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Son YE, Yu JH, Park HS. Regulators of the Asexual Life Cycle of Aspergillus nidulans. Cells 2023; 12:1544. [PMID: 37296664 PMCID: PMC10253035 DOI: 10.3390/cells12111544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/01/2023] [Accepted: 06/02/2023] [Indexed: 06/12/2023] Open
Abstract
The genus Aspergillus, one of the most abundant airborne fungi, is classified into hundreds of species that affect humans, animals, and plants. Among these, Aspergillus nidulans, as a key model organism, has been extensively studied to understand the mechanisms governing growth and development, physiology, and gene regulation in fungi. A. nidulans primarily reproduces by forming millions of asexual spores known as conidia. The asexual life cycle of A. nidulans can be simply divided into growth and asexual development (conidiation). After a certain period of vegetative growth, some vegetative cells (hyphae) develop into specialized asexual structures called conidiophores. Each A. nidulans conidiophore is composed of a foot cell, stalk, vesicle, metulae, phialides, and 12,000 conidia. This vegetative-to-developmental transition requires the activity of various regulators including FLB proteins, BrlA, and AbaA. Asymmetric repetitive mitotic cell division of phialides results in the formation of immature conidia. Subsequent conidial maturation requires multiple regulators such as WetA, VosA, and VelB. Matured conidia maintain cellular integrity and long-term viability against various stresses and desiccation. Under appropriate conditions, the resting conidia germinate and form new colonies, and this process is governed by a myriad of regulators, such as CreA and SocA. To date, a plethora of regulators for each asexual developmental stage have been identified and investigated. This review summarizes our current understanding of the regulators of conidial formation, maturation, dormancy, and germination in A. nidulans.
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Affiliation(s)
- Ye-Eun Son
- Major in Food Biomaterials, School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Jae-Hyuk Yu
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, Madison, WI 53706, USA;
| | - Hee-Soo Park
- Major in Food Biomaterials, School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea;
- Department of Integrative Biology, Kyungpook National University, Daegu 41566, Republic of Korea
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2
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Le THT, Le TN, Yoshimi A, Abe K, Imanishi-Shimizu Y, Shimizu K. Hyperosmotic medium partially restores the growth defect and the impaired production of sterigmatocystin of an Aspergillus nidulans ΔpmtC mutant in a HogA-independent manner. FEMS Microbiol Lett 2021; 368:6373441. [PMID: 34549285 DOI: 10.1093/femsle/fnab127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
The protein O-mannosyltransferase catalyzes O-mannosylation in the endoplasmic reticulum by transferring mannose to the seryl or threonyl residues of substrate proteins. We previously reported a deletion mutant of O-mannosyltransferase C (ΔpmtC) in Aspergillus nidulans with impaired vegetative growth and sterigmatocystin (ST) production. In this study, we investigated whether osmotic conditions contribute to the developmental processes and ST biosynthesis of the ΔpmtC deletion mutant. We found that hyphal growth and ST production partially improved in the presence of NaCl, KCl or sorbitol as osmotic stabilizers. Conidiation of the ΔpmtC deletion mutant was not restored under osmotic stress conditions when the hogA gene was deleted. The hogA gene encodes a protein required for the cellular response to osmotic pressure. However, the yield of ST and the vegetative growth of the ΔhogA ΔpmtC double deletant was restored by high osmolarity in a HogA-independent manner.
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Affiliation(s)
- Thi Huynh Tram Le
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan.,Division of Microbial Biotechnology, Biotechnology Center of Ho Chi Minh City, Vietnam
| | - Thy Nhan Le
- Faculty of Biological Sciences, Nong Lam University of Ho Chi Minh City, Vietnam
| | - Akira Yoshimi
- New Industry Creation Hatchery Center, Tohoku University, Miyagi, Japan.,Laboratory of Environmental Interface Technology of Filamentous Fungi, Kyoto University, Kyoto, Japan
| | - Keietsu Abe
- New Industry Creation Hatchery Center, Tohoku University, Miyagi, Japan.,Laboratory of Applied Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Sciences, Tohoku University, Miyagi, Japan
| | - Yumi Imanishi-Shimizu
- Department of Bioscience, College of Science and Engineering, Kanto Gakuin University, Yokohama, Japan
| | - Kiminori Shimizu
- Department of Biological Science and Technology, Tokyo University of Science, Tokyo, Japan.,Medical Mycology Research Center, Chiba University, Chiba, Japan
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O-mannosyltransferase MaPmt2 contributes to stress tolerance, cell wall integrity and virulence in Metarhizium acridum. J Invertebr Pathol 2021; 184:107649. [PMID: 34343571 DOI: 10.1016/j.jip.2021.107649] [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] [Received: 05/23/2021] [Revised: 07/24/2021] [Accepted: 07/25/2021] [Indexed: 11/22/2022]
Abstract
As a conserved post-translational modification, O-mannosyltransferase families play important roles in many cellular processes. Three subfamilies (MaPmt1, MaPmt2 and MaPmt4) are grouped in Metarhizium acridum according to sequence homology. The functions of MaPmt1 and MaPmt4 have been characterized in M. acridum previously. In this study, the functions of another member belonging to the Pmt2 subfamily, MaPmt2, were identified through RNAi strategy. The three MaPmt2 knockdown mutants showed dramatically decreased expression of MaPmt2. Phenotypic analyses showed that the mutants exhibited decreased tolerances to wet-heat, UV-B irradiation and cell wall perturbing chemicals. Further studies revealed that the mutants presented thinner cell walls observed by transmission electron microscope combined with changed cell wall components. Besides, knockdown of MaPmt2 decelerated conidial germination and decreased conidial yield. Compared with the wild-type strain, the MaPmt2 knockdown mutants caused impaired virulence only by topical inoculation. Results illustrated that the decreased virulence by inoculation could result from the delayed conidial germination on locust wings, reduced appressorium formation, as well as reduced turgor pressure in MaPmt2 knockdown mutants.
