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Pandit SS, Zheng J, Yin Y, Lorber S, Puel O, Dhingra S, Espeso EA, Calvo AM. Homeobox transcription factor HbxA influences expression of over one thousand genes in the model fungus Aspergillus nidulans. PLoS One 2023; 18:e0286271. [PMID: 37478074 PMCID: PMC10361519 DOI: 10.1371/journal.pone.0286271] [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] [Received: 02/24/2023] [Accepted: 05/11/2023] [Indexed: 07/23/2023] Open
Abstract
In fungi, conserved homeobox-domain proteins are transcriptional regulators governing development. In Aspergillus species, several homeobox-domain transcription factor genes have been identified, among them, hbxA/hbx1. For instance, in the opportunistic human pathogen Aspergillus fumigatus, hbxA is involved in conidial production and germination, as well as virulence and secondary metabolism, including production of fumigaclavines, fumiquinazolines, and chaetominine. In the agriculturally important fungus Aspergillus flavus, disruption of hbx1 results in fluffy aconidial colonies unable to produce sclerotia. hbx1 also regulates production of aflatoxins, cyclopiazonic acid and aflatrem. Furthermore, transcriptome studies revealed that hbx1 has a broad effect on the A. flavus genome, including numerous genes involved in secondary metabolism. These studies underline the importance of the HbxA/Hbx1 regulator, not only in developmental processes but also in the biosynthesis of a broad number of fungal natural products, including potential medical drugs and mycotoxins. To gain further insight into the regulatory scope of HbxA in Aspergilli, we studied its role in the model fungus Aspergillus nidulans. Our present study of the A. nidulans hbxA-dependent transcriptome revealed that more than one thousand genes are differentially expressed when this regulator was not transcribed at wild-type levels, among them numerous transcription factors, including those involved in development as well as in secondary metabolism regulation. Furthermore, our metabolomics analyses revealed that production of several secondary metabolites, some of them associated with A. nidulans hbxA-dependent gene clusters, was also altered in deletion and overexpression hbxA strains compared to the wild type, including synthesis of nidulanins A, B and D, versicolorin A, sterigmatocystin, austinol, dehydroaustinol, and three unknown novel compounds.
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Affiliation(s)
- Sandesh S. Pandit
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
| | - Jinfang Zheng
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Yanbin Yin
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Sophie Lorber
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Sourabh Dhingra
- Department of Biological Sciences and Eukaryotic Pathogen Innovation Center, Clemson University, Clemson, South Carolina, United States of America
| | - Eduardo A. Espeso
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas Margarita Salas (CSIC), Madrid, Spain
| | - Ana M. Calvo
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, United States of America
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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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srdA mutations suppress the rseA/cpsA deletion mutant conidiation defect in Aspergillus nidulans. Sci Rep 2023; 13:4285. [PMID: 36922566 PMCID: PMC10017718 DOI: 10.1038/s41598-023-31363-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
Conidiation is an important reproductive process in Aspergillus. We previously reported, in A. nidulans, that the deletion of a putative glycosyltransferase gene, rseA/cpsA, causes an increase in the production of extracellular hydrolases and a severe reduction in conidiation. The aim of this study was to obtain novel genetic factors involved in the repression of conidiation in the rseA deletion mutant. We isolated mutants in which the rseA deletion mutant conidiation defect is suppressed and performed a comparative genomic analysis of these mutants. A gene encoding a putative transcription factor was identified as the associated candidate causative gene. The candidate gene was designated as srdA (suppressor gene for the conidiation defect of the rseA deletion mutant). The conidiation efficiency of the rseAsrdA double-deletion mutant was increased. Introduction of wild-type srdA into the suppressor mutants caused a conidiation defect similar to that of the rseA deletion mutant. Notably, the conidiation efficiencies of the rseAsrdA double-deletion and srdA single-deletion mutants were higher than that of the wild-type strain. These results indicate that srdA is a novel genetic factor that strongly represses conidiation of the rseA deletion mutant, and a putative transcriptional regulator, SrdA is a negative regulator of conidiation in A. nidulans.
