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Kotani A, Ozaki T, Takino J, Mochizuki S, Akimitsu K, Minami A, Oikawa H. Heterologous expression of a polyketide synthase ACRTS2 in Aspergillus oryzae produces host-selective ACR toxins: coproduction of minor metabolites. Biosci Biotechnol Biochem 2022; 86:287-293. [PMID: 34894229 DOI: 10.1093/bbb/zbab214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/03/2021] [Indexed: 11/14/2022]
Abstract
Previously, we succeeded to produce the core structure of the host-selective ACR toxin (1) on brown leaf spot on rough lemon when the polyketide synthase ACRTS2 gene was heterologously expressed in Aspergillus oryzae (AO). To confirm the production of 1 in AO, the detection limit and suppressing decarboxylation were improved, and these efforts led us to conclude the direct production of 1 instead of its decarboxylation product. During this examination, minor ACR-toxin-related metabolites were found. Their structure determination enabled us to propose a decarboxylation mechanism and a novel branching route forming byproducts from the coupling of the dihydropyrone moiety of 1 with the acetaldehyde and kojic acid abundant in AO. The involvement of putative cyclase ACRTS3 in the chain release of linear polyketide was excluded by the coexpression analysis of ACRTS2 and ACRTS3. Taken together, we concluded that the production of 1 in AO is solely responsible for ACRTS2.
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Affiliation(s)
- Akari Kotani
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Taro Ozaki
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Junya Takino
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Susumu Mochizuki
- International Institute of Rare Sugar Research and Education and Faculty of Agriculture, Kagawa University, Kagawa, Japan
| | - Kazuya Akimitsu
- International Institute of Rare Sugar Research and Education and Faculty of Agriculture, Kagawa University, Kagawa, Japan
| | - Atsushi Minami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Hideaki Oikawa
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Japan
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2
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Wang H, Guo Y, Luo Z, Gao L, Li R, Zhang Y, Kalaji HM, Qiang S, Chen S. Recent Advances in Alternaria Phytotoxins: A Review of Their Occurrence, Structure, Bioactivity and Biosynthesis. J Fungi (Basel) 2022; 8:jof8020168. [PMID: 35205922 PMCID: PMC8878860 DOI: 10.3390/jof8020168] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/04/2022] Open
Abstract
Alternaria is a ubiquitous fungal genus in many ecosystems, consisting of species and strains that can be saprophytic, endophytic, or pathogenic to plants or animals, including humans. Alternaria species can produce a variety of secondary metabolites (SMs), especially low molecular weight toxins. Based on the characteristics of host plant susceptibility or resistance to the toxin, Alternaria phytotoxins are classified into host-selective toxins (HSTs) and non-host-selective toxins (NHSTs). These Alternaria toxins exhibit a variety of biological activities such as phytotoxic, cytotoxic, and antimicrobial properties. Generally, HSTs are toxic to host plants and can cause severe economic losses. Some NHSTs such as alternariol, altenariol methyl-ether, and altertoxins also show high cytotoxic and mutagenic activities in the exposed human or other vertebrate species. Thus, Alternaria toxins are meaningful for drug and pesticide development. For example, AAL-toxin, maculosin, tentoxin, and tenuazonic acid have potential to be developed as bioherbicides due to their excellent herbicidal activity. Like altersolanol A, bostrycin, and brefeldin A, they exhibit anticancer activity, and ATX V shows high activity to inhibit the HIV-1 virus. This review focuses on the classification, chemical structure, occurrence, bioactivity, and biosynthesis of the major Alternaria phytotoxins, including 30 HSTs and 50 NHSTs discovered to date.