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Plaza V, Silva-Moreno E, Castillo L. Breakpoint: Cell Wall and Glycoproteins and their Crucial Role in the Phytopathogenic Fungi Infection. Curr Protein Pept Sci 2021; 21:227-244. [PMID: 31490745 DOI: 10.2174/1389203720666190906165111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/02/2019] [Accepted: 08/17/2019] [Indexed: 01/09/2023]
Abstract
The cell wall that surrounds fungal cells is essential for their survival, provides protection against physical and chemical stresses, and plays relevant roles during infection. In general, the fungal cell wall is composed of an outer layer of glycoprotein and an inner skeletal layer of β-glucans or α- glucans and chitin. Chitin synthase genes have been shown to be important for septum formation, cell division and virulence. In the same way, chitin can act as a potent elicitor to activate defense response in several plant species; however, the fungi can convert chitin to chitosan during plant infection to evade plant defense mechanisms. Moreover, α-1,3-Glucan, a non-degradable polysaccharide in plants, represents a key feature in fungal cell walls formed in plants and plays a protective role for this fungus against plant lytic enzymes. A similar case is with β-1,3- and β-1,6-glucan which are essential for infection, structure rigidity and pathogenicity during fungal infection. Cell wall glycoproteins are also vital to fungi. They have been associated with conidial separation, the increase of chitin in conidial cell walls, germination, appressorium formation, as well as osmotic and cell wall stress and virulence; however, the specific roles of glycoproteins in filamentous fungi remain unknown. Fungi that can respond to environmental stimuli distinguish these signals and relay them through intracellular signaling pathways to change the cell wall composition. They play a crucial role in appressorium formation and penetration, and release cell wall degrading enzymes, which determine the outcome of the interaction with the host. In this review, we highlight the interaction of phypatophogen cell wall and signaling pathways with its host and their contribution to fungal pathogenesis.
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Affiliation(s)
- Verónica Plaza
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
| | - Evelyn Silva-Moreno
- Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Temuco, Chile
| | - Luis Castillo
- Laboratorio de Biología Molecular y Bioquímica, Departamento de Biología, Universidad de La Serena, La Serena, Chile
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Wen Z, Tian H, Xia Y, Jin K. MaPmt1, a protein O-mannosyltransferase, contributes to virulence through governing the appressorium turgor pressure in Metarhizium acridum. Fungal Genet Biol 2020; 145:103480. [DOI: 10.1016/j.fgb.2020.103480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022]
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Son YE, Cho HJ, Chen W, Son SH, Lee MK, Yu JH, Park HS. The role of the VosA-repressed dnjA gene in development and metabolism in Aspergillus species. Curr Genet 2020; 66:621-633. [PMID: 32060628 DOI: 10.1007/s00294-020-01058-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/27/2020] [Accepted: 01/30/2020] [Indexed: 12/13/2022]
Abstract
The DnaJ family of proteins (or J-proteins) are molecular chaperones that govern protein folding, degradation, and translocation in many organisms. Although J-proteins play key roles in eukaryotic and prokaryotic biology, the role of J-proteins in Aspergillus species is currently unknown. In this study, we characterized the dnjA gene, which encodes a putative DnaJ protein, in two Aspergillus species: Aspergillus nidulans and Aspergillus flavus. Expression of the dnjA gene is inhibited by the velvet regulator VosA, which plays a pivotal role in spore survival and metabolism in Aspergillus. The deletion of dnjA decreased the number of asexual spores (conidia), produced abnormal conidiophores, and reduced sexual fruiting bodies (cleistothecia) or sclerotia. In addition, the absence of dnjA caused increased sterigmatocystin or aflatoxin production in A. nidulans and A. flavus, respectively. These results suggest that DnjA plays a conserved role in asexual and sexual development and mycotoxin production in Aspergillus species. However, DnjA also plays a species-specific role; AniDnjA but not AflDnjA, affects conidial viability, trehalose contents, and thermal tolerance of conidia. In plant virulence assay, the infection ability of the ΔAfldnjA mutant decreased in the kernels, suggesting that DnjA plays a crucial role in the pathogenicity of A. flavus. Taken together, these results demonstrate that DnjA is multifunctional in Aspergillus species; it is involved in diverse biological processes, including fungal differentiation and secondary metabolism.
