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Steyer JT, Todd RB. Branched-chain amino acid biosynthesis in fungi. Essays Biochem 2023; 67:865-876. [PMID: 37455545 DOI: 10.1042/ebc20230003] [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: 05/03/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/18/2023]
Abstract
Branched-chain amino acids (BCAAs)-isoleucine, leucine, and valine-are synthesized by fungi. These amino acids are important components of proteins and secondary metabolites. The biochemical pathway for BCAA biosynthesis is well-characterized in the yeast Saccharomyces cerevisiae. The biosynthesis of these three amino acids is interconnected. Different precursors are metabolized in multiple steps through shared enzymes to produce isoleucine and valine, and the valine biosynthesis pathway branches before the penultimate step to a series of leucine biosynthesis-specific steps to produce leucine. Recent efforts have made advances toward characterization of the BCAA biosynthesis pathway in several fungi, revealing diversity in gene duplication and functional divergence in the genes for these enzymatic steps in different fungi. The BCAA biosynthesis pathway is regulated by the transcription factor LEU3 in S. cerevisiae, and LeuB in Aspergillus nidulans and Aspergillus fumigatus, and the activity of these transcription factors is modulated by the leucine biosynthesis pathway intermediate α-isopropylmalate. Herein, we discuss recent advances in our understanding of the BCAA pathway and its regulation, focusing on filamentous ascomycete fungi and comparison with the well-established process in yeast.
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Affiliation(s)
- Joel T Steyer
- Department of Plant Pathology, Kansas State University, Manhattan KS, 66506, U.S.A
| | - Richard B Todd
- Department of Plant Pathology, Kansas State University, Manhattan KS, 66506, U.S.A
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Sharma T, Sridhar PS, Blackman C, Foote SJ, Allingham JS, Subramaniam R, Loewen MC. Fusarium graminearum Ste3 G-Protein Coupled Receptor: A Mediator of Hyphal Chemotropism and Pathogenesis. mSphere 2022; 7:e0045622. [PMID: 36377914 PMCID: PMC9769807 DOI: 10.1128/msphere.00456-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022] Open
Abstract
Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Previous studies on Fusarium species have highlighted the involvement of the Ste2 G-protein-coupled receptor (GPCR) in mediating polarized hyphal growth toward host-released peroxidase. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to Fusarium graminearum chemotropism and pathogenicity. Fgste3Δ deletion strains were found to be compromised in the chemotropic response toward peroxidase, development of lesions on germinating wheat, and infection of Arabidopsis thaliana leaves. In the absence of FgSte3 or FgSte2, F. graminearum cells exposed to peroxidase showed no phosphorylation of the cell-wall integrity, mitogen-activated protein kinase pathway component Mgv1. In addition, transcriptomic gene expression profiling yielded a list of genes involved in cellular reorganization, cell wall remodeling, and infection-mediated responses that were differentially modulated by peroxidase when FgSte3 was present. Deletion of FgSte3 yielded the downregulation of genes associated with mycotoxin biosynthesis and appressorium development, compared to the wild-type strain, both in the presence of peroxidase. Together, these findings contribute to our understanding of the mechanism underlying fungal chemotropism and pathogenesis while raising the novel hypothesis that FgSte2 and FgSte3 are interdependent on each other for the mediation of the redirection of hyphal growth in response to host-derived peroxidase. IMPORTANCE Fusarium head blight of wheat, caused by the filamentous fungus Fusarium graminearum, leads to devastating global food shortages and economic losses. Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to F. graminearum chemotropism and pathogenicity. These findings contribute to our understanding of the mechanisms underlying fungal chemotropism and pathogenesis.