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Zhuang Z, Pan X, Zhang M, Liu Y, Huang C, Li Y, Hao L, Wang S. Set2 family regulates mycotoxin metabolism and virulence via H3K36 methylation in pathogenic fungus Aspergillus flavus. Virulence 2022; 13:1358-1378. [PMID: 35943142 PMCID: PMC9364737 DOI: 10.1080/21505594.2022.2101218] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Aspergillus flavus infects various crops with aflatoxins, and leads to aspergillosis opportunistically. Though H3K36 methylation plays an important role in fungal toxin metabolism and virulence, no data about the biological function of H3K36 methylation in A. flavus virulence has been reported. Our study showed that the Set2 histone methyltransferase family, AshA and SetB, involves in morphogenesis and mycotoxin anabolism by regulating related transcriptional factors, and they are important for fungal virulence to crops and animals. Western-blotting and double deletion analysis revealed that AshA mainly regulates H3K36me2, whereas SetB is mainly responsible for H3K36me3 in the nucleus. By construction of domain deletion A. flavus strain and point mutation strains by homologous recombination, the study revealed that SET domain is indispensable in mycotoxin anabolism and virulence of A. flavus, and N455 and V457 in it are the key amino acid residues. ChIP analysis inferred that the methyltransferase family controls fungal reproduction and regulates the production of AFB1 by directly regulating the production of the transcriptional factor genes, including wetA, steA, aflR and amylase, through H3K36 trimethylation in their chromatin fragments, based on which this study proposed that, by H3K36 trimethylation, this methyltransferase family controls AFB1 anabolism through transcriptional level and substrate utilization level. This study illuminates the epigenetic mechanism of the Set2 family in regulating fungal virulence and mycotoxin production, and provides new targets for controlling the virulence of the fungus A. flavus.
AUTHOR SUMMARY
The methylation of H3K36 plays an important role in the fungal secondary metabolism and virulence, but no data about the regulatory mechanism of H3K36 methylation in the virulence of A. flavus have been reported. Our study revealed that, in the histone methyltransferase Set2 family, AshA mainly catalyzes H3K36me2, and involves in the methylation of H3K36me1, and SetB mainly catalyzes H3K36me3 and H3K36me1. Through domain deletion and point mutation analysis, this study also revealed that the SET domain was critical for the normal biological function of the Set2 family and that N455 and V457 in the domain were critical for AshA. By ChIP-seq and ChIP-qPCR analysis, H3K36 was found to be trimethylation modified in the promotors and ORF positions of wetA, steA, aflR and the amylase gene (AFLA_084340), and further qRT-PCR results showed that these methylation modifications regulate the expression levels of these genes. According to the results of ChIP-seq analysis, we proposed that, by H3K36 trimethylation, this methyltransferase family controls the metabolism of mycotoxin through transcriptional level and substrate utilization level. All the results from this study showed that Set2 family is essential for fungal secondary metabolism and virulence, which lays a theoretical groundwork in the early prevention and treatment of A. flavus pollution, and also provides an effective strategy to fight against other pathogenic fungi.
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Affiliation(s)
- Zhenhong Zhuang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaohua Pan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Key Laboratory of Propagated Sensation along Meridian, Fujian Academy of Chinese Medical Sciences, Fuzhou, China
| | - Mengjuan Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yaju Liu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chuanzhong Huang
- Immuno-Oncology Laboratory of Fujian Cancer Hospital, Fujian Provincial Key Laboratory of Translational Cancer Medicine, Fujian Medical University Cancer Hospital, Fuzhou, China
| | - Yu Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ling Hao
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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5
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Studying Soil Ecology and Growth Conditions of Phellorinia herculeana, a Wild Edible Mushroom. Processes (Basel) 2022. [DOI: 10.3390/pr10091797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Phellorinia herculeana is an edible mushroom growing in nutritionally poor and desert soil. There has been little information available about its edaphic and culturing conditions for achieving the vigorous mycelial growth essential for its artificial cultivation, bioaugmentation and biodegradation in unfertile soil. Thus, the present study was conducted to assess its edaphic conditions and find a suitable culturing medium for obtaining maximum growth. It grows commonly in coastal soil with saline conditions, barren land soil unfit for cultivation, and desert soil. It forms a basidiocarp singly around xerophytic trees and annual plants and also in soil without vegetation. In addition to a well-developed pileus and stipe, it has a typical rhizoid that grows horizontally in soil. The rhizoid was thick at the base of the stipe and became thin into the mycelial strand. In our earlier study, we reported that its mycelial growth was very poor on nutrient-rich media containing simple sugar, for example, glucose. In the present study, we observed that cereal-grain-based agar media supported its mycelial growth and among the cereal-grain-based agar media, maize agar medium at the 5% level supported the maximum mycelial growth. Incorporation of glucose into the maize agar medium reduced its mycelial growth compared to its growth on maize agar medium without glucose. Its mycelial growth was at a maximum between 34 °C and 37 °C and at a pH between 7 and 8. Mass multiplication using sand-maize medium prepared at the ratio of 19:1 (sand: maize) supported the maximum mycelial growth. The results of this study would certainly pave a way for the scientific community to develop a protocol for its artificial cultivation and also for its mass multiplication, bioaugmentation and biodegradation in unfertile soil.
