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Sun J, Zhao J, Liu M, Li J, Cheng J, Li W, Yuan M, Xiao S, Xue C. SreC-dependent adaption to host iron environments regulates the transition of trophic stages and developmental processes of Curvularia lunata. MOLECULAR PLANT PATHOLOGY 2024; 25:e13444. [PMID: 38481338 PMCID: PMC10938068 DOI: 10.1111/mpp.13444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/17/2024]
Abstract
Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism of plant pathogens rapidly adapting to the dynamic host iron environments to assimilate iron for invasion and colonization remains largely unexplored. Here, we found that the GATA transcription factor SreC in Curvularia lunata is required for virulence and adaption to the host iron excess environment. SreC directly binds to the ATGWGATAW element in an iron-dependent manner to regulate the switch between different iron assimilation pathways, conferring adaption to host iron environments in different trophic stages of C. lunata. SreC also regulates the transition of trophic stages and developmental processes in C. lunata. SreC-dependent adaption to host iron environments is essential to the infectious growth and survival of C. lunata. We also demonstrate that CgSreA (a SreC orthologue) plays a similar role in Colletotrichum graminicola. We conclude that Sre mediates adaption to the host iron environment during infection, and the function is conserved in hemibiotrophic fungi.
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Affiliation(s)
- Jiaying Sun
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Jiamei Zhao
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Miaomiao Liu
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Jiayang Li
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Jie Cheng
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Wenling Li
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Mingyue Yuan
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
- Section of Microbial Ecology, Department of BiologyLund UniversityLundSweden
| | - Shuqin Xiao
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
| | - Chunsheng Xue
- College of Plant ProtectionShenyang Agriculture UniversityShenyangChina
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2
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Yu H, Zhang J, Fan J, Jia W, Lv Y, Pan H, Zhang X. Infection-specific transcriptional patterns of the maize pathogen Cochliobolus heterostrophus unravel genes involved in asexual development and virulence. MOLECULAR PLANT PATHOLOGY 2024; 25:e13413. [PMID: 38279855 PMCID: PMC10775821 DOI: 10.1111/mpp.13413] [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: 08/02/2023] [Revised: 11/24/2023] [Accepted: 12/10/2023] [Indexed: 01/29/2024]
Abstract
Southern corn leaf blight (SCLB) caused by Cochliobolus heterostrophus is a destructive disease that threatens global maize (Zea mays) production. Despite many studies being conducted, very little is known about molecular processes employed by the pathogen during infection. There is a need to understand the fungal arms strategy and identify novel functional genes as targets for fungicide development. Transcriptome analysis based on RNA sequencing was carried out across conidia germination and host infection by C. heterostrophus. The present study revealed major changes in C. heterostrophus gene expression during host infection. Several differentially expressed genes (DEGs) induced during C. heterostrophus infection could be involved in the biosynthesis of secondary metabolites, peroxisome, energy metabolism, amino acid degradation and oxidative phosphorylation. In addition, histone acetyltransferase, secreted proteins, peroxisomal proteins, NADPH oxidase and transcription factors were selected for further functional validation. Here, we demonstrated that histone acetyltransferases (Hat2 and Rtt109), secreted proteins (Cel61A and Mep1), peroxisomal proteins (Pex11A and Pex14), NADPH oxidases (NoxA, NoxD and NoxR) and transcription factors (Crz1 and MtfA) play essential roles in C. heterostrophus conidiation, stress adaption and virulence. Taken together, our study revealed major changes in gene expression associated with C. heterostrophus infection and identified a diverse repertoire of genes critical for successful infection.
