Septoria Tritici Blotch (STB), which is one of the most devastating diseases of wheat in Europe. There are currently no fully durable methods of control against Z. tritici, so novel strategies are urgently required. One of the ways in which fungi are able to respond to their surrounding environment is through the use of photoreceptor proteins which detect light signals. Although previous evidence suggests that Z. tritici can detect light, no photoreceptor genes have been characterised in this pathogen. This study characterises ZtWco-1, a predicted photoreceptor gene in Z. tritici. The ZtWco-1 gene is a putative homolog to the blue light photoreceptor from Neurospora crassa, wc-1. Z. tritici mutants with deletions in ZtWco-1 have defects in hyphal branching, melanisation and virulence on wheat. In addition, we identify the putative circadian clock gene ZtFrq in Z. tritici. This study provides evidence for the genetic regulation of light detection in Z. tritici and it open avenues for future research into whether this pathogen has a circadian clock.
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Affiliation(s)
- Anna M M Tiley
- Agri-Food Biosciences Institute, 18a Newforge Ln, Belfast BT9 5PX, United Kingdom; School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland.
| | - Colleen Lawless
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland; School of Biology and Environmental Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Paola Pilo
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Sujit J Karki
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Jijun Lu
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Zhuowei Long
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland
| | - Hesham Gibriel
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland; Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Andy M Bailey
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - Angela Feechan
- School of Agriculture and Food Science, University College Dublin, Dublin 4, Republic of Ireland.
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15
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Kracmarova M, Uhlik O, Strejcek M, Szakova J, Cerny J, Balik J, Tlustos P, Kohout P, Demnerova K, Stiborova H. Soil microbial communities following 20 years of fertilization and crop rotation practices in the Czech Republic. ENVIRONMENTAL MICROBIOME 2022; 17:13. [PMID: 35346385 PMCID: PMC8962459 DOI: 10.1186/s40793-022-00406-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/08/2022] [Indexed: 05/25/2023]
Abstract
BACKGROUND Although fertilization and crop rotation practices are commonly used worldwide in agriculture to maximize crop yields, their long-term effect on the structures of soil microorganisms is still poorly understood. This study investigated the long-term impact of fertilization and crop rotation on soil microbial diversity and the microbial community structure in four different locations with three soil types. Since 1996, manure (MF; 330 kg N/ha), sewage sludge (SF; 330 and SF3x; 990 kg N/ha), and NPK (NPK; 330 kg N/ha) fertilizers were periodically applied to the soils classified as chernozem, luvisol and cambisol, which are among the most abundant or fertile soils used for agricultural purposes in the world. In these soils, potato (Solanum tuberosum L.), winter wheat (Triticum aestivum L.), and spring barley (Hordeum vulgare L.) were rotated every three years. RESULTS Soil chemistry, which was significantly associated with location, fertilization, crop rotation, and the interaction of fertilization and location, was the dominant driver of soil microbial communities, both prokaryotic and fungal. A direct effect of long-term crop rotation and fertilization on the structure of their communities was confirmed, although there was no evidence of their influence on microbial diversity. Fungal and bacterial communities responded differently to fertilization treatments; prokaryotic communities were only significantly different from the control soil (CF) in soils treated with MF and SF3x, while fungal communities differed across all treatments. Indicator genera were identified for different treatments. These taxa were either specific for their decomposition activities or fungal plant pathogens. Sequential rotation of the three crops restricted the growth of several of the indicator plant pathogens. CONCLUSIONS Long-term fertilization and crop rotation significantly altered microbial community structure in the soil. While fertilization affected soil microorganisms mainly through changes in nutrient profile, crop rotations lead to the attraction and repulsion of specific plant pathogens. Such changes in soil microbial communities need to be considered when planning soil management.
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Affiliation(s)
- Martina Kracmarova
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague 6, Czech Republic.
| | - Ondrej Uhlik
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague 6, Czech Republic
| | - Michal Strejcek
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague 6, Czech Republic
| | - Jirina Szakova
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague - Suchdol, Czech Republic
| | - Jindrich Cerny
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague - Suchdol, Czech Republic
| | - Jiri Balik
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague - Suchdol, Czech Republic
| | - Pavel Tlustos
- Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague - Suchdol, Czech Republic
| | - Petr Kohout
- Laboratory of Environmental Microbiology, Institute of Microbiology of the CAS, Videnska 1083, 142 20, Praha 4, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Vinicna 5, 128 44, Praha 2, Czech Republic
| | - Katerina Demnerova
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague 6, Czech Republic
| | - Hana Stiborova
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Technicka 3, 166 28, Prague 6, Czech Republic.
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16
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Abbasi PA, Hildebrand PD, Ali S, Moreau DL, Renderos WE. Effect of RH, Temperature, Light, and Plant Age on Infection of Lowbush Blueberry by Sphaerulina vaccinii. PLANT DISEASE 2022; 106:297-303. [PMID: 34372680 DOI: 10.1094/pdis-12-20-2747-re] [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: 06/13/2023]
Abstract
Leaf spot and stem canker caused by Sphaerulina vaccinii is associated with premature defoliation in lowbush blueberry resulting in reduced yields. In this study, we investigated the impact of free water, RH, temperature, light, and plant age on leaf infection under controlled conditions. On potato dextrose agar, germination of conidia was usually polar. Growth was minimal at 5 and 10°C, increased at 15 and 20°C, was maximal at 25°C and decreased at 30°C. Percentage of germinated conidia on inoculated blueberry leaves incubated in dark controlled-humidity chambers for 3 days (25°C) was 86.0, 90.5, 81.3, and 28.3 in free water, 100, 97.5 or 95% RH, respectively. Germination did not occur at 90 or 85% RH. Infection of inoculated plants, however, was not favored by free water, but rather by high RH (>95%) and a 14-h photoperiod (180 μmol/m2 per second). Infection failed in continuous darkness, continuous light, or continuous darkness followed by 4, 8, or 12 h of light. Light and scanning electron microscopy showed that hyphal penetration into stomata on abaxial leaf surfaces was strongly tropic. When germ tubes grew in close proximity to a stomate, a penetration hypha formed at ∼90° angles to the germ tube and took the closest path to the stomate. Stomatal penetration was usually direct, but occasionally appressorium-like hyphal swellings formed over stomatal openings. When inoculated plants were exposed to high RH (>95%) at various temperatures, infection occurred after 4 days at 10°C, after 3 days at 15°C and after 1 day at 20 and 25°C. Infection failed to occur at 30°C. Disease severity also increased with duration of the humid period. When leaves were examined microscopically, those that had been incubated for 6 days showed a substantially greater network of epiphytic growth with more stomatal penetrations compared with those incubated for 3 days. Infection was substantially reduced when the humid period was interrupted by alternating days of low RH (60%). Two-week-old leaves were 2.7 times more susceptible than 8-week-old leaves.
