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Feng Y, Cui J, Xu B, Jiang Y, Fu C, Tan L. A Potentially Practicable Halotolerant Yeast Meyerozyma guilliermondii A4 for Decolorizing and Detoxifying Azo Dyes and Its Possible Halotolerance Mechanisms. J Fungi (Basel) 2023; 9:851. [PMID: 37623622 PMCID: PMC10456123 DOI: 10.3390/jof9080851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/09/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023] Open
Abstract
In this study, a halotolerant yeast that is capable of efficiently decolorizing and detoxifying azo dyes was isolated, identified and characterized for coping with the treatment of azo-dye-containing wastewaters. A characterization of the yeast, including the optimization of its metabolism and growth conditions, its detoxification effectiveness and the degradation pathway of the target azo dye, as well as a determination of the key activities of the enzyme, was performed. Finally, the possible halotolerance mechanisms of the yeast were proposed through a comparative transcriptome analysis. The results show that a halotolerant yeast, A4, which could decolorize various azo dyes, was isolated from a marine environment and was identified as Meyerozyma guilliermondii. Its optimal conditions for dye decolorization were ≥1.0 g/L of sucrose, ≥0.2 g/L of (NH4)2SO4, 0.06 g/L of yeast extract, pH 6.0, a temperature of 35 °C and a rotation speed of ≥160 rpm. The yeast, A4, degraded and detoxified ARB through a series of steps, relying on the key enzymes that might be involved in the degradation of azo dye and aromatic compounds. The halotolerance of the yeast, A4, was mainly related to the regulation of the cell wall components and the excessive uptake of Na+/K+ and/or compatible organic solutes into the cells under different salinity conditions. The up-regulation of genes encoding Ca2+-ATPase and casein kinase II as well as the enrichment of KEGG pathways associated with proteasome and ribosome might also be responsible for its halotolerance.
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Affiliation(s)
- Yue Feng
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, Dalian 116081, China; (Y.F.); (J.C.); (Y.J.); (C.F.)
| | - Jingru Cui
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, Dalian 116081, China; (Y.F.); (J.C.); (Y.J.); (C.F.)
| | - Bingwen Xu
- Dalian Center for Certification and Food and Drug Control, Dalian 116037, China;
| | - Yifan Jiang
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, Dalian 116081, China; (Y.F.); (J.C.); (Y.J.); (C.F.)
| | - Chunqing Fu
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, Dalian 116081, China; (Y.F.); (J.C.); (Y.J.); (C.F.)
| | - Liang Tan
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Science, Liaoning Normal University, Dalian 116081, China; (Y.F.); (J.C.); (Y.J.); (C.F.)
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López-Lorca VM, Molina-Luzón MJ, Ferrol N. Characterization of the NRAMP Gene Family in the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis. J Fungi (Basel) 2022; 8:jof8060592. [PMID: 35736075 PMCID: PMC9224570 DOI: 10.3390/jof8060592] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/18/2022] [Accepted: 05/25/2022] [Indexed: 12/04/2022] Open
Abstract
Transporters of the NRAMP family are ubiquitous metal-transition transporters, playing a key role in metal homeostasis, especially in Mn and Fe homeostasis. In this work, we report the characterization of the NRAMP family members (RiSMF1, RiSMF2, RiSMF3.1 and RiSMF3.2) of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis. Phylogenetic analysis of the NRAMP sequences of different AM fungi showed that they are classified in two groups, which probably diverged early in their evolution. Functional analyses in yeast revealed that RiSMF3.2 encodes a protein mediating Mn and Fe transport from the environment. Gene-expression analyses by RT-qPCR showed that the RiSMF genes are differentially expressed in the extraradical (ERM) and intraradical (IRM) mycelium and differentially regulated by Mn and Fe availability. Mn starvation decreased RiSMF1 transcript levels in the ERM but increased RiSMF3.1 expression in the IRM. In the ERM, RiSMF1 expression was up-regulated by Fe deficiency, suggesting a role for its encoded protein in Fe-deficiency alleviation. Expression of RiSMF3.2 in the ERM was up-regulated at the early stages of Fe toxicity but down-regulated at later stages. These data suggest a role for RiSMF3.2 not only in Fe transport but also as a sensor of high external-Fe concentrations. Both Mn- and Fe-deficient conditions affected ERM development. While Mn deficiency increased hyphal length, Fe deficiency reduced sporulation.
