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Chen A, Liu N, Xu C, Wu S, Liu C, Qi H, Ren Y, Han X, Yang K, Liu X, Ma Z, Chen Y. The STRIPAK complex orchestrates cell wall integrity signalling to govern the fungal development and virulence of Fusarium graminearum. Mol Plant Pathol 2023; 24:1139-1153. [PMID: 37278525 PMCID: PMC10423325 DOI: 10.1111/mpp.13359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/04/2023] [Accepted: 05/16/2023] [Indexed: 06/07/2023]
Abstract
Striatin-interacting phosphatases and kinases (STRIPAKs) are evolutionarily conserved supramolecular complexes that control various important cellular processes such as signal transduction and development. However, the role of the STRIPAK complex in pathogenic fungi remains elusive. In this study, the components and function of the STRIPAK complex were investigated in Fusarium graminearum, an important plant-pathogenic fungus. The results obtained from bioinformatic analyses and the protein-protein interactome suggested that the fungal STRIPAK complex consisted of six proteins: Ham2, Ham3, Ham4, PP2Aa, Ppg1, and Mob3. Deletion mutations of individual components of the STRIPAK complex were created, and observed to cause a significant reduction in fungal vegetative growth and sexual development, and dramatically attenuae virulence, excluding the essential gene PP2Aa. Further results revealed that the STRIPAK complex interacted with the mitogen-activated protein kinase Mgv1, a key component in the cell wall integrity pathway, subsequently regulating the phosphorylation level and nuclear accumulation of Mgv1 to control the fungal stress response and virulence. Our results also suggested that the STRIPAK complex was interconnected with the target of rapamycin pathway through Tap42-PP2A cascade. Taken together, our findings revealed that the STRIPAK complex orchestrates cell wall integrity signalling to govern the fungal development and virulence of F. graminearum and highlighted the importance of the STRIPAK complex in fungal virulence.
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Affiliation(s)
- Ahai Chen
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Na Liu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
- College of Plant Health and MedicineQingdao Agricultural UniversityQingdaoChina
| | - Chenghui Xu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Siqi Wu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Chao Liu
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Hao Qi
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Yiyi Ren
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Xingmin Han
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Kunlong Yang
- Department of Biomedicine and Food Science, School of Life ScienceJiangsu Normal UniversityXuzhouChina
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Zhonghua Ma
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
| | - Yun Chen
- State Key Laboratory of Rice Biology, the Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhouChina
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Abstract
Anthracnose stalk rot (ASR) of maize results in millions of dollars in losses annually in the United States. ASR, together with anthracnose leaf blight and anthracnose top dieback, is caused by the fungus Colletotrichum graminicola. Current ASR management recommendations emphasize host resistance and reduction of plant stressors (e.g., drought, heat, low fertility, or soil acidity). Stress reduction may be more difficult to achieve in the future due to more high-intensity production protocols and climate change. Moreover, cultural and chemical management practices may conflict with other important goals, including environmental sustainability and maximization of yield potential. Thus, future ASR management may rely more heavily on host resistance, for which there are relatively few highly effective sources. The last comprehensive review of C. graminicola and maize anthracnose was written over two decades ago. The genomic age has brought important new insights into mechanisms governing the host-pathogen interaction from the application of molecular and cytological technologies. This review provides a summary of our current model of maize anthracnose etiology, including how increased knowledge of molecular and cellular events could contribute to better ASR management. Improved understanding of C. graminicola taxonomy has confirmed that the fungus is specific to Zea mays, and that it colonizes living maize tissues via a critical biotrophic phase. Successful biotrophic establishment relies on an array of secreted protein effectors and secondary metabolites produced at different stages of infection and dispersed to multiple locations. These molecules could provide therapeutic targets for the next generation of transgenic or gene-edited ASR-resistant hybrids.