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Affiliation(s)
- Pervaiz A Abbasi
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, Nova Scotia B4N 1J5, Canada
| | - Paul D Hildebrand
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, Nova Scotia B4N 1J5, Canada
| | - Shawkat Ali
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, Nova Scotia B4N 1J5, Canada
| | - Debra L Moreau
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, Nova Scotia B4N 1J5, Canada
| | - Willy E Renderos
- Kentville Research and Development Centre, Agriculture and Agri-Food Canada, Kentville, Nova Scotia B4N 1J5, Canada
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17
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Battache M, Lebrun MH, Sakai K, Soudière O, Cambon F, Langin T, Saintenac C. Blocked at the Stomatal Gate, a Key Step of Wheat Stb16q-Mediated Resistance to Zymoseptoria tritici. FRONTIERS IN PLANT SCIENCE 2022; 13:921074. [PMID: 35832231 PMCID: PMC9271956 DOI: 10.3389/fpls.2022.921074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/03/2022] [Indexed: 05/11/2023]
Abstract
Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is among the most threatening wheat diseases in Europe. Genetic resistance remains one of the main environmentally sustainable strategies to efficiently control STB. However, the molecular and physiological mechanisms underlying resistance are still unknown, limiting the implementation of knowledge-driven management strategies. Among the 22 known major resistance genes (Stb), the recently cloned Stb16q gene encodes a cysteine-rich receptor-like kinase conferring a full broad-spectrum resistance against Z. tritici. Here, we showed that an avirulent Z. tritici inoculated on Stb16q quasi near isogenic lines (NILs) either by infiltration into leaf tissues or by brush inoculation of wounded tissues partially bypasses Stb16q-mediated resistance. To understand this bypass, we monitored the infection of GFP-labeled avirulent and virulent isolates on Stb16q NILs, from germination to pycnidia formation. This quantitative cytological analysis revealed that 95% of the penetration attempts were unsuccessful in the Stb16q incompatible interaction, while almost all succeeded in compatible interactions. Infectious hyphae resulting from the few successful penetration events in the Stb16q incompatible interaction were arrested in the sub-stomatal cavity of the primary-infected stomata. These results indicate that Stb16q-mediated resistance mainly blocks the avirulent isolate during its stomatal penetration into wheat tissue. Analyses of stomatal aperture of the Stb16q NILs during infection revealed that Stb16q triggers a temporary stomatal closure in response to an avirulent isolate. Finally, we showed that infiltrating avirulent isolates into leaves of the Stb6 and Stb9 NILs also partially bypasses resistances, suggesting that arrest during stomatal penetration might be a common major mechanism for Stb-mediated resistances.
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Affiliation(s)
- Mélissa Battache
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Marc-Henri Lebrun
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Kaori Sakai
- Université Paris-Saclay, INRAE, UR BIOGER, Thiverval-Grignon, France
| | - Olivier Soudière
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Florence Cambon
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Thierry Langin
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
| | - Cyrille Saintenac
- Université Clermont Auvergne, INRAE, GDEC, Clermont-Ferrand, France
- *Correspondence: Cyrille Saintenac,
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18
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Karki SJ, Reilly A, Zhou B, Mascarello M, Burke J, Doohan F, Douchkov D, Schweizer P, Feechan A. A small secreted protein from Zymoseptoria tritici interacts with a wheat E3 ubiquitin ligase to promote disease. JOURNAL OF EXPERIMENTAL BOTANY 2021. [PMID: 33095257 DOI: 10.5061/dryad.9w0vt4bcx] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici, is a major threat to wheat production worldwide. The Z. tritici genome encodes many small secreted proteins (ZtSSPs) that are likely to play a key role in the successful colonization of host tissues. However, few of these ZtSSPs have been functionally characterized for their role during infection. In this study, we identified and characterized a small, conserved cysteine-rich secreted effector from Z. tritici which has homologues in other plant pathogens in the Dothideomycetes. ZtSSP2 was expressed throughout Z. tritici infection in wheat, with the highest levels observed early during infection. A yeast two-hybrid assay revealed an interaction between ZtSSP2 and wheat E3 ubiquitin ligase (TaE3UBQ) in yeast, and this was further confirmed in planta using bimolecular fluorescence complementation and co-immunoprecipitation. Down-regulation of this wheat E3 ligase using virus-induced gene silencing increased the susceptibility of wheat to STB. Together, these results suggest that TaE3UBQ is likely to play a role in plant immunity to defend against Z. tritici.
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Affiliation(s)
- Sujit Jung Karki
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Reilly
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Binbin Zhou
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maurizio Mascarello
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Ecology, Evolution and Biodiversity Conservation, Charles Deberiotstraat 8 32, 3000 Leuven, Belgium
| | - James Burke
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fiona Doohan
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitar Douchkov
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Patrick Schweizer
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Angela Feechan
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
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19
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Karki SJ, Reilly A, Zhou B, Mascarello M, Burke J, Doohan F, Douchkov D, Schweizer P, Feechan A. A small secreted protein from Zymoseptoria tritici interacts with a wheat E3 ubiquitin ligase to promote disease. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:733-746. [PMID: 33095257 PMCID: PMC7853600 DOI: 10.1093/jxb/eraa489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/15/2020] [Indexed: 05/05/2023]
Abstract
Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria tritici, is a major threat to wheat production worldwide. The Z. tritici genome encodes many small secreted proteins (ZtSSPs) that are likely to play a key role in the successful colonization of host tissues. However, few of these ZtSSPs have been functionally characterized for their role during infection. In this study, we identified and characterized a small, conserved cysteine-rich secreted effector from Z. tritici which has homologues in other plant pathogens in the Dothideomycetes. ZtSSP2 was expressed throughout Z. tritici infection in wheat, with the highest levels observed early during infection. A yeast two-hybrid assay revealed an interaction between ZtSSP2 and wheat E3 ubiquitin ligase (TaE3UBQ) in yeast, and this was further confirmed in planta using bimolecular fluorescence complementation and co-immunoprecipitation. Down-regulation of this wheat E3 ligase using virus-induced gene silencing increased the susceptibility of wheat to STB. Together, these results suggest that TaE3UBQ is likely to play a role in plant immunity to defend against Z. tritici.