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Affiliation(s)
- Tanya Sharma
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
- Aquatic and Crop Resources Development Research Center, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Pooja S. Sridhar
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Christopher Blackman
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
| | - Simon J. Foote
- Human Health Therapeutics Research Center, National Research Council of Canada, Ottawa, Ontario, Canada
| | - John S. Allingham
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
| | - Rajagopal Subramaniam
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Agriculture and Agri-Food Canada, Ottawa, Ontario, Canada
| | - Michele C. Loewen
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
- Aquatic and Crop Resources Development Research Center, National Research Council of Canada, Ottawa, Ontario, Canada
- Department of Biomedical and Molecular Science, Queen’s University, Kingston, Ontario, Canada
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Duplication and Functional Divergence of Branched-Chain Amino Acid Biosynthesis Genes in Aspergillus nidulans. mBio 2021; 12:e0076821. [PMID: 34154419 PMCID: PMC8262921 DOI: 10.1128/mbio.00768-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Fungi, bacteria, and plants, but not animals, synthesize the branched-chain amino acids: leucine, isoleucine, and valine. While branched-chain amino acid (BCAA) biosynthesis has been well characterized in the yeast Saccharomyces cerevisiae, it is incompletely understood in filamentous fungi. The three BCAAs share several early biosynthesis steps before divergence into specific pathways. In Aspergillus nidulans, the genes for the first two dedicated steps in leucine biosynthesis have been characterized, but the final two have not. We used sequence searches of the A. nidulans genome to identify two genes encoding β-isopropylmalate dehydrogenase, which catalyzes the penultimate step of leucine biosynthesis, and six genes encoding BCAA aminotransferase, which catalyzes the final step in biosynthesis of all three BCAA. We have used combinations of gene knockouts to determine the relative contribution of each of these genes to BCAA biosynthesis. While both β-isopropylmalate dehydrogenase genes act in leucine biosynthesis, the two most highly expressed BCAA aminotransferases are responsible for BCAA biosynthesis. We have also characterized the expression of leucine biosynthesis genes using reverse transcriptase-quantitative PCR and found regulation in response to leucine availability is mediated through the Zn(II)2Cys6 transcription factor LeuB. IMPORTANCE Branched-chain amino acid (BCAA) biosynthesis is important for pathogenic fungi to successfully cause disease in human and plant hosts. The enzymes for their production are absent from humans and, therefore, provide potential antifungal targets. While BCAA biosynthesis is well characterized in yeasts, it is poorly understood in filamentous fungal pathogens. Developing a thorough understanding of both the genes encoding the metabolic enzymes for BCAA biosynthesis and how their expression is regulated will inform target selection for antifungal drug development.
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Tini F, Beccari G, Marconi G, Porceddu A, Sulyok M, Gardiner DM, Albertini E, Covarelli L. Identification of Putative Virulence Genes by DNA Methylation Studies in the Cereal Pathogen Fusarium graminearum. Cells 2021; 10:cells10051192. [PMID: 34068122 PMCID: PMC8152758 DOI: 10.3390/cells10051192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/03/2021] [Accepted: 05/10/2021] [Indexed: 01/17/2023] Open
Abstract
DNA methylation mediates organisms’ adaptations to environmental changes in a wide range of species. We investigated if a such a strategy is also adopted by Fusarium graminearum in regulating virulence toward its natural hosts. A virulent strain of this fungus was consecutively sub-cultured for 50 times (once a week) on potato dextrose agar. To assess the effect of subculturing on virulence, wheat seedlings and heads (cv. A416) were inoculated with subcultures (SC) 1, 23, and 50. SC50 was also used to re-infect (three times) wheat heads (SC50×3) to restore virulence. In vitro conidia production, colonies growth and secondary metabolites production were also determined for SC1, SC23, SC50, and SC50×3. Seedling stem base and head assays revealed a virulence decline of all subcultures, whereas virulence was restored in SC50×3. The same trend was observed in conidia production. The DNA isolated from SC50 and SC50×3 was subject to a methylation content-sensitive enzyme and double-digest, restriction-site-associated DNA technique (ddRAD-MCSeEd). DNA methylation analysis indicated 1024 genes, whose methylation levels changed in response to the inoculation on a healthy host after subculturing. Several of these genes are already known to be involved in virulence by functional analysis. These results demonstrate that the physiological shifts following sub-culturing have an impact on genomic DNA methylation levels and suggest that the ddRAD-MCSeEd approach can be an important tool for detecting genes potentially related to fungal virulence.
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Affiliation(s)
- Francesco Tini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Giovanni Beccari
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Gianpiero Marconi
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
- Correspondence:
| | - Andrea Porceddu
- Department of Agriculture, University of Sassari, Viale Italia, 39a, 07100 Sassari, Italy;
| | - Micheal Sulyok
- Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Applied Life Sciences, Vienna (BOKU), Konrad Lorenz Strasse, 20, A-3430 Tulln, Austria;
| | - Donald M. Gardiner
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food, 306 Carmody Road, St Lucia, QLD 4067, Australia;
| | - Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
| | - Lorenzo Covarelli
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno, 74, 06121 Perugia, Italy; (F.T.); (G.B.); (E.A.); (L.C.)