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Affiliation(s)
- Huilin Yu
- College of Plant ScienceJilin UniversityChangchunChina
| | - Jiyue Zhang
- College of Plant ScienceJilin UniversityChangchunChina
| | - Jinyu Fan
- College of Plant ScienceJilin UniversityChangchunChina
| | - Wantong Jia
- College of Plant ScienceJilin UniversityChangchunChina
| | - Yanan Lv
- College of Plant ScienceJilin UniversityChangchunChina
| | - Hongyu Pan
- College of Plant ScienceJilin UniversityChangchunChina
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3
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Potenciano da Silva KL, Moraes D, Lechner B, Lindner H, Haas H, Almeida Soares CM, Silva-Bailão MG, Bailão AM. Fonsecaea pedrosoi produces ferricrocin and can utilize different host iron sources. Fungal Biol 2023; 127:1512-1523. [PMID: 38097325 DOI: 10.1016/j.funbio.2023.07.002] [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: 02/01/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 12/18/2023]
Abstract
The survival of living organisms depends on iron, one of the most abundant metals in the Earth's crust. Nevertheless, this micronutrient is poorly available in our aerobic atmosphere as well as inside the mammalian host. This problem is circumvented by the expression of high affinity iron uptake machineries, including the production of siderophores, in pathogenic fungi. Here we demonstrated that F. pedrosoi, the causative agent of the neglected tropical disease chromoblastomycosis, presents gene clusters for siderophore production. In addition, ten putative siderophore transporters were identified. Those genes are upregulated under iron starvation, a condition that induces the secretion of hydroxamates, as revealed by chrome azurol S assays. RP-HPLC and mass spectrometry analysis allowed the identification of ferricrocin as an intra- and extracellular siderophore. F. pedrosoi can grow in different iron sources, including the bacterial ferrioxamine B and the host proteins ferritin, hemoglobin and holotransferrin. Of note, addition of hemoglobin, lactoferrin and holotransferrin to the growth medium of macrophages infected with F. pedrosoi enhanced significantly fungal survival. The ability to produce siderophores in iron limited conditions added to the versatility to utilize different sources of iron are strategies that certainly may contribute to fungal survival inside the host.
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Affiliation(s)
| | - Dayane Moraes
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Beatrix Lechner
- Institute of Molecular Biology/ Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | - Herbert Lindner
- Institute of Medical Biochemistry/Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | - Hubertus Haas
- Institute of Molecular Biology/ Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | | | | | - Alexandre Melo Bailão
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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Sun K, Li Y, Gai Y, Wang J, Jian Y, Liu X, Wu L, Shim WB, Lee YW, Ma Z, Haas H, Yin Y. HapX-mediated H2B deub1 and SreA-mediated H2A.Z deposition coordinate in fungal iron resistance. Nucleic Acids Res 2023; 51:10238-10260. [PMID: 37650633 PMCID: PMC10602907 DOI: 10.1093/nar/gkad708] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 07/26/2023] [Accepted: 08/15/2023] [Indexed: 09/01/2023] Open
Abstract
Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism through which pathogens counteract iron stress is unclear. Here, we found that Fusarium graminearum encounters iron excess during the colonization of wheat heads. Deletion of heme activator protein X (FgHapX), siderophore transcription factor A (FgSreA) or both attenuated virulence. Further, we found that FgHapX activates iron storage under iron excess by promoting histone H2B deubiquitination (H2B deub1) at the promoter of the responsible gene. Meanwhile, FgSreA is shown to inhibit genes mediating iron acquisition during iron excess by facilitating the deposition of histone variant H2A.Z and histone 3 lysine 27 trimethylation (H3K27 me3) at the first nucleosome after the transcription start site. In addition, the monothiol glutaredoxin FgGrx4 is responsible for iron sensing and control of the transcriptional activity of FgHapX and FgSreA via modulation of their enrichment at target genes and recruitment of epigenetic regulators, respectively. Taken together, our findings elucidated the molecular mechanisms for adaptation to iron excess mediated by FgHapX and FgSreA during infection in F. graminearum and provide novel insights into regulation of iron homeostasis at the chromatin level in eukaryotes.
