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Davis KA, Jones AM, Panaccione DG. Two Satellite Gene Clusters Enhance Ergot Alkaloid Biosynthesis Capacity of Aspergillus leporis. Appl Environ Microbiol 2023; 89:e0079323. [PMID: 37432119 PMCID: PMC10467348 DOI: 10.1128/aem.00793-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 06/25/2023] [Indexed: 07/12/2023] Open
Abstract
Ergot alkaloids are fungal specialized metabolites that are important in agriculture and serve as sources of several pharmaceuticals. Aspergillus leporis is a soil saprotroph that possesses two ergot alkaloid biosynthetic gene clusters encoding lysergic acid amide production. We identified two additional, partial biosynthetic gene clusters within the A. leporis genome containing some of the ergot alkaloid synthesis (eas) genes required to make two groups of clavine ergot alkaloids, fumigaclavines and rugulovasines. Clavines possess unique biological properties compared to lysergic acid derivatives. Bioinformatic analyses indicated the fumigaclavine cluster contained functional copies of easA, easG, easD, easM, and easN. Genes resembling easQ and easH, which are required for rugulovasine production, were identified in a separate gene cluster. The pathways encoded by these partial, or satellite, clusters would require intermediates from the previously described lysergic acid amide pathway to synthesize a product. Chemical analyses of A. leporis cultures revealed the presence of fumigaclavine A. However, rugulovasine was only detected in a single sample, prompting a heterologous expression approach to confirm functionality of easQ and easH. An easA knockout strain of Metarhizium brunneum, which accumulates the rugulovasine precursor chanoclavine-I aldehyde, was chosen as expression host. Strains of M. brunneum expressing easQ and easH from A. leporis accumulated rugulovasine as demonstrated through mass spectrometry analysis. These data indicate that A. leporis is exceptional among fungi in having the capacity to synthesize products from three branches of the ergot alkaloid pathway and for utilizing an unusual satellite cluster approach to achieve that outcome. IMPORTANCE Ergot alkaloids are chemicals produced by several species of fungi and are notable for their impacts on agriculture and medicine. The ability to make ergot alkaloids is typically encoded by a clustered set of genes that are physically adjacent on a chromosome. Different ergot alkaloid classes are formed via branching of a complex pathway that begins with a core set of the same five genes. Most ergot alkaloid-producing fungi have a single cluster of genes that is complete, or self-sufficient, and produce ergot alkaloids from one or occasionally two branches from that single cluster. Our data show that Aspergillus leporis is exceptional in having the genetic capacity to make products from three pathway branches. Moreover, it uses a satellite cluster approach, in which gene products of partial clusters rely on supplementation with a chemical intermediate produced via another gene cluster, to diversify its biosynthetic potential without duplicating all the steps.
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Affiliation(s)
- Kyle A. Davis
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Abigail M. Jones
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Daniel G. Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
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Jones AM, Panaccione DG. Ergot Alkaloids Contribute to the Pathogenic Potential of the Fungus Aspergillus leporis. Appl Environ Microbiol 2023; 89:e0041523. [PMID: 37212708 PMCID: PMC10304750 DOI: 10.1128/aem.00415-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/06/2023] [Indexed: 05/23/2023] Open
Abstract
Opportunistically pathogenic fungi have varying potential to cause disease in animals. Factors contributing to their virulence include specialized metabolites, which in some cases evolved in contexts unrelated to pathogenesis. Specialized metabolites that increase fungal virulence in the model insect Galleria mellonella include the ergot alkaloids fumigaclavine C in Aspergillus fumigatus (syn. Neosartorya fumigata) and lysergic acid α-hydroxyethylamide (LAH) in the entomopathogen Metarhizium brunneum. Three species of Aspergillus recently found to accumulate high concentrations of LAH were investigated for their pathogenic potential in G. mellonella. Aspergillus leporis was most virulent, A. hancockii was intermediate, and A. homomorphus had very little pathogenic potential. Aspergillus leporis and A. hancockii emerged from and sporulated on dead insects, thus completing their asexual life cycles. Inoculation by injection resulted in more lethal infections than did topical inoculation, indicating that A. leporis and A. hancockii were preadapted for insect pathogenesis but lacked an effective means to breach the insect's cuticle. All three species accumulated LAH in infected insects, with A. leporis accumulating the most. Concentrations of LAH in A. leporis were similar to those observed in the entomopathogen M. brunneum. LAH was eliminated from A. leporis through a CRISPR/Cas9-based gene knockout, and the resulting strain had reduced virulence to G. mellonella. The data indicate that A. leporis and A. hancockii have considerable pathogenic potential and that LAH increases the virulence of A. leporis. IMPORTANCE Certain environmental fungi infect animals occasionally or conditionally, whereas others do not. Factors that affect the virulence of these opportunistically pathogenic fungi may have originally evolved to fill some other role for the fungus in its primary environmental niche. Among the factors that may improve the virulence of opportunistic fungi are specialized metabolites--chemicals that are not essential for basic life functions but provide producers with an advantage in particular environments or under specific conditions. Ergot alkaloids are a large family of fungal specialized metabolites that contaminate crops in agriculture and serve as the foundations of numerous pharmaceuticals. Our results show that two ergot alkaloid-producing fungi that were not previously known to be opportunistic pathogens can infect a model insect and that, in at least one of the species, an ergot alkaloid increases the virulence of the fungus.
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Affiliation(s)
- Abigail M. Jones
- West Virginia University, Division of Plant and Soil Sciences, Morgantown, West Virginia, USA
| | - Daniel G. Panaccione
- West Virginia University, Division of Plant and Soil Sciences, Morgantown, West Virginia, USA
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Panaccione DG. Derivation of the multiply-branched ergot alkaloid pathway of fungi. Microb Biotechnol 2023; 16:742-756. [PMID: 36636806 PMCID: PMC10034635 DOI: 10.1111/1751-7915.14214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/16/2022] [Accepted: 01/02/2023] [Indexed: 01/14/2023] Open
Abstract
Ergot alkaloids are a large family of fungal specialized metabolites that are important as toxins in agriculture and as the foundation of powerful pharmaceuticals. Fungi from several lineages and diverse ecological niches produce ergot alkaloids from at least one of several branches of the ergot alkaloid pathway. The biochemical and genetic bases for the different branches have been established and are summarized briefly herein. Several pathway branches overlap among fungal lineages and ecological niches, indicating activities of ergot alkaloids benefit fungi in different environments and conditions. Understanding the functions of the multiple genes in each branch of the pathway allows researchers to parse the abundant genomic sequence data available in public databases in order to assess the ergot alkaloid biosynthesis capacity of previously unexplored fungi. Moreover, the characterization of the genes involved in the various branches provides opportunities and resources for the biotechnological manipulation of ergot alkaloids for experimentation and pharmaceutical development.
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Affiliation(s)
- Daniel G Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA
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Britton KN, Steen CR, Davis KA, Sampson JK, Panaccione DG. Contribution of a novel gene to lysergic acid amide synthesis in Metarhizium brunneum. BMC Res Notes 2022; 15:183. [PMID: 35585609 PMCID: PMC9118626 DOI: 10.1186/s13104-022-06068-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 05/05/2022] [Indexed: 12/04/2022] Open
Abstract
Objective The fungus Metarhizium brunneum produces ergot alkaloids of the lysergic acid amide class, most abundantly lysergic acid α-hydroxyethylamide (LAH). Genes for making ergot alkaloids are clustered in the genomes of producers. Gene clusters of LAH-producing fungi contain an α/β hydrolase fold protein-encoding gene named easP whose presence correlates with LAH production but whose contribution to LAH synthesis in unknown. We tested whether EasP contributes to LAH accumulation through gene knockout studies. Results We knocked out easP in M. brunneum via a CRISPR/Cas9-based approach, and accumulation of LAH was reduced to less than half the amount observed in the wild type. Because LAH accumulation was reduced and not eliminated, we identified and mutated the only close homolog of easP in the M. brunneum genome, a gene we named estA. An easP/estA double mutant did not differ from the easP mutant in lysergic acid amide accumulation, indicating estA had no role in the pathway. We conclude EasP contributes to LAH accumulation but is not absolutely required. Either a gene encoding redundant function and lacking sequence identity with easP resides outside the ergot alkaloid synthesis gene cluster, or EasP plays an accessory role in the synthesis of LAH. Supplementary Information The online version contains supplementary material available at 10.1186/s13104-022-06068-2.
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Affiliation(s)
- Kelcie N Britton
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Chey R Steen
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Kyle A Davis
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Jessi K Sampson
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Daniel G Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA.