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Affiliation(s)
- Renata Belisário
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY 40546-0312
| | - Alison E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University, 1344 Advanced Teaching and Research Building, 2213 Pammel Drive, Ames, IA 50011
| | - Lisa J Vaillancourt
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY 40546-0312
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Kück U, Stein V. STRIPAK, a Key Regulator of Fungal Development, Operates as a Multifunctional Signaling Hub. J Fungi (Basel) 2021; 7:443. [PMID: 34206073 DOI: 10.3390/jof7060443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/26/2021] [Accepted: 05/29/2021] [Indexed: 01/26/2023] Open
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) multi subunit complex is a highly conserved signaling complex that controls diverse developmental processes in higher and lower eukaryotes. In this perspective article, we summarize how STRIPAK controls diverse developmental processes in euascomycetes, such as fruiting body formation, cell fusion, sexual and vegetative development, pathogenicity, symbiosis, as well as secondary metabolism. Recent structural investigations revealed information about the assembly and stoichiometry of the complex enabling it to act as a signaling hub. Multiple organellar targeting of STRIPAK subunits suggests how this complex connects several signaling transduction pathways involved in diverse cellular developmental processes. Furthermore, recent phosphoproteomic analysis shows that STRIPAK controls the dephosphorylation of subunits from several signaling complexes. We also refer to recent findings in yeast, where the STRIPAK homologue connects conserved signaling pathways, and based on this we suggest how so far non-characterized proteins may functions as receptors connecting mitophagy with the STRIPAK signaling complex. Such lines of investigation should contribute to the overall mechanistic understanding of how STRIPAK controls development in euascomycetes and beyond.
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Wang S, Li G, Wei Y, Wang G, Dang Y, Zhang P, Zhang SH. Involvement of the Mitochondrial Protein Tyrosine Phosphatase PTPM1 in the Promotion of Conidiation, Development, and Pathogenicity in Colletotrichum graminicola. Front Microbiol 2021; 11:605738. [PMID: 33519752 PMCID: PMC7841309 DOI: 10.3389/fmicb.2020.605738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
The phosphorylation status of proteins, which is determined by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs), governs many cellular actions. In fungal pathogens, phosphorylation-mediated signal transduction has been considered to be one of the most important mechanisms in pathogenicity. Colletotrichum graminicola is an economically important corn pathogen. However, whether phosphorylation is involved in its pathogenicity is unknown. A mitochondrial protein tyrosine phosphatase gene, designated CgPTPM1, was deduced in C. graminicola through the use of bioinformatics and confirmed by enzyme activity assays and observation of its subcellular localization. We then created a CgPTPM1 deletion mutant (ΔCgPTPM1) to analyze its biological function. The results indicated that the loss of CgPTPM1 dramatically affected the formation of conidia and the development and differentiation into appressoria. However, the colony growth and conidial morphology of the ΔCgPTPM1 strains were unaffected. Importantly, the ΔCgPTPM1 mutant strains exhibited an obvious reduction of virulence, and the delayed infected hyphae failed to expand in the host cells. In comparison with the wild-type, ΔCgPTPM1 accumulated a larger amount of H2O2 and was sensitive to exogenous H2O2. Interestingly, the host cells infected by the mutant also exhibited an increased accumulation of H2O2 around the infection sites. Since the expression of the CgHYR1, CgGST1, CgGLR1, CgGSH1 and CgPAP1 genes was upregulated with the H2O2 treatment, our results suggest that the mitochondrial protein tyrosine phosphatase PTPM1 plays an essential role in promoting the pathogenicity of C. graminicola by regulating the excessive in vivo and in vitro production of H2O2.