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Affiliation(s)
- Kewei Sun
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yiqing Li
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yunpeng Gai
- School of Grassland Science, Beijing Forestry University, Beijing, China
| | - Jingrui Wang
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yunqing Jian
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xin Liu
- Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Liang Wu
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, USA
| | - Yin-Won Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Hubertus Haas
- Instiute of Molecular Biology, Biocenter, Medical University Innsbruck, Innsbruck A-6020, Austria
| | - Yanni Yin
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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Bailão AM, Silva KLPD, Moraes D, Lechner B, Lindner H, Haas H, Soares CMA, Silva-Bailão MG. Iron Starvation Induces Ferricrocin Production and the Reductive Iron Acquisition System in the Chromoblastomycosis Agent Cladophialophora carrionii. J Fungi (Basel) 2023; 9:727. [PMID: 37504717 PMCID: PMC10382037 DOI: 10.3390/jof9070727] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023] Open
Abstract
Iron is a micronutrient required by almost all living organisms. Despite being essential, the availability of this metal is low in aerobic environments. Additionally, mammalian hosts evolved strategies to restrict iron from invading microorganisms. In this scenario, the survival of pathogenic fungi depends on high-affinity iron uptake mechanisms. Here, we show that the production of siderophores and the reductive iron acquisition system (RIA) are employed by Cladophialophora carrionii under iron restriction. This black fungus is one of the causative agents of chromoblastomycosis, a neglected subcutaneous tropical disease. Siderophore biosynthesis genes are arranged in clusters and, interestingly, two RIA systems are present in the genome. Orthologs of putative siderophore transporters were identified as well. Iron starvation regulates the expression of genes related to both siderophore production and RIA systems, as well as of two transcription factors that regulate iron homeostasis in fungi. A chrome azurol S assay demonstrated the secretion of hydroxamate-type siderophores, which were further identified via RP-HPLC and mass spectrometry as ferricrocin. An analysis of cell extracts also revealed ferricrocin as an intracellular siderophore. The presence of active high-affinity iron acquisition systems may surely contribute to fungal survival during infection.
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Affiliation(s)
- Alexandre Melo Bailão
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia 74690-900, Brazil
| | | | - Dayane Moraes
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia 74690-900, Brazil
| | - Beatrix Lechner
- Institute of Molecular Biology/Biocenter, Medical University of Innsbruck, 795J+RF Innsbruck, Austria
| | - Herbert Lindner
- Institute of Medical Biochemistry/Biocenter, Medical University of Innsbruck, 795J+RF Innsbruck, Austria
| | - Hubertus Haas
- Institute of Molecular Biology/Biocenter, Medical University of Innsbruck, 795J+RF Innsbruck, Austria
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6
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Wu JJ, Wu PC, Yago JI, Chung KR. The Regulatory Hub of Siderophore Biosynthesis in the Phytopathogenic Fungus Alternaria alternata. J Fungi (Basel) 2023; 9:jof9040427. [PMID: 37108881 PMCID: PMC10146468 DOI: 10.3390/jof9040427] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
A GATA zinc finger-containing repressor (AaSreA) suppresses siderophore biosynthesis in the phytopathogenic fungus Alternaria alternata under iron-replete conditions. In this study, targeted gene deletion revealed two bZIP-containing transcription factors (AaHapX and AaAtf1) and three CCAAT-binding proteins (AaHapB, AaHapC, and AaHapE) that positively regulate gene expression in siderophore production. This is a novel phenotype regarding Atf1 and siderophore biosynthesis. Quantitative RT-PCR analyses revealed that only AaHapX and AaSreA were regulated by iron. AaSreA and AaHapX form a transcriptional feedback negative loop to regulate iron acquisition in response to the availability of environmental iron. Under iron-limited conditions, AaAtf1 enhanced the expression of AaNps6, thus playing a positive role in siderophore production. However, under nutrient-rich conditions, AaAtf1 plays a negative role in resistance to sugar-induced osmotic stress, and AaHapX plays a negative role in resistance to salt-induced osmotic stress. Virulence assays performed on detached citrus leaves revealed that AaHapX and AaAtf1 play no role in fungal pathogenicity. However, fungal strains carrying the AaHapB, AaHapC, or AaHapE deletion failed to incite necrotic lesions, likely due to severe growth deficiency. Our results revealed that siderophore biosynthesis and iron homeostasis are regulated by a well-organized network in A. alternata.
