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Anand G, Gupta R, Marash I, Leibman-Markus M, Bar M. Cytokinin production and sensing in fungi. Microbiol Res 2022; 262:127103. [DOI: 10.1016/j.micres.2022.127103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/07/2022] [Accepted: 06/22/2022] [Indexed: 10/17/2022]
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Luo X, Tian T, Bonnave M, Tan X, Huang X, Li Z, Ren M. The Molecular Mechanisms of Phytophthora infestans in Response to Reactive Oxygen Species Stress. PHYTOPATHOLOGY 2021; 111:2067-2079. [PMID: 33787286 DOI: 10.1094/phyto-08-20-0321-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: 06/12/2023]
Abstract
Reactive oxygen species (ROSs) are critical for the growth, development, proliferation, and pathogenicity of microbial pathogens; however, excessive levels of ROSs are toxic. Little is known about the signaling cascades in response to ROS stress in oomycetes such as Phytophthora infestans, the causal agent of potato late blight. Here, P. infestans was used as a model system to investigate the mechanism underlying the response to ROS stress in oomycete pathogens. Results showed severe defects in sporangium germination, mycelium growth, appressorium formation, and virulence of P. infestans in response to H2O2 stress. Importantly, these phenotypes mimic those of P. infestans treated with rapamycin, the inhibitor of target of rapamycin (TOR, 1-phosphatidylinositol-3-kinase). Strong synergism occurred when P. infestans was treated with a combination of H2O2 and rapamycin, suggesting that a crosstalk exists between ROS stress and the TOR signaling pathway. Comprehensive analysis of transcriptome, proteome, and phosphorylation omics showed that H2O2 stress significantly induced the operation of the TOR-mediated autophagy pathway. Monodansylcadaverine staining showed that in the presence of H2O2 and rapamycin, the autophagosome level increased in a dosage-dependent manner. Furthermore, transgenic potatoes containing double-stranded RNA of TOR in P. infestans (PiTOR) displayed high resistance to P. infestans. Therefore, TOR is involved in the ROS response and is a potential target for control of oomycete diseases, because host-mediated silencing of PiTOR increases potato resistance to late blight.
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Affiliation(s)
- Xiumei Luo
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Tingting Tian
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Maxime Bonnave
- Centre for Agriculture and Agro-Industry of Hainaut Province, Ath 7800, Belgium
| | - Xue Tan
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Xiaoqing Huang
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Zhengguo Li
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
| | - Maozhi Ren
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China
- Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 401331, China
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450000, China
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Liu W, Triplett L, Chen XL. Emerging Roles of Posttranslational Modifications in Plant-Pathogenic Fungi and Bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:99-124. [PMID: 33909479 DOI: 10.1146/annurev-phyto-021320-010948] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Posttranslational modifications (PTMs) play crucial roles in regulating protein function and thereby control many cellular processes and biological phenotypes in both eukaryotes and prokaryotes. Several recent studies illustrate how plant fungal and bacterial pathogens use these PTMs to facilitate development, stress response, and host infection. In this review, we discuss PTMs that have key roles in the biological and infection processes of plant-pathogenic fungi and bacteria. The emerging roles of PTMs during pathogen-plant interactions are highlighted. We also summarize traditional tools and emerging proteomics approaches for PTM research. These discoveries open new avenues for investigating the fundamental infection mechanisms of plant pathogens and the discovery of novel strategies for plant disease control.
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Affiliation(s)
- Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
| | - Lindsay Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA;
| | - Xiao-Lin Chen
- State Key Laboratory of Agricultural Microbiology and Provincial Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China;
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Zhang ZQ, Chen T, Li BQ, Qin GZ, Tian SP. Molecular basis of pathogenesis of postharvest pathogenic Fungi and control strategy in fruits: progress and prospect. MOLECULAR HORTICULTURE 2021; 1:2. [PMID: 37789422 PMCID: PMC10509826 DOI: 10.1186/s43897-021-00004-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 03/15/2021] [Indexed: 10/05/2023]
Abstract
The disease caused by pathogenic fungi is the main cause of postharvest loss of fresh fruits. The formulation of disease control strategies greatly depends on the understanding of pathogenic mechanism of fungal pathogens and control strategy. In recent years, based on the application of various combinatorial research methods, some pathogenic genes of important postharvest fungal pathogens in fruit have been revealed, and their functions and molecular regulatory networks of virulence have been explored. These progresses not only provide a new perspective for understanding the molecular basis and regulation mechanism of pathogenicity of postharvest pathogenic fungi, but also are beneficial to giving theoretical guidance for the creation of new technologies of postharvest disease control. Here, we synthesized these recent advances and illustrated conceptual frameworks, and identified several issues on the focus of future studies.