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Affiliation(s)
- Sujit Jung Karki
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Reilly
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Binbin Zhou
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maurizio Mascarello
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Ecology, Evolution and Biodiversity Conservation, Charles Deberiotstraat 8 32, 3000 Leuven, Belgium
| | - James Burke
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Fiona Doohan
- School of Biology and Environmental Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Dimitar Douchkov
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Patrick Schweizer
- Institute of Plant Genetics and Crop Plant Research (IPK), Cytogenetics, Gatersleben, Germany
| | - Angela Feechan
- School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
- Correspondence:
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20
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Reilly A, Karki SJ, Twamley A, Tiley AMM, Kildea S, Feechan A. Isolate-Specific Responses of the Nonhost Grass Brachypodium distachyon to the Fungal Pathogen Zymoseptoria tritici Compared with Wheat. PHYTOPATHOLOGY 2021; 111:356-368. [PMID: 32720875 DOI: 10.1094/phyto-02-20-0041-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: 06/11/2023]
Abstract
Septoria tritici blotch (STB) is an important foliar disease of wheat that is caused by the fungal pathogen Zymoseptoria tritici. The grass Brachypodium distachyon has been used previously as a model system for cereal-pathogen interactions. In this study, we examined the nonhost resistance (NHR) response of B. distachyon to two different Z. tritici isolates in comparison with wheat. These isolates vary in aggressiveness on wheat cultivar Remus, displaying significant differences in disease and pycnidia coverage. Using microscopy, we found that similar isolate-specific responses were observed for hydrogen peroxide accumulation and cell death in both wheat and B. distachyon. Despite this, induction of isolate-specific patterns of defense gene expression by Z. tritici did differ between B. distachyon and wheat. Our results suggest that expression of the phenylalanine ammonia lyase PAL gene may be important for NHR in B. distachyon, while pathogenesis-related PR genes and expression of genes regulating reactive oxygen species may be important to limit disease in wheat. Future studies of the B. distachyon-Z. tritici interaction may allow identification of conserved plant immunity targets that are responsible for the isolate-specific responses observed in both plant species.
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Affiliation(s)
- Aisling Reilly
- School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Sujit Jung Karki
- School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Anthony Twamley
- School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Anna M M Tiley
- School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Steven Kildea
- Department of Crop Science, Teagasc Crops Environment and Land Use Programme, Teagasc, Oak Park, County Carlow, Ireland
| | - Angela Feechan
- School of Agriculture and Food Science and UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
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21
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Fantozzi E, Kilaru S, Cannon S, Schuster M, Gurr SJ, Steinberg G. Conditional promoters to investigate gene function during wheat infection by Zymoseptoria tritici. Fungal Genet Biol 2021; 146:103487. [PMID: 33309991 PMCID: PMC7812376 DOI: 10.1016/j.fgb.2020.103487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/27/2022]
Abstract
The fungus Zymoseptoria tritici causes Septoria tritici leaf blotch, which poses a serious threat to temperate-grown wheat. Recently, we described a raft of molecular tools to study the biology of this fungus in vitro. Amongst these are 5 conditional promoters (Pnar1, Pex1A, Picl1, Pgal7, PlaraB), which allow controlled over-expression or repression of target genes in cells grown in liquid culture. However, their use in the host-pathogen interaction in planta was not tested. Here, we investigate the behaviour of these promoters by quantitative live cell imaging of green-fluorescent protein-expressing cells during 6 stages of the plant infection process. We show that Pnar1 and Picl1 are repressed in planta and demonstrate their suitability for studying essential gene expression and function in plant colonisation. The promoters Pgal7 and Pex1A are not fully-repressed in planta, but are induced during pycnidiation. This indicates the presence of inducing galactose or xylose and/or arabinose, released from the plant cell wall by the activity of fungal hydrolases. In contrast, the PlaraB promoter, which normally controls expression of an α-l-arabinofuranosidase B, is strongly induced inside the leaf. This suggests that the fungus is exposed to L-arabinose in the mesophyll apoplast. Taken together, this study establishes 2 repressible promoters (Pnar1 and Picl1) and three inducible promoters (Pgal7, Pex1A, PlaraB) for molecular studies in planta. Moreover, we provide circumstantial evidence for plant cell wall degradation during the biotrophic phase of Z. tritici infection.
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Affiliation(s)
- Elena Fantozzi
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Sreedhar Kilaru
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Stuart Cannon
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Sarah J Gurr
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, UK; University of Utrecht, Padualaan 8, Utrecht 3584 CH, the Netherlands.
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22
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Asynchronous development of Zymoseptoria tritici infection in wheat. Fungal Genet Biol 2020; 146:103504. [PMID: 33326850 PMCID: PMC7812371 DOI: 10.1016/j.fgb.2020.103504] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/04/2020] [Accepted: 12/04/2020] [Indexed: 12/22/2022]
Abstract
Zymoseptoria tritici passes 6 morphologically defined stages during infection. Surface-located spores and hyphae are found for up to 17/18 days. Entry through stomata occurs from 1 to 13 days post infection. Mesophyll apoplast colonisation continuously increases during infection. Up to 5 stages co-exist in infected leaves at a given time.
The fungus Zymoseptoria tritici causes Septoria tritici blotch of wheat. Pathogenicity begins with spore germination, followed by stomata invasion by hyphae, mesophyll colonization and fruiting body formation. It was previously found that entry into the plant via stomata occurs in a non-synchronized way over several days, while later developmental steps, such as early and late fruiting body formation, were reported to follow each other in time. This suggests synchronization of the pathogen population in planta prior to sporulation. Here, we image a fluorescent Z. tritici IPO323-derived strain during infection. We describe 6 morphologically distinct developmental stages, and determine their abundance in infected leaves, with time post inoculation. This demonstrates that 3-5 stages co-exist in infected tissues at any given time. Thus, later stages of pathogen development also occur asynchronously amongst the population of infecting cells. This merits consideration when interpreting transcriptomics or proteomics data gathered from infected plants.
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23
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Fones HN. Presence of ice-nucleating Pseudomonas on wheat leaves promotes Septoria tritici blotch disease (Zymoseptoria tritici) via a mutually beneficial interaction. Sci Rep 2020; 10:17738. [PMID: 33082401 PMCID: PMC7575590 DOI: 10.1038/s41598-020-74615-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 09/09/2020] [Indexed: 11/09/2022] Open
Abstract
Zymoseptoria tritici causes Septoria tritici blotch (STB) of wheat, an economically important disease causing yield losses of up to 10% despite the use of fungicides and resistant cultivars. Z. tritici infection is symptomless for around 10 days, during which time the fungus grows randomly across the leaf surface prior to entry through stomata. Wounded leaves show faster, more extensive STB, suggesting that wounds facilitate fungal entry. Wheat leaves also host epiphytic bacteria; these include ice-nucleating (INA+) bacteria, which induce frost damage at warmer temperatures than it otherwise occurs. Here, STB is shown to be more rapid and severe when wheat is exposed to both INA+ bacteria and sub-zero temperatures. This suggests that ice-nucleation-induced wounding of the wheat leaf provides additional openings for fungal entry. INA+ bacterial populations are shown to benefit from the presence of Z. tritici, indicating that this microbial interaction is mutualistic. Finally, control of INA+ bacteria is shown to reduce STB.