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Evidencing New Roles for the Glycosyl-Transferase Cps1 in the Phytopathogenic Fungus Botrytis cinerea. J Fungi (Basel) 2022; 8:jof8090899. [PMID: 36135623 PMCID: PMC9500679 DOI: 10.3390/jof8090899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/13/2022] [Accepted: 08/16/2022] [Indexed: 11/28/2022] Open
Abstract
The fungal cell wall occupies a central place in the interaction between fungi and their environment. This study focuses on the role of the putative polysaccharide synthase Cps1 in the physiology, development and virulence of the grey mold-causing agent Botrytis cinerea. Deletion of the Bccps1 gene does not affect the germination of the conidia (asexual spores) or the early mycelial development, but it perturbs hyphal expansion after 24 h, revealing a two-phase hyphal development that has not been reported so far. It causes a severe reduction of mycelial growth in a solid medium and modifies hyphal aggregation into pellets in liquid cultures. It strongly impairs plant penetration, plant colonization and the formation of sclerotia (survival structures). Loss of the BcCps1 protein associates with a decrease in glucans and glycoproteins in the fungus cell wall and the up-accumulation of 132 proteins in the mutant’s exoproteome, among which are fungal cell wall enzymes. This is accompanied by an increased fragility of the mutant mycelium, an increased sensitivity to some environmental stresses and a reduced adhesion to plant surface. Taken together, the results support a significant role of Cps1 in the cell wall biology of B. cinerea.
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7
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Deng Q, Wu H, Gu Q, Tang G, Liu W. Glycosyltransferase FvCpsA Regulates Fumonisin Biosynthesis and Virulence in Fusarium verticillioides. Toxins (Basel) 2021; 13:toxins13100718. [PMID: 34679011 PMCID: PMC8539240 DOI: 10.3390/toxins13100718] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/29/2021] [Indexed: 12/18/2022] Open
Abstract
Fusarium verticillioides is the major maize pathogen associated with ear rot and stalk rot worldwide. Fumonisin B1 (FB1) produced by F. verticillioides, poses a serious threat to human and animal health. However, our understanding of FB1 synthesis and virulence mechanism in this fungus is still very limited. Glycosylation catalyzed by glycosyltransferases (GTs) has been identified as contributing to fungal infection and secondary metabolism synthesis. In this study, a family 2 glycosyltransferase, FvCpsA, was identified and characterized in F. verticillioides. ΔFvcpsA exhibited significant defects in vegetative growth. Moreover, ΔFvcpsA also increased resistance to osmotic and cell wall stress agents. In addition, expression levels of FUM genes involved in FB1 production were greatly up-regulated in ΔFvcpsA. HPLC (high performance liquid chromatography) analysis revealed that ΔFvcpsA significantly increased FB1 production. Interestingly, we found that the deletion of FvCPSA showed penetration defects on cellophane membrane, and thus led to obvious defects in pathogenicity. Characterization of FvCpsA domain experiments showed that conserved DXD and QXXRW domains were vital for the biological functions of FvCpsA. Taken together, our results indicate that FvCpsA is critical for fungal growth, FB1 biosynthesis and virulence in F. verticillioides.
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Affiliation(s)
- Qi Deng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
| | - Hanxiang Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
| | - Qin Gu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China;
| | - Guangfei Tang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
- Correspondence: (G.T.); (W.L.)
| | - 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; (Q.D.); (H.W.)
- Correspondence: (G.T.); (W.L.)