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Affiliation(s)
- Zhan-Quan Zhang
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tong Chen
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China
| | - Bo-Qiang Li
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China
| | - Guo-Zheng Qin
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China
| | - Shi-Ping Tian
- Key Laboratory of Plant Resources, Institute of Botany, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Antioxidant ability of glutaredoxins and their role in symbiotic nitrogen fixation in Rhizobium leguminosarum bv. viciae 3841. Appl Environ Microbiol 2021; 87:AEM.01956-20. [PMID: 33277272 PMCID: PMC7851698 DOI: 10.1128/aem.01956-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Glutaredoxins (Grx) are redoxin family proteins that reduce disulfides and mixed disulfides between glutathione and proteins. Rhizobium leguminosarum bv. Viciae 3841 contains three genes coding for glutaredoxins: RL4289 (grxA) codes for a dithiolic glutaredoxin, RL2615 (grxB) codes for a monothiol glutaredoxin, while RL4261 (grxC) codes for a glutaredoxin-like NrdH protein. We generated mutants interrupted in one, two, or three glutaredoxin genes. These mutants had no obvious differences in growth phenotypes from the wild type RL3841. However, while a mutant of grxC did not affect the antioxidant or symbiotic capacities of R. leguminosarum, grxA-derived or grxB mutants decreased antioxidant and nitrogen fixation capacities. Furthermore, grxA mutants were severely impaired in rhizosphere colonization, and formed smaller nodules with defects of bacteroid differentiation, whereas nodules induced by grxB mutants contained abnormally thick cortices and prematurely senescent bacteroids. The grx triple mutant had the greatest defect in antioxidant and symbiotic capacities of R. leguminosarum and quantitative proteomics revealed it had 56 up-regulated and 81 down-regulated proteins relative to wildtype. Of these proteins, twenty-eight are involved in transporter activity, twenty are related to stress response and virulence, and sixteen are involved in amino acid metabolism. Overall, R. leguminosarum glutaredoxins behave as antioxidant proteins mediating root nodule symbiosis.IMPORTANCE Glutaredoxin catalyzes glutathionylation/deglutathionylation reactions, protects SH-groups from oxidation and restores functionally active thiols. Three glutaredoxins exist in R. leguminosarum and their properties were investigated in free-living bacteria and during nitrogen-fixing symbiosis. All the glutaredoxins were necessary for oxidative stress defense. Dithiol GrxA affects nodulation and nitrogen fixation of bacteroids by altering deglutathionylation reactions, monothiol GrxB is involved in symbiotic nitrogen fixation by regulating Fe-S cluster biogenesis, and GrxC may participate in symbiosis by an unknown mechanism. Proteome analysis provides clues to explain the differences between the grx triple mutant and wild-type nodules.