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Affiliation(s)
- Helen N Fones
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
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24
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Rosli H, Batzer JC, Hernández E, Beruski G, Dixon PM, Gleason ML. Precipitation Impacts Dissemination of Three Sooty Blotch and Flyspeck Taxa on Apple Fruit. PLANT DISEASE 2020; 104:2398-2405. [PMID: 32689919 DOI: 10.1094/pdis-11-19-2340-re] [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: 06/11/2023]
Abstract
The spatial dissemination of three prevalent taxa of sooty blotch and flyspeck (SBFS) fungi under several levels of precipitation was compared during 2015 and 2016 in an Iowa apple orchard. Overhead irrigation was used to supplement ambient precipitation in order to insure SBFS spore dissemination and colony development. There were five irrigation levels, involving 1-min-long periods of irrigation that were imposed either once or twice per hour at intervals of 3, 6, or 12 h, as well as a nonirrigated control. Preselected apple fruit were inoculated with one of the three SBFS taxa to serve as sources of inoculum. Dissemination from these inoculated apple fruit was assessed at harvest by counting SBFS colonies on water-sprayed and nontreated fruit. As a further control, additional fruit were enclosed in fruit bags throughout the fruit development period. In both 2015 and 2016, the number of colonies of the SBFS fungus Peltaster gemmifer per apple increased sharply as the duration of irrigation increased, whereas the number of colonies of Microcyclosporella mali increased to a lesser extent and Stomiopeltis sp. RS1 showed no increase. In 2015, the linear relationship between the duration of irrigation-imposed precipitation levels and the number of colonies on the water-sprayed apple fruit was similar for P. gemmifer (slope = 0.09), Stomiopeltis sp. RS1 (slope = 0.07), and Microcyclosporella mali (slope = 0.13); whereas, in 2016, the slope was higher for P. gemmifer (0.28) than for Stomiopeltis sp. RS1 (-0.09) or M. mali (0.06). The results indicated that dissemination of P. gemmifer increased sharply in response to increased irrigation-imposed precipitation, and that dissemination patterns differed considerably among the three SBFS taxa. The apparent advantage of P. gemmifer in precipitation-triggered dissemination may stem from its ability to produce spores rapidly by budding. To our knowledge, this is the first article to assess splash dispersal by SBFS fungi in the field and the first to document taxon-specific patterns of dissemination in this pathogen complex.
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Affiliation(s)
- Hafizi Rosli
- School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Jean C Batzer
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, U.S.A
| | - Edward Hernández
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, U.S.A
| | - Gustavo Beruski
- Department of Biosystems Engineering, ESALQ, University of São Paulo, Piracicaba, Brazil
| | - Philip M Dixon
- Department of Statistics, Iowa State University, Ames, IA, U.S.A
| | - Mark L Gleason
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, U.S.A
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25
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Fones HN, Bebber DP, Chaloner TM, Kay WT, Steinberg G, Gurr SJ. Threats to global food security from emerging fungal and oomycete crop pathogens. ACTA ACUST UNITED AC 2020; 1:332-342. [PMID: 37128085 DOI: 10.1038/s43016-020-0075-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/09/2020] [Indexed: 11/09/2022]
Abstract
Emerging fungal and oomycete pathogens infect staple calorie crops and economically important commodity crops, thereby posing a significant risk to global food security. Our current agricultural systems - with emphasis on intensive monoculture practices - and globalized markets drive the emergence and spread of new pathogens and problematic traits, such as fungicide resistance. Climate change further promotes the emergence of pathogens on new crops and in new places. Here we review the factors affecting the introduction and spread of pathogens and current disease control strategies, illustrating these with the historic example of the Irish potato famine and contemporary examples of soybean rust, wheat blast and blotch, banana wilt and cassava root rot. Our Review looks to the future, summarizing what we see as the main challenges and knowledge gaps, and highlighting the direction that research must take to face the challenge of emerging crop pathogens.
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26
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Rahman A, Doohan F, Mullins E. Quantification of In Planta Zymoseptoria tritici Progression Through Different Infection Phases and Related Association with Components of Aggressiveness. PHYTOPATHOLOGY 2020; 110:1208-1215. [PMID: 32133920 DOI: 10.1094/phyto-09-19-0339-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In planta growth of Zymoseptoria tritici, causal agent of Septoria tritici blotch of wheat, during the infection process has remained an understudied topic due to the long symptomless latent period before the emergence of fruiting bodies. In this study, we attempted to understand the relationship between in planta growth of Z. tritici relative to the primary components of aggressiveness, i.e., latent period and pycnidia coverage in regard to contrasting host resistance. We tested isolates collected from Ireland against the susceptible cultivar Gallant and cultivar Stigg, which has strong partial resistance. A clear isolate-host interaction effect (F = 3.018; P = 0.005, and F = 6.008; P < 0.001) for latent period and pycnidia coverage, respectively, was identified. Furthermore, during the early infection phase of latency from 5 to 11 days postinoculation (dpi), in planta growth rate of fungal biomass was significantly (F = 30.06; P < 0.001) more affected by host resistance than isolate specificity (F = 1.27; P = 0.27), indicating the importance of host resistance in the early infection phase. In planta Z. tritici growth rates in cultivar Gallant spiked between 11 and 16 dpi followed by a continuous fall onward, whereas in cultivar Stigg it was slowly progressive in nature. From correlation and regression analysis, we found that the in planta growth rate preceding the average latent period of cultivar Gallant has more influence on latency duration and pycnidia production. Likewise, correlation between component of aggressiveness and in planta growth rate of pathogen supports our understanding of aggressiveness to be driven by the pathogen's multiplication capacity within host tissue.
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Affiliation(s)
- Atikur Rahman
- Crop Science Department, Teagasc, Oakpark, Carlow, R93 XE12, Ireland
- School of Biological and Environmental Sciences, UCD Earth Institute and UCD Institute of Food and Health, University College of Dublin, Dublin, D04 V1W8, Ireland
| | - Fiona Doohan
- School of Biological and Environmental Sciences, UCD Earth Institute and UCD Institute of Food and Health, University College of Dublin, Dublin, D04 V1W8, Ireland
| | - Ewen Mullins
- Crop Science Department, Teagasc, Oakpark, Carlow, R93 XE12, Ireland
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27
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Seybold H, Demetrowitsch TJ, Hassani MA, Szymczak S, Reim E, Haueisen J, Lübbers L, Rühlemann M, Franke A, Schwarz K, Stukenbrock EH. A fungal pathogen induces systemic susceptibility and systemic shifts in wheat metabolome and microbiome composition. Nat Commun 2020; 11:1910. [PMID: 32313046 PMCID: PMC7171108 DOI: 10.1038/s41467-020-15633-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 03/13/2020] [Indexed: 12/14/2022] Open
Abstract
Yield losses caused by fungal pathogens represent a major threat to global food production. One of the most devastating fungal wheat pathogens is Zymoseptoria tritici. Despite the importance of this fungus, the underlying mechanisms of plant–pathogen interactions are poorly understood. Here we present a conceptual framework based on coinfection assays, comparative metabolomics, and microbiome profiling to study the interaction of Z. tritici in susceptible and resistant wheat. We demonstrate that Z. tritici suppresses the production of immune-related metabolites in a susceptible cultivar. Remarkably, this fungus-induced immune suppression spreads within the leaf and even to other leaves, a phenomenon that we term “systemic induced susceptibility”. Using a comparative metabolomics approach, we identify defense-related biosynthetic pathways that are suppressed and induced in susceptible and resistant cultivars, respectively. We show that these fungus-induced changes correlate with changes in the wheat leaf microbiome. Our findings suggest that immune suppression by this hemibiotrophic pathogen impacts specialized plant metabolism, alters its associated microbial communities, and renders wheat vulnerable to further infections. The fungal plant pathogen Zymoseptoria tritici is a major threat to wheat yield. Here Seybold et al. show that Z. tritici can suppress immune responses not only in infected tissue but also on other leaves, a phenomenon termed “systemic induced susceptibility” that is correlated with systemic changes in metabolite accumulation.
