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Zhu XM, Li L, Bao JD, Wang JY, Daskalov A, Liu XH, Del Poeta M, Lin FC. The biological functions of sphingolipids in plant pathogenic fungi. PLoS Pathog 2023; 19:e1011733. [PMID: 37943805 PMCID: PMC10635517 DOI: 10.1371/journal.ppat.1011733] [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] [Indexed: 11/12/2023] Open
Abstract
Sphingolipids are critically significant in a range of biological processes in animals, plants, and fungi. In mammalian cells, they serve as vital components of the plasma membrane (PM) in maintaining its structure, tension, and fluidity. They also play a key role in a wide variety of biological processes, such as intracellular signal transduction, cell polarization, differentiation, and migration. In plants, sphingolipids are important for cell development and for cell response to environmental stresses. In pathogenic fungi, sphingolipids are crucial for the initiation and the development of infection processes afflicting humans. However, our knowledge on the metabolism and function of the sphingolipid metabolic pathway of pathogenic fungi affecting plants is still very limited. In this review, we discuss recent developments on sphingolipid pathways of plant pathogenic fungi, highlighting their uniqueness and similarity with plants and animals. In addition, we discuss recent advances in the research and development of fungal-targeted inhibitors of the sphingolipid pathway, to gain insights on how we can better control the infection process occurring in plants to prevent or/and to treat fungal infections in crops.
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Affiliation(s)
- Xue-Ming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Lin Li
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jian-Dong Bao
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jiao-Yu Wang
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Asen Daskalov
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Xiao-Hong Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, United States of America
- Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America
- Veterans Affairs Medical Center, Northport, New York, United States of America
| | - Fu-Cheng Lin
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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The Rheb GTPase promotes pheromone blindness via a TORC1-independent pathway in the phytopathogenic fungus Ustilago maydis. PLoS Genet 2022; 18:e1010483. [DOI: 10.1371/journal.pgen.1010483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 11/28/2022] [Accepted: 10/17/2022] [Indexed: 11/15/2022] Open
Abstract
The target of the rapamycin (TOR) signaling pathway plays a negative role in controlling virulence in phytopathogenic fungi. However, the actual targets involved in virulence are currently unknown. Using the corn smut fungus Ustilago maydis, we tried to address the effects of the ectopic activation of TOR on virulence. We obtained gain-of-function mutations in the Rheb GTPase, one of the conserved TOR kinase regulators. We have found that unscheduled activation of Rheb resulted in the alteration of the proper localization of the pheromone receptor, Pra1, and thereby pheromone insensitivity. Since pheromone signaling triggers virulence in Ustilaginales, we believe that the Rheb-induced pheromone blindness was responsible for the associated lack of virulence. Strikingly, although these effects required the concourse of the Rsp5 ubiquitin ligase and the Art3 α-arrestin, the TOR kinase was not involved. Several eukaryotic organisms have shown that Rheb transmits environmental information through TOR-dependent and -independent pathways. Therefore, our results expand the range of signaling manners at which environmental conditions could impinge on the virulence of phytopathogenic fungi.
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de la Torre A, Castanheira S, Pérez-Martín J. Incompatibility between proliferation and plant invasion is mediated by a regulator of appressorium formation in the corn smut fungus Ustilago maydis. Proc Natl Acad Sci U S A 2020; 117:30599-30609. [PMID: 33199618 PMCID: PMC7720189 DOI: 10.1073/pnas.2006909117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plant pathogenic fungi often developed specialized infection structures to breach the outer surface of a host plant. These structures, called appressoria, lead the invasion of the plant by the fungal hyphae. Studies in different phytopathogenic fungi showed that appressorium formation seems to be subordinated to the cell cycle. This subordination ensures the loading in the invading hypha of the correct genetic information to proceed with plant infection. However, how the cell cycle transmits its condition to the genetic program controlling appressorium formation and promoting the plant's invasion is unknown. Our results have uncovered how this process occurs for the appressorium of Ustilago maydis, the agent responsible for corn smut disease. Here, we described that the complex Clb2-cyclin-dependent kinase (Cdk)1, one of the master regulators of G2/M cell cycle progression in U. maydis, interacts and controls the subcellular localization of Biz1, a transcriptional factor required for the activation of the appressorium formation. Besides, Biz1 can arrest the cell cycle by down-regulation of the gene encoding a second b-cyclin Clb1 also required for the G2/M transition. These results revealed a negative feedback loop between appressorium formation and cell cycle progression in U. maydis, which serves as a "toggle switch" to control the fungal decision between infecting the plant or proliferating out of the plant.