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8
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Ogawa M, Wada H, Yoshimura T, Sato A, Fukuda R, Koyama Y, Horiuchi H. Deletion of Aspergillus nidulans cpsA/rseA induces increased extracellular hydrolase production in solid-state culture partly through the high osmolarity glycerol pathway. J Biosci Bioeng 2021; 131:589-598. [PMID: 33827772 DOI: 10.1016/j.jbiosc.2021.03.002] [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: 11/10/2020] [Revised: 02/21/2021] [Accepted: 03/01/2021] [Indexed: 12/17/2022]
Abstract
Koji molds, such as Aspergillus oryzae and Aspergillus sojae, are used in the food industry in East Asia and have been explored for the large-scale production of extracellular hydrolases. We previously found that the deletion of a gene encoding a putative GT2 glycosyltransferase increased production of extracellular hydrolases in A. sojae. The gene was named rseA (regulator of the secretory enzyme A). We predicted that intracellular signaling pathways were involved in the increased production of hydrolases in the ΔrseA mutant of A. sojae. However, little has been reported on molecular biological knowledge about A. sojae. Hence, Aspergillus nidulans, a typical model organism used in molecular biology, was employed for the functional characterization of rseA in this study. Deletion of the rseA ortholog in A. nidulans induced increased extracellular production of hydrolases under the solid-state cultivation condition, similar to that in A. sojae. The involvement of the cell wall integrity pathway and the high osmolarity glycerol pathway in ΔrseA was further investigated. The results indicated that the HOG pathway played an important role in the increased extracellular production of hydrolases caused by the deletion of the rseA gene. rseA ortholog in A. nidulans was identical to cpsA, which was reported to function as a regulator of mycotoxin production, morphogenesis, and cell wall biosynthesis. However, this is the first study reporting that rseA/cpsA regulates extracellular hydrolase production in A. nidulans.
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Affiliation(s)
- Masahiro Ogawa
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Noda Institute for Scientific Research, 338 Noda, Noda City, Chiba 278-0037, Japan.
| | - Hiroki Wada
- Research and Development Division, Kikkoman Corporation, 338 Noda, Noda City, Chiba 278-0037, Japan.
| | - Taro Yoshimura
- Research and Development Division, Kikkoman Corporation, 338 Noda, Noda City, Chiba 278-0037, Japan.
| | - Atsushi Sato
- Research and Development Division, Kikkoman Corporation, 338 Noda, Noda City, Chiba 278-0037, Japan.
| | - Ryouichi Fukuda
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
| | - Yasuji Koyama
- Noda Institute for Scientific Research, 338 Noda, Noda City, Chiba 278-0037, Japan.
| | - Hiroyuki Horiuchi
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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Wang S, Yuan A, Zeng L, Hou S, Wang M, Li L, Cai Z, Zhong G. The putative polysaccharide synthase AfCps1 regulates Aspergillus fumigatus morphogenesis and conidia immune response in mouse bone marrow-derived macrophages. J Microbiol 2020; 59:64-75. [PMID: 33201436 DOI: 10.1007/s12275-021-0347-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/13/2020] [Accepted: 10/13/2020] [Indexed: 10/23/2022]
Abstract
Aspergillus fumigatus is a well-known opportunistic pathogen that causes invasive aspergillosis (IA) infections with high mortality in immunosuppressed individuals. Morphogenesis, including hyphal growth, conidiation, and cell wall biosynthesis is crucial in A. fumigatus pathogenesis. Based on a previous random insertional mutagenesis library, we identified the putative polysaccharide synthase gene Afcps1 and its para-log Afcps2. Homologs of the cps gene are commonly found in the genomes of most fungal and some bacterial pathogens. Afcps1/cpsA is important in sporulation, cell wall composition, and virulence. However, the precise regulation patterns of cell wall integrity by Afcps1/cpsA and further effects on the immune response are poorly understood. Specifically, our in-depth study revealed that Afcps1 affects cell-wall stability, showing an increased resistance of ΔAfcps1 to the chitinmicrofibril destabilizing compound calcofluor white (CFW) and susceptibility of ΔAfcps1 to the β-(1,3)-glucan synthase inhibitor echinocandin caspofungin (CS). Additionally, deletion of Afcps2 had a normal sporulation phenotype but caused hypersensitivity to Na+ stress, CFW, and Congo red (CR). Specifically, quantitative analysis of cell wall composition using high-performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD) analysis revealed that depletion of Afcps1 reduced cell wall glucan and chitin contents, which was consistent with the down-regulation of expression of the corresponding biosynthesis genes. Moreover, an elevated immune response stimulated by conidia of the ΔAfcps1 mutant in marrow-derived macrophages (BMMs) during phagocytosis was observed. Thus, our study provided new insights into the function of polysaccharide synthase Cps1, which is necessary for the maintenance of cell wall stability and the adaptation of conidia to the immune response of macrophages in A. fumigatus.