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Affiliation(s)
- He Wang
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Yanjing Guo
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Zhi Luo
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Liwen Gao
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Rui Li
- Agricultural and Animal Husbandry Ecology and Resource Protection Center, Ordos Agriculture and Animal Husbandry Bureau, Ordos 017010, China;
| | - Yaxin Zhang
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Hazem M. Kalaji
- Department of Plant Physiology, Institute of Biology, Warsaw University of Life Sciences SGGW, 159 Nowoursynowska 159, 02-776 Warsaw, Poland;
- Institute of Technology and Life Sciences—National Research Institute, Falenty, Al. Hrabska 3, 05-090 Raszyn, Poland
| | - Sheng Qiang
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
| | - Shiguo Chen
- Weed Research Laboratory, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China; (H.W.); (Y.G.); (Z.L.); (L.G.); (Y.Z.); (S.Q.)
- Correspondence: ; Tel.: +86-25-84395117
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3
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Gai Y, Li L, Liu B, Ma H, Chen Y, Zheng F, Sun X, Wang M, Jiao C, Li H. Distinct and essential roles of bZIP transcription factors in the stress response and pathogenesis in Alternaria alternata. Microbiol Res 2021; 256:126915. [PMID: 34953292 DOI: 10.1016/j.micres.2021.126915] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/05/2021] [Accepted: 10/15/2021] [Indexed: 12/27/2022]
Abstract
The ability to cope with environmental abiotic stress and biotic stress is crucial for the survival of plants and microorganisms, which enable them to occupy multiple niches in the environment. Previous studies have shown that transcription factors play crucial roles in regulating various biological processes including multiple stress tolerance and response in eukaryotes. This work identified multiple critical transcription factor genes, metabolic pathways and gene ontology (GO) terms related to abiotic stress response were broadly activated by analyzing the transcriptome of phytopathogenic fungus Alternaria alternata under metal ions stresses, oxidative stress, salt stresses, and host-pathogen interaction. We investigated the biological functions and regulatory roles of the bZIP transcriptional factor (TF) genes in the phytopathogenic fungus A.alternata by analyzing targeted gene disrupted mutants. Morphological analysis provides evidence that the bZIP transcription factors (Gcn4, MeaB, Atf1, the ER stress regulator Hac1, and the all development altered-1 gene Ada1) are required for morphogenesis as the colony morphology of these gene deletion mutants was significantly different from that of the wild-type. In addition, bZIPs are involved in the resistance to multiple stresses such as oxidative stress (Ada1, Yap1, MetR) and virulence (Hac1, MetR, Yap1, Ada1) at varying degrees. Transcriptome data demonstrated that the inactivation of bZIPs (Hac1, Atf1, Ada1 and Yap1) significantly affected many genes in multiple critical metabolism pathways and gene ontology (GO) terms. Moreover,the ΔHac1 mutants displayed reduced aerial hypha and are hypersensitivity to endoplasmic reticulum disruptors such as tunicamycin and dithiothreitol. Transcriptome analysis showed that inactivation of Hac1 significantly affected the proteasome process and its downstream unfolded protein binding, indicating that Hac1 participates in the endoplasmic reticulum stress response through the conserved unfolded protein response. Taken together, our findings reveal that bZIP transcription factors function as key regulators of fungal morphogenesis, abiotic stress response and pathogenesis, and expand our understanding of how microbial pathogens utilize these genes to deal with environmental stresses and achieve successful infection in the host plant.
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Affiliation(s)
- Yunpeng Gai
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China; School of Grassland Science, Beijing Forestry University, Beijing, 100083, China.
| | - Lei Li
- Department of Plant Pathology, South China Agricultural University, Guangzhou 510640, China
| | - Bing Liu
- Yangzhou Polytechnic College, Yangzhou 225009, China
| | - Haijie Ma
- School of Agriculture and Food Sciences, Zhejiang Agriculture & Forestry University, Hangzhou, 311300, China
| | - Yanan Chen
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Fang Zheng
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Xuepeng Sun
- School of Agriculture and Food Sciences, Zhejiang Agriculture & Forestry University, Hangzhou, 311300, China
| | - Mingshuang Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China
| | - Chen Jiao
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Hongye Li
- Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.