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Affiliation(s)
- Ye-Eun Son
- School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea
| | - He-Jin Cho
- School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea
| | - Wanping Chen
- Department of Molecular Microbiology and Genetics, University of Gottingen, Göttingen, Germany
| | - Sung-Hun Son
- School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea
| | - Mi-Kyung Lee
- Biological Resource Center (BRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup-si, Republic of Korea
| | - Jae-Hyuk Yu
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA.,Department of Systems Biotechnology, Konkuk University, Seoul, 05030, Republic of Korea
| | - Hee-Soo Park
- School of Food Science and Biotechnology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
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Identification and Characterization of Aspergillus nidulans Mutants Impaired in Asexual Development under Phosphate Stress. Cells 2019; 8:cells8121520. [PMID: 31779253 PMCID: PMC6952808 DOI: 10.3390/cells8121520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 01/04/2023] Open
Abstract
The transcription factor BrlA plays a central role in the production of asexual spores (conidia) in the fungus Aspergillus nidulans. BrlA levels are controlled by signal transducers known collectively as UDAs. Furthermore, it governs the expression of CDP regulators, which control most of the morphological transitions leading to the production of conidia. In response to the emergence of fungal cells in the air, the main stimulus triggering conidiation, UDA mutants such as the flbB deletant fail to induce brlA expression. Nevertheless, ΔflbB colonies conidiate profusely when they are cultured on a medium containing high H2PO4− concentrations, suggesting that the need for FlbB activity is bypassed. We used this phenotypic trait and an UV-mutagenesis procedure to isolate ΔflbB mutants unable to conidiate under these stress conditions. Transformation of mutant FLIP166 with a wild-type genomic library led to the identification of the putative transcription factor SocA as a multicopy suppressor of the FLIP (Fluffy, aconidial, In Phosphate) phenotype. Deregulation of socA altered both growth and developmental patterns. Sequencing of the FLIP166 genome enabled the identification and characterization of PmtCP282L as the recessive mutant form responsible for the FLIP phenotype. Overall, results validate this strategy for identifying genes/mutations related to the control of conidiation.
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The endocytic cargo adaptor complex is required for cell-wall integrity via interacting with the sensor FgWsc2B in Fusarium graminearum. Curr Genet 2019; 65:1071-1080. [DOI: 10.1007/s00294-019-00961-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 01/09/2023]
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MaPmt4, a protein O-mannosyltransferase, contributes to cell wall integrity, stress tolerance and virulence in Metarhizium acridum. Curr Genet 2019; 65:1025-1040. [DOI: 10.1007/s00294-019-00957-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 03/04/2019] [Accepted: 03/16/2019] [Indexed: 12/23/2022]
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Zhang F, Geng L, Huang L, Deng J, Fasoyin OE, Yao G, Wang S. Contribution of peroxisomal protein importer AflPex5 to development and pathogenesis in the fungus Aspergillus flavus. Curr Genet 2018; 64:1335-1348. [PMID: 29869688 DOI: 10.1007/s00294-018-0851-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
Abstract
Peroxisomes are important organelles that have diverse metabolic functions and participate in the pathogenicity of fungal pathogens. Previous studies indicate that most functions of peroxisomes are dependent on peroxisomal matrix proteins, which are delivered from the cytoplasm into peroxisomes by peroxisomal protein importers. In this study, the roles of peroxisomal protein importer AflPex5 were investigated in Aspergillus flavus with the application of gene disruption. AflPex5 deletion mutants failed to localize the fluorescently fused peroxisomal targeting signal 1 (PTS1) proteins to peroxisomes. Deletion of AflPex5 caused defects in sporulation, sclerotial formation, aflatoxin biosynthesis, stress response, and plant infection. Moreover, AflPex5 null mutants exhibited a significant defect in carbon metabolism and oxidants' clearance. These results indicate that the PTS1 pathway mediated by AflPex5 serves as an important role in the development, metabolism, and pathogenesis of A. flavus.
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Affiliation(s)
- Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Longpo Geng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Luhua Huang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jili Deng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Opemipo Esther Fasoyin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Guangshan Yao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
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