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Affiliation(s)
- Sha Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, Huzhou University, Huzhou Central Hospital, Huzhou, P. R. China
| | - Anjie Yuan
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China
| | - Liping Zeng
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China
| | - Sikai Hou
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China
| | - Meng Wang
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China
| | - Lei Li
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China
| | - Zhendong Cai
- Key Laboratory of Animal Protein Deep Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, 315800, P. R. China.
| | - Guowei Zhong
- Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, P. R. China.
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10
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Lv B, Jiang N, Hasan R, Chen Y, Sun M, Li S. Cell Wall Biogenesis Protein Phosphatase CrSsd1 Is Required for Conidiation, Cell Wall Integrity, and Mycoparasitism in Clonostachys rosea. Front Microbiol 2020; 11:1640. [PMID: 32760382 PMCID: PMC7373758 DOI: 10.3389/fmicb.2020.01640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 06/24/2020] [Indexed: 12/29/2022] Open
Abstract
Cell wall biogenesis protein phosphatases play important roles in various cellular processes in fungi. However, their functions in the widely distributed mycoparasitic fungus Clonostachys rosea remain unclear, as do their potential for controlling plant fungal diseases. Herein, the function of cell wall biogenesis protein phosphatase CrSsd1 in C. rosea 67-1 was investigated using gene disruption and complementation approaches. The gene-deficient mutant ΔCrSsd1 exhibited much lower conidiation, hyphal growth, mycoparasitic ability, and biocontrol efficacy than the wild-type (WT) strain, and it was more sensitive to sorbitol and Congo red. The results indicate that CrSsd1 is involved in fungal conidiation, osmotic stress adaptation, cell wall integrity, and mycoparasitism in C. rosea.
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Affiliation(s)
- Binna Lv
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Na Jiang
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rakibul Hasan
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingying Chen
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Manhong Sun
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shidong Li
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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11
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Mesnage R, Oestreicher N, Poirier F, Nicolas V, Boursier C, Vélot C. Transcriptome profiling of the fungus Aspergillus nidulans exposed to a commercial glyphosate-based herbicide under conditions of apparent herbicide tolerance. ENVIRONMENTAL RESEARCH 2020; 182:109116. [PMID: 32069763 DOI: 10.1016/j.envres.2020.109116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 12/18/2019] [Accepted: 01/02/2020] [Indexed: 05/20/2023]
Abstract
Glyphosate-based herbicides, such as Roundup®, are the most widely used non-selective, broad-spectrum herbicides. The release of these compounds in large amounts into the environment is susceptible to affect soil quality and health, especially because of the non-target effects on a large range of organisms including soil microorganisms. The soil filamentous fungus Aspergillus nidulans, a well-characterized experimental model organism that can be used as a bio-indicator for agricultural soil health, has been previously shown to be highly affected by Roundup GT Plus (R450: 450 g/L of glyphosate) at concentrations far below recommended agricultural application rate, including at a dose that does not cause any macroscopic effect. In this study, we determined alterations in the transcriptome of A. nidulans when exposed to R450 at a dose corresponding to the no-observed-adverse-effect level (NOAEL) for macroscopic parameters. A total of 1816 distinct genes had their expression altered. The most affected biological functions were protein synthesis, amino acids and secondary metabolisms, stress response, as well as detoxification pathways through cytochromes P450, glutathione-S-transferases, and ABC transporters. These results partly explain the molecular mechanisms underlying alterations in growth parameters detected at higher concentrations for this ascomycete fungus. In conclusion, our results highlight molecular disturbances in a soil fungus under conditions of apparent tolerance to the herbicide, and thus confirm the need to question the principle of "substantial equivalence" when applied to plants made tolerant to herbicides.