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Affiliation(s)
- Heike Seybold
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany.,Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, 9190401, Israel
| | - Tobias J Demetrowitsch
- Institute of Human Nutrition and Food Science, Kiel University, Heinrich-Hecht-Platz 10, 24118, Kiel, Germany
| | - M Amine Hassani
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany
| | - Silke Szymczak
- Institute of Medical Informatics and Statistics, Kiel University, University Hospital Schleswig Holstein Campus Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Ekaterina Reim
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.,Institute of Human Nutrition and Food Science, Kiel University, Heinrich-Hecht-Platz 10, 24118, Kiel, Germany
| | - Janine Haueisen
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.,Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany
| | - Luisa Lübbers
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| | - Malte Rühlemann
- Institute of Clinical Molecular Biology, Kiel University, Am Botanischen Garten 11, 24118, Kiel, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Kiel University, Am Botanischen Garten 11, 24118, Kiel, Germany
| | - Karin Schwarz
- Institute of Human Nutrition and Food Science, Kiel University, Heinrich-Hecht-Platz 10, 24118, Kiel, Germany
| | - Eva H Stukenbrock
- Botanical Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany. .,Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306, Plön, Germany.
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28
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Agrobacterium tumefaciens-mediated transformation and expression of GFP in Ascochyta lentis to characterize ascochyta blight disease progression in lentil. PLoS One 2019; 14:e0223419. [PMID: 31647840 PMCID: PMC6812748 DOI: 10.1371/journal.pone.0223419] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/20/2019] [Indexed: 11/25/2022] Open
Abstract
The plant immune system is made up of a complex response network that involves several lines of defense to fight invading pathogens. Fungal plant pathogens on the other hand, have evolved a range of ways to infect their host. The interaction between Ascochyta lentis and two lentil genotypes was explored to investigate the progression of ascochyta blight (AB) in lentils. In this study, we developed an Agrobacterium tumefaciens-mediated transformation system for A. lentis by constructing a new binary vector, pATMT-GpdGFP, for the constitutive expression of green fluorescent protein (EGFP). Green fluorescence was used as a highly efficient vital marker to study the developmental changes in A. lentis during AB disease progression on the susceptible and resistant lentil accessions, ILL6002 and ILL7537, respectively. The initial infection stages were similar in both the resistant and susceptible accessions where A. lentis uses infection structures such as germ tubes and appressoria to gain entry into the host while the host uses defense mechanisms to prevent pathogen entry. Penetration was observed at the junctions between neighbouring epidermal cells and occasionally, through the stomata. The pathogen attempted to penetrate and colonize ILL7537, but further fungal advancement appeared to be halted, and A. lentis did not enter the mesophyll. Successful entry and colonization of ILL6002 coincided with structural changes in A. lentis and the onset of necrotic lesions 5–7 days post inoculation. Once inside the leaf, A. lentis continued to grow, colonizing all parts of the leaf followed by plant cell collapse. Pycnidia-bearing spores appeared 14 days post inoculation, which marks the completion of the infection cycle. The use of fluorescent proteins in plant pathogenic fungi together with confocal laser scanning microscopy, provide a valuable tool to study the intracellular dynamics, colonization strategy and infection mechanisms during plant-pathogen interaction.
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29
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Tiley AMM, White HJ, Foster GD, Bailey AM. The ZtvelB Gene Is Required for Vegetative Growth and Sporulation in the Wheat Pathogen Zymoseptoria tritici. Front Microbiol 2019; 10:2210. [PMID: 31632366 PMCID: PMC6779691 DOI: 10.3389/fmicb.2019.02210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/10/2019] [Indexed: 11/13/2022] Open
Abstract
The ascomycete fungus Zymoseptoria tritici is the causal agent of Septoria Tritici Blotch (STB), a major disease of wheat across Europe. Current understanding of the genetic components and the environmental cues which influence development and pathogenicity of this fungus is limited. The velvet B gene, velB, has conserved roles in development, secondary metabolism, and pathogenicity across fungi. The function of this gene is best characterised in the model ascomycete fungus Aspergillus nidulans, where it is involved in co-ordinating the light response with downstream processes. There is limited knowledge of the role of light in Z. tritici, and of the molecular mechanisms underpinning the light response. We show that Z. tritici is able to detect light, and that the vegetative morphology of this fungus is influenced by light conditions. We also identify and characterise the Z. tritici velB gene, ZtvelB, by gene disruption. The ΔztvelB deletion mutants were fixed in a filamentous growth pattern and are unable to form yeast-like vegetative cells. Their morphology was similar under light and dark conditions, showing an impairment in light-responsive growth. In addition, the ΔztvelB mutants produced abnormal pycnidia that were impaired in macropycnidiospore production but could still produce viable infectious micropycnidiospores. Our results show that ZtvelB is required for yeast-like growth and asexual sporulation in Z. tritici, and we provide evidence for a role of ZtvelB in integrating light perception and developmental regulation in this important plant pathogenic fungus.
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Affiliation(s)
- Anna M M Tiley
- Molecular Plant Pathology and Fungal Biology, School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Hannah J White
- School of Biology and Environmental Science, O'Brien Centre for Science, University College Dublin, Dublin, Ireland
| | - Gary D Foster
- Molecular Plant Pathology and Fungal Biology, School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Andy M Bailey
- Molecular Plant Pathology and Fungal Biology, School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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30
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Liu Y, Maierhofer T, Rybak K, Sklenar J, Breakspear A, Johnston MG, Fliegmann J, Huang S, Roelfsema MRG, Felix G, Faulkner C, Menke FL, Geiger D, Hedrich R, Robatzek S. Anion channel SLAH3 is a regulatory target of chitin receptor-associated kinase PBL27 in microbial stomatal closure. eLife 2019; 8:44474. [PMID: 31524595 PMCID: PMC6776436 DOI: 10.7554/elife.44474] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 09/13/2019] [Indexed: 12/15/2022] Open
Abstract
In plants, antimicrobial immune responses involve the cellular release of anions and are responsible for the closure of stomatal pores. Detection of microbe-associated molecular patterns (MAMPs) by pattern recognition receptors (PRRs) induces currents mediated via slow-type (S-type) anion channels by a yet not understood mechanism. Here, we show that stomatal closure to fungal chitin is conferred by the major PRRs for chitin recognition, LYK5 and CERK1, the receptor-like cytoplasmic kinase PBL27, and the SLAH3 anion channel. PBL27 has the capacity to phosphorylate SLAH3, of which S127 and S189 are required to activate SLAH3. Full activation of the channel entails CERK1, depending on PBL27. Importantly, both S127 and S189 residues of SLAH3 are required for chitin-induced stomatal closure and anti-fungal immunity at the whole leaf level. Our results demonstrate a short signal transduction module from MAMP recognition to anion channel activation, and independent of ABA-induced SLAH3 activation.