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Navarro-Arias MJ, Dementhon K, Defosse TA, Foureau E, Courdavault V, Clastre M, Le Gal S, Nevez G, Le Govic Y, Bouchara JP, Giglioli-Guivarc'h N, Noël T, Mora-Montes HM, Papon N. Group X hybrid histidine kinase Chk1 is dispensable for stress adaptation, host–pathogen interactions and virulence in the opportunistic yeast Candida guilliermondii. Res Microbiol 2017; 168:644-654. [DOI: 10.1016/j.resmic.2017.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/03/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
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Liu J, Tong SM, Qiu L, Ying SH, Feng MG. Two histidine kinases can sense different stress cues for activation of the MAPK Hog1 in a fungal insect pathogen. Environ Microbiol 2017; 19:4091-4102. [DOI: 10.1111/1462-2920.13851] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 06/20/2017] [Accepted: 06/25/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Jing Liu
- Institute of Microbiology, College of Life Sciences, Zhejiang University; Hangzhou, Zhejiang 310058 China
| | - Sen-Miao Tong
- Institute of Microbiology, College of Life Sciences, Zhejiang University; Hangzhou, Zhejiang 310058 China
| | - Lei Qiu
- School of Bioengineering; Qilu University of Technology; Jinan, Shandong 250353 China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University; Hangzhou, Zhejiang 310058 China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University; Hangzhou, Zhejiang 310058 China
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Defosse TA, Sharma A, Mondal AK, Dugé de Bernonville T, Latgé JP, Calderone R, Giglioli-Guivarc'h N, Courdavault V, Clastre M, Papon N. Hybrid histidine kinases in pathogenic fungi. Mol Microbiol 2015; 95:914-24. [DOI: 10.1111/mmi.12911] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2014] [Indexed: 12/27/2022]
Affiliation(s)
- Tatiana A. Defosse
- Biomolécules et Biotechnologies Végétales; EA 2106; Université François-Rabelais de Tours; Tours France
| | | | - Alok K. Mondal
- Institute of Microbial Technology; Chandigarh India
- School of Life Sciences; Jawaharlal Nehru University; New Delhi India
| | | | | | - Richard Calderone
- Georgetown University Medical Center; Department of Microbiology & Immunology; Washington DC USA
| | | | - Vincent Courdavault
- Biomolécules et Biotechnologies Végétales; EA 2106; Université François-Rabelais de Tours; Tours France
| | - Marc Clastre
- Biomolécules et Biotechnologies Végétales; EA 2106; Université François-Rabelais de Tours; Tours France
| | - Nicolas Papon
- Biomolécules et Biotechnologies Végétales; EA 2106; Université François-Rabelais de Tours; Tours France
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de Castro PA, Chen C, de Almeida RSC, Freitas FZ, Bertolini MC, Morais ER, Brown NA, Ramalho LNZ, Hagiwara D, Mitchell TK, Goldman GH. ChIP-seq reveals a role for CrzA in the Aspergillus fumigatus high-osmolarity glycerol response (HOG) signalling pathway. Mol Microbiol 2014; 94:655-74. [PMID: 25196896 DOI: 10.1111/mmi.12785] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2014] [Indexed: 12/28/2022]
Abstract
Aspergillus fumigatus is an opportunistic pathogen and allergen of mammals. Calcium signalling is essential for A. fumigatus pathogenicity and is regulated by the CrzA transcription factor. We used ChIP-seq (Chromatin Immunoprecipitation DNA sequencing) to explore CrzA gene targets in A. fumigatus. In total, 165 potential binding peaks including 102 directly regulated genes were identified, resulting in the prediction of the A[GT][CG]CA[AC][AG] CrzA-binding motif. The 102 CrzA putatively regulated genes exhibited a diverse array of functions. The phkB (Afu3g12530) histidine kinase and the sskB (Afu1g10940) MAP kinase kinase kinase of the HOG (high-osmolarity glycerol response) pathway were regulated by CrzA. Several members of the two-component system (TCS) and the HOG pathway were more sensitive to calcium. CrzA::GFP was translocated to the nucleus upon osmotic stress. CrzA is important for the phosphorylation of the SakA MAPK in response to osmotic shock. The ΔsskB was more sensitive to CaCl2 , NaCl, and paraquat stress, while being avirulent in a murine model of invasive pulmonary aspergillosis. The presence of CaCl2 and osmotic stresses resulted in synergistic inhibition of ΔcrzA and ΔsskB growth. These results suggest there is a genetic interaction between the A. fumigatus calcineurin-CrzA and HOG pathway that is essential for full virulence.