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Affiliation(s)
- Robin Mesnage
- Gene Expression and Therapy Group, King's College London, Faculty of Life Sciences & Medicine, Department of Medical and Molecular Genetics, 8th Floor, Tower Wing, Guy's Hospital, Great Maze Pond, London, SE1 9RT, United Kingdom; CRIIGEN, 42 Rue de Lisbonne, 75008, Paris, France.
| | - Nathalie Oestreicher
- Equipe VEAC, Université Paris-Sud, Faculté des Sciences, Bât. 350, Avenue Jean Perrin, 91405, Orsay, France; Pôle Risques MRSH-CNRS, EA2608, Université de Caen, Esplanade de la Paix, 14032, Caen, France.
| | - Florence Poirier
- Université Paris 13, UFR SMBH, Plateforme PPUP13, 1 Rue de Chablis, 93017, Bobigny Cedex, France.
| | - Valérie Nicolas
- UMS-IPSIT, US31 Inserm-UMS3679 CNRS, Plateformes Trans-Prot et d'Imagerie Cellulaire, Université Paris-Sud, Faculté de Pharmacie, Tour E1, 5 Rue Jean-Baptiste Clément, 92296, Châtenay-Malabry, France.
| | - Céline Boursier
- UMS-IPSIT, US31 Inserm-UMS3679 CNRS, Plateformes Trans-Prot et d'Imagerie Cellulaire, Université Paris-Sud, Faculté de Pharmacie, Tour E1, 5 Rue Jean-Baptiste Clément, 92296, Châtenay-Malabry, France.
| | - Christian Vélot
- CRIIGEN, 42 Rue de Lisbonne, 75008, Paris, France; Equipe VEAC, Université Paris-Sud, Faculté des Sciences, Bât. 350, Avenue Jean Perrin, 91405, Orsay, France; Pôle Risques MRSH-CNRS, EA2608, Université de Caen, Esplanade de la Paix, 14032, Caen, France.
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Nepal B, Myers R, Lohmar JM, Puel O, Thompson B, Van Cura M, Calvo AM. Characterization of the putative polysaccharide synthase CpsA and its effects on the virulence of the human pathogen Aspergillus fumigatus. PLoS One 2019; 14:e0216092. [PMID: 31026268 PMCID: PMC6485754 DOI: 10.1371/journal.pone.0216092] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 04/12/2019] [Indexed: 11/18/2022] Open
Abstract
The fungus Aspergillus fumigatus is a ubiquitous opportunistic human pathogen capable of causing a life-threatening disease called invasive aspergillosis, or IA, with an associated 40-90% mortality rate in immunocompromised patients. Of the approximately 250 species known in the genus Aspergillus, A. fumigatus is responsible for up to 90% of IA infections. This study focuses on examining the role of the putative polysaccharide synthase cpsA gene in A. fumigatus virulence. Additionally, we evaluated its role in cellular processes that influence invasion and colonization of host tissue. Importantly, our results support that cpsA is indispensable for virulence in A. fumigatus infection of non-neutropenic hosts. Our study revealed that cpsA affects growth and sporulation in this fungus. Absence of cpsA resulted in a drastic reduction in conidiation, and forced overexpression of cpsA produced partially fluffy colonies with low sporulation levels, suggesting that wild-type cpsA expression levels are required for proper conidiation in this fungus. This study also showed that cpsA is necessary for normal cell wall integrity and composition. Furthermore, both deletion and overexpression of cpsA resulted in a reduction in the ability of A. fumigatus to adhere to surfaces, and caused increased sensitivity to oxidative stress. Interestingly, metabolomics analysis indicated that cpsA affects A. fumigatus secondary metabolism. Forced overexpression of cpsA resulted in a statistically significant difference in the production of fumigaclavine A, fumigaclavine B, fumigaclavine C, verruculogen TR-2, and tryprostatin A.