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7
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Comparative genomic analysis reveals cellulase plays an important role in the pathogenicity of Setosphaeria turcica f. sp. zeae. Fungal Biol 2022. [DOI: 10.1016/j.funbio.2022.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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John E, Singh KB, Oliver RP, Tan K. Transcription factor control of virulence in phytopathogenic fungi. MOLECULAR PLANT PATHOLOGY 2021; 22:858-881. [PMID: 33973705 PMCID: PMC8232033 DOI: 10.1111/mpp.13056] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 05/12/2023]
Abstract
Plant-pathogenic fungi are a significant threat to economic and food security worldwide. Novel protection strategies are required and therefore it is critical we understand the mechanisms by which these pathogens cause disease. Virulence factors and pathogenicity genes have been identified, but in many cases their roles remain elusive. It is becoming increasingly clear that gene regulation is vital to enable plant infection and transcription factors play an essential role. Efforts to determine their regulatory functions in plant-pathogenic fungi have expanded since the annotation of fungal genomes revealed the ubiquity of transcription factors from a broad range of families. This review establishes the significance of transcription factors as regulatory elements in plant-pathogenic fungi and provides a systematic overview of those that have been functionally characterized. Detailed analysis is provided on regulators from well-characterized families controlling various aspects of fungal metabolism, development, stress tolerance, and the production of virulence factors such as effectors and secondary metabolites. This covers conserved transcription factors with either specialized or nonspecialized roles, as well as recently identified regulators targeting key virulence pathways. Fundamental knowledge of transcription factor regulation in plant-pathogenic fungi provides avenues to identify novel virulence factors and improve our understanding of the regulatory networks linked to pathogen evolution, while transcription factors can themselves be specifically targeted for disease control. Areas requiring further insight regarding the molecular mechanisms and/or specific classes of transcription factors are identified, and direction for future investigation is presented.
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Affiliation(s)
- Evan John
- Centre for Crop and Disease ManagementCurtin UniversityBentleyWestern AustraliaAustralia
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| | - Karam B. Singh
- Agriculture and FoodCommonwealth Scientific and Industrial Research OrganisationFloreatWestern AustraliaAustralia
| | - Richard P. Oliver
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
| | - Kar‐Chun Tan
- Centre for Crop and Disease ManagementCurtin UniversityBentleyWestern AustraliaAustralia
- School of Molecular and Life SciencesCurtin UniversityBentleyWestern AustraliaAustralia
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9
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Jung WH, Sánchez-León E, Kronstad JW. Coordinated regulation of iron metabolism in Cryptococcus neoformans by GATA and CCAAT transcription factors: connections with virulence. Curr Genet 2021; 67:583-593. [PMID: 33760942 DOI: 10.1007/s00294-021-01172-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 10/21/2022]
Abstract
Iron acquisition is critical for pathogenic fungi to adapt to and survive within the host environment. However, to same extent, the fungi must also avoid the detrimental effects caused by excess iron. The importance of iron has been demonstrated for the physiology and virulence of major fungal pathogens of humans including Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans. In particular, numerous studies have revealed that aspects of iron acquisition, metabolism, and homeostasis in the fungal pathogens are tightly controlled by conserved transcriptional regulators including a GATA-type iron transcription factor and the CCAAT-binding complex (CBC)/HapX orthologous protein complex. However, the specific downstream regulatory networks are slightly different in each fungus. In addition, roles have been proposed or demonstrated for other factors including monothiol glutaredoxins, BolA-like proteins, and Fe-S cluster incorporation on the GATA-type iron transcription factor and the CBC/HapX orthologous protein complex, although limited information is available. Here we focus on recent work on C. neoformans in the context of an emerging framework for fungal regulation of iron acquisition, metabolism, and homeostasis. Our specific goal is to summarize recent findings on transcriptional networks governed by the iron regulators Cir1 and HapX in C. neoformans.
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Affiliation(s)
- Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 17546, Korea.
| | - Eddy Sánchez-León
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - James W Kronstad
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
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Misslinger M, Hortschansky P, Brakhage AA, Haas H. Fungal iron homeostasis with a focus on Aspergillus fumigatus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118885. [PMID: 33045305 DOI: 10.1016/j.bbamcr.2020.118885] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/15/2020] [Accepted: 10/01/2020] [Indexed: 02/08/2023]
Abstract
To maintain iron homeostasis, fungi have to balance iron acquisition, storage, and utilization to ensure sufficient supply and to avoid toxic excess of this essential trace element. As pathogens usually encounter iron limitation in the host niche, this metal plays a particular role during virulence. Siderophores are iron-chelators synthesized by most, but not all fungal species to sequester iron extra- and intracellularly. In recent years, the facultative human pathogen Aspergillus fumigatus has become a model for fungal iron homeostasis of siderophore-producing fungal species. This article summarizes the knowledge on fungal iron homeostasis and its links to virulence with a focus on A. fumigatus. It covers mechanisms for iron acquisition, storage, and detoxification, as well as the modes of transcriptional iron regulation and iron sensing in A. fumigatus in comparison to other fungal species. Moreover, potential translational applications of the peculiarities of fungal iron metabolism for treatment and diagnosis of fungal infections is addressed.