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Beaulieu WT, Panaccione DG, Quach QN, Smoot KL, Clay K. Diversification of ergot alkaloids and heritable fungal symbionts in morning glories. Commun Biol 2021; 4:1362. [PMID: 34873267 PMCID: PMC8648897 DOI: 10.1038/s42003-021-02870-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/08/2021] [Indexed: 11/12/2022] Open
Abstract
Heritable microorganisms play critical roles in life cycles of many macro-organisms but their prevalence and functional roles are unknown for most plants. Bioactive ergot alkaloids produced by heritable Periglandula fungi occur in some morning glories (Convolvulaceae), similar to ergot alkaloids in grasses infected with related fungi. Ergot alkaloids have been of longstanding interest given their toxic effects, psychoactive properties, and medical applications. Here we show that ergot alkaloids are concentrated in four morning glory clades exhibiting differences in alkaloid profiles and are more prevalent in species with larger seeds than those with smaller seeds. Further, we found a phylogenetically-independent, positive correlation between seed mass and alkaloid concentrations in symbiotic species. Our findings suggest that heritable symbiosis has diversified among particular clades by vertical transmission through seeds combined with host speciation, and that ergot alkaloids are particularly beneficial to species with larger seeds. Our results are consistent with the defensive symbiosis hypothesis where bioactive ergot alkaloids from Periglandula symbionts protect seeds and seedlings from natural enemies, and provide a framework for exploring microbial chemistry in other plant-microbe interactions.
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Affiliation(s)
- Wesley T Beaulieu
- Department of Biology, Indiana University, Bloomington, IN, USA
- Jaeb Center for Health Research, Tampa, FL, USA
| | - Daniel G Panaccione
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Quynh N Quach
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA
| | - Katy L Smoot
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, USA
| | - Keith Clay
- Department of Biology, Indiana University, Bloomington, IN, USA.
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, USA.
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Macias AM, Marek PE, Morrissey EM, Brewer MS, Short DP, Stauder CM, Wickert KL, Berger MC, Metheny AM, Stajich JE, Boyce G, Rio RVM, Panaccione DG, Wong V, Jones TH, Kasson MT. Diversity and function of fungi associated with the fungivorous millipede, Brachycybe lecontii. FUNGAL ECOL 2019; 41:187-197. [PMID: 31871487 PMCID: PMC6927558 DOI: 10.1016/j.funeco.2019.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fungivorous millipedes (subterclass Colobognatha) likely represent some of the earliest known mycophagous terrestrial arthropods, yet their fungal partners remain elusive. Here we describe relationships between fungi and the fungivorous millipede, Brachycybe lecontii. Their fungal community is surprisingly diverse, including 176 genera, 39 orders, four phyla, and several undescribed species. Of particular interest are twelve genera conserved across wood substrates and millipede clades that comprise the core fungal community of B. lecontii. Wood decay fungi, long speculated to serve as the primary food source for Brachycybe species, were absent from this core assemblage and proved lethal to millipedes in pathogenicity assays while entomopathogenic Hypocreales were more common in the core but had little effect on millipede health. This study represents the first survey of fungal communities associated with any colobognath millipede, and these results offer a glimpse into the complexity of millipede fungal communities.
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Affiliation(s)
- Angie M. Macias
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Paul E. Marek
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Ember M. Morrissey
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Michael S. Brewer
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | | | - Cameron M. Stauder
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Kristen L. Wickert
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Matthew C. Berger
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Amy M. Metheny
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Jason E. Stajich
- Department of Microbiology and Plant Pathology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Greg Boyce
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Rita V. M. Rio
- Department of Biology, West Virginia University, Morgantown, WV, 26506, USA
| | - Daniel G. Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Victoria Wong
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Tappey H. Jones
- Department of Chemistry, Virginia Military Institute, Lexington, VA, 24450, USA
| | - Matt T. Kasson
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
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Cook D, Lee ST, Panaccione DG, Leadmon CE, Clay K, Gardner DR. Biodiversity of Convolvulaceous species that contain Ergot Alkaloids, Indole Diterpene Alkaloids, and Swainsonine. BIOCHEM SYST ECOL 2019; 86. [PMID: 31496550 DOI: 10.1016/j.bse.2019.103921] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Convolvulaceous species have been reported to contain several bioactive principles thought to be toxic to livestock including the calystegines, swainsonine, ergot alkaloids, and indole diterpene alkaloids. Swainsonine, ergot alkaloids, and indole diterpene alkaloids are produced by seed transmitted fungal symbionts associated with their respective plant host, while the calystegines are produced by the plant. To date, Ipomoea asarifolia and Ipomoea muelleri represent the only Ipomoea species and members of the Convolvulaceae known to contain indole diterpene alkaloids, however several other Convolvulaceous species are reported to contain ergot alkaloids. To further explore the biodiversity of species that may contain indole diterpenes, we analyzed several Convolvulaceous species (n=30) for indole diterpene alkaloids, representing four genera, Argyreia, Ipomoea, Stictocardia, and Turbina, that had been previously reported to contain ergot alkaloids. These species were also verified to contain ergot alkaloids and subsequently analyzed for swainsonine. Ergot alkaloids were detected in 18 species representing all four genera screened, indole diterpenes were detected in two Argyreia species and eight Ipomoea species of the 18 that contained ergot alkaloids, and swainsonine was detected in two Ipomoea species. The data suggest a strong association exists between the relationship of the Periglandula species associated with each host and the occurrence of the ergot alkaloids and/or the indole diterpenes reported here. Likewise there appears to be an association between the occurrence of the respective bioactive principle and the genetic relatedness of the respective host plant species.
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Affiliation(s)
- Daniel Cook
- Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 1150 E. 1400 N., Logan, UT 84341, USA
| | - Stephen T Lee
- Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 1150 E. 1400 N., Logan, UT 84341, USA
| | - Daniel G Panaccione
- West Virginia University, Division of Plant and Soil Sciences, Morgantown, WV 26506, USA
| | - Caroline E Leadmon
- West Virginia University, Division of Plant and Soil Sciences, Morgantown, WV 26506, USA
| | - Keith Clay
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA
| | - Dale R Gardner
- Poisonous Plant Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 1150 E. 1400 N., Logan, UT 84341, USA
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Boyce GR, Gluck-Thaler E, Slot JC, Stajich JE, Davis WJ, James TY, Cooley JR, Panaccione DG, Eilenberg J, De Fine Licht HH, Macias AM, Berger MC, Wickert KL, Stauder CM, Spahr EJ, Maust MD, Metheny AM, Simon C, Kritsky G, Hodge KT, Humber RA, Gullion T, Short DPG, Kijimoto T, Mozgai D, Arguedas N, Kasson MT. Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens. FUNGAL ECOL 2019; 41:147-164. [PMID: 31768192 PMCID: PMC6876628 DOI: 10.1016/j.funeco.2019.06.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but a few species keep insects alive while sporulating, which enhances dispersal. Transcriptomics- and metabolomics-based studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses. However, the mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadina-infected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which likely represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.