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Affiliation(s)
| | - Sónia Castanheira
- Instituto de Biología Funcional y Genómica (CSIC), 37007 Salamanca, Spain
| | - José Pérez-Martín
- Instituto de Biología Funcional y Genómica (CSIC), 37007 Salamanca, Spain
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Mateus ID, Rojas EC, Savary R, Dupuis C, Masclaux FG, Aletti C, Sanders IR. Coexistence of genetically different Rhizophagus irregularis isolates induces genes involved in a putative fungal mating response. THE ISME JOURNAL 2020; 14:2381-2394. [PMID: 32514118 PMCID: PMC7490403 DOI: 10.1038/s41396-020-0694-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/16/2020] [Accepted: 05/27/2020] [Indexed: 02/07/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are of great ecological importance because of their effects on plant growth. Closely related genotypes of the same AMF species coexist in plant roots. However, almost nothing is known about the molecular interactions occurring during such coexistence. We compared in planta AMF gene transcription in single and coinoculation treatments with two genetically different isolates of Rhizophagus irregularis in symbiosis independently on three genetically different cassava genotypes. Remarkably few genes were specifically upregulated when the two fungi coexisted. Strikingly, almost all of the genes with an identifiable putative function were known to be involved in mating in other fungal species. Several genes were consistent across host plant genotypes but more upregulated genes involved in putative mating were observed in host genotype (COL2215) compared with the two other host genotypes. The AMF genes that we observed to be specifically upregulated during coexistence were either involved in the mating pheromone response, in meiosis, sexual sporulation or were homologs of MAT-locus genes known in other fungal species. We did not observe the upregulation of the expected homeodomain genes contained in a putative AMF MAT-locus, but observed upregulation of HMG-box genes similar to those known to be involved in mating in Mucoromycotina species. Finally, we demonstrated that coexistence between the two fungal genotypes in the coinoculation treatments explained the number of putative mating response genes activated in the different plant host genotypes. This study demonstrates experimentally the activation of genes involved in a putative mating response and represents an important step towards the understanding of coexistence and sexual reproduction in these important plant symbionts.
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Affiliation(s)
- Ivan D Mateus
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland.
| | - Edward C Rojas
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland
| | - Romain Savary
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland
| | - Cindy Dupuis
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland
| | - Frédéric G Masclaux
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland
| | - Consolée Aletti
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland
| | - Ian R Sanders
- Department of Ecology and Evolution, University of Lausanne, Biophore building, 1015, Lausanne, Switzerland.
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Aschenbroich J, Hussnaetter KP, Stoffels P, Langner T, Zander S, Sandrock B, Bölker M, Feldbrügge M, Schipper K. The germinal centre kinase Don3 is crucial for unconventional secretion of chitinase Cts1 in Ustilago maydis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:140154. [DOI: 10.1016/j.bbapap.2018.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/28/2018] [Accepted: 10/05/2018] [Indexed: 01/02/2023]
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MrArk1, an actin-regulating kinase gene, is required for endocytosis and involved in sustaining conidiation capacity and virulence in Metarhizium robertsii. Appl Microbiol Biotechnol 2019; 103:4859-4868. [PMID: 31025075 DOI: 10.1007/s00253-019-09836-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/25/2019] [Accepted: 04/07/2019] [Indexed: 01/19/2023]
Abstract
Actin-regulating kinase (Ark) plays an important role in controlling endocytosis, which has been shown to be involved in the development and virulence of several fungal pathogens. However, it remains unclear whether Ark1 is required for the development and pathogenicity of an entomopathogenic fungus. Here, MrArk1 (MAA_03415), a homologue of yeast Ark1, was characterized in the insect pathogenic fungus, Metarhizium robertsii. Disruption of MrArk1 led to defects in endocytosis and a marked reduction (58%) in conidiation capacity. The reduced conidiation level was accompanied by repression of several key conidiation-related genes, including brlA, abaA, and wetA. Additionally, the deletion mutant showed a significant decrease in its tolerance to heat shock, but not to UV-B irradiation. Bioassays demonstrated attenuated virulence for the deletion mutant against Galleria mellonella via normal cuticle infection, accompanied by suppressed appressorium formation and reduced transcript levels of several genes involved in cuticle penetration. Taken together, our results indicate that MrArk1 is involved in the heat tolerance, sporulation, and virulence of M. robertsii, and thus is an important factor for sustaining the fungal potential against insect pests.