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Mori T, Masuda A, Kawagishi H, Hirai H. Ethanol fermentation by saprotrophic white-rot fungus Phanerochaete sordida YK-624 during wood decay as a system for short-term resistance to hypoxic conditions. J Biosci Bioeng 2021; 133:64-69. [PMID: 34728154 DOI: 10.1016/j.jbiosc.2021.10.002] [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: 07/20/2021] [Revised: 09/26/2021] [Accepted: 10/04/2021] [Indexed: 10/19/2022]
Abstract
In this study, major factors involved in regulating ethanol production from wood by the saprotrophic white-rot fungus Phanerochaete sordida YK-624 were investigated. P. sordida YK-624 produced ethanol from wood meal culture without the addition of any nutrients, and ethanol was produced from wood culture only when the oxygen concentration in headspace was reduced to ≤5%; thereafter, ethanol production ceased within a few days. Analyses of gene expression during aerobic incubation indicated that P. sordida simultaneously upregulates the glycolytic pathway from sugar uptake to pyruvate conversion during ethanol fermentation and suppresses pyruvate influx into the TCA cycle. Upon termination of ethanol fermentation, the expression of all tested genes was repressed, and the fungus ceased to grow. In contrast, the fungus could utilize ethanol for aerobic growth. These results suggest that ethanol fermentation by P. sordida functions as a short-term stress response system under anaerobic conditions during wood decay, enabling the fungus to rapidly resume growing when oxygen is supplied (e.g., following breakdown of plant cell walls or removal of the fungus from water immersion). This is the first report to describe the physiologic significance of ethanol fermentation in saprotrophic white-rot fungi.
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Affiliation(s)
- Toshio Mori
- Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.
| | - Akane Masuda
- Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Hirokazu Kawagishi
- Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan; Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan; Graduate School of Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Hirofumi Hirai
- Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan; Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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Identification and characterization of Nramp transporter AoNramp1 in Aspergillus oryzae. 3 Biotech 2021; 11:452. [PMID: 34631353 DOI: 10.1007/s13205-021-02998-z] [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: 05/04/2021] [Accepted: 09/17/2021] [Indexed: 01/27/2023] Open
Abstract
The Nramp (natural resistance-associated macrophage protein) family of genes has been identified and characterized widely in many species. However, the Nramp genes and their characterizations have not been reported for Aspergillus oryzae. Here, only one Nramp gene AoNramp1 in A. oryzae genome was identified. Phylogenetic analysis revealed that AoNramp1 is not clustered with Nramps from yeast genus. Expression analysis showed that the transcript level of AoNramp1 was strongly induced under both Zn/Mn-replete and -deplete conditions. The GUS-staining assay indicated that the expression of AoNramp1 was strongly induced by Zn/Mn. Moreover, the AoNramp1 deletion and overexpression strains were constructed by the CRISPR/Cas9 system and A. oryzae amyB promoter, respectively. Phenotypic analysis showed that overexpression and deletion of AoNramp1 caused growth defects under Zn/Mn-deplete and -replete conditions, including mycelium growth and conidia formation. Together, these findings provide valuable information for further study on the biological roles of AoNramp1 in A. oryzae. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02998-z.
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Robinson JR, Isikhuemhen OS, Anike FN. Fungal-Metal Interactions: A Review of Toxicity and Homeostasis. J Fungi (Basel) 2021; 7:225. [PMID: 33803838 PMCID: PMC8003315 DOI: 10.3390/jof7030225] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022] Open
Abstract
Metal nanoparticles used as antifungals have increased the occurrence of fungal-metal interactions. However, there is a lack of knowledge about how these interactions cause genomic and physiological changes, which can produce fungal superbugs. Despite interest in these interactions, there is limited understanding of resistance mechanisms in most fungi studied until now. We highlight the current knowledge of fungal homeostasis of zinc, copper, iron, manganese, and silver to comprehensively examine associated mechanisms of resistance. Such mechanisms have been widely studied in Saccharomyces cerevisiae, but limited reports exist in filamentous fungi, though they are frequently the subject of nanoparticle biosynthesis and targets of antifungal metals. In most cases, microarray analyses uncovered resistance mechanisms as a response to metal exposure. In yeast, metal resistance is mainly due to the down-regulation of metal ion importers, utilization of metallothionein and metallothionein-like structures, and ion sequestration to the vacuole. In contrast, metal resistance in filamentous fungi heavily relies upon cellular ion export. However, there are instances of resistance that utilized vacuole sequestration, ion metallothionein, and chelator binding, deleting a metal ion importer, and ion storage in hyphal cell walls. In general, resistance to zinc, copper, iron, and manganese is extensively reported in yeast and partially known in filamentous fungi; and silver resistance lacks comprehensive understanding in both.