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The Intermediates in Branched-Chain Amino Acid Biosynthesis Are Indispensable for Conidial Germination of the Insect-Pathogenic Fungus Metarhizium robertsii. Appl Environ Microbiol 2020; 86:AEM.01682-20. [PMID: 32769188 DOI: 10.1128/aem.01682-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 07/30/2020] [Indexed: 12/26/2022] Open
Abstract
Metarhizium spp. are well-known biocontrol agents used worldwide to control different insect pests. Keto-acid reductoisomerase (ILVC) is a key enzyme for branched-chain amino acid (BCAA) biosynthesis, and it regulates many physiological activities. However, its functions in insect-pathogenic fungi are poorly understood. In this work, we identified MrilvC in M. robertsii and dissected its roles in fungal growth, conidiation, germination, destruxin biosynthesis, environmental stress response, and insecticidal virulence. BCAA metabolism affects conidial yields and germination. However, BCAAs cannot recover the conidial germination of an MrilvC-deficient strain. Further feeding assays with intermediates showed that some conidia of the ΔMrilvC mutant start to germinate. Therefore, it is the germination defect that causes the complete failures of conidial penetration and pathogenicity in the ΔMrilvC mutant. In conclusion, we found intermediates in BCAA biosynthesis are indispensable for Metarhizium robertsii conidial germination. This study will advance our understanding of the fungal germination mechanism.IMPORTANCE Branched-chain amino acid (BCAA) metabolism plays a significant role in many biological activities beyond protein synthesis. Spore germination initiates the first stage of vegetative growth, which is critical for the virulence of pathogenic fungi. In this study, we demonstrated that the keto-acid reductoisomerase MrILVC, a key enzyme for BCAA biosynthesis, from the insect-pathogenic fungus Metarhizium robertsii is associated with conidial germination and fungal pathogenicity. Surprisingly, the germination of the ΔMrilvC mutant was restored when supplemented with the intermediates of BCAA metabolism rather than three BCAAs. The result was significantly different from that of plant-pathogenic fungi. Therefore, this report highlights that the intermediates in BCAA biosynthesis are indispensable for conidial germination of M. robertsii.
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Guo M, Liu J, Xu Z, Wang J, Li T, Lei H, Duan X, Sun Y, Zhang X, Huang R. 2-Methoxy-1,4-naphthoquinone Induces Metabolic Shifts in Penicillium Digitatum Revealed by High-Dimensional Biological Data. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9697-9706. [PMID: 32803964 DOI: 10.1021/acs.jafc.0c03396] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Penicillium digitatum is the primary pathogen causing the green mold of citrus. The need for the development of higher effective and lower toxic natural antifungal agents is urgent, owing to the lack of antifungal agents that can successfully combat P. digitatum. Herein, the effects and mechanisms of 2-methoxy-1,4-naphthoquinone (MNQ) as a potential inhibitor of P. digitatumwere studied. First, MNQ showed a significant anti-P. digitatum effect with a minimum inhibitory concentration value of 5.0 μg/mL. Then, transcriptome, proteome, and metabolome profiling were performed on the MNQ-treated P. digitatum. A total of 910 genes, 297 proteins, and 174 metabolites changed significantly. The omics analysis indicated that it could be seen that MNQ mainly inhibits the growth of P. digitatum by affecting the synthesis of branched-chain amino acids and cell walls. These findings will be a great contribution to the further understanding of the possible molecular action of MNQ.
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Affiliation(s)
- Meixia Guo
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Jun Liu
- Laboratory of Pathogenic Biology, Guangdong Medical University, Zhanjiang 524023, China
| | - Zhenlin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Jie Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Hongtao Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xuewu Duan
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yuanming Sun
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiaoyong Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Riming Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
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7
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Wei YY, Yu Q, Dong B, Zhang Y, Liu XH, Lin FC, Liang S. MoLEU1, MoLEU2, and MoLEU4 regulated by MoLEU3 are involved in leucine biosynthesis, fungal development, and pathogenicity in Magnaporthe oryzae. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:784-796. [PMID: 31621205 DOI: 10.1111/1758-2229.12800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/13/2019] [Accepted: 10/13/2019] [Indexed: 06/10/2023]
Abstract
Amino acids are vital components in cell metabolism. Leucine is a regulatory factor that generates significant impact on protein synthesis/turnover, modulates diverse cellular signalling pathways and participates in oxidative processes and immune responses. Here, we identified and characterized the functions of a leucine-associated Zn2 Cys6 -type transcription factor, MoLeu3. Disruption of MoLEU3 resulted in significantly reduced pathogenicity in barley and rice. Quantitative RT-PCR showed that the expression levels of the putative leucine biosynthesis-related genes, MoLEU1, MoLEU2 and MoLEU4 were downregulated in the ΔMoleu3 mutant. We used high-throughput gene knockout method to generate the null mutants of MoLEU1, MoLEU2 and MoLEU4 respectively. The ΔMoleu1, ΔMoleu2 and ΔMoleu4 mutants are leucine auxotroph and showed similar phenotypic characterizations, including reduced conidiation, delayed mobilization and degradation of glycogen and lipid droplets, limited appressorium-mediated penetration, and restricted invasive hyphae growth within host cells. Collectively, MoLEU1, MoLEU2, and MoLEU4 regulated by MoLEU3 play crucial roles in fungal development and infectious processes through modulation of leucine biosynthesis in Magnaporthe oryzae.