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Affiliation(s)
- Patrícia A de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Turrà D, Segorbe D, Di Pietro A. Protein kinases in plant-pathogenic fungi: conserved regulators of infection. ANNUAL REVIEW OF PHYTOPATHOLOGY 2014; 52:267-88. [PMID: 25090477 DOI: 10.1146/annurev-phyto-102313-050143] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Phytopathogenic fungi have evolved an amazing diversity of infection modes and nutritional strategies, yet the signaling pathways that govern pathogenicity are remarkably conserved. Protein kinases (PKs) catalyze the reversible phosphorylation of proteins, regulating a variety of cellular processes. Here, we present an overview of our current understanding of the different classes of PKs that contribute to fungal pathogenicity on plants and of the mechanisms that regulate and coordinate PK activity during infection-related development. In addition to the well-studied PK modules, such as MAPK (mitogen-activated protein kinase) and cAMP (cyclic adenosine monophosphate)-PKA (protein kinase A) cascades, we also discuss new PK pathways that have emerged in recent years as key players of pathogenic development and disease. Understanding how conserved PK signaling networks have been recruited during the evolution of fungal pathogenicity not only advances our knowledge of the highly elaborate infection process but may also lead to the development of novel strategies for the control of plant disease.
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Affiliation(s)
- David Turrà
- Departamento de Genética and Campus de Excelencia Agroalimentario (ceiA3), Universidad de Córdoba, 14071 Córdoba, Spain; , ,
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Ishiga Y, Upplapapti SR, Mysore KS. Expression analysis reveals a role for hydrophobic or epicuticular wax signals in pre-penetration structure formation of Phakopsora pachyrhizi. PLANT SIGNALING & BEHAVIOR 2013; 8:e26959. [PMID: 24184888 PMCID: PMC4091598 DOI: 10.4161/psb.26959] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 05/23/2023]
Abstract
Asian soybean rust (ASR) caused by the fungus Phakopsora pachyrhizi is one of the most devastating foliar diseases affecting soybean production worldwide. Even though several resistance sources have been identified in soybean, they do not show resistance to all races of P. pachyrhizi. Identification of genes that confer nonhost resistance (NHR) against P. pachyrhizi in another legume species will provide an avenue to engineer soybean to have durable and broad spectrum resistance against P. pachyrhizi strains. Recently, we identified a Medicago truncatula gene, IRG1 (INHIBITOR OF RUST GERM-TUBE DIFFERENTIATION1), that when mutated inhibits the growth of P. pachyrhizi. IRG1 encodes a Cys(2)His(2) zinc finger transcription factor that controls wax-biosynthesis-related genes. The irg1 mutant shows a complete loss of abaxial epicuticular wax crystals and surface hydrophobicity, resulting in the inhibition of pre-penetration structure formation. In order to confirm the role of surface hydrophobicity in the formation of pre-penetration structures, we examined the expression profiles of P. pachyrhizi putative pre-penetration structure-development-related genes on a solid surface or a M. truncatula abaxial leaf surface. Interestingly, the expression of kinase family genes was upregulated on the hydrophobic surface and M. truncatula wild-type leaf surface, but not on the M. truncatula irg1 mutant leaf surface, suggesting that these genes play a role in P. pachyrhizi pre-penetration structure development. In addition, our results suggest that hydrophobicity on the M. truncatula leaf surface may function as a key signal to induce the P. pachyrhizi genes involved in pre-penetration structure development.
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Hulvová H, Galuszka P, Frébortová J, Frébort I. Parasitic fungus Claviceps as a source for biotechnological production of ergot alkaloids. Biotechnol Adv 2013; 31:79-89. [DOI: 10.1016/j.biotechadv.2012.01.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 12/21/2011] [Accepted: 01/05/2012] [Indexed: 01/03/2023]
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Chung KR. Stress Response and Pathogenicity of the Necrotrophic Fungal Pathogen Alternaria alternata. SCIENTIFICA 2012; 2012:635431. [PMID: 24278721 PMCID: PMC3820455 DOI: 10.6064/2012/635431] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 10/03/2012] [Indexed: 05/07/2023]
Abstract
The production of host-selective toxins by the necrotrophic fungus Alternaria alternata is essential for the pathogenesis. A. alternata infection in citrus leaves induces rapid lipid peroxidation, accumulation of hydrogen peroxide (H2O2), and cell death. The mechanisms by which A. alternata avoids killing by reactive oxygen species (ROS) after invasion have begun to be elucidated. The ability to coordinate of signaling pathways is essential for the detoxification of cellular stresses induced by ROS and for pathogenicity in A. alternata. A low level of H2O2, produced by the NADPH oxidase (NOX) complex, modulates ROS resistance and triggers conidiation partially via regulating the redox-responsive regulators (YAP1 and SKN7) and the mitogen-activated protein (MAP) kinase (HOG1) mediated pathways, which subsequently regulate the genes required for the biosynthesis of siderophore, an iron-chelating compound. Siderophore-mediated iron acquisition plays a key role in ROS detoxification because of the requirement of iron for the activities of antioxidants (e.g., catalase and SOD). Fungal strains impaired for the ROS-detoxifying system severely reduce the virulence on susceptible citrus cultivars. This paper summarizes the current state of knowledge of signaling pathways associated with cellular responses to multidrugs, oxidative and osmotic stress, and fungicides, as well as the pathogenicity/virulence in the tangerine pathotype of A. alternata.