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Affiliation(s)
- Matthias Misslinger
- Institute of Molecular Biology - Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Peter Hortschansky
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Jena, Germany; Department Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Hubertus Haas
- Institute of Molecular Biology - Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
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The siderophore repressor SreA maintains growth, hydrogen peroxide resistance, and cell wall integrity in the phytopathogenic fungus Alternaria alternata. Fungal Genet Biol 2020; 139:103384. [PMID: 32278718 DOI: 10.1016/j.fgb.2020.103384] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 01/18/2023]
Abstract
The siderophore-mediated iron uptake machinery is required by the tangerine pathotype of Alternaria alternata to colonize host plants. The present study reports the functions of the GATA-type transcription regulator SreA by analyzing loss- and gain-of-function mutants. The expression of sreA is transiently upregulated by excess iron. The sreA deficiency mutant (ΔsreA) shows severe growth defect but produces ACT toxin and incites necrotic lesions on citrus leaves as efficiently as wild type. SreA suppresses the expression of genes encoding polypeptides required for siderophore biosynthesis and transport under iron-replete conditions. Under iron-replete conditions, SreA impacts the expression of the genes encoding the NADPH oxidase complex involved in H2O2 production. SreA negatively impacts H2O2 resistance as ΔsreA increases resistance to H2O2. However, sreA deficiency has no effects on the expression of genes encoding several key factors (Yap1, Hog1, and Skn7) involved in oxidative stress resistance. ΔsreA increases resistance to calcofluor white and Congo red, which may suggest a role of SreA in the maintenance of cell wall integrity. Those are novel phenotypes associated with fungal sreA. Overall, our results indicate that SreA is required to protect fungal cells from cytotoxicity caused by excess iron. The results also highlight the regulatory functions of SreA and provide insights into the critical role of siderophore-mediated iron homeostasis in resistance to oxidative stress in A. alternata.
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12
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Yu M, Yu J, Cao H, Yong M, Liu Y. Genome-wide identification and analysis of the GATA transcription factor gene family in Ustilaginoidea virens. Genome 2019; 62:807-816. [PMID: 31437416 DOI: 10.1139/gen-2018-0190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In filamentous fungi, the conserved transcription factors play important roles in multiple cellular and developmental processes. The GATA proteins, a family of GATA-binding zinc finger transcription factors, play diverse functions in fungi. Ustilaginoidea virens is an economically important pathogen-causing rice false smut worldwide. To gain additional insight into the cellular and molecular mechanisms of this pathogen, in this study, we identified and functionally characterized seven GATA proteins from the U. virens genome (UvGATA). Sequences analysis indicated that these GATA proteins are divided into seven clades. The proteins in each clade contained conserved clade-specific sequences and structures, thus leading to the same motif serving different purposes in various contexts. The expression profiles of UvGATA genes at different infection stages and under H2O2 stress were detected. Results showed that the majority of UvGATA genes performed functions at both processes, thereby confirming the roles of these genes in pathogenicity and reactive oxygen species stress tolerance. This study provided an important starting point to further explore the biological functions of UvGATA genes and increased our understanding of their potential transcriptional regulatory mechanisms in U. virens.
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Affiliation(s)
- Mina Yu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.,Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Junjie Yu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.,Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Huijuan Cao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.,Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Mingli Yong
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.,Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
| | - Yongfeng Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China.,Institute of Plant Protection, Jiangsu Academy of Agricultural Science, Nanjing 210014, China
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13
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Simaan H, Lev S, Horwitz BA. Oxidant-Sensing Pathways in the Responses of Fungal Pathogens to Chemical Stress Signals. Front Microbiol 2019; 10:567. [PMID: 30941117 PMCID: PMC6433817 DOI: 10.3389/fmicb.2019.00567] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/05/2019] [Indexed: 12/04/2022] Open
Abstract
Host defenses expose fungal pathogens to oxidants and antimicrobial chemicals. The fungal cell employs conserved eukaryotic signaling pathways and dedicated transcription factors to program its response to these stresses. The oxidant-sensitive transcription factor of yeast, YAP1, and its orthologs in filamentous fungi, are central to tolerance to oxidative stress. The C-terminal domain of YAP1 contains cysteine residues that, under oxidizing conditions, form an intramolecular disulfide bridge locking the molecule in a conformation where the nuclear export sequence is masked. YAP1 accumulates in the nucleus, promoting transcription of genes that provide the cell with the ability to counteract oxidative stress. Chemicals including xenobiotics and plant signals can also promote YAP1 nuclearization in yeast and filamentous fungi. This could happen via direct or indirect oxidative stress, or by a different biochemical pathway. Plant phenolics are known antioxidants, yet they have been shown to elicit cellular responses that would usually be triggered to counter oxidant stress. Here we will discuss the evidence that YAP1 and MAPK pathways respond to phenolic compounds. Following this and other examples, we explore here how oxidative-stress sensing networks of fungi might have evolved to detect chemical stressors. Furthermore, we draw functional parallels between fungal YAP1 and mammalian Keap1-Nrf2 signaling systems.