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Affiliation(s)
- Yun-Yun Wei
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Qin Yu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Bo Dong
- Markey Cancer Center, the University of Kentucky, College of Medicine, Lexington, KY, 40506, USA
| | - Yong Zhang
- Quzhou Municipal Plant Protection and Quarantine Station, Quzhou Municipal Bureau of Agriculture, Quzhou, 324000, China
| | - Xiao-Hong Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Fu-Cheng Lin
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Shuang Liang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, 310024, China
- Laboratory of Proteomic Big Data, Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, 310024, China
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8
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Que Y, Yue X, Yang N, Xu Z, Tang S, Wang C, Lv W, Xu L, Talbot NJ, Wang Z. Leucine biosynthesis is required for infection-related morphogenesis and pathogenicity in the rice blast fungus Magnaporthe oryzae. Curr Genet 2019; 66:155-171. [PMID: 31263943 DOI: 10.1007/s00294-019-01009-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 11/29/2022]
Abstract
The rice blast fungus Magnaporthe oryzae causes one of the most devastating crop diseases world-wide and new control strategies for blast disease are urgently required. We have used insertional mutagenesis in M. oryzae to define biological processes that are critical for blast disease. Here, we report the identification of LEU2A by T-DNA mutagenesis, which putatively encodes 3-isopropylmalate dehydrogenase (3-IPMDH) required for leucine biosynthesis, implicating that synthesis of this amino acid is required for fungal pathogenesis. M. oryzae contains a further predicted 3-IPMDH gene (LEU2B), two 2-isopropylmalate synthase (2-IPMS) genes (LEU4 and LEU9) and an isopropylmalate isomerase (IPMI) gene (LEU1). Targeted gene deletion mutants of LEU1, LEU2A or LEU4 are leucine auxotrophs, and severely defective in pathogenicity. All phenotypes associated with mutants lacking LEU1, LEU2A or LEU4 could be overcome by adding exogenous leucine. The expression levels of LEU1, LEU2A or LEU4 genes were significantly down-regulated by deletion of the transcription factor gene LEU3, an ortholog of Saccharomyces cerevisiae LEU3. We also functionally characterized leucine biosynthesis genes in the wheat pathogen Fusarium graminearum and found that FgLEU1, FgLEU3 and FgLEU4 are essential for wheat head blight disease, suggesting that leucine biosynthesis in filamentous fungal pathogens may be a conserved factor for fungal pathogenicity and, therefore, a potential target for disease control.
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Affiliation(s)
- Yawei Que
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Xiaofeng Yue
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Nan Yang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Zhe Xu
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Shuai Tang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Chunyan Wang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Wuyun Lv
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Lin Xu
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China
| | - Nicholas J Talbot
- The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Zhengyi Wang
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, People's Republic of China.