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Affiliation(s)
- Yi Liu
- The Sainsbury Laboratory, Norwich, United Kingdom
| | - Tobias Maierhofer
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Katarzyna Rybak
- LMU Biocenter, Ludwig-Maximilian-University of Munich, Martinsried, Germany
| | - Jan Sklenar
- The Sainsbury Laboratory, Norwich, United Kingdom
| | | | | | - Judith Fliegmann
- Department of Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tuebingen, Tuebingen, Germany
| | - Shouguang Huang
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - M Rob G Roelfsema
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Georg Felix
- Department of Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), University of Tuebingen, Tuebingen, Germany
| | | | | | - Dietmar Geiger
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Biocenter, University of Wuerzburg, Wuerzburg, Germany
| | - Silke Robatzek
- The Sainsbury Laboratory, Norwich, United Kingdom.,LMU Biocenter, Ludwig-Maximilian-University of Munich, Martinsried, Germany
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31
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Šoltys K, Planý M, Biocca P, Vianello V, Bučková M, Puškárová A, Sclocchi MC, Colaizzi P, Bicchieri M, Pangallo D, Pinzari F. Lead soaps formation and biodiversity in a XVIII Century wax seal coloured with minium. Environ Microbiol 2019; 22:1517-1534. [PMID: 31291047 DOI: 10.1111/1462-2920.14735] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/24/2019] [Accepted: 07/08/2019] [Indexed: 01/30/2023]
Abstract
A multidisciplinary approach was carried out in order to study the biodeterioration and the associated microbiome of a XVIII Century wax seal coloured with minium. A small wax seal fragment was observed by scanning electron microscopy combined with energy dispersive spectroscopy in non-destructive mode. The same object was analysed by Raman and Fourier-transform infrared spectroscopy. The identification of the microbiota growing on the seal was performed with both a culture-dependent strategy, combined with hydrolytic assays, and high-throughput sequencing using the MinION platform. The whole bacterial 16S rRNA gene and the fungal markers ITS and 28S rRNA were targeted. It was observed that the carnauba wax coloured with lead tetroxide (minium) was covered by a biofilm consisting of a network of filaments and other structures of microbial origin. The culture-dependent and culture-independent investigations showed the presence of a complex microbiota composed mainly by fungal members, which demonstrated interesting properties related to lipids and lead processing. The formation of lead soaps and secondary biogenic minerals was also described.
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Affiliation(s)
- Katarína Šoltys
- Comenius University in Bratislava, Comenius University Science Park, Ilkovičova 8, Bratislava, 84104, Slovakia.,Faculty of Natural Sciences, Department of Molecular Biology, Comenius University in Bratislava, Mlynská dolina Ilkovičova 6, Bratislava, 84215, Slovakia
| | - Matej Planý
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, Bratislava, 84551, Slovakia
| | - Paola Biocca
- Department of Chemistry, Istituto centrale restauro conservazione patrimonio archivistico librario, Via Milano 76, 00184, Roma, Italy
| | - Valentina Vianello
- Department of Restoration, Istituto centrale restauro conservazione patrimonio archivistico librario, Via Milano 76, 00184, Roma, Italy
| | - Mária Bučková
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, Bratislava, 84551, Slovakia
| | - Andrea Puškárová
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, Bratislava, 84551, Slovakia
| | - Maria Carla Sclocchi
- Department of Biology, Istituto centrale restauro conservazione patrimonio archivistico librario, Via Milano 76, 00184, Roma, Italy
| | - Piero Colaizzi
- Department of Biology, Istituto centrale restauro conservazione patrimonio archivistico librario, Via Milano 76, 00184, Roma, Italy
| | - Marina Bicchieri
- Department of Chemistry, Istituto centrale restauro conservazione patrimonio archivistico librario, Via Milano 76, 00184, Roma, Italy
| | - Domenico Pangallo
- Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, Bratislava, 84551, Slovakia.,Caravella s.r.o., Tupolevova 2, Bratislava, 85101, Slovakia
| | - Flavia Pinzari
- Council for Agricultural Research and Economics, Research Centre for Agriculture and Environment, Via della Navicella 2-4, 00184, Rome, Italy.,Life Sciences Department, Natural History Museum, Cromwell Road, SW7 5BD, London, UK
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32
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Kettles GJ, Hofinger BJ, Hu P, Bayon C, Rudd JJ, Balmer D, Courbot M, Hammond-Kosack KE, Scalliet G, Kanyuka K. sRNA Profiling Combined With Gene Function Analysis Reveals a Lack of Evidence for Cross-Kingdom RNAi in the Wheat - Zymoseptoria tritici Pathosystem. FRONTIERS IN PLANT SCIENCE 2019; 10:892. [PMID: 31333714 PMCID: PMC6620828 DOI: 10.3389/fpls.2019.00892] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/21/2019] [Indexed: 05/19/2023]
Abstract
Cross-kingdom small RNA (sRNA) silencing has recently emerged as a mechanism facilitating fungal colonization and disease development. Here we characterized RNAi pathways in Zymoseptoria tritici, a major fungal pathogen of wheat, and assessed their contribution to pathogenesis. Computational analysis of fungal sRNA and host mRNA sequencing datasets was used to define the global sRNA populations in Z. tritici and predict their mRNA targets in wheat. 389 in planta-induced sRNA loci were identified. sRNAs generated from some of these loci were predicted to target wheat mRNAs including those potentially involved in pathogen defense. However, molecular approaches failed to validate targeting of selected wheat mRNAs by fungal sRNAs. Mutant strains of Z. tritici carrying deletions of genes encoding key components of RNAi such as Dicer-like (DCL) and Argonaute (AGO) proteins were generated, and virulence bioassays suggested that these are dispensable for full infection of wheat. Nonetheless, our results did suggest the existence of non-canonical DCL-independent pathway(s) for sRNA biogenesis in Z. tritici. dsRNA targeting essential fungal genes applied in vitro or generated from an RNA virus vector in planta in a procedure known as HIGS (Host-Induced Gene Silencing) was ineffective in preventing Z. tritici growth or disease. We also demonstrated that Z. tritici is incapable of dsRNA uptake. Collectively, our data suggest that RNAi approaches for gene function analyses in this fungal species and potentially also as a control measure may not be as effective as has been demonstrated for some other plant pathogenic fungi.