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Affiliation(s)
| | - Omoanghe S. Isikhuemhen
- Department of Natural Resources and Environmental Design, North Carolina Agricultural and Technical State University, 1601 East Market Street, Greensboro, NC 27411, USA; (J.R.R.); (F.N.A.)
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Fejes B, Ouedraogo JP, Fekete E, Sándor E, Flipphi M, Soós Á, Molnár ÁP, Kovács B, Kubicek CP, Tsang A, Karaffa L. The effects of external Mn 2+ concentration on hyphal morphology and citric acid production are mediated primarily by the NRAMP-family transporter DmtA in Aspergillus niger. Microb Cell Fact 2020; 19:17. [PMID: 32000778 PMCID: PMC6993379 DOI: 10.1186/s12934-020-1286-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/17/2020] [Indexed: 11/18/2022] Open
Abstract
Background Citric acid, a commodity product of industrial biotechnology, is produced by fermentation of the filamentous fungus Aspergillus niger. A requirement for high-yield citric acid production is keeping the concentration of Mn2+ ions in the medium at or below 5 µg L−1. Understanding manganese metabolism in A. niger is therefore of critical importance to citric acid production. To this end, we investigated transport of Mn2+ ions in A. niger NRRL2270. Results we identified an A. niger gene (dmtA; NRRL3_07789), predicted to encode a transmembrane protein, with high sequence identity to the yeast manganese transporters Smf1p and Smf2p. Deletion of dmtA in A. niger eliminated the intake of Mn2+ at low (5 µg L−1) external Mn2+ concentration, and reduced the intake of Mn2+ at high (> 100 µg L−1) external Mn2+ concentration. Compared to the parent strain, overexpression of dmtA increased Mn2+ intake at both low and high external Mn2+ concentrations. Cultivation of the parent strain under Mn2+ ions limitation conditions (5 µg L−1) reduced germination and led to the formation of stubby, swollen hyphae that formed compact pellets. Deletion of dmtA caused defects in germination and hyphal morphology even in the presence of 100 µg L−1 Mn2+, while overexpression of dmtA led to enhanced germination and normal hyphal morphology at limiting Mn2+ concentration. Growth of both the parent and the deletion strains under citric acid producing conditions resulted in molar yields (Yp/s) of citric acid of > 0.8, although the deletion strain produced ~ 30% less biomass. This yield was reduced only by 20% in the presence of 100 µg L−1 Mn2+, whereas production by the parent strain was reduced by 60%. The Yp/s of the overexpressing strain was 17% of that of the parent strain, irrespective of the concentrations of external Mn2+. Conclusions Our results demonstrate that dmtA is physiologically important in the transport of Mn2+ ions in A. niger, and manipulation of its expression modulates citric acid overflow.
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Affiliation(s)
- Balázs Fejes
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary.,Juhász-Nagy Pál Doctoral School of Biology and Environmental Sciences, University of Debrecen, Debrecen, Hungary
| | - Jean-Paul Ouedraogo
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, Canada
| | - Erzsébet Fekete
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Erzsébet Sándor
- Institute of Food Science, Faculty of Agricultural and Food Science and Environmental Management, University of Debrecen, Böszörményi út 138, Debrecen, 4032, Hungary
| | - Michel Flipphi
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Áron Soós
- Institute of Food Science, Faculty of Agricultural and Food Science and Environmental Management, University of Debrecen, Böszörményi út 138, Debrecen, 4032, Hungary
| | - Ákos P Molnár
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - Béla Kovács
- Institute of Food Science, Faculty of Agricultural and Food Science and Environmental Management, University of Debrecen, Böszörményi út 138, Debrecen, 4032, Hungary
| | - Christian P Kubicek
- Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, Canada
| | - Levente Karaffa
- Department of Biochemical Engineering, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary.
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