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Liu X, Jiang Y, Zhang Y, Yu M, Jiang H, Xu J, Shi J. FgIlv3a is crucial in branched-chain amino acid biosynthesis, vegetative differentiation, and virulence in Fusarium graminearum. J Microbiol 2019; 57:694-703. [PMID: 31079334 DOI: 10.1007/s12275-019-9123-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 03/25/2019] [Accepted: 03/27/2019] [Indexed: 12/22/2022]
Abstract
Dihydroxyacid dehydratase (DHAD), encoded by ILV3, catalyses the third step in the biosynthetic pathway of branched-chain amino acids (BCAAs), which include isoleucine (Ile), leucine (Leu), and valine (Val). Enzymes involved in BCAA biosynthesis exist in bacteria, plants, and fungi but not in mammals and are therefore attractive targets for antimicrobial or herbicide development. In this study, three paralogous ILV3 genes (FgILV3A, FgILV3B, and FgILV3C) were identified in the genome of Fusarium graminearum, the causal agent of Fusarium head blight (FHB). Deletion of FgILV3A alone or combined with FgILV3B or FgILV3C indicated an important role for FgILV3A in BCAA biosynthesis. FgILV3A deletion mutants lost the ability to grow on medium lacking amino acids. Exogenous supplementation of 1 mM Ile and Val rescued the auxotrophy of ΔFgIlv3A, though 5 mM was required to recover the growth defects in ΔFgIlv3AB and ΔFgIlv3AC strains, indicating that FgIlv3b and FgIlv3c exhibit redundant but accessory roles with FgIlv3a in BCAA biosynthesis. The auxotrophy of ΔFgIlv3A resulted in pleiotropic defects in aerial hyphal growth, in conidial formation and germination, and in aurofusarin accumulation. In addition, the mutants showed reduced virulence and deoxynivalenol production. Overall, our study demonstrates that FgIlv3a is crucial for BCAA biosynthesis in F. graminearum and a candidate fungicide target for FHB management.
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Affiliation(s)
- Xin Liu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China.,School of Food and Biological Engineering, Jiangsu Univeristy, Zhenjiang, 212013, Jiangsu, P. R. China
| | - Yichen Jiang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China.,College of Food Science, Tibet Agriculture and Animal Husbandry University, Linzhi, 860000, Tibet, P. R. China
| | - Yinghui Zhang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China.,College of Life Science, Sanquan College of Xinxiang Medical University, Xinxiang, 453003, Henan, P. R. China
| | - Mingzheng Yu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China
| | - Hongjun Jiang
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China.,College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, Jiangsu, P. R. China
| | - Jianhong Xu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China.,School of Food and Biological Engineering, Jiangsu Univeristy, Zhenjiang, 212013, Jiangsu, P. R. China
| | - Jianrong Shi
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture and Rural Affairs/Key Laboratory for Agro-product Safety Risk Evaluation (Nanjing), Ministry of Agriculture and Rural Affairs/Collaborative Innovation Center for Modern Grain Circulation and Safety/Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, Jiangsu, P. R. China. .,School of Food and Biological Engineering, Jiangsu Univeristy, Zhenjiang, 212013, Jiangsu, P. R. China.
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10
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Tang W, Jiang H, Zheng Q, Chen X, Wang R, Yang S, Zhao G, Liu J, Norvienyeku J, Wang Z. Isopropylmalate isomerase MoLeu1 orchestrates leucine biosynthesis, fungal development, and pathogenicity in Magnaporthe oryzae. Appl Microbiol Biotechnol 2018; 103:327-337. [PMID: 30357439 DOI: 10.1007/s00253-018-9456-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/07/2018] [Accepted: 10/09/2018] [Indexed: 01/16/2023]
Abstract
The biosynthesis of branched-chain amino acids (BCAAs) is conserved in fungi and plants, but not in animals. The Leu1 gene encodes isopropylmalate isomerase that catalyzes the conversion of α-isopropylmalate into β-isopropylmalate in the second step of leucine biosynthesis in yeast. Here, we identified and characterized the functions of MoLeu1, an ortholog of yeast Leu1 in the rice blast fungus Magnaporthe oryzae. The transcriptional level of MoLEU1 was increased during conidiation and in infectious stages. Cellular localization analysis indicated that MoLeu1 localizes to the cytoplasm at all stages of fungal development. Targeted gene deletion of MoLEU1 led to leucine auxotrophy, and phenotypic analysis of the generated ∆Moleu1 strain revealed that MoLeu1-mediated leucine biosynthesis was required for vegetative growth, asexual development, and pathogenesis of M. oryzae. We further observed that invasive hyphae produced by the ∆Moleu1 strain were mainly limited to the primary infected host cells. The application of exogenous leucine fully restored vegetative growth and partially restored conidiation as well as pathogenicity defects in the ∆Moleu1 strain. In summary, our results suggested that MoLeu1-mediated leucine biosynthesis crucially promotes vegetative growth, conidiogenesis, and pathogenicity of M. oryzae. This study helps unveil the regulatory mechanisms that are essential for infection-related morphogenesis and pathogenicity of the rice blast fungus.
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Affiliation(s)
- Wei Tang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
| | - Haolang Jiang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Qiaojia Zheng
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xuehang Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Rufeng Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shuai Yang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Guiyuan Zhao
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jiao Liu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Justice Norvienyeku
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Institute of Ocean Science, Minjiang University, Fuzhou, 350108, China.
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