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Affiliation(s)
- Hiba Simaan
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
| | - Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Benjamin A Horwitz
- Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel
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Zainudin NAIM, Condon B, De Bruyne L, Van Poucke C, Bi Q, Li W, Höfte M, Turgeon BG. Virulence, Host-Selective Toxin Production, and Development of Three Cochliobolus Phytopathogens Lacking the Sfp-Type 4'-Phosphopantetheinyl Transferase Ppt1. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:1130-1141. [PMID: 26168137 DOI: 10.1094/mpmi-03-15-0068-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The Sfp-type 4'-phosphopantetheinyl transferase Ppt1 is required for activation of nonribosomal peptide synthetases, including α-aminoadipate reductase (AAR) for lysine biosynthesis and polyketide synthases, enzymes that biosynthesize peptide and polyketide secondary metabolites, respectively. Deletion of the PPT1 gene, from the maize pathogen Cochliobolus heterostrophus and the rice pathogen Cochliobolus miyabeanus, yielded strains that were significantly reduced in virulence to their hosts. In addition, ppt1 mutants of C. heterostrophus race T and Cochliobolus victoriae were unable to biosynthesize the host-selective toxins (HST) T-toxin and victorin, respectively, as judged by bioassays. Interestingly, ppt1 mutants of C. miyabeanus were shown to produce tenfold higher levels of the sesterterpene-type non-HST ophiobolin A, as compared with the wild-type strain. The ppt1 strains of all species were also reduced in tolerance to oxidative stress and iron depletion; both phenotypes are associated with inability to produce extracellular siderophores biosynthesized by the nonribosomal peptide synthetase Nps6. Colony surfaces were hydrophilic, a trait previously associated with absence of C. heterostrophus Nps4. Mutants were decreased in asexual sporulation and C. heterostrophus strains were female-sterile in sexual crosses; the latter phenotype was observed previously with mutants lacking Nps2, which produces an intracellular siderophore. As expected, mutants were albino, since they cannot produce the polyketide melanin and were auxotrophic for lysine because they lack an AAR.
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Affiliation(s)
- Nur Ain Izzati Mohd Zainudin
- 1 Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
- 2 Department of Biology, Faculty of Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Bradford Condon
- 1 Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Lieselotte De Bruyne
- 3 Department of Crop Protection, Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Christof Van Poucke
- 4 Department of Bioanalysis, Laboratory of Food Analysis, Faculty of Pharmaceutical Sciences, Ghent University; and
| | - Qing Bi
- 1 Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
| | - Wei Li
- 1 Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
- 5 Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, P.R. China
| | - Monica Höfte
- 3 Department of Crop Protection, Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - B Gillian Turgeon
- 1 Section of Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, U.S.A
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Giuliano Garisto Donzelli B, Gibson DM, Krasnoff SB. Intracellular siderophore but not extracellular siderophore is required for full virulence in Metarhizium robertsii. Fungal Genet Biol 2015; 82:56-68. [PMID: 26135511 DOI: 10.1016/j.fgb.2015.06.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/26/2015] [Accepted: 06/27/2015] [Indexed: 10/23/2022]
Abstract
Efficient iron acquisition mechanisms are fundamental for microbial survival in the environment and for pathogen virulence within their hosts. M. robertsii produces two known iron-binding natural products: metachelins, which are used to scavenge extracellular iron, and ferricrocin, which is strictly intracellular. To study the contribution of siderophore-mediated iron uptake and storage to M. robertsii fitness, we generated null mutants for each siderophore synthase gene (mrsidD and mrsidC, respectively), as well as for the iron uptake transcriptional repressor mrsreA. All of these mutants showed impaired germination speed, differential sensitivity to hydrogen peroxide, and differential ability to overcome iron chelation on growth-limiting iron concentrations. RT-qPCR data supported regulation of mrsreA, mrsidC, and mrsidD by supplied iron in vitro and during growth within the insect host, Spodoptera exigua. We also observed strong upregulation of the insect iron-binding proteins, transferrins, during infection. Insect bioassays revealed that ferricrocin is required for full virulence against S. exigua; neither the loss of metachelin production nor the deletion of the transcription factor mrsreA significantly affected M. robertsii virulence.