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Affiliation(s)
- Binita Nepal
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
| | - Ryan Myers
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
| | - Jessica M. Lohmar
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
| | - Olivier Puel
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Brett Thompson
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
| | - Matthew Van Cura
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
| | - Ana M. Calvo
- Department of Biological Sciences, Northern Illinois University, Dekalb, Illinois, United States of America
- * E-mail:
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The Aspergillus flavus rtfA Gene Regulates Plant and Animal Pathogenesis and Secondary Metabolism. Appl Environ Microbiol 2019; 85:AEM.02446-18. [PMID: 30635379 DOI: 10.1128/aem.02446-18] [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: 10/08/2018] [Accepted: 12/31/2018] [Indexed: 02/04/2023] Open
Abstract
Aspergillus flavus is an opportunistic fungal plant and human pathogen and a producer of mycotoxins, including aflatoxin B1 (AFB1). As part of our ongoing studies to elucidate the biological functions of the A. flavus rtfA gene, we examined its role in the pathogenicity of both plant and animal model systems. rtfA encodes a putative RNA polymerase II (Pol II) transcription elongation factor previously characterized in Saccharomyces cerevisiae, Aspergillus nidulans, and Aspergillus fumigatus, where it was shown to regulate several important cellular processes, including morphogenesis and secondary metabolism. In addition, an initial study in A. flavus indicated that rtfA also influences development and production of AFB1; however, its effect on virulence is unknown. The current study reveals that the rtfA gene is indispensable for normal pathogenicity in plants when using peanut seed as an infection model, as well as in animals, as shown in the Galleria mellonella infection model. Interestingly, rtfA positively regulates several processes known to be necessary for successful fungal invasion and colonization of host tissue, such as adhesion to surfaces, protease and lipase activity, cell wall composition and integrity, and tolerance to oxidative stress. In addition, metabolomic analysis revealed that A. flavus rtfA affects the production of several secondary metabolites, including AFB1, aflatrem, leporins, aspirochlorine, ditryptophenaline, and aflavinines, supporting a role of rtfA as a global regulator of secondary metabolism. Heterologous complementation of an A. flavus rtfA deletion strain with rtfA homologs from A. nidulans or S. cerevisiae fully rescued the wild-type phenotype, indicating that these rtfA homologs are functionally conserved among these three species.IMPORTANCE In this study, the epigenetic global regulator rtfA, which encodes a putative RNA-Pol II transcription elongation factor-like protein, was characterized in the mycotoxigenic and opportunistic pathogen A. flavus Specifically, its involvement in A. flavus pathogenesis in plant and animal models was studied. Here, we show that rtfA positively regulates A. flavus virulence in both models. Furthermore, rtfA-dependent effects on factors necessary for successful invasion and colonization of host tissue by A. flavus were also assessed. Our study indicates that rtfA plays a role in A. flavus adherence to surfaces, hydrolytic activity, normal cell wall formation, and response to oxidative stress. This study also revealed a profound effect of rtfA on the metabolome of A. flavus, including the production of potent mycotoxins.
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UrdA Controls Secondary Metabolite Production and the Balance between Asexual and Sexual Development in Aspergillus nidulans. Genes (Basel) 2018; 9:genes9120570. [PMID: 30477161 PMCID: PMC6316066 DOI: 10.3390/genes9120570] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/15/2018] [Accepted: 11/19/2018] [Indexed: 01/07/2023] Open
Abstract
The genus Aspergillus includes important plant pathogens, opportunistic human pathogens and mycotoxigenic fungi. In these organisms, secondary metabolism and morphogenesis are subject to a complex genetic regulation. Here we functionally characterized urdA, a gene encoding a putative helix-loop-helix (HLH)-type regulator in the model fungus Aspergillus nidulans. urdA governs asexual and sexual development in strains with a wild-type veA background; absence of urdA resulted in severe morphological alterations, with a significant reduction of conidial production and an increase in cleistothecial formation, even in the presence of light, a repressor of sex. The positive effect of urdA on conidiation is mediated by the central developmental pathway (CDP). However, brlA overexpression was not sufficient to restore wild-type conidiation in the ΔurdA strain. Heterologous complementation of ΔurdA with the putative Aspergillus flavus urdA homolog also failed to rescue conidiation wild-type levels, indicating that both genes perform different functions, probably reflected by key sequence divergence. UrdA also represses sterigmatocystin (ST) toxin production in the presence of light by affecting the expression of aflR, the activator of the ST gene cluster. Furthermore, UrdA regulates the production of several unknown secondary metabolites, revealing a broader regulatory scope. Interestingly, UrdA affects the abundance and distribution of the VeA protein in hyphae, and our genetics studies indicated that veA appears epistatic to urdA regarding ST production. However, the distinct fluffy phenotype of the ΔurdAΔveA double mutant suggests that both regulators conduct independent developmental roles. Overall, these results suggest that UrdA plays a pivotal role in the coordination of development and secondary metabolism in A. nidulans.
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