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Affiliation(s)
- Graeme J. Kettles
- Biointeractions and Crop Protection, Rothamsted Research, Harpenden, United Kingdom
| | - Bernhard J. Hofinger
- Biointeractions and Crop Protection, Rothamsted Research, Harpenden, United Kingdom
| | - Pingsha Hu
- Syngenta Biotechnology, Inc., Research Triangle Park, NC, United States
| | - Carlos Bayon
- Biointeractions and Crop Protection, Rothamsted Research, Harpenden, United Kingdom
| | - Jason J. Rudd
- Biointeractions and Crop Protection, Rothamsted Research, Harpenden, United Kingdom
| | - Dirk Balmer
- Syngenta Crop Protection AG, Stein, Switzerland
| | | | | | | | - Kostya Kanyuka
- Biointeractions and Crop Protection, Rothamsted Research, Harpenden, United Kingdom
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33
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Kay WT, Fones HN, Gurr SJ. Rapid loss of virulence during submergence of Z. tritici asexual spores. Fungal Genet Biol 2019; 128:14-19. [DOI: 10.1016/j.fgb.2019.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/08/2019] [Accepted: 03/08/2019] [Indexed: 11/28/2022]
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Chaloner TM, Fones HN, Varma V, Bebber DP, Gurr SJ. A new mechanistic model of weather-dependent Septoria tritici blotch disease risk. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180266. [PMID: 31056050 PMCID: PMC6553599 DOI: 10.1098/rstb.2018.0266] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2019] [Indexed: 12/31/2022] Open
Abstract
We present a new mechanistic model for predicting Septoria tritici blotch (STB) disease, parameterized with experimentally derived data for temperature- and wetness-dependent germination, growth and death of the causal agent, Zymoseptoria tritici. The output of this model (A) was compared with observed disease data for UK wheat over the period 2002-2016. In addition, we compared the output of a second model (B), in which experimentally derived parameters were replaced by a modified version of a published Z. tritici thermal performance equation, with the same observed disease data. Neither model predicted observed annual disease, but model A was able to differentiate UK regions with differing average disease risks over the entire period. The greatest limitations of both models are: broad spatial resolution of the climate data, and lack of host parameters. Model B is further limited by its lack of explicitly defined pathogen death, leading to a cumulative overestimation of disease over the course of the growing season. Comparison of models A and B demonstrates the importance of accounting for the temperature-dependency of pathogen processes important in the initiation and progression of disease. However, effective modelling of STB will probably require similar experimentally derived parameters for host and environmental factors, completing the disease triangle. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'. This issue is linked with the subsequent theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'.
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Affiliation(s)
| | | | | | | | - Sarah J. Gurr
- Department of Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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Haueisen J, Möller M, Eschenbrenner CJ, Grandaubert J, Seybold H, Adamiak H, Stukenbrock EH. Highly flexible infection programs in a specialized wheat pathogen. Ecol Evol 2019; 9:275-294. [PMID: 30680113 PMCID: PMC6342133 DOI: 10.1002/ece3.4724] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/21/2022] Open
Abstract
Many filamentous plant pathogens exhibit high levels of genomic variability, yet the impact of this variation on host-pathogen interactions is largely unknown. We have addressed host specialization in the wheat pathogen Zymoseptoria tritici. Our study builds on comparative analyses of infection and gene expression phenotypes of three isolates and reveals the extent to which genomic variation translates into phenotypic variation. The isolates exhibit genetic and genomic variation but are similarly virulent. By combining confocal microscopy, disease monitoring, staining of ROS, and comparative transcriptome analyses, we conducted a detailed comparison of the infection processes of these isolates in a susceptible wheat cultivar. We characterized four core infection stages: establishment, biotrophic growth, lifestyle transition, and necrotrophic growth and asexual reproduction that are shared by the three isolates. However, we demonstrate differentiated temporal and spatial infection development and significant differences in the expression profiles of the three isolates during the infection stages. More than 20% of the genes were differentially expressed and these genes were located significantly closer to transposable elements, suggesting an impact of epigenetic regulation. Further, differentially expressed genes were enriched in effector candidates suggesting that isolate-specific strategies for manipulating host defenses are present in Z. tritici. We demonstrate that individuals of a host-specialized pathogen have highly differentiated infection programs characterized by flexible infection development and functional redundancy. This illustrates how high genetic diversity in pathogen populations results in highly differentiated infection phenotypes, which fact needs to be acknowledged to understand host-pathogen interactions and pathogen evolution.
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Affiliation(s)
- Janine Haueisen
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Mareike Möller
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Christoph J. Eschenbrenner
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Jonathan Grandaubert
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Fungal Biology and PathogenicityInstitute PasteurParisFrance
| | - Heike Seybold
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Holger Adamiak
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Eva H. Stukenbrock
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
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36
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Suffert F, Delestre G, Gélisse S. Sexual Reproduction in the Fungal Foliar Pathogen Zymoseptoria tritici Is Driven by Antagonistic Density Dependence Mechanisms. MICROBIAL ECOLOGY 2019; 77:110-123. [PMID: 29876608 DOI: 10.1007/s00248-018-1211-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 05/22/2018] [Indexed: 05/13/2023]
Abstract
This study provides empirical evidence for antagonistic density dependence mechanisms driving sexual reproduction in the wheat fungal pathogen Zymoseptoria tritici. Biparental crosses with 12 increasing inoculum concentrations, in controlled conditions, showed that sexual reproduction in Z. tritici was impacted by an Allee effect due to mate limitation and a competition with asexual multiplication for resource allocation. The highest number of ascospores discharged was reached at intermediate inoculum concentrations (from 5 × 104 conidia mL-1 to 106 conidia mL-1). Consistent with these results for controlled co-inoculation, we found that the intensity of sexual reproduction varied with both cropping period and the vertical position of the host tissues in the field, with a maximum between 25 and 35 cm above the ground. An optimal lesion density (disease severity of 30 to 45%) maximizing offspring (ascospores) number was established, and its eco-evolutionary consequences are considered here. Two ecological mechanisms may be involved: competition for resources between the two modes of reproduction (decrease in the host resources available for sexual reproduction due to their prior use in asexual multiplication), and competitive disequilibrium between the two parental isolates, due to differential interaction dynamics with the host, for example, leading to an imbalance between mating types. A conceptual model based on these results suggests that sexual reproduction plays a key role in the evolution of pathogenicity traits, including virulence and aggressiveness. Ecological knowledge about the determinants of sexual reproduction in Z. tritici may, therefore, open up new perspectives for the management of other fungal foliar pathogens with dual modes of reproduction.