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Affiliation(s)
- Bruno Giuliano Garisto Donzelli
- School of Integrative Plant Science - Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853, United States.
| | - Donna M Gibson
- USDA ARS, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, NY 14853, United States
| | - Stuart B Krasnoff
- USDA ARS, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, NY 14853, United States
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Sheridan KJ, Dolan SK, Doyle S. Endogenous cross-talk of fungal metabolites. Front Microbiol 2015; 5:732. [PMID: 25601857 PMCID: PMC4283610 DOI: 10.3389/fmicb.2014.00732] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 12/04/2014] [Indexed: 12/21/2022] Open
Abstract
Non-ribosomal peptide (NRP) synthesis in fungi requires a ready supply of proteogenic and non-proteogenic amino acids which are subsequently incorporated into the nascent NRP via a thiotemplate mechanism catalyzed by NRP synthetases. Substrate amino acids can be modified prior to or during incorporation into the NRP, or following incorporation into an early stage amino acid-containing biosynthetic intermediate. These post-incorporation modifications involve a range of additional enzymatic activities including but not exclusively, monooxygenases, methyltransferases, epimerases, oxidoreductases, and glutathione S-transferases which are essential to effect biosynthesis of the final NRP. Likewise, polyketide biosynthesis is directly by polyketide synthase megaenzymes and cluster-encoded ancillary decorating enzymes. Additionally, a suite of additional primary metabolites, for example: coenzyme A (CoA), acetyl CoA, S-adenosylmethionine, glutathione (GSH), NADPH, malonyl CoA, and molecular oxygen, amongst others are required for NRP and polyketide synthesis (PKS). Clearly these processes must involve exquisite orchestration to facilitate the simultaneous biosynthesis of different types of NRPs, polyketides, and related metabolites requiring identical or similar biosynthetic precursors or co-factors. Moreover, the near identical structures of many natural products within a given family (e.g., ergot alkaloids), along with localization to similar regions within fungi (e.g., conidia) suggests that cross-talk may exist, in terms of biosynthesis and functionality. Finally, we speculate if certain biosynthetic steps involved in NRP and PKS play a role in cellular protection or environmental adaptation, and wonder if these enzymatic reactions are of equivalent importance to the actual biosynthesis of the final metabolite.
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Affiliation(s)
| | - Stephen K Dolan
- Department of Biology, Maynooth University Maynooth, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University Maynooth, Ireland
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Abstract
Siderophores are chelators synthesized by microbes to sequester iron. This article summarizes the knowledge on the fungal siderophore metabolism with a focus on Aspergillus fumigatus. In recent years, A. fumigatus became a role model for fungal biosynthesis, uptake and degradation of siderophores as well as regulation of siderophore-mediated iron handling and the elucidation of siderophore functions. Siderophore functions comprise uptake, intracellular transport and storage of iron. This proved to be crucial not only for adaptation to iron starvation conditions but also for germination, asexual and sexual propagation, antioxidative defense, mutual interaction, microbial competition as well as virulence in plant and animal hosts. Recent studies also indicate the high potential of siderophores and its biosynthetic pathway to improve diagnosis and therapy of fungal infections.
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Affiliation(s)
- Hubertus Haas
- Division of Molecular Biology/Biocenter, Innsbruck Medical University, Innrain 80-82, A-6020 Innsbruck, Austria.