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Affiliation(s)
- Greg R Boyce
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Emile Gluck-Thaler
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
| | - Jason C Slot
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology and Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - William J Davis
- Department of Ecology and Evolution, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Tim Y James
- Department of Ecology and Evolution, University of Michigan, Ann Arbor, MI, 48109, USA
| | - John R Cooley
- Department of Ecology and Evolutionary Biology, University of Connecticut, Hartford, CT, 06103, USA
| | - Daniel G Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Jørgen Eilenberg
- Department of Plant and Environmental Science, University of Copenhagen, Denmark
| | | | - Angie M Macias
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Matthew C Berger
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Kristen L Wickert
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Cameron M Stauder
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Ellie J Spahr
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Matthew D Maust
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Amy M Metheny
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Chris Simon
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Gene Kritsky
- Department of Biology, Mount St. Joseph University, Cincinnati, OH, 45233, USA
| | - Kathie T Hodge
- Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Richard A Humber
- Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.,USDA-ARS-NAA-BioIPM, Ithaca, NY, 14853, USA
| | - Terry Gullion
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Teiya Kijimoto
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
| | - Dan Mozgai
- Cicadamania.com, Sea Bright, New Jersey, 07760, USA
| | | | - Matt T Kasson
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
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Affiliation(s)
- Daniel G. Panaccione
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, West Virginia 26506-6057
| | - Nancy L. Sheets
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506-6057
| | - Susan P. Miller
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506-6057
| | - Jonathan R. Cumming
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506-6057
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Affiliation(s)
- Daniel G. Panaccione
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Lisa J. Vaillancourt
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
| | - Robert M. Hanau
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
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11
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Affiliation(s)
- Suiyuan Zhang
- Division of Plant & Soil Sciences, 401 Brooks Hall, West Virginia University, Morgantown, West Virginia 26506-6057
| | - Daniel G. Panaccione
- Division of Plant & Soil Sciences, 401 Brooks Hall, West Virginia University, Morgantown, West Virginia 26506-6057
| | - Mannon E. Gallegly
- Division of Plant & Soil Sciences, 401 Brooks Hall, West Virginia University, Morgantown, West Virginia 26506-6057
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12
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Yi M, Hendricks WQ, Kaste J, Charlton ND, Nagabhyru P, Panaccione DG, Young CA. Molecular identification and characterization of endophytes from uncultivated barley. Mycologia 2018; 110:453-472. [PMID: 29923795 DOI: 10.1080/00275514.2018.1464818] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Epichloë species (Clavicipitaceae, Ascomycota) are endophytic symbionts of many cool-season grasses. Many interactions between Epichloë and their host grasses contribute to plant growth promotion, protection from many pathogens and insect pests, and tolerance to drought stress. Resistance to insect herbivores by endophytes associated with Hordeum species has been previously shown to vary depending on the endophyte-grass-insect combination. We explored the genetic and chemotypic diversity of endophytes present in wild Hordeum species. We analyzed seeds of Hordeum bogdanii, H. brevisubulatum, and H. comosum obtained from the US Department of Agriculture's (USDA) National Plant Germplasm System (NPGS), of which some have been reported as endophyte-infected. Using polymerase chain reaction (PCR) with primers specific to Epichloë species, we were able to identify endophytes in seeds from 17 of the 56 Plant Introduction (PI) lines, of which only 9 lines yielded viable seed. Phylogenetic analyses of housekeeping, alkaloid biosynthesis, and mating type genes suggest that the endophytes of the infected PI lines separate into five taxa: Epichloë bromicola, Epichloë tembladerae, and three unnamed interspecific hybrid species. One PI line contained an endophyte that is considered a new taxonomic group, Epichloë sp. HboTG-3 (H. bogdanii Taxonomic Group 3). Phylogenetic analyses of the interspecific hybrid endophytes from H. bogdanii and H. brevisubulatum indicate that these taxa all have an E. bromicola allele but the second allele varies. We verified in planta alkaloid production from the five genotypes yielding viable seed. Morphological characteristics of the isolates from the viable Hordeum species were analyzed for their features in culture and in planta. In the latter, we observed epiphyllous growth and in some cases sporulation on leaves of infected plants.
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Affiliation(s)
- Mihwa Yi
- a Noble Research Institute, LLC , Ardmore , Oklahoma 73401
| | | | - Joshua Kaste
- a Noble Research Institute, LLC , Ardmore , Oklahoma 73401
| | | | - Padmaja Nagabhyru
- b Department of Plant Pathology , University of Kentucky , Lexington , Kentucky 40546
| | - Daniel G Panaccione
- c Division of Plant and Soil Sciences , West Virginia University , Morgantown , West Virginia 26506
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Shi C, An S, Yao Z, Young CA, Panaccione DG, Lee ST, Schardl CL, Li C. Toxin-producing Epichloë bromicola strains symbiotic with the forage grass Elymus dahuricus in China. Mycologia 2018. [PMID: 29528270 DOI: 10.1080/00275514.2018.1426941] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cool-season grasses (Poaceae subfamily Poöideae) are an important forage component for livestock in western China, and many have seed-transmitted symbionts of the genus Epichloë, fungal endophytes that are broadly distributed geographically and in many tribes of the Poöideae. Epichloë strains can produce any of several classes of alkaloids, of which ergot alkaloids and indole-diterpenes can be toxic to mammalian and invertebrate herbivores, whereas lolines and peramine are more selective against invertebrates. The authors characterized genotypes and alkaloid profiles of Epichloë bromicola isolates symbiotic with Elymus dahuricus, an important forage grass in rangelands of China. The endophyte was seed-transmitted and occasionally produced fruiting bodies (stromata), but its sexual state was not observed on this host. The genome sequence of E. bromicola isolate E7626 from El. dahuricus in Xinjiang Province revealed gene sets for peramine, ergot alkaloids, and indole-diterpenes. In multiplex polymerase chain reaction (PCR) screens of El. dahuricus-endophyte isolates from Beijing and two locations in Shanxi Province, most were also positive for these genes. Ergovaline and other ergot alkaloids, terpendoles and other indole-diterpenes, and peramine were confirmed in El. dahuricus plants with E. bromicola. The presence of ergot alkaloids and indole-diterpenes in this grass is a potential concern for managers of grazing livestock.
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Affiliation(s)
- Chong Shi
- a College of Grassland and Environmental Science, Xinjiang Agricultural University , Urumqi , Xinjiang , China 830052
| | - Shazhou An
- a College of Grassland and Environmental Science, Xinjiang Agricultural University , Urumqi , Xinjiang , China 830052
| | - Zhengpei Yao
- b College of Agriculture, Xinjiang Agricultural University , Urumqi , Xinjiang , China 830052
| | - Carolyn A Young
- c Noble Research Institute , 2510 Sam Noble Parkway, Ardmore , Oklahoma 73401
| | - Daniel G Panaccione
- d Division of Plant and Soil Sciences , West Virginia University , Morgantown , West Virginia 26506-6108
| | - Stephen T Lee
- e Poisonous Plant Research Laboratory, Agricultural Research Service , United States Department of Agriculture , 1150 E. 1400 N., Logan , Utah 84341
| | - Christopher L Schardl
- f Department of Plant Pathology , University of Kentucky , Lexington , Kentucky 40546-0312
| | - Chunjie Li
- g State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University , Lanzhou , Gansu , China 730000
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Abstract
Biosynthesis of the dihydrogenated forms of ergot alkaloids is of interest because many of the ergot alkaloids used as pharmaceuticals may be derived from dihydrolysergic acid (DHLA) or its precursor dihydrolysergol. The maize (Zea mays) ergot pathogen Claviceps gigantea has been reported to produce dihydrolysergol, a hydroxylated derivative of the common ergot alkaloid festuclavine. We hypothesized expression of C. gigantea cloA in a festuclavine-accumulating mutant of the fungus Neosartorya fumigata would yield dihydrolysergol because the P450 monooxygenase CloA from other fungi performs similar oxidation reactions. We engineered such a strain, and high performance liquid chromatography and liquid chromatography-mass spectrometry analyses demonstrated the modified strain produced DHLA, the fully oxidized product of dihydrolysergol. Accumulation of high concentrations of DHLA in field-collected C. gigantea sclerotia and discovery of a mutation in the gene lpsA, downstream from DHLA formation, supported our finding that DHLA rather than dihydrolysergol is the end product of the C. gigantea pathway.
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Affiliation(s)
- Paige E. Bragg
- Division of Plant and Soil Sciences, Genetics and Developmental Biology Program, West Virginia University, 333 Evansdale Drive, Morgantown, West Virginia 26506, United States
| | - Matthew D. Maust
- Division of Plant and Soil Sciences, Genetics and Developmental Biology Program, West Virginia University, 333 Evansdale Drive, Morgantown, West Virginia 26506, United States
- Protea Biosciences, 1311 Pineview Drive, Morgantown, West Virginia 26505, United States
| | - Daniel G. Panaccione
- Protea Biosciences, 1311 Pineview Drive, Morgantown, West Virginia 26505, United States
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Arnold SL, Panaccione DG. Biosynthesis of the Pharmaceutically Important Fungal Ergot Alkaloid Dihydrolysergic Acid Requires a Specialized Allele of cloA. Appl Environ Microbiol 2017; 83:e00805-17. [PMID: 28476772 PMCID: PMC5494617 DOI: 10.1128/aem.00805-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/03/2017] [Indexed: 11/20/2022] Open
Abstract
Ergot alkaloids are specialized fungal metabolites that are important as the bases of several pharmaceuticals. Many ergot alkaloids are derivatives of lysergic acid (LA) and have vasoconstrictive activity, whereas several dihydrolysergic acid (DHLA) derivatives are vasorelaxant. The pathway to LA is established, with the P450 monooxygenase CloA playing a key role in oxidizing its substrate agroclavine to LA. We analyzed the activities of products of cloA alleles from different fungi relative to DHLA biosynthesis by expressing them in a mutant of the fungus Neosartorya fumigata that accumulates festuclavine, the precursor to DHLA. Transformants expressing CloA from Epichloë typhina × Epichloë festucae, which oxidizes agroclavine to LA, failed to oxidize festuclavine to DHLA. In substrate feeding experiments, these same transformants oxidized exogenously supplied agroclavine to LA, indicating that a functional CloA was produced. A genomic clone of cloA from Claviceps africana, a sorghum ergot fungus that produces a DHLA derivative, was cloned and expressed in the festuclavine-accumulating mutant of N. fumigata, but several introns in this genomic clone were not processed properly. Expression of a synthetic intron-free version of C. africanacloA resulted in the accumulation of DHLA as assessed by fluorescence high-pressure liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). In substrate feeding experiments, the C. africana CloA also accepted agroclavine as the substrate, oxidizing it to LA. The data indicate that a specialized allele of cloA is required for DHLA biosynthesis and that the pharmaceutically important compound DHLA can be produced in engineered N. fumigataIMPORTANCE Ergot alkaloids are fungal metabolites that have impacted humankind historically as poisons and more recently as pharmaceuticals used to treat dementia, migraines, and other disorders. Much is known about the biosynthesis of ergot alkaloids that are derived from lysergic acid (LA), but important questions remain about a parallel pathway to ergot alkaloids derived from dihydrolysergic acid (DHLA). DHLA-derived alkaloids have minor structural differences compared to LA-derived alkaloids but can have very different activities. To understand how DHLA is made, we analyzed activities of a key enzyme in the DHLA pathway and found that it differed from its counterpart in the LA pathway. Our data indicate a critical difference between the two pathways and provide a strategy for producing DHLA by modifying a model fungus. The ability to produce DHLA in a model fungus may facilitate synthesis of DHLA-derived pharmaceuticals.