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Wang C, Shen D, Wang J, Chen Y, Dong Y, Tang Z, Xia A. An AGC kinase, PgAGC1 regulates virulence in the entomopathogenic oomycete Pythium guiyangense. Fungal Biol 2018; 123:87-93. [PMID: 30654961 DOI: 10.1016/j.funbio.2018.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 10/27/2022]
Abstract
Mosquitoes are the most important medical species by transmitting some of deadly infectious diseases to human. In recent years extensive studies of vector control have been focused on biological control agents due to the grave issue raised by continuous application of chemical compounds. Pythium guiyangense X.Q. Su was first isolated from infected larvae of Aedes albopictus in 2006 in China and it has been proven to be a promising mosquito control agent. However, the molecular mechanisms of this oomycete pathogenic to mosquitoes are still not clear. In this study, we identified a new gene from the genome of P. guiyangense, PgAGC1 that belongs to the AGC kinase group and we found that the transcriptional expression levels of this gene were significantly up-regulated during infection of mosquito Culex pipiens pallens. Disruption of the PgAGC1gene via genetic transformation methods affects colony growth and stress responses and results in reduced mortality and infection rates. All the evidence revealed that, besides its role in growth and stress resistance, PgAGC1 is putative determinants of P. guiyangense virulence. The results of this study become of particular importance in understanding the mechanisms of oomycete-mosquito interactions.
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Affiliation(s)
- Cong Wang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China.
| | - Danyu Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.
| | - Jing Wang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China.
| | - Yang Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.
| | - Yumei Dong
- Department of Entomology, Nanjing Agricultural University, Nanjing, China.
| | - Zhaoyang Tang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.
| | - Ai Xia
- Department of Entomology, Nanjing Agricultural University, Nanjing, China.
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Castanheira S, Mielnichuk N, Pérez-Martín J. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis. Development 2014; 141:4817-26. [PMID: 25411209 DOI: 10.1242/dev.113415] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue.
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Affiliation(s)
- Sónia Castanheira
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
| | - Natalia Mielnichuk
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
| | - José Pérez-Martín
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas, Zacarías González 2, Salamanca 37007, Spain
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Tanaka S, Brefort T, Neidig N, Djamei A, Kahnt J, Vermerris W, Koenig S, Feussner K, Feussner I, Kahmann R. A secreted Ustilago maydis effector promotes virulence by targeting anthocyanin biosynthesis in maize. eLife 2014; 3:e01355. [PMID: 24473076 PMCID: PMC3904489 DOI: 10.7554/elife.01355] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/18/2013] [Indexed: 11/13/2022] Open
Abstract
The biotrophic fungus Ustilago maydis causes smut disease in maize with characteristic tumor formation and anthocyanin induction. Here, we show that anthocyanin biosynthesis is induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with maize protein kinase ZmTTK1. Tin2 masks a ubiquitin-proteasome degradation motif in ZmTTK1, thus stabilizing the active kinase. Active ZmTTK1 controls activation of genes in the anthocyanin biosynthesis pathway. Without Tin2, enhanced lignin biosynthesis is observed in infected tissue and vascular bundles show strong lignification. This is presumably limiting access of fungal hyphae to nutrients needed for massive proliferation. Consistent with this assertion, we observe that maize brown midrib mutants affected in lignin biosynthesis are hypersensitive to U. maydis infection. We speculate that Tin2 rewires metabolites into the anthocyanin pathway to lower their availability for other defense responses. DOI: http://dx.doi.org/10.7554/eLife.01355.001.