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Affiliation(s)
- Shaowei Wang
- College of Plant Sciences, Jilin University, Changchun, China
| | - Guihua Li
- College of Plant Sciences, Jilin University, Changchun, China
- Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, China
| | - Yi Wei
- College of Plant Sciences, Jilin University, Changchun, China
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Gang Wang
- School of Life Sciences, Henan University, Kaifeng, China
| | - Yuejia Dang
- College of Plant Sciences, Jilin University, Changchun, China
| | - Penghui Zhang
- College of Plant Sciences, Jilin University, Changchun, China
| | - Shi-Hong Zhang
- College of Plant Sciences, Jilin University, Changchun, China
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
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Nordzieke DE, Sanken A, Antelo L, Raschke A, Deising HB, Pöggeler S. Specialized infection strategies of falcate and oval conidia of Colletotrichum graminicola. Fungal Genet Biol 2019; 133:103276. [PMID: 31550526 DOI: 10.1016/j.fgb.2019.103276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 09/19/2019] [Accepted: 09/19/2019] [Indexed: 01/12/2023]
Abstract
For many filamentous fungi with pathogenic lifestyles, the presence of distinct asexual conidia has been described. However, the role of these spore types remains mostly obscure. Colletotrichum graminicola is a hemibiotrophic filamentous fungus, causing anthracnose on maize plants with a high potential of epidemic disease spreading. C. graminicola generates two types of conidia. Falcate shaped conidia formed in necrotic lesions on maize tissues are able to generate appressoria with high efficiency and are considered key disease spreading propagules. The second conidia type, the smaller oval conidia, is formed in the vascular system of the infected plant, probably causing the distribution of the disease in planta. Barely any knowledge exists about how these conidia are able to exhibit their specific functions in the life cycle and pathogenicity of C. graminicola. Here, we show that germlings derived from both falcate and oval conidia differ in the secretion of a germination inhibitor and signals for germling fusion. Germination experiments combined with HPLC and mass spectrometry analyses revealed that germination of falcate conidia is regulated by the self-inhibitor mycosporine-glutamine, whereas this compound is absent from oval conidia cultures. Additionally, germlings derived from oval conidia undergo germling fusions at high frequencies and are able to induce such a fusion when co-incubated with falcate conidia. Falcate conidia germlings alone, however, were never observed to fuse. Plant infection experiments showed a positive correlation between germling fusions and efficient leaf infection by oval conidia. However, this correlation was not observed for infection by falcate conidia. Together, our findings reveal significant differences of two types of conidia derived from the same pathogenic fungus with distinct roles in pathogenesis.
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Affiliation(s)
- Daniela E Nordzieke
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg August University Göttingen, Grisebachstrasse 8, DE-37081 Göttingen, Germany.
| | - Alina Sanken
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg August University Göttingen, Grisebachstrasse 8, DE-37081 Göttingen, Germany
| | - Luis Antelo
- Institut für Biotechnologie und Wirkstoff-Forschung gGmbH (IBWF), Erwin-Schrödinger-Strasse 56, DE-67663 Kaiserslautern, Germany
| | - Anja Raschke
- Institute for Agricultural and Nutritional Sciences, Faculty for Natural Sciences III, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Strasse 3, DE-06120 Halle (Saale), Germany
| | - Holger B Deising
- Institute for Agricultural and Nutritional Sciences, Faculty for Natural Sciences III, Martin-Luther-University Halle-Wittenberg, Betty-Heimann-Strasse 3, DE-06120 Halle (Saale), Germany
| | - Stefanie Pöggeler
- Department of Genetics of Eukaryotic Microorganisms, Institute of Microbiology and Genetics, Georg August University Göttingen, Grisebachstrasse 8, DE-37081 Göttingen, Germany
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6
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J Reschka E, Nordzieke S, Valerius O, Braus GH, Pöggeler S. A novel STRIPAK complex component mediates hyphal fusion and fruiting-body development in filamentous fungi. Mol Microbiol 2018; 110:513-532. [PMID: 30107058 DOI: 10.1111/mmi.14106] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2018] [Indexed: 01/17/2023]
Abstract
The STRIPAK complex is involved in growth, cell fusion, development and signaling pathways, and thus malfunctions in the human STRIPAK complex often result in severe neuronal diseases and cancer. Despite the high degree of general conservation throughout the complex, several STRIPAK complex-associated small coiled-coil proteins of animals and yeasts are not conserved across species. As there are no data for filamentous ascomycetes, we addressed this through affinity purification with HA-tagged striatin ortholog PRO11 in Sordaria macrospora. Combining the method with liquid chromatography-mass spectrometry, we were able to co-purify STRIPAK complex interactor 1 (SCI1), the first STRIPAK-associated small coiled-coil protein in filamentous ascomycetes. Using yeast two-hybrid experiments, we identified SCI1 protein regions required for SCI1-PRO11 interaction, dimerization of SCI1 and interaction with other STRIPAK components. Further, both proteins PRO11 and SCI1 co-localize with the nuclear basket protein SmPOM152 at the nuclear envelope. Expression of the gene sci1 occurs during early developmental stages of S. macrospora, and the protein SCI1 in combination with PRO11 is required for cell fusion, vegetative growth and sexual development. The results of the present study will help to understand the underlying molecular mechanisms of STRIPAK signaling and function in cellular development and diseases in higher eukaryotes.