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Affiliation(s)
- Stephanie L Arnold
- West Virginia University, Division of Plant and Soil Sciences, Genetics and Developmental Biology Program, Morgantown, West Virginia, USA
| | - Daniel G Panaccione
- West Virginia University, Division of Plant and Soil Sciences, Genetics and Developmental Biology Program, Morgantown, West Virginia, USA
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Affiliation(s)
| | | | | | - Daniel G. Panaccione
- Division of Plant & Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, West Virginia 26506-6108
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Mulinti P, Florea S, Schardl CL, Panaccione DG. Modulation of Ergot Alkaloids in a Grass-Endophyte Symbiosis by Alteration of mRNA Concentrations of an Ergot Alkaloid Synthesis Gene. J Agric Food Chem 2016; 64:4982-4989. [PMID: 27248330 DOI: 10.1021/acs.jafc.6b01604] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The profile of ergot alkaloids in perennial ryegrass (Lolium perenne) containing the endophytic fungus Epichloë typhina × festucae includes high concentrations of the early pathway metabolites ergotryptamine and chanoclavine-I in addition to the pathway end-product ergovaline. Because these alkaloids differ in activity, we investigated strategies to alter their relative concentrations. An RNAi-based approach reduced the concentration of mRNA from the gene easA, which encodes an enzyme required for a ring closure that separates ergotryptamine and chanoclavine-I from ergovaline. Lower easA mRNA concentrations correlated with lower concentrations of ergovaline and higher concentrations of ergotryptamine and chanoclavine-I. Overexpression of easA led to higher concentrations of ergovaline in leaf blades but not in pseudostems; concentrations of the early pathway metabolites were not altered in overexpression strains. The data indicate that altering the concentration of mRNA from a single gene can change alkaloid flux, but the magnitude of the change was limited and variable.
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Affiliation(s)
- Prashanthi Mulinti
- Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University , Morgantown, West Virginia 26506-6108, United States
| | - Simona Florea
- Department of Plant Pathology, University of Kentucky , Lexington, Kentucky 40546-0312, United States
| | - Christopher L Schardl
- Department of Plant Pathology, University of Kentucky , Lexington, Kentucky 40546-0312, United States
| | - Daniel G Panaccione
- Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University , Morgantown, West Virginia 26506-6108, United States
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Beaulieu WT, Panaccione DG, Ryan KL, Kaonongbua W, Clay K. Phylogenetic and chemotypic diversity of Periglandula species in eight new morning glory hosts (Convolvulaceae). Mycologia 2015; 107:667-78. [PMID: 25977213 DOI: 10.3852/14-239] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 04/17/2015] [Indexed: 11/10/2022]
Abstract
Periglandula ipomoeae and P. turbinae (Ascomycota, Clavicipitaceae) are recently described fungi that form symbiotic associations with the morning glories (Convolvulaceae) Ipomoea asarifolia and Turbina corymbosa, respectively. These Periglandula species are vertically transmitted and produce bioactive ergot alkaloids in seeds of infected plants and ephemeral mycelia on the adaxial surface of young leaves. Whether other morning glories that contain ergot alkaloids also are infected by Periglandula fungi is a central question. Here we report on a survey of eight species of Convolvulaceae (Argyreia nervosa, I. amnicola, I. argillicola, I. gracilis, I. hildebrandtii, I. leptophylla, I. muelleri, I. pes-caprae) for ergot alkaloids in seeds and associated clavicipitaceous fungi potentially responsible for their production. All host species contained ergot alkaloids in four distinct chemotypes with concentrations of 15.8-3223.0 μg/g. Each chemotype was a combination of four or five ergot alkaloids out of seven alkaloids detected across all hosts. In addition, each host species exhibited characteristic epiphytic mycelia on adaxial surfaces of young leaves with considerable interspecific differences in mycelial density. We sequenced three loci from fungi infecting each host: the nuclear rDNA internal transcribed spacer region (ITS), introns of the translation factor 1-α gene (tefA) and the dimethylallyl-tryptophan synthase gene (dmaW), which codes for the enzyme that catalyzes the first step in ergot alkaloid biosynthesis. Phylogenetic analyses confirmed that these fungi are in the family Clavicipitaceae and form a monophyletic group with the two described Periglandula species. This study is the first to report Periglandula spp. from Asian, Australian, African and North American species of Convolvulaceae, including host species with a shrub growth form and host species occurring outside of the tropics. This study demonstrates that ergot alkaloids in morning glories always co-occur with Periglandula spp. and that closely related Periglandula spp. produce alkaloid chemotypes more similar than more distantly related species.
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Affiliation(s)
- Wesley T Beaulieu
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, Indiana 47405
| | - Daniel G Panaccione
- Division of Plant & Soil Sciences, West Virginia University, 1090 Agricultural Sciences Building, Morgantown, West Virginia 26506-6108
| | - Katy L Ryan
- Division of Plant & Soil Sciences, West Virginia University, 1090 Agricultural Sciences Building, Morgantown, West Virginia 26506-6108
| | - Wittaya Kaonongbua
- Department of Microbiology, King Mongkut's University of Technology Thonburi, 126 Pracha Uthit Road, Bang Mod, Thung Khru, Bangkok 10140 Thailand
| | - Keith Clay
- Department of Biology, Indiana University, Bloomington, Indiana 47405
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Ryan KL, Akhmedov NG, Panaccione DG. Identification and structural elucidation of ergotryptamine, a new ergot alkaloid produced by genetically modified aspergillus nidulans and natural isolates of Epichloë species. J Agric Food Chem 2015; 63:61-67. [PMID: 25491167 DOI: 10.1021/jf505718x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ergot alkaloid pathway reconstruction in Aspergillus nidulans is an approach used to better understand the biosynthesis of these mycotoxins. An engineered strain named A. nidulans WFC (expressing ergot alkaloid synthesis genes dmaW, easF, and easC) produced the established intermediate N-methyl-4-dimethylallyltryptophan, as well as an uncharacterized ergot alkaloid. We investigated the chemical structure of the new metabolite and its role in the ergot alkaloid pathway. Mass spectrometry, labeling, and NMR studies showed that the unknown ergot alkaloid, designated here as ergotryptamine, differed from N-methyl-4-dimethylallyltryptophan by the loss of the carboxyl group, addition of a hydroxyl group, and shift in position of a carbon–carbon double bond. Feeding studies with Aspergillus mutants did not show ergotryptamine turnover, suggesting it is a pathway byproduct as opposed to an authentic intermediate. Several Epichloë species also produced this metabolite, and further investigations revealed the equivalency of ergotryptamine with an Epichloë-derived ergot alkaloid provisionally described as 6,7-secolysergine.