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Huang K, Tang J, Zou Y, Sun X, Lan J, Wang W, Xu P, Wu X, Ma R, Wang Q, Wang Z, Liu J. Whole Genome Sequence of Alternaria alternata, the Causal Agent of Black Spot of Kiwifruit. Front Microbiol 2021; 12:713462. [PMID: 34616379 PMCID: PMC8488381 DOI: 10.3389/fmicb.2021.713462] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/16/2021] [Indexed: 02/05/2023] Open
Abstract
Alternaria alternata is a pathogen in a wide range of agriculture crops and causes significant economic losses. A strain of A. alternata (Y784-BC03) was isolated and identified from “Hongyang” kiwifruit and demonstrated to cause black spot infections on fruits. The genome sequence of Y784-BC03 was obtained using Nanopore MinION technology. The assembled genome is composed of 33,869,130bp (32.30Mb) comprising 10 chromosomes and 11,954 genes. A total of 2,180 virulence factors were predicted to be present in the obtained genome sequence. The virulence factors comprised genes encoding secondary metabolites, including non-host-specific toxins, cell wall-degrading enzymes, and major transcriptional regulators. The predicted gene clusters encoding genes for the biosynthesis and export of secondary metabolites in the genome of Y784-BC03 were associated with non-host-specific toxins, including cercosporin, dothistromin, and versicolorin B. Major transcriptional regulators of different mycotoxin biosynthesis pathways were identified, including the transcriptional regulators, polyketide synthase, P450 monooxygenase, and major facilitator superfamily transporters.
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Affiliation(s)
- Ke Huang
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China.,Institute of Microbial Ecology, Chongqing University of Arts and Sciences, Chongqing, China
| | - Jianming Tang
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China
| | - Yong Zou
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China
| | - Xiangcheng Sun
- College of Life Sciences, Northwest A&F University, Yangling, China.,West China Biopharm Research Institute, West China Hospital, Sichuan University, Chengdu, China
| | - Jianbin Lan
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China
| | - Wei Wang
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China.,Institute of Microbial Ecology, Chongqing University of Arts and Sciences, Chongqing, China
| | - Panpan Xu
- College of Life Sciences, Northwest A&F University, Yangling, China
| | | | - Rui Ma
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China
| | - Qi Wang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Zhenshuo Wang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jia Liu
- College of Landscape Architecture and Life Science, Institute of Special Plants, Chongqing University of Arts and Sciences, Chongqing, China
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Witte TE, Villeneuve N, Boddy CN, Overy DP. Accessory Chromosome-Acquired Secondary Metabolism in Plant Pathogenic Fungi: The Evolution of Biotrophs Into Host-Specific Pathogens. Front Microbiol 2021; 12:664276. [PMID: 33968000 PMCID: PMC8102738 DOI: 10.3389/fmicb.2021.664276] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022] Open
Abstract
Accessory chromosomes are strain- or pathotype-specific chromosomes that exist in addition to the core chromosomes of a species and are generally not considered essential to the survival of the organism. Among pathogenic fungal species, accessory chromosomes harbor pathogenicity or virulence factor genes, several of which are known to encode for secondary metabolites that are involved in plant tissue invasion. Accessory chromosomes are of particular interest due to their capacity for horizontal transfer between strains and their dynamic "crosstalk" with core chromosomes. This review focuses exclusively on secondary metabolism (including mycotoxin biosynthesis) associated with accessory chromosomes in filamentous fungi and the role accessory chromosomes play in the evolution of secondary metabolite gene clusters. Untargeted metabolomics profiling in conjunction with genome sequencing provides an effective means of linking secondary metabolite products with their respective biosynthetic gene clusters that reside on accessory chromosomes. While the majority of literature describing accessory chromosome-associated toxin biosynthesis comes from studies of Alternaria pathotypes, the recent discovery of accessory chromosome-associated biosynthetic genes in Fusarium species offer fresh insights into the evolution of biosynthetic enzymes such as non-ribosomal peptide synthetases (NRPSs), polyketide synthases (PKSs) and regulatory mechanisms governing their expression.