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Affiliation(s)
- Eva J Reschka
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
| | - Steffen Nordzieke
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany
| | - Oliver Valerius
- Institute of Microbiology and Genetics, Department of Molecular Microbiology & Genetics, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
| | - Gerhard H Braus
- Institute of Microbiology and Genetics, Department of Molecular Microbiology & Genetics, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
| | - Stefanie Pöggeler
- Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences (GZMB), Georg-August University, Göttingen, Germany
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7
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Scott B, Green K, Berry D. The fine balance between mutualism and antagonism in the Epichloë festucae-grass symbiotic interaction. Curr Opin Plant Biol 2018; 44:32-38. [PMID: 29454183 DOI: 10.1016/j.pbi.2018.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 05/27/2023]
Abstract
Epichloë endophytes form mutualistic symbiotic associations with aerial tissues of temperate grasses. Intercalary growth of hyphae within the leaves enables fungal growth to be synchronized with host leaf growth, leading to formation of a highly structured and tightly regulated symbiotic network. Mutations in fungal genes that disrupt cell-cell fusion and other key signalling pathways lead to an antagonistic interaction characterized by unregulated growth of endophytic hyphae and detrimental effects on host growth. Transcriptome analysis of these mutant associations provides key insights into the regulation of the symbiosis. In nature a similar switch in growth occurs when hyphae transition into the sexual cycle forming stromata that abort host inflorescences. Endophyte infection of the grass host leads to a major reprogramming of host metabolism and alters host development. Changes in endophyte cell wall structure and the repertoire of effectors secreted into the host apoplast accompany establishment of a mutualistic interaction within the leaves.
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Affiliation(s)
- Barry Scott
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
| | - Kimberly Green
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
| | - Daniel Berry
- Institute of Molecular BioSciences and Bioprotection Research Centre, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand
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Kim MS, Zhang H, Yan H, Yoon BJ, Shim WB. Characterizing co-expression networks underpinning maize stalk rot virulence in Fusarium verticillioides through computational subnetwork module analyses. Sci Rep 2018; 8:8310. [PMID: 29844502 PMCID: PMC5974142 DOI: 10.1038/s41598-018-26505-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/11/2018] [Indexed: 11/15/2022] Open
Abstract
Fusarium verticillioides is recognized as an important stalk rot pathogen of maize worldwide, but our knowledge of genetic mechanisms underpinning this pathosystem is limited. Previously, we identified a striatin-like protein Fsr1 that plays an important role in stalk rot. To further characterize transcriptome networks downstream of Fsr1, we performed next-generation sequencing (NGS) to investigate relative read abundance and also to infer co-expression networks utilizing the preprocessed expression data through partial correlation. We used a probabilistic pathway activity inference strategy to identify functional subnetwork modules likely involved in virulence. Each subnetwork modules consisted of multiple correlated genes with coordinated expression patterns, but the collective activation levels were significantly different in F. verticillioides wild type versus fsr1 mutant. We also identified putative hub genes from predicted subnetworks for functional validation and network robustness studies through mutagenesis, virulence and qPCR assays. Our results suggest that these genes are important virulence genes that regulate the expression of closely correlated genes, demonstrating that these are important hubs of their respective subnetworks. Lastly, we used key F. verticillioides virulence genes to computationally predict a subnetwork of maize genes that potentially respond to fungal genes by applying cointegration-correlation-expression strategy.
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Affiliation(s)
- Man S Kim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States.,Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843, United States
| | - Huan Zhang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States
| | - Huijuan Yan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States
| | - Byung-Jun Yoon
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843, United States
| | - Won Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States.
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9
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Zhang H, Mukherjee M, Kim J, Yu W, Shim W. Fsr1, a striatin homologue, forms an endomembrane-associated complex that regulates virulence in the maize pathogen Fusarium verticillioides. Mol Plant Pathol 2018; 19:812-826. [PMID: 28467007 PMCID: PMC6638083 DOI: 10.1111/mpp.12562] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/06/2017] [Indexed: 05/09/2023]
Abstract
Fsr1, a homologue of mammalian striatin, containing multiple protein-binding domains and a coiled-coil (CC) domain, is critical for Fusarium verticillioides virulence. In mammals, striatin interacts with multiple proteins to form a STRIPAK (striatin-interacting phosphatase and kinase) complex that regulates a variety of developmental processes and cellular mechanisms. In this study, we identified the homologue of a key mammalian STRIPAK component STRIP1/2 (striatin-interacting proteins 1 and 2) in F. verticillioides, FvStp1, which interacts with Fsr1 in vivo. Gene deletion analysis indicates that FvStp1 is critical for F. verticillioides stalk rot virulence. In addition, we identified three proteins, designated FvCyp1, FvScp1 and FvSel1, which interact with the Fsr1 CC domain via a yeast two-hybrid screen. Importantly, FvCyp1, FvScp1 and FvSel1 co-localize to endomembrane structures, each having a preferred localization in the cell, and they are all required for F. verticillioides stalk rot virulence. Moreover, these proteins are necessary for the correct localization of Fsr1 to the endoplasmic reticulum (ER) and nuclear envelope. Thus, we identified several novel components in the STRIPAK complex that regulates F. verticillioides virulence, and propose that the correct organization and localization of Fsr1 are critical for STRIPAK complex function.