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20
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Morton JB, Benedito VA, Panaccione DG, Jenks MA. Potential for Industrial Application of Microbes in Symbioses that Influence Plant Productivity and Sustainability in Agricultural, Natural, or Restored Ecosystems. Ind Biotechnol (New Rochelle N Y) 2014. [DOI: 10.1089/ind.2014.0014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Joseph B. Morton
- Division of Plant and Soil Sciences, Davis College of Agriculture, Natural Resources and Design, West Virginia University, Morgantown, WV
| | - Vagner A. Benedito
- Division of Plant and Soil Sciences, Davis College of Agriculture, Natural Resources and Design, West Virginia University, Morgantown, WV
| | - Daniel G. Panaccione
- Division of Plant and Soil Sciences, Davis College of Agriculture, Natural Resources and Design, West Virginia University, Morgantown, WV
| | - Matthew A. Jenks
- Division of Plant and Soil Sciences, Davis College of Agriculture, Natural Resources and Design, West Virginia University, Morgantown, WV
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Mulinti P, Allen NA, Coyle CM, Gravelat FN, Sheppard DC, Panaccione DG. Accumulation of ergot alkaloids during conidiophore development in Aspergillus fumigatus. Curr Microbiol 2013; 68:1-5. [PMID: 23925951 DOI: 10.1007/s00284-013-0434-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/30/2013] [Indexed: 12/26/2022]
Abstract
Production of ergot alkaloids in the opportunistic fungal pathogen Aspergillus fumigatus is restricted to conidiating cultures. These cultures typically accumulate several pathway intermediates at concentrations comparable to that of the pathway end product. We investigated the contribution of different cell types that constitute the multicellular conidiophore of A. fumigatus to the production of ergot alkaloid pathway intermediates versus the pathway end product, fumigaclavine C. A relatively minor share (11 %) of the ergot alkaloid yield on a molar basis was secreted into the medium, whereas the remainder was associated with the conidiating colonies. Entire conidiating cultures (containing hyphae, vesicle of conidiophore, phialides of conidiophore, and conidia) accumulated higher levels of the pathway intermediate festuclavine and lower levels of the pathway end product fumigaclavine C than did isolated, abscised conidia, indicating that conidiophores and/or hyphae have a quantitatively different ergot alkaloid profile compared to that of conidia. Differences in alkaloid accumulation among cell types also were indicated by studies with conidiophore development mutants. A ∆medA mutant, in which conidiophores are numerous but develop poorly, accumulated higher levels of pathway intermediates than did the wildtype or a complemented ∆medA mutant. A ∆stuA mutant, which grows mainly as hyphae and produces very few, abnormal conidiophores, produced no detectable ergot alkaloids. The data indicated heterogeneous spatial distribution of ergot alkaloid pathway intermediates versus pathway end product in conidiating cultures of A. fumigatus. This skewed distribution may reflect differences in abundance or activity of pathway enzymes among cell types of those conidiating cultures.
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Affiliation(s)
- Prashanthi Mulinti
- Genetics & Developmental Biology Program, Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, 26506-6108, USA
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22
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Schardl CL, Young CA, Pan J, Florea S, Takach JE, Panaccione DG, Farman ML, Webb JS, Jaromczyk J, Charlton ND, Nagabhyru P, Chen L, Shi C, Leuchtmann A. Currencies of mutualisms: sources of alkaloid genes in vertically transmitted epichloae. Toxins (Basel) 2013; 5:1064-88. [PMID: 23744053 PMCID: PMC3717770 DOI: 10.3390/toxins5061064] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/17/2013] [Accepted: 05/29/2013] [Indexed: 11/17/2022] Open
Abstract
The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS), indole-diterpenes (IDT), and lolines (LOL) in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed.
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Affiliation(s)
- Christopher L. Schardl
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
| | - Carolyn A. Young
- Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA; E-Mails: (C.A.Y.); (J.E.T.); (N.D.C.)
| | - Juan Pan
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
| | - Simona Florea
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
| | - Johanna E. Takach
- Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA; E-Mails: (C.A.Y.); (J.E.T.); (N.D.C.)
| | - Daniel G. Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506, USA; E-Mail:
| | - Mark L. Farman
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
| | - Jennifer S. Webb
- Advanced Genetic Technologies Center, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.S.W.); (J.J.)
| | - Jolanta Jaromczyk
- Advanced Genetic Technologies Center, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.S.W.); (J.J.)
| | - Nikki D. Charlton
- Forage Improvement Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA; E-Mails: (C.A.Y.); (J.E.T.); (N.D.C.)
| | - Padmaja Nagabhyru
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
| | - Li Chen
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
- School of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
| | - Chong Shi
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA; E-Mails: (J.P.); (S.F.); (M.L.F.); (P.N.); (L.C.); (C.S.)
- School of Grassland & Environmental Science, Xinjiang Agricultural University, Urumqi 830052, China
| | - Adrian Leuchtmann
- Institute of Integrative Biology, ETH Zürich, Zürich CH-8092, Switzerland; E-Mail:
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Affiliation(s)
- Daniel G. Panaccione
- Division of Plant & Soil Sciences; West Virginia University; 1090 Agricultural Sciences Building Morgantown WV 26506-6108 USA
| | | | - Daniel Cook
- USDA ARS Poisonous Plant Research Laboratory; Logan UT USA
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Schardl CL, Young CA, Hesse U, Amyotte SG, Andreeva K, Calie PJ, Fleetwood DJ, Haws DC, Moore N, Oeser B, Panaccione DG, Schweri KK, Voisey CR, Farman ML, Jaromczyk JW, Roe BA, O'Sullivan DM, Scott B, Tudzynski P, An Z, Arnaoudova EG, Bullock CT, Charlton ND, Chen L, Cox M, Dinkins RD, Florea S, Glenn AE, Gordon A, Güldener U, Harris DR, Hollin W, Jaromczyk J, Johnson RD, Khan AK, Leistner E, Leuchtmann A, Li C, Liu J, Liu J, Liu M, Mace W, Machado C, Nagabhyru P, Pan J, Schmid J, Sugawara K, Steiner U, Takach JE, Tanaka E, Webb JS, Wilson EV, Wiseman JL, Yoshida R, Zeng Z. Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the clavicipitaceae reveals dynamics of alkaloid loci. PLoS Genet 2013; 9:e1003323. [PMID: 23468653 PMCID: PMC3585121 DOI: 10.1371/journal.pgen.1003323] [Citation(s) in RCA: 271] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/31/2012] [Indexed: 01/01/2023] Open
Abstract
The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some-including the infamous ergot alkaloids-have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses.
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Ryan KL, Moore CT, Panaccione DG. Partial reconstruction of the ergot alkaloid pathway by heterologous gene expression in Aspergillus nidulans. Toxins (Basel) 2013; 5:445-55. [PMID: 23435153 PMCID: PMC3640544 DOI: 10.3390/toxins5020445] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 02/08/2013] [Accepted: 02/17/2013] [Indexed: 12/28/2022] Open
Abstract
Ergot alkaloids are pharmaceutically and agriculturally important secondary metabolites produced by several species of fungi. Ergot alkaloid pathways vary among different fungal lineages, but the pathway intermediate chanoclavine-I is evolutionarily conserved among ergot alkaloid producers. At least four genes, dmaW, easF, easE, and easC, are necessary for pathway steps prior to chanoclavine-I; however, the sufficiency of these genes for chanoclavine-I synthesis has not been established. A fragment of genomic DNA containing dmaW, easF, easE, and easC was amplified from the human-pathogenic, ergot alkaloid-producing fungus Aspergillus fumigatus and transformed into Aspergillus nidulans, a model fungus that does not contain any of the ergot alkaloid synthesis genes. HPLC and LC-MS analyses demonstrated that transformed A. nidulans strains produced chanoclavine-I and an earlier pathway intermediate. Aspergillus nidulans transformants containing dmaW, easF, and either easE or easC did not produce chanoclavine-I but did produce an early pathway intermediate and, in the case of the easC transformant, an additional ergot alkaloid-like compound. We conclude that dmaW, easF, easE, and easC are sufficient for the synthesis of chanoclavine-I in A. nidulans and expressing ergot alkaloid pathway genes in A. nidulans provides a novel approach to understanding the early steps in ergot alkaloid synthesis.
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Affiliation(s)
- Katy L Ryan
- Genetics and Developmental Biology Program, Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506, USA.
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O'Connell RJ, Thon MR, Hacquard S, Amyotte SG, Kleemann J, Torres MF, Damm U, Buiate EA, Epstein L, Alkan N, Altmüller J, Alvarado-Balderrama L, Bauser CA, Becker C, Birren BW, Chen Z, Choi J, Crouch JA, Duvick JP, Farman MA, Gan P, Heiman D, Henrissat B, Howard RJ, Kabbage M, Koch C, Kracher B, Kubo Y, Law AD, Lebrun MH, Lee YH, Miyara I, Moore N, Neumann U, Nordström K, Panaccione DG, Panstruga R, Place M, Proctor RH, Prusky D, Rech G, Reinhardt R, Rollins JA, Rounsley S, Schardl CL, Schwartz DC, Shenoy N, Shirasu K, Sikhakolli UR, Stüber K, Sukno SA, Sweigard JA, Takano Y, Takahara H, Trail F, van der Does HC, Voll LM, Will I, Young S, Zeng Q, Zhang J, Zhou S, Dickman MB, Schulze-Lefert P, Ver Loren van Themaat E, Ma LJ, Vaillancourt LJ. Lifestyle transitions in plant pathogenic Colletotrichum fungi deciphered by genome and transcriptome analyses. Nat Genet 2012; 44:1060-5. [PMID: 22885923 DOI: 10.1038/ng.2372] [Citation(s) in RCA: 561] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 07/05/2012] [Indexed: 11/09/2022]
Abstract
Colletotrichum species are fungal pathogens that devastate crop plants worldwide. Host infection involves the differentiation of specialized cell types that are associated with penetration, growth inside living host cells (biotrophy) and tissue destruction (necrotrophy). We report here genome and transcriptome analyses of Colletotrichum higginsianum infecting Arabidopsis thaliana and Colletotrichum graminicola infecting maize. Comparative genomics showed that both fungi have large sets of pathogenicity-related genes, but families of genes encoding secreted effectors, pectin-degrading enzymes, secondary metabolism enzymes, transporters and peptidases are expanded in C. higginsianum. Genome-wide expression profiling revealed that these genes are transcribed in successive waves that are linked to pathogenic transitions: effectors and secondary metabolism enzymes are induced before penetration and during biotrophy, whereas most hydrolases and transporters are upregulated later, at the switch to necrotrophy. Our findings show that preinvasion perception of plant-derived signals substantially reprograms fungal gene expression and indicate previously unknown functions for particular fungal cell types.