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Affiliation(s)
- Kuang-Ren Chung
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
- Department of Plant Pathology, IFAS, University of Florida, Gainesville, FL 32611, USA
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Fillinger S, Ajouz S, Nicot PC, Leroux P, Bardin M. Functional and structural comparison of pyrrolnitrin- and iprodione-induced modifications in the class III histidine-kinase Bos1 of Botrytis cinerea. PLoS One 2012; 7:e42520. [PMID: 22912706 PMCID: PMC3418262 DOI: 10.1371/journal.pone.0042520] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 07/10/2012] [Indexed: 11/22/2022] Open
Abstract
Dicarboximides and phenylpyrroles are commonly used fungicides against plant pathogenic ascomycetes. Although their effect on fungal osmosensing systems has been shown in many studies, their modes-of-action still remain unclear. Laboratory- or field-mutants of fungi resistant to either or both fungicide categories generally harbour point mutations in the sensor histidine kinase of the osmotic signal transduction cascade.In the present study we compared the mechanisms of resistance to the dicarboximide iprodione and to pyrrolnitrin, a structural analogue of phenylpyrrole fungicides, in Botrytis cinerea. Pyrrolnitrin-induced mutants and iprodione-induced mutants of B. cinerea were produced in vitro. For the pyrrolnitrin-induced mutants, a high level of resistance to pyrrolnitrin was associated with a high level of resistance to iprodione. For the iprodione-induced mutants, the high level of resistance to iprodione generated variable levels of resistance to pyrrolnitrin and phenylpyrroles. All selected mutants showed hypersensitivity to high osmolarity and regardless of their resistance levels to phenylpyrroles, they showed strongly reduced fitness parameters (sporulation, mycelial growth, aggressiveness on plants) compared to the parental phenotypes. Most of the mutants presented modifications in the osmosensing class III histidine kinase affecting the HAMP domains. Site directed mutagenesis of the bos1 gene was applied to validate eight of the identified mutations. Structure modelling of the HAMP domains revealed that the replacements of hydrophobic residues within the HAMP domains generally affected their helical structure, probably abolishing signal transduction. Comparing mutant phenotypes to the HAMP structures, our study suggests that mutations perturbing helical structures of HAMP2-4 abolish signal-transduction leading to loss-of-function phenotype. The mutation of residues E529, M427, and T581, without consequences on HAMP structure, highlighted their involvement in signal transduction. E529 and M427 seem to be principally involved in osmotic signal transduction.