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Affiliation(s)
- Frédéric Suffert
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
| | - Ghislain Delestre
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France
| | - Sandrine Gélisse
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France
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Duba A, Goriewa-Duba K, Wachowska U. A Review of the Interactions between Wheat and Wheat Pathogens: Zymoseptoria tritici, Fusarium spp. and Parastagonospora nodorum. Int J Mol Sci 2018; 19:E1138. [PMID: 29642627 PMCID: PMC5979484 DOI: 10.3390/ijms19041138] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/24/2018] [Accepted: 04/06/2018] [Indexed: 12/11/2022] Open
Abstract
Zymoseptoria tritici is a hemibiotrophic pathogen which causes Septoria leaf blotch in wheat. The pathogenesis of the disease consists of a biotrophic phase and a necrotrophic phase. The pathogen infects the host plant by suppressing its immune response in the first stage of infection. Hemibiotrophic pathogens of the genus Fusarium cause Fusarium head blight, and the necrotrophic Parastagonosporanodorum is responsible for Septoria nodorum blotch in wheat. Cell wall-degrading enzymes in plants promote infections by necrotrophic and hemibiotrophic pathogens, and trichothecenes, secondary fungal metabolites, facilitate infections caused by fungi of the genus Fusarium. There are no sources of complete resistance to the above pathogens in wheat. Defense mechanisms in wheat are controlled by many genes encoding resistance traits. In the wheat genome, the characteristic features of loci responsible for resistance to pathogenic infections indicate that at least several dozen genes encode resistance to pathogens. The molecular interactions between wheat and Z. tritici, P. nodorum and Fusarium spp. pathogens have been insufficiently investigated. Most studies focus on the mechanisms by which the hemibiotrophic Z. tritici suppresses immune responses in plants and the role of mycotoxins and effector proteins in infections caused by P. nodorum and Fusarium spp. fungi. Trichothecene glycosylation and effector proteins, which are involved in defense responses in wheat, have been described at the molecular level. Recent advances in molecular biology have produced interesting findings which should be further elucidated in studies of molecular interactions between wheat and fungal pathogens. The Clustered Regularly-Interspaced Short Palindromic Repeats/ CRISPR associated (CRISPR/Cas) system can be used to introduce targeted mutations into the wheat genome and confer resistance to selected fungal diseases. Host-induced gene silencing and spray-induced gene silencing are also useful tools for analyzing wheat-pathogens interactions which can be used to develop new strategies for controlling fungal diseases.
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Affiliation(s)
- Adrian Duba
- Department of Entomology, Phytopathology and Molecular Diagnostics, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 17, 10-719 Olsztyn, Poland.
| | - Klaudia Goriewa-Duba
- Department of Plant Breeding and Seed Production, University of Warmia and Mazury in Olsztyn, pl. Łódzki 3, 10-724 Olsztyn, Poland.
| | - Urszula Wachowska
- Department of Entomology, Phytopathology and Molecular Diagnostics, University of Warmia and Mazury in Olsztyn, Prawocheńskiego 17, 10-719 Olsztyn, Poland.
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38
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Lopez D, Ribeiro S, Label P, Fumanal B, Venisse JS, Kohler A, de Oliveira RR, Labutti K, Lipzen A, Lail K, Bauer D, Ohm RA, Barry KW, Spatafora J, Grigoriev IV, Martin FM, Pujade-Renaud V. Genome-Wide Analysis of Corynespora cassiicola Leaf Fall Disease Putative Effectors. Front Microbiol 2018; 9:276. [PMID: 29551995 PMCID: PMC5840194 DOI: 10.3389/fmicb.2018.00276] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 02/07/2018] [Indexed: 12/26/2022] Open
Abstract
Corynespora cassiicola is an Ascomycetes fungus with a broad host range and diverse life styles. Mostly known as a necrotrophic plant pathogen, it has also been associated with rare cases of human infection. In the rubber tree, this fungus causes the Corynespora leaf fall (CLF) disease, which increasingly affects natural rubber production in Asia and Africa. It has also been found as an endophyte in South American rubber plantations where no CLF outbreak has yet occurred. The C. cassiicola species is genetically highly diverse, but no clear relationship has been evidenced between phylogenetic lineage and pathogenicity. Cassiicolin, a small glycosylated secreted protein effector, is thought to be involved in the necrotrophic interaction with the rubber tree but some virulent C. cassiicola isolates do not have a cassiicolin gene. This study set out to identify other putative effectors involved in CLF. The genome of a highly virulent C. cassiicola isolate from the rubber tree (CCP) was sequenced and assembled. In silico prediction revealed 2870 putative effectors, comprising CAZymes, lipases, peptidases, secreted proteins and enzymes associated with secondary metabolism. Comparison with the genomes of 44 other fungal species, focusing on effector content, revealed a striking proximity with phylogenetically unrelated species (Colletotrichum acutatum, Colletotrichum gloesporioides, Fusarium oxysporum, nectria hematococca, and Botrosphaeria dothidea) sharing life style plasticity and broad host range. Candidate effectors involved in the compatible interaction with the rubber tree were identified by transcriptomic analysis. Differentially expressed genes included 92 putative effectors, among which cassiicolin and two other secreted singleton proteins. Finally, the genomes of 35 C. cassiicola isolates representing the genetic diversity of the species were sequenced and assembled, and putative effectors identified. At the intraspecific level, effector-based classification was found to be highly consistent with the phylogenomic trees. Identification of lineage-specific effectors is a key step toward understanding C. cassiicola virulence and host specialization mechanisms.
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Affiliation(s)
- David Lopez
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France
| | - Sébastien Ribeiro
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France.,CIRAD, UMR AGAP, Clermont-Ferrand, France.,AGAP, Université Montpellier, CIRAD, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
| | - Philippe Label
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France
| | - Boris Fumanal
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France
| | - Jean-Stéphane Venisse
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France
| | - Annegret Kohler
- Institut National de la Recherche Agronomique, UMR INRA-Université de Lorraine "Interaction Arbres/Microorganismes", Champenoux, France
| | | | - Kurt Labutti
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Anna Lipzen
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Kathleen Lail
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Diane Bauer
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Robin A Ohm
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States.,Department of Microbiology, Utrecht University, Utrecht, Netherlands
| | - Kerrie W Barry
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States
| | - Joseph Spatafora
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Igor V Grigoriev
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, United States.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Francis M Martin
- Institut National de la Recherche Agronomique, UMR INRA-Université de Lorraine "Interaction Arbres/Microorganismes", Champenoux, France
| | - Valérie Pujade-Renaud
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, UMR PIAF, Clermont-Ferrand, France.,CIRAD, UMR AGAP, Clermont-Ferrand, France.,AGAP, Université Montpellier, CIRAD, Institut National de la Recherche Agronomique, Montpellier SupAgro, Montpellier, France
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