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Condon BJ, Oide S, Gibson DM, Krasnoff SB, Turgeon BG. Reductive iron assimilation and intracellular siderophores assist extracellular siderophore-driven iron homeostasis and virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:793-808. [PMID: 24762221 DOI: 10.1094/mpmi-11-13-0328-r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Iron is an essential nutrient and prudent iron acquisition and management are key traits of a successful pathogen. Fungi use nonribosomally synthesized secreted iron chelators (siderophores) or reductive iron assimilation (RIA) mechanisms to acquire iron in a high affinity manner. Previous studies with the maize pathogen Cochliobolus heterostrophus identified two genes, NPS2 and NPS6, encoding different nonribosomal peptide synthetases responsible for biosynthesis of intra- and extracellular siderophores, respectively. Deletion of NPS6 results in loss of extracellular siderophore biosynthesis, attenuated virulence, hypersensitivity to oxidative and iron-depletion stress, and reduced asexual sporulation, while nps2 mutants are phenotypically wild type in all of these traits but defective in sexual spore development when NPS2 is missing from both mating partners. Here, it is reported that nps2nps6 mutants have more severe phenotypes than both nps2 and nps6 single mutants. In contrast, mutants lacking the FTR1 or FET3 genes encoding the permease and ferroxidase components, respectively, of the alternate RIA system, are like wild type in all of the above phenotypes. However, without supplemental iron, combinatorial nps6ftr1 and nps2nps6ftr1 mutants are less virulent, are reduced in growth, and are less able to combat oxidative stress and to sporulate asexually, compared with nps6 mutants alone. These findings demonstrate that, while the role of RIA in metabolism and virulence is overshadowed by that of extracellular siderophores as a high-affinity iron acquisition mechanism in C. heterostrophus, it functions as a critical backup for the fungus.
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Rodríguez-Decuadro S, Silva P, Bentancur O, Gamba F, Pritsch C. Histochemical characterization of early response to Cochliobolus sativus infection in selected barley genotypes. PHYTOPATHOLOGY 2014; 104:715-23. [PMID: 24521486 DOI: 10.1094/phyto-05-13-0133-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Much effort is being made to breed barley with durable resistance to leaf spot blotch incited by Bipolaris sorokiniana (teleomorph: Cochliobolus sativus). We hypothesized that susceptibility and resistance traits in 11 diverse barley genotypes inoculated with a single C. sativus isolate might specify a range of distinct host cell responses. Quantitative descriptions of interaction microphenotypes exhibited by different barley genotype seedlings after infection with C. sativus are provided. Early oxidative responses occurring in epidermis and mesophyll leaf tissue were monitored by histochemical analysis of H2O2 accumulation at 8, 24, and 48 h after inoculation. Cell wall apposition (CWA) in epidermal cells and hypersensitive reaction (HR) of epidermal or mesophyll tissue were early defenses in both resistant and susceptible genotypes. There were differences in level, duration, and frequency of occurrence for CWA and HR for the different barley genotypes. Occurrence of HR in epidermal cells at post-penetration stages was indicative of compatibility. Patterns of cell responses were microphenotypically diverse between different resistant and susceptible genotypes. This suggests that timing and level of response are key features of microphenotypic diversity that distinguish different functional mechanisms of resistance and susceptibility present in barley.
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Shalaby S, Larkov O, Lamdan NL, Horwitz BA. Genetic interaction of the stress response factors ChAP1 and Skn7 in the maize pathogen Cochliobolus heterostrophus. FEMS Microbiol Lett 2013; 350:83-9. [PMID: 24164316 DOI: 10.1111/1574-6968.12314] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/16/2013] [Accepted: 10/22/2013] [Indexed: 11/27/2022] Open
Abstract
The transcription factors ChAP1 and Skn7 of the maize pathogen Cochliobolus heterostrophus are orthologs of Yap1 and Skn7 in yeast, where they are predicted to work together in a complex. Previous work showed that in C. heterostrophus, as in yeast, ChAP1 accumulates in the nucleus in response to reactive oxygen species (ROS). The expression of genes whose products counteract oxidative stress depends on ChAP1, as shown by impaired ability of a Δchap1 mutant to induce these 'antioxidant' genes. In this study, we found that under oxidative stress, antioxidant gene expression is also partially impaired in the Δskn7 mutant but to a milder extent than in the Δchap1 mutant, whereas in the double mutant - Δchap1-Δskn7 - none of the tested genes was induced, with the exception of one catalase gene, CAT2. Both single mutants are capable of infecting the plant, showing similar virulence to the WT. The double mutant, however, showed clearly decreased virulence, pointing to additive contributions of ChAP1 and Skn7. Possible mechanisms are discussed, including additive regulation of gene expression by oxidative stress.
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Affiliation(s)
- Samer Shalaby
- Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel
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