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Affiliation(s)
- Shigeyuki Tanaka
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Thomas Brefort
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nina Neidig
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Armin Djamei
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Jörg Kahnt
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Wilfred Vermerris
- Department of Microbiology & Cell Science, University of Florida, Gainesville, United States
- Genetics Institute, University of Florida, Gainesville, United States
| | - Stefanie Koenig
- Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Göttingen, Germany
| | - Kirstin Feussner
- Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Göttingen, Germany
| | - Ivo Feussner
- Albrecht-von-Haller-Institute, Georg-August-University Göttingen, Göttingen, Germany
| | - Regine Kahmann
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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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: 154] [Impact Index Per Article: 15.4] [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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Tanaka S, Brefort T, Neidig N, Djamei A, Kahnt J, Vermerris W, Koenig S, Feussner K, Feussner I, Kahmann R. A secreted Ustilago maydis effector promotes virulence by targeting anthocyanin biosynthesis in maize. eLife 2014. [PMID: 24473076 DOI: 10.7554/elife.01355.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023] Open
Abstract
The biotrophic fungus Ustilago maydis causes smut disease in maize with characteristic tumor formation and anthocyanin induction. Here, we show that anthocyanin biosynthesis is induced by the virulence promoting secreted effector protein Tin2. Tin2 protein functions inside plant cells where it interacts with maize protein kinase ZmTTK1. Tin2 masks a ubiquitin-proteasome degradation motif in ZmTTK1, thus stabilizing the active kinase. Active ZmTTK1 controls activation of genes in the anthocyanin biosynthesis pathway. Without Tin2, enhanced lignin biosynthesis is observed in infected tissue and vascular bundles show strong lignification. This is presumably limiting access of fungal hyphae to nutrients needed for massive proliferation. Consistent with this assertion, we observe that maize brown midrib mutants affected in lignin biosynthesis are hypersensitive to U. maydis infection. We speculate that Tin2 rewires metabolites into the anthocyanin pathway to lower their availability for other defense responses. DOI: http://dx.doi.org/10.7554/eLife.01355.001.
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Affiliation(s)
- Shigeyuki Tanaka
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Wang L, Berndt P, Xia X, Kahnt J, Kahmann R. A seven-WD40 protein related to human RACK1 regulates mating and virulence in Ustilago maydis. Mol Microbiol 2011; 81:1484-98. [PMID: 21815950 DOI: 10.1111/j.1365-2958.2011.07783.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In mammalian cells RACK1 serves as a scaffold protein that has a role in integrating inputs from different signalling pathways and affects translation through association with ribosomes. Ustilago maydis contains a seven-WD40 repeat motif protein designated Rak1, which shows 68% identity to RACK1 and 51% identity to Asc1p of Saccharomyces cerevisiae. An asc1 mutant could be complemented by introduction of U. maydis rak1. The deletion of rak1 affected cell growth, cell wall integrity and specifically attenuated cell fusion. This latter defect was caused by reduced expression of prf1 encoding the regulator for pheromone (mfa) and pheromone-receptor genes. Rak1 interacts with a variety of ribosomal proteins and microarray analysis revealed that the deletion of rak1 led to severely reduced expression of rop1, a transcriptional activator of prf1. The constitutive expression of rop1 could rescue the defect of mfa1 expression as well as conjugation tube formation in response to pheromone induction in the rak1 mutant. Moreover, a solopathogenic rak1 mutant failed to respond to plant-derived stimuli, resulting in attenuated filamentation and pathogenicity. This could be partially rescued by constitutive expression of the b heterodimer. These data suggest that rak1 is a regulator of rop1 expression with additional roles after cell fusion.
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Affiliation(s)
- Lei Wang
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse 10, D-35043 Marburg, Germany
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Vollmeister E, Schipper K, Baumann S, Haag C, Pohlmann T, Stock J, Feldbrügge M. Fungal development of the plant pathogen Ustilago maydis. FEMS Microbiol Rev 2011; 36:59-77. [PMID: 21729109 DOI: 10.1111/j.1574-6976.2011.00296.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The maize pathogen Ustilago maydis has to undergo various morphological transitions for the completion of its sexual life cycle. For example, haploid cells respond to pheromone by forming conjugation tubes that fuse at their tips. The resulting dikaryon grows filamentously, expanding rapidly at the apex and inserting retraction septa at the basal pole. In this review, we present progress on the underlying mechanisms regulating such defined developmental programmes. The key findings of the postgenomic era are as follows: (1) endosomes function not only during receptor recycling, but also as multifunctional transport platforms; (2) a new transcriptional master regulator for pathogenicity is part of an intricate transcriptional network; (3) determinants for uniparental mitochondrial inheritance are encoded at the a2 mating-type locus; (4) microtubule-dependent mRNA transport is important in determining the axis of polarity; and (5) a battery of fungal effectors encoded in gene clusters is crucial for plant infection. Importantly, most processes are tightly controlled at the transcriptional, post-transcriptional and post-translational levels, resulting in a complex regulatory network. This intricate system is crucial for the timing of the correct order of developmental phases. Thus, new insights from all layers of regulation have substantially advanced our understanding of fungal development.
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Affiliation(s)
- Evelyn Vollmeister
- Institute for Microbiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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