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Affiliation(s)
- Richard J O'Connell
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
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Abstract
Aspergillus fumigatus is an opportunistic human pathogen that synthesizes a group of mycotoxins via a branch of the ergot alkaloid pathway. This fungus is globally distributed, and genetic data indicate that isolates recombine freely over that range; however, previous work on ergot alkaloids has focused on a limited number of isolates. We hypothesized that A. fumigatus harbors variation in the chemotype of ergot alkaloids and genotype of the ergot alkaloid gene cluster. Analysis of 13 isolates by high performance liquid chromatography revealed four distinct ergot alkaloid profiles or chemotypes. Five isolates completed the A. fumigatus branch of the ergot alkaloid pathway to fumigaclavine C. Six independent isolates accumulated fumigaclavine A, the pathway intermediate immediately before fumigaclavine C. One isolate accumulated only the early pathway intermediates chanoclavine-i and chanocla-vine-i aldehyde, and one isolate lacked ergot alkaloids altogether. A genetic basis for each of the observed chemotypes was obtained either by PCR analysis of the ergot alkaloid gene cluster or through sequencing of easL, the gene encoding the prenyl transferase that reverse prenylates fumigaclavine A to fumigaclavine C. Isolates also exhibited differences in pigmentation and sporulation. The ergot alkaloid chemotypes were widely distributed geographically and among substrate of origin.
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Affiliation(s)
- Sarah L Robinson
- Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV 26506-6108, USA
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Goetz KE, Coyle CM, Cheng JZ, O'Connor SE, Panaccione DG. Ergot cluster-encoded catalase is required for synthesis of chanoclavine-I in Aspergillus fumigatus. Curr Genet 2011; 57:201-11. [PMID: 21409592 DOI: 10.1007/s00294-011-0336-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/02/2011] [Accepted: 03/04/2011] [Indexed: 01/02/2023]
Abstract
Genes required for ergot alkaloid biosynthesis are clustered in the genomes of several fungi. Several conserved ergot cluster genes have been hypothesized, and in some cases demonstrated, to encode early steps of the pathway shared among fungi that ultimately make different ergot alkaloid end products. The deduced amino acid sequence of one of these conserved genes (easC) indicates a catalase as the product, but a role for a catalase in the ergot alkaloid pathway has not been established. We disrupted easC of Aspergillus fumigatus by homologous recombination with a truncated copy of that gene. The resulting mutant (ΔeasC) failed to produce the ergot alkaloids typically observed in A. fumigatus, including chanoclavine-I, festuclavine, and fumigaclavines B, A, and C. The ΔeasC mutant instead accumulated N-methyl-4-dimethylallyltryptophan (N-Me-DMAT), an intermediate recently shown to accumulate in Claviceps purpurea strains mutated at ccsA (called easE in A. fumigatus) (Lorenz et al. Appl Environ Microbiol 76:1822-1830, 2010). A ΔeasE disruption mutant of A. fumigatus also failed to accumulate chanoclavine-I and downstream ergot alkaloids and, instead, accumulated N-Me-DMAT. Feeding chanoclavine-I to the ΔeasC mutant restored ergot alkaloid production. Complementation of either ΔeasC or ΔeasE mutants with the respective wild-type allele also restored ergot alkaloid production. The easC gene was expressed in Escherichia coli, and the protein product displayed in vitro catalase activity with H(2)O(2) but did not act, in isolation, on N-Me-DMAT as substrate. The data indicate that the products of both easC (catalase) and easE (FAD-dependent oxidoreductase) are required for conversion of N-Me-DMAT to chanoclavine-I.
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Affiliation(s)
- Kerry E Goetz
- Division of Plant and Soil Sciences, Genetics and Developmental Biology Program, Morgantown, WV 26506, USA
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29
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Abstract
The ergot alkaloids are a diverse class of fungal-derived indole alkaloid natural products with potent pharmacological activities. The biosynthetic intermediate chanoclavine-I aldehyde 1 represents a branch point in ergot biosynthesis. Ergot alkaloids festuclavine 2 and agroclavine 3 derive from alternate enzymatic pathways originating from the common biosynthetic precursor chanoclavine-I aldehyde 1. Here we show that while the Old Yellow Enzyme homologue EasA from the ergot biosynthetic gene cluster of Aspergillus fumigatus acts on chanoclavine-I aldehyde 1 to yield festuclavine 2, EasA from Neotyphodium lolii, in contrast, produces agroclavine 3. Mutational analysis suggests a mechanistic rationale for the switch in activity that controls this critical branch point of ergot alkaloid biosynthesis.
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Affiliation(s)
- Johnathan Z Cheng
- Massachusetts Institute of Technology, Department of Chemistry, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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30
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Abstract
Ergot alkaloids, secondary metabolites produced by filamentous fungi, elicit a diverse array of pharmacological effects. The biosynthesis of this class of natural products has not been fully elucidated. Here we demonstrate that a homologue of Old Yellow Enzyme encoded in the Aspergillus fumigatus ergot gene cluster catalyzes reduction of the alpha,beta unsaturated alkene of chanoclavine-I aldehyde 3. This reduction, which yields dihydrochanoclavine aldehyde, facilitates an intramolecular reaction between a secondary amine and aldehyde to form the D ring of the ergot alkaloid structural framework.
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Affiliation(s)
- Johnathan Z Cheng
- Massachusetts Institute of Technology, Department of Chemistry, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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Damrongkool P, Sedlock AB, Young CA, Johnson RD, Goetz KE, Scott B, Schardl CL, Panaccione DG. Structural analysis of a peptide synthetase gene required for ergopeptine production in the endophytic fungusNeotyphodium lolii. ACTA ACUST UNITED AC 2009; 16:379-85. [PMID: 16243728 DOI: 10.1080/10425170500273005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lysergyl peptide synthetase 1 catalyzes the assembly of toxic ergopeptines from activated D-lysergic acid and three amino acids. The gene encoding this enzyme in the endophytic fungus Neotyphodium lolii was analyzed and compared to a homologous gene from the ergot fungus Claviceps purpurea. Each gene contained two introns, which were found in the same relative position within two modules of the gene. The 5' ends of the two genes were unusually divergent. Signature sequences determining substrate specificity were similar in adenylation domains that recognized identical amino acids but differed within the adenylation domain for the amino acid that varies between the major ergopeptines of the two fungi. Homologues were detected in several related endophytic fungi; the tall fescue endophyte Neotyphodium coenophialum contained a divergent, second copy of the gene. Our results provide new information on the structure and distribution of this important peptide synthetase involved in ergot alkaloid biosynthesis.
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Abstract
Ergot alkaloids are indole-derived mycotoxins that are important in agriculture and medicine. Ergot alkaloids are produced by a few representatives of two distantly related fungal lineages, the Clavicipitaceae and the Trichocomaceae. Comparison of the ergot alkaloid gene clusters from these two lineages revealed differences in the relative positions and orientations of several genes. The question arose: is ergot alkaloid biosynthetic capability from a common origin? We used a molecular phylogenetic approach to gain insights into the evolution of ergot alkaloid biosynthesis. The 4-γ,γ-dimethylallyltryptophan synthase gene, dmaW, encodes the first step in the pathway. Amino acid sequences deduced from dmaW and homologs were submitted to phylogenetic analysis, and the results indicated that dmaW of Aspergillus fumigatus (mitosporic Trichocomaceae) has the same origin as corresponding genes from clavicipitaceous fungi. Relationships of authentic dmaW genes suggest that they originated from multiple gene duplications with subsequent losses of original or duplicate versions in some lineages.