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Affiliation(s)
- Huan Zhang
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Mala Mukherjee
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Jung‐Eun Kim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Wenying Yu
- College of Life Science, Fujian Agricultural and Forestry UniversityFuzhou 350002China
| | - Won‐Bo Shim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
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10
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Zhao X, Spraker JE, Bok JW, Velk T, He ZM, Keller NP. A Cellular Fusion Cascade Regulated by LaeA Is Required for Sclerotial Development in Aspergillus flavus. Front Microbiol 2017; 8:1925. [PMID: 29051754 PMCID: PMC5633613 DOI: 10.3389/fmicb.2017.01925] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/21/2017] [Indexed: 11/13/2022] Open
Abstract
Aspergillus flavus is a saprophytic soil fungus that poses a serious threat worldwide as it contaminates many food and feed crops with the carcinogenic mycotoxin called aflatoxin. This pathogen persists as sclerotia in the soil which enables fungal survival in harsh environmental conditions. Sclerotia formation by A. flavus depends on successful cell communication and hyphal fusion events. Loss of LaeA, a conserved developmental regulator in fungi, abolishes sclerotia formation in this species whereas overexpression (OE) of laeA results in enhanced sclerotia production. Here we demonstrate that sclerotia loss and inability to form heterokaryons in A. flavusΔlaeA is mediated by homologs of the Neurospora crassa ham (hyphal anastomosis) genes termed hamE-I in A. flavus. LaeA positively regulates ham gene expression and deletion of hamF, G, H, or I phenocopies ΔlaeA as demonstrated by heterokaryon and sclerotia loss and reduced aflatoxin synthesis and virulence of these mutants. Deletion of hamE showed a less severe phenotype. hamE-I homologs are positively regulated by the clock controlled transcription factor ADV-1 in N. crassa. Similarly, the ADV-1 homolog NosA regulates hamE-I expression in A. flavus, is required for sclerotial development and is itself positively regulated by LaeA. We speculate that a putative LaeA>NosA>fusion cascade underlies the previously described circadian clock regulation of sclerotia production in A. flavus.
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Affiliation(s)
- Xixi Zhao
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph E Spraker
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jin Woo Bok
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Thomas Velk
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Zhu-Mei He
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States
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11
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Islam KT, Bond JP, Fakhoury AM. FvSTR1, a striatin orthologue in Fusarium virguliforme, is required for asexual development and virulence. Appl Microbiol Biotechnol 2017; 101:6431-6445. [PMID: 28643182 DOI: 10.1007/s00253-017-8387-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/07/2017] [Accepted: 06/10/2017] [Indexed: 02/07/2023]
Abstract
The soil-borne fungus Fusarium virguliforme causes sudden death syndrome (SDS), one of the most devastating diseases of soybean in North and South America. Despite the importance of SDS, a clear understanding of the fungal pathogenicity factors that affect the development of this disease is still lacking. We have identified FvSTR1, a F. virguliforme gene, which encodes a protein similar to a family of striatin proteins previously reported to regulate signalling pathways, cell differentiation, conidiation, sexual development, and virulence in filamentous fungi. Striatins are multi-domain proteins that serve as scaffolding units in the striatin-interacting phosphatase and kinase (STRIPAK) complex in fungi and animals. To address the function of a striatin homologue in F. virguliforme, FvSTR1 was disrupted and functionally characterized using a gene knock out strategy. The resulting Fvstr1 mutants were largely impaired in conidiation and pigmentation, and displayed defective conidia and conidiophore morphology compared to the wild-type and ectopic transformants. Greenhouse virulence assays revealed that the disruption of FvSTR1 resulted in complete loss of virulence in F. virguliforme. Microtome studies using fluorescence microscopy showed that the Fvstr1 mutants were defective in their ability to colonize the vascular system. The Fvstr1 mutants also showed a reduced transcript level of genes involved in asexual reproduction and in the production of secondary metabolites. These results suggest that FvSTR1 has a critical role in asexual development and virulence in F. virguliforme.