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Affiliation(s)
| | - Sakhr Ajouz
- INRA, UR407, Plant Pathology Unit, Montfavet, France
| | | | | | - Marc Bardin
- INRA, UR407, Plant Pathology Unit, Montfavet, France
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15
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Zhou G, Wang J, Qiu L, Feng MG. A Group III histidine kinase (mhk1) upstream of high-osmolarity glycerol pathway regulates sporulation, multi-stress tolerance and virulence of Metarhizium robertsii, a fungal entomopathogen. Environ Microbiol 2011; 14:817-29. [PMID: 22118192 DOI: 10.1111/j.1462-2920.2011.02643.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of Metarhizium robertsii Group III histidine kinase (mhk1) in regulating various phenotypes of the fungal entomopathogen and the transcripts of 25 downstream genes likely associated with the phenotypes were probed by constructing Δmhk1 and Δmhk1/mhk1 mutants. All examined Δmhk1 phenotypes except unchanged sensitivity to fungicide (dimethachlon) differed significantly from those of wild type and Δmhk1/mhk1, which were similar to each other. Significant phenotypic changes in Δmhk1 included increased conidial yields on two media, increased tolerance to H(2)O(2) , decreased tolerance to menadione, increased tolerance to hyperosmolarity, increased conidial thermotolerance, decreased conidial UV-B resistance and reduced virulence to Tenebrio molitor larvae. The mhk1 disruption elevated the transcripts of nine genes, including two associated with conidiation (flbC and hymA) and three encoding catalases but decreased seven other gene transcripts, including three for superoxide dismultases, under normal conditions. The high-osmolarity glycerol pathway MAPK phosphorylation level in Δmhk1 culture was increased 1.0- to 1.8-fold by KCl, sucrose and menadione stresses but reduced drastically by H(2)O(2) or heat (40°C) stress, accompanied with different transcript patterns of all examined genes under the stresses. Our results confirmed the crucial role of mhk1 in regulating the expression of the downstream genes and associated phenotypes important for the fungal biocontrol potential.
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Affiliation(s)
- Gang Zhou
- Institute of Microbiology, College of Life Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
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16
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Heller J, Tudzynski P. Reactive oxygen species in phytopathogenic fungi: signaling, development, and disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:369-90. [PMID: 21568704 DOI: 10.1146/annurev-phyto-072910-095355] [Citation(s) in RCA: 305] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Reactive oxygen species (ROS) play a major role in pathogen-plant interactions: recognition of a pathogen by the plant rapidly triggers the oxidative burst, which is necessary for further defense reactions. The specific role of ROS in pathogen defense is still unclear. Studies on the pathogen so far have focused on the importance of the oxidative stress response (OSR) systems to overcome the oxidative burst or of its avoidance by effectors. This review focuses on the role of ROS for fungal virulence and development. In the recent years, it has become obvious that (a) fungal OSR systems might not have the predicted crucial role in pathogenicity, (b) fungal pathogens, especially necrotrophs, can actively contribute to the ROS level in planta and even take advantage of the host's response, (c) fungi possess superoxide-generating NADPH oxidases similar to mammalian Nox complexes that are important for pathogenicity; however, recent data indicate that they are not directly involved in pathogen-host communication but in fungal differentiation processes that are necessary for virulence.
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Affiliation(s)
- Jens Heller
- Molecular Biology and Biotechnology of Fungi, Institute of Biology and Biotechnology of Plants, Westfälische Wilhelms-Universität Münster, Germany.
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17
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Lin CH, Chung KR. Specialized and shared functions of the histidine kinase- and HOG1 MAP kinase-mediated signaling pathways in Alternaria alternata, a filamentous fungal pathogen of citrus. Fungal Genet Biol 2010; 47:818-27. [PMID: 20601043 DOI: 10.1016/j.fgb.2010.06.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 06/02/2010] [Accepted: 06/17/2010] [Indexed: 12/16/2022]
Abstract
Signal transduction pathways are critical for the coordination of complex cellular processes in cells. In Alternaria alternata, a necrotrophic fungal pathogen of citrus, cloning and characterization of a gene coding a Group III histidine kinase (AaHSK1) and the yeast HOG1 ortholog (AaHOG1) showed the two genes to operate, both uniquely and synergistically, in a number of physiological and pathological functions. Systemic loss-of-function genetics in A. alternata revealed that AaHSK1 is a primary regulator for cellular resistance to sugar osmotic stress and for sensitivity to dicarboximide or phenylpyrrole fungicides. These functions were likely modulated by unknown mechanisms rather than solely by the AaHOG1-mediated pathway. AaHOG1, which conferred cellular resistance to salts and oxidative stress, also bypassed AaHSK1, even though deletion of AaHSK1 affected AaHOG1 phosphorylation. Phosphorylation of AaHOG1 was increased when the fungus was treated with osmotic stress, fungicides or H(2)O(2). Fungal mutants impaired in AaHSK1, AaHOG1, AaAP1 (encoding a redox-responsive transcription factor) or AaFUS3 (encoding a MAP kinase) were all hypersensitive to 2-chloro-5-hydroxypyridine (CHP) or 2,3,5-triiodobenzoic acid (TIBA). An AaHOG1::sGFP (synthetic green fluorescent protein) fusion protein became localized in the nucleus in response to H(2)O(2), CHP, TIBA, fungicides, but not glucose. Glucose, however, enhanced AaHOG1 phosphorylation and nuclear localization in the AaHSK1 deficient background. Accumulation of the AaHSK1 gene transcript was negatively regulated by AaHOG1, AaAP1 or AaFUS3. AaHOG1 was necessary for fungal pathogenicity, yet AaHSK1 was completely dispensable for pathogenicity. Our results highlight a dramatic flexibility and uniqueness in the signaling pathways that are involved in responding to diverse environmental stimuli in A. alternata.