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Affiliation(s)
- Miao Liu
- 201 F Plant Science Bldg, University of Kentucky, Lexington, KY 40546, USA
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33
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Abstract
Ergot alkaloids are mycotoxins that affect the nervous and reproductive systems of exposed individuals through interactions with monoamine receptors. They have been studied more widely in ergot fungi and grass endophytes but also are found in Aspergillus fumigatus, an opportunistic human pathogen that reproduces and disseminates exclusively through conidia. The ergot alkaloids festucla-vine and fumigaclavines A, B and C are present in or on conidia of A. fumigatus. Cultures of the fungus that are free of conidia are difficult to obtain, obscuring comparisons of conidia versus vegetative hyphae as sources of the ergot alkaloids. To create conidiation-deficient strains of A. fumigatus we manipulated the bristle A gene (brlA), which controls vesicle formation or budding growth necessary for conidiation in Aspergillus spp. Disruption of brlA in A. fumigatus, via homologous recombination, resulted in a nonconidiating mutant that produced bristle-like structures instead of conidiophores and conidia. Moreover the disrupted strain failed to produce ergot alkaloids as verified by HPLC analyses. Complementation with a wild-type allele restored conidiation and ergot alkaloid production. These results suggest that ergot alkaloids are not produced within the vegetative mycelium of the fungus and are associated directly with conidiation.
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Affiliation(s)
- Christine M Coyle
- Division of Plant & Soil Sciences, West Virginia University, P.O. Box 6108, Morgantown, West Virginia 26506-6108, USA
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Panaccione DG, Cipoletti JR, Sedlock AB, Blemings KP, Schardl CL, Machado C, Seidel GE. Effects of ergot alkaloids on food preference and satiety in rabbits, as assessed with gene-knockout endophytes in perennial ryegrass (Lolium perenne). J Agric Food Chem 2006; 54:4582-7. [PMID: 16787001 DOI: 10.1021/jf060626u] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Neotyphodium species are fungal endophytes best known for their protection of grass hosts and production of bioactive metabolites including ergot alkaloids. Perennial ryegrass-Neotyphodium sp. Lp1 symbiota that have altered ergot alkaloid profiles (resulting from knockouts in two different endophyte genes) were fed, along with controls, to rabbits to test the effects of ergot alkaloids on food preference and satiety. Interestingly, rabbits dramatically preferred plants that were endophyte-infected but free of ergot alkaloids over endophyte-free plants (P = 0.01). Accumulation of ergot alkaloids of the clavine class counteracted the added appeal of endophyte-infected plants. In satiety tests, consumption of ergovaline (the ultimate ergot pathway product in wild-type endophyte), but not of several other ergot alkaloids, during an initial meal had a negative effect on subsequent rabbit chow consumption (P < 0.05). The data indicate that clavines were sufficient to reduce the appeal of endophyte-infected grasses, whereas only ergovaline reduced appetite.
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Affiliation(s)
- Daniel G Panaccione
- Division of Plant and Soil Sciences, P.O. Box 6108, Division of Animal and Veterinary Sciences, and Department of Statistics, West Virginia University, Morgantown, West Virginia, 26506, USA.
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35
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Abstract
Ergot alkaloids are a diverse family of indole-derived mycotoxins that collectively have activities against a variety of organisms including bacteria, nematodes, insects, and mammals. Different fungi accumulate different, often characteristic, profiles of ergot alkaloids rather than a single pathway end product. These ergot alkaloid profiles result from inefficiency in the pathway leading to accumulation of certain intermediates or diversion of intermediates into shunts along the pathway. The inefficiency generating these ergot alkaloid profiles may have been selected for as a means of accumulating a diversity of ergot alkaloids, potentially contributing in different ways to benefit the producing fungus.
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Affiliation(s)
- Daniel G Panaccione
- Division of Plant and Soil Sciences, West Virginia University, P.O. Box 6058, Morgantown, WV 26506-6058, USA.
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Abstract
EA have been a major benefit, and a major detriment, to humans since early in recorded history. Their medicinal properties have been used, and continue to be used, to aid in childbirth, with new uses being found in the treatment of neurological and cardiovascular disorders. The surprisingly broad range of pharmaceutical uses for EA stems from their affinities for multiple receptors for three distinct neurotransmitters (serotonin, dopamine, and adrenaline), from the great structural diversity of natural EA, and from the application of chemical techniques that further expand that structural diversity. The dangers posed by EA to humans and their livestock stem from the ubiquity of ergot fungi (Claviceps species) as parasites of cereals, and of related grass endophytes (Epichloë, Neotyphodium, and Balansia species) that may inhabit pasture grasses and produce toxic levels of EA. Further concerns stem from saprophytic EA producers in the genera Aspergillus and Penicillium, especially A. fumigatus, an opportunistic pathogen of humans. Numerous fungal species produce EA with a wide variety of structures and properties. These alkaloids are associated with plants in the families Poaceae, Cyperaceae, and Convolvulaceae, apparently because these plants can have symbiotic fungi that produce EA. Pharmacological activities of EA relate to their specific structures. Known as potent vasoconstrictors, the ergopeptines include a lysergic acid substituent with an amide linkage to a complex cyclol-lactam ring structure generated from three amino acids. Simpler lysergyl amides and clavines are more apt to have oxytonic or psychotropic activities. One of the lysergyl amides is LSD (5), the most potent hallucinogen known. The EA biosynthetic pathway in Claviceps species has been studied extensively for many decades, and recent studies have also employed epichloës and A. fumigatus. The early pathway, shared among these fungi, begins with the action of an aromatic prenyl transferase, DMATrp synthase, which links a dimethylallyl chain to L-tryptophan. When the dmaW gene encoding DMATrp synthase was cloned and sequenced, the predicted product bore no identifiable resemblance to other known prenyl transferases. The dma W genes of Claviceps species are present in clusters of genes, several of which also have demonstrated roles in EA biosynthesis. In many other fungi, dma W homologues are identifiable in otherwise very different gene clusters. The roles of DMA Trp synthase homologues in these other fungi are probably quite variable. One of them is thought to prenylate the phenolic oxygen of L-tyrosine, and another catalyzes the unusual reverse prenylation reaction in the biosynthesis of fumigaclavine C(10), an EA characteristic of A. fumigatus. The second step of the EA pathway is N-methylation of DMATrp (12) to form 13, which is then subjected to a series of oxidation/oxygenation and reduction reactions to generate, in order, chanoclavine-I (16), agroclavine (19), and elymoclavine (6). Shunt reactions generate a wide variety of other clavines. Two epimerizations occur in this pathway: one from 12 to 16, the other from 16 to 19. Further oxidation of 6, catalyzed by the cytochrome-P450 CloA, generates lysergic acid (1). An unusual NRPS complex, lysergyl peptide synthetase (LPS), is responsible for linking 1 to three hydrophobic L-amino acids to generate the ergopeptide lactams. The LPS complex includes two polypeptides, one (LPS 2) possessing a single module for activation of 1, and the other (LPS 1) possessing three modules, each specifying one of the L-amino acids. Variations in LPS 1 sequences are associated with variations in the incorporated amino acids, leading to differences between strain chemotypes, and even multiple ergopeptines within strains. For example, C. purpurea P1 produces two distinct ergopeptines (ergotamine (4) and ergocryptine (Table I)), each of which is believed to be generated by multiple LPS 1 subunits encoded by separate, but related, genes (lpsA1 and lpsA2). The main ecological roles of EA in nature are probably to protect the fungi from consumption by vertebrate and invertebrate animals. The EA produced by plant-symbiotic fungi (such as epichloë endophytes) may protect the fungus by protecting the health and productivity of the host, which may otherwise suffer excessive grazing by animals. The EA, at levels typical of plants bearing these symbionts, can negatively affect the health of large mammals as well herbivorous insects. Some clavines have substantial anti-bacterial properties, which might protect the fungus and, in some cases, their host plants from infection. However, the fact that a large number of epichloë, and even several Claviceps species, produce no detectable EA indicates that the selection for their production is not universal. An unfortunate fact for many livestock producers is that some of the most popular forage grasses tend to possess EA-producing epichloë endophytes. Such endophytes are easily eliminated, but confer such fitness enhancements to their hosts that their presence is often preferred, despite the toxic EA. The future looks promising for continued interest in EA. Research continues into their pharmacological properties, medicinal uses, and structure-function relationships. New clavines and lysergic acid derivatives are identified regularly from new sources, such as marine animals. Also, programs are well underway to modify or replace epichloë endophytes of forage grasses in order to produce new grass cultivars that lack these toxins.