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Affiliation(s)
- Kazi T Islam
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Jason P Bond
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Ahmad M Fakhoury
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA.
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Green KA, Becker Y, Tanaka A, Takemoto D, Fitzsimons HL, Seiler S, Lalucque H, Silar P, Scott B. SymB and SymC, two membrane associated proteins, are required forEpichloë festucaehyphal cell-cell fusion and maintenance of a mutualistic interaction withLolium perenne. Mol Microbiol 2016; 103:657-677. [DOI: 10.1111/mmi.13580] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Bioprotection Research Centre, Massey University; Palmerston North 4442 New Zealand
| | - Yvonne Becker
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Leibniz Institute of Vegetable and Ornamental Crops; Großbeeren 14979 Germany
| | - Aiko Tanaka
- Graduate School of Bioagricultural Sciences; Nagoya University; Nagoya 464-8601 Japan
| | - Daigo Takemoto
- Graduate School of Bioagricultural Sciences; Nagoya University; Nagoya 464-8601 Japan
| | - Helen L. Fitzsimons
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
| | - Stephan Seiler
- Freiburg Institute for Advanced Studies, Albert-Ludwigs Universität Freiburg; Freiburg Germany
| | - Hervé Lalucque
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire des Energies de Demain; Paris 75205 France
| | - Philippe Silar
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire des Energies de Demain; Paris 75205 France
| | - Barry Scott
- Institute of Fundamental Sciences, Massey University; Palmerston North 4442 New Zealand
- Bioprotection Research Centre, Massey University; Palmerston North 4442 New Zealand
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Green KA, Becker Y, Fitzsimons HL, Scott B. An Epichloë festucae homologue of MOB3, a component of the STRIPAK complex, is required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. Mol Plant Pathol 2016; 17:1480-1492. [PMID: 27277141 PMCID: PMC5132070 DOI: 10.1111/mpp.12443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/06/2016] [Indexed: 05/13/2023]
Abstract
In both Sordaria macrospora and Neurospora crassa, components of the conserved STRIPAK (striatin-interacting phosphatase and kinase) complex regulate cell-cell fusion, hyphal network development and fruiting body formation. Interestingly, a number of Epichloë festucae genes that are required for hyphal cell-cell fusion, such as noxA, noxR, proA, mpkA and mkkA, are also required for the establishment of a mutualistic symbiotic interaction with Lolium perenne. To determine whether MobC, a homologue of the STRIPAK complex component MOB3 in S. macrospora and N. crassa, is required for E. festucae hyphal fusion and symbiosis, a mobC deletion strain was generated. The ΔmobC mutant showed reduced rates of hyphal cell-cell fusion, formed intrahyphal hyphae and exhibited enhanced conidiation. Plants infected with ΔmobC were severely stunted. Hyphae of ΔmobC showed a proliferative pattern of growth within the leaves of Lolium perenne with increased colonization of the intercellular spaces and vascular bundles. Although hyphae were still able to form expressoria, structures allowing the colonization of the leaf surface, the frequency of formation was significantly reduced. Collectively, these results show that the STRIPAK component MobC is required for the establishment of a mutualistic symbiotic association between E. festucae and L. perenne, and plays an accessory role in the regulation of hyphal cell-cell fusion and expressorium development in E. festucae.
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Affiliation(s)
- Kimberly A. Green
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Yvonne Becker
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Helen L. Fitzsimons
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
| | - Barry Scott
- Institute of Fundamental Sciences, Massey UniversityPalmerston North 4442New Zealand
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Fleißner A, Herzog S. Signal exchange and integration during self-fusion in filamentous fungi. Semin Cell Dev Biol 2016; 57:76-83. [DOI: 10.1016/j.semcdb.2016.03.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/06/2016] [Accepted: 03/22/2016] [Indexed: 11/16/2022]
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