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Affiliation(s)
- Thomas E. Witte
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicolas Villeneuve
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Christopher N. Boddy
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - David P. Overy
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
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6
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Bordoloi M, Saikia S, Bordoloi PK, Kolita B, Dutta PP, Bhuyan PD, Dutta SC, Rao PG. Isolation, characterization and antifungal activity of very long chain alkane derivatives from Cinnamomum obtusifolium, Elaeocarpus lanceifolius and Baccaurea sapida. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.04.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Nishimura S, Tatano S, Miyamoto Y, Ohtani K, Fukumoto T, Gomi K, Tada Y, Ichimura K, Akimitsu K. A zinc-binding citrus protein metallothionein can act as a plant defense factor by controlling host-selective ACR-toxin production. PLANT MOLECULAR BIOLOGY 2013; 81:1-11. [PMID: 23086497 DOI: 10.1007/s11103-012-9976-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 10/04/2012] [Indexed: 06/01/2023]
Abstract
Metallothionein is a small cysteine-rich protein known to have a metal-binding function. We isolated three different lengths of rough lemon cDNAs encoding a metallothionein (RlemMT1, RlemMT2 and RlemMT3), and only RlemMT1-recombinant protein had zinc-binding activity. Appropriate concentration of zinc is an essential micronutrient for living organisms, while excess zinc is toxic. Zinc also stimulates the production of host-selective ACR-toxin for citrus leaf spot pathogen of Alternaria alternata rough lemon pathotype. Trapping of zinc by RlemMT1-recombinant protein or by a zinc-scavenging agent in the culture medium caused suppression of ACR-toxin production by the fungus. Since ACR-toxin is the disease determinant for A. alternata rough lemon pathotype, addition of RlemMT1 to the inoculum suspension led to a significant decrease in symptoms on rough lemon leaves as a result of reduced ACR-toxin production from the zinc trap around infection sites. RlemMT1-overexpression mutant of A. alternata rough lemon pathotype also produced less ACR-toxin and reduced virulence on rough lemon. This suppression was caused by an interruption of zinc absorption by cells from the trapping of the mineral by RlemMT1 and an excess supplement of ZnSO(4) restored toxin production and pathogenicity. Based on these results, we propose that zinc adsorbents including metallothionein likely can act as a plant defense factor by controlling toxin biosynthesis via inhibition of zinc absorption by the pathogen.
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Izumi Y, Ohtani K, Miyamoto Y, Masunaka A, Fukumoto T, Gomi K, Tada Y, Ichimura K, Peever TL, Akimitsu K. A polyketide synthase gene, ACRTS2, is responsible for biosynthesis of host-selective ACR-toxin in the rough lemon pathotype of Alternaria alternata. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1419-1429. [PMID: 22835272 DOI: 10.1094/mpmi-06-12-0155-r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The rough lemon pathotype of Alternaria alternata produces host-selective ACR-toxin and causes Alternaria leaf spot disease of rough lemon (Citrus jambhiri). The structure of ACR-toxin I (MW = 496) consists of a polyketide with an α-dihydropyrone ring in a 19-carbon polyalcohol. Genes responsible for toxin production were localized to a 1.5-Mb chromosome in the genome of the rough lemon pathotype. Sequence analysis of this chromosome revealed an 8,338-bp open reading frame, ACRTS2, that was present only in the genomes of ACR-toxin-producing isolates. ACRTS2 is predicted to encode a putative polyketide synthase of 2,513 amino acids and belongs to the fungal reducing type I polyketide synthases. Typical polyketide functional domains were identified in the predicted amino acid sequence, including β-ketoacyl synthase, acyl transferase, methyl transferase, dehydratase, β-ketoreductase, and phosphopantetheine attachment site domains. Combined use of homologous recombination-mediated gene disruption and RNA silencing allowed examination of the functional role of multiple paralogs in ACR-toxin production. ACRTS2 was found to be essential for ACR-toxin production and pathogenicity of the rough lemon pathotype of A. alternata.
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Affiliation(s)
- Y Izumi
- Kagawa University, Kagawa, Japan
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