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Affiliation(s)
- Ching-Hsuan Lin
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
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Haarmann T, Rolke Y, Giesbert S, Tudzynski P. Ergot: from witchcraft to biotechnology. MOLECULAR PLANT PATHOLOGY 2009; 10:563-77. [PMID: 19523108 PMCID: PMC6640538 DOI: 10.1111/j.1364-3703.2009.00548.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The ergot diseases of grasses, caused by members of the genus Claviceps, have had a severe impact on human history and agriculture, causing devastating epidemics. However, ergot alkaloids, the toxic components of Claviceps sclerotia, have been used intensively (and misused) as pharmaceutical drugs, and efficient biotechnological processes have been developed for their in vitro production. Molecular genetics has provided detailed insight into the genetic basis of ergot alkaloid biosynthesis and opened up perspectives for the design of new alkaloids and the improvement of production strains; it has also revealed the refined infection strategy of this biotrophic pathogen, opening up the way for better control. Nevertheless, Claviceps remains an important pathogen worldwide, and a source for potential new drugs for central nervous system diseases.
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Affiliation(s)
- Thomas Haarmann
- Institut für Botanik, Westf. Wilhelms-Universität Münster, Germany
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Scott B, Eaton CJ. Role of reactive oxygen species in fungal cellular differentiations. Curr Opin Microbiol 2008; 11:488-93. [DOI: 10.1016/j.mib.2008.10.008] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 10/13/2008] [Accepted: 10/21/2008] [Indexed: 11/16/2022]
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Giesbert S, Schürg T, Scheele S, Tudzynski P. The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea. MOLECULAR PLANT PATHOLOGY 2008; 9:317-27. [PMID: 18705873 PMCID: PMC6640299 DOI: 10.1111/j.1364-3703.2008.00466.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The role of reactive oxygen species (ROS) in interactions between phytopathogenic fungi and their hosts is well established. An oxidative burst mainly caused by superoxide formation by membrane-associated NADPH oxidases is an essential element of plant defence reactions. Apart from primary effects, ROS play a major role as a second messenger in host response. Recently, NADPH oxidase (nox)-encoding genes have been identified in filamentous fungi. Functional analyses have shown that these fungal enzymes are involved in sexual differentiation, and there is growing evidence that they also affect developmental programmes involved in fungus-plant interactions. Here we show that in the biotrophic plant pathogen Claviceps purpurea deletion of the cpnox1 gene, probably encoding an NADPH oxidase, has impact on germination of conidia and pathogenicity: Deltacpnox1 mutants can penetrate the host epidermis, but they are impaired in colonization of the plant ovarian tissue. In the few cases where macroscopic signs of infection (honeydew) appear, they are extremely delayed and fully developed sclerotia have never been observed. C. purpurea Nox1 is important for the interaction with its host, probably by directly affecting pathogenic differentiation of the fungus.
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Affiliation(s)
- Sabine Giesbert
- Institut für Botanik, Westf. Wilhelms-Universität, Schlossgarten 3, D-48149 Münster, Germany
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