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Affiliation(s)
- Christopher L Schardl
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546-0312, USA
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Haarmann T, Machado C, Lübbe Y, Correia T, Schardl CL, Panaccione DG, Tudzynski P. The ergot alkaloid gene cluster in Claviceps purpurea: extension of the cluster sequence and intra species evolution. Phytochemistry 2005; 66:1312-20. [PMID: 15904941 DOI: 10.1016/j.phytochem.2005.04.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Revised: 02/24/2005] [Accepted: 04/07/2005] [Indexed: 05/02/2023]
Abstract
The genomic region of Claviceps purpurea strain P1 containing the ergot alkaloid gene cluster [Tudzynski, P., Hölter, K., Correia, T., Arntz, C., Grammel, N., Keller, U., 1999. Evidence for an ergot alkaloid gene cluster in Claviceps purpurea. Mol. Gen. Genet. 261, 133-141] was explored by chromosome walking, and additional genes probably involved in the ergot alkaloid biosynthesis have been identified. The putative cluster sequence (extending over 68.5kb) contains 4 different nonribosomal peptide synthetase (NRPS) genes and several putative oxidases. Northern analysis showed that most of the genes were co-regulated (repressed by high phosphate), and identified probable flanking genes by lack of co-regulation. Comparison of the cluster sequences of strain P1, an ergotamine producer, with that of strain ECC93, an ergocristine producer, showed high conservation of most of the cluster genes, but significant variation in the NRPS modules, strongly suggesting that evolution of these chemical races of C. purpurea is determined by evolution of NRPS module specificity.
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Affiliation(s)
- Thomas Haarmann
- Institut für Botanik, Westf. Wilhelms-Universität Münster, Schlossgarten 3, D-48149 Münster, Germany
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Abstract
The ergot alkaloids are a family of indole-derived mycotoxins with a variety of significant biological activities. Aspergillus fumigatus, a common airborne fungus and opportunistic human pathogen, and several fungi in the relatively distant taxon Clavicipitaceae (clavicipitaceous fungi) produce different sets of ergot alkaloids. The ergot alkaloids of these divergent fungi share a four-member ergoline ring but differ in the number, type, and position of the side chains. Several genes required for ergot alkaloid production are known in the clavicipitaceous fungi, and these genes are clustered in the genome of the ergot fungus Claviceps purpurea. We investigated whether the ergot alkaloids of A. fumigatus have a common biosynthetic and genetic origin with those of the clavicipitaceous fungi. A homolog of dmaW, the gene controlling the determinant step in the ergot alkaloid pathway of clavicipitaceous fungi, was identified in the A. fumigatus genome. Knockout of dmaW eliminated all known ergot alkaloids from A. fumigatus, and complementation of the mutation restored ergot alkaloid production. Clustered with dmaW in the A. fumigatus genome are sequences corresponding to five genes previously proposed to encode steps in the ergot alkaloid pathway of C. purpurea, as well as additional sequences whose deduced protein products are consistent with their involvement in the ergot alkaloid pathway. The corresponding genes have similarities in their nucleotide sequences, but the orientations and positions within the cluster of several of these genes differ. The data indicate that the ergot alkaloid biosynthetic capabilities in A. fumigatus and the clavicipitaceous fungi had a common origin.
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Affiliation(s)
- Christine M Coyle
- Division of Plant & Soil Sciences, Genetics & Developmental Biology Program, 401 Brooks Hall, West Virginia University, Morgantown, West Virginia 26506-6058, USA
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40
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Panaccione DG, Coyle CM. Abundant respirable ergot alkaloids from the common airborne fungus Aspergillus fumigatus. Appl Environ Microbiol 2005; 71:3106-11. [PMID: 15933008 PMCID: PMC1151833 DOI: 10.1128/aem.71.6.3106-3111.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Accepted: 12/20/2004] [Indexed: 11/20/2022] Open
Abstract
Ergot alkaloids are mycotoxins that interact with several monoamine receptors, negatively affecting cardiovascular, nervous, reproductive, and immune systems of exposed humans and animals. Aspergillus fumigatus, a common airborne fungus and opportunistic human pathogen, can produce ergot alkaloids in broth culture. The objectives of this study were to determine if A. fumigatus accumulates ergot alkaloids in a respirable form in or on its conidia, to quantify ergot alkaloids associated with conidia produced on several different substrates, and to measure relevant physical properties of the conidia. We found at least four ergot alkaloids, fumigaclavine C, festuclavine, fumigaclavine A, and fumigaclavine B (in order of abundance), associated with conidia of A. fumigatus. Under environmentally relevant conditions, the total mass of ergot alkaloids often constituted >1% of the mass of the conidium. Ergot alkaloids were extracted from conidia produced on all media tested, and the greatest quantities were observed when the fungus was cultured on latex paint or cultured maize seedlings. The values for physical properties of conidia likely to affect their respirability (i.e., diameter, mass, and specific gravity) were significantly lower for A. fumigatus than for Aspergillus nidulans, Aspergillus niger, and Stachybotrys chartarum. The demonstration of relatively high concentrations of ergot alkaloids associated with conidia of A. fumigatus presents opportunities for investigations of potential contributions of the toxins to adverse health effects associated with the fungus and to aspects of the biology of the fungus that contribute to its success.
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Affiliation(s)
- Daniel G Panaccione
- Division of Plant & Soil Sciences, Genetics & Developmental Biology Program, 401 Brooks Hall, West Virginia University, Morgantown, West Virginia 26506-6058, USA.
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41
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Wang J, Machado C, Panaccione DG, Tsai HF, Schardl CL. The determinant step in ergot alkaloid biosynthesis by an endophyte of perennial ryegrass. Fungal Genet Biol 2004; 41:189-98. [PMID: 14732265 DOI: 10.1016/j.fgb.2003.10.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many cool-season grasses harbor fungal endophytes in the genus Neotyphodium, which enhance host fitness, but some also produce metabolites--such as ergovaline--believed to cause livestock toxicoses. In Claviceps species the first step in ergot alkaloid biosynthesis is thought to be dimethylallyltryptophan (DMAT) synthase, encoded by dmaW, previously cloned from Claviceps fusiformis. Here we report the cloning and characterization of dmaW from Neotyphodium sp. isolate Lp1, an endophyte of perennial ryegrass (Lolium perenne). The gene was then disrupted, and the mutant failed to produce any detectable ergovaline or simpler ergot and clavine alkaloids. The disruption was complemented with the C. fusiformis gene, which restored ergovaline production. Thus, the biosynthetic role of DMAT synthase was confirmed, and a mutant was generated for future studies of the ecological and agricultural importance of ergot alkaloids in endophytes of grasses.
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Affiliation(s)
- Jinghong Wang
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546-0312, USA
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Panaccione DG, Tapper BA, Lane GA, Davies E, Fraser K. Biochemical outcome of blocking the ergot alkaloid pathway of a grass endophyte. J Agric Food Chem 2003; 51:6429-6437. [PMID: 14558758 DOI: 10.1021/jf0346859] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Neotyphodium sp. Lp1, an endophytic fungus from perennial ryegrass (Lolium perenne), produces the mycotoxin ergovaline in infected grasses, whereas a mutant in which a particular peptide synthetase gene is knocked out does not. We examined the impact of this knockout on other constituents of the ergot alkaloid pathway. Two simple lysergic acid amides, ergine and a previously undescribed amide, were eliminated by the knockout. Lysergic acid accumulated in the knockout endophyte, but quantities were only 13% of the total lysergic acid derivatives accumulated in the wild type. Concentrations of several clavines were not substantially affected. However, a novel clavine accumulated to higher concentrations in perennial ryegrass containing the knockout strain. The results indicate that production of simple lysergic acid amides requires the activity or products of the ergovaline-associated peptide synthetase and that the regulation of ergot alkaloid production is modified in response to the relatively late block in the pathway.
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Affiliation(s)
- Daniel G Panaccione
- Division of Plant & Soil Sciences, 401 Brooks Hall, P.O. Box 6058, West Virginia University, Morgantown, WV 26506-6058, USA.
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Panaccione DG, Johnson RD, Wang J, Young CA, Damrongkool P, Scott B, Schardl CL. Elimination of ergovaline from a grass-Neotyphodium endophyte symbiosis by genetic modification of the endophyte. Proc Natl Acad Sci U S A 2001; 98:12820-5. [PMID: 11592979 PMCID: PMC60137 DOI: 10.1073/pnas.221198698] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2001] [Indexed: 11/18/2022] Open
Abstract
The fungal endophytes Neotyphodium lolii and Neotyphodium sp. Lp1 from perennial ryegrass (Lolium perenne), and related endophytes in other grasses, produce the ergopeptine toxin ergovaline, among other alkaloids, while also increasing plant fitness and resistance to biotic and abiotic stress. In the related fungus, Claviceps purpurea, the biosynthesis of ergopeptines requires the activities of two peptide synthetases, LPS1 and LPS2. A peptide synthetase gene hypothesized to be important for ergopeptine biosynthesis was identified in C. purpurea by its clustering with another ergot alkaloid biosynthetic gene, dmaW. Sequence analysis conducted independently of the research presented here indicates that this gene encodes LPS1 [Tudzynski, P., Holter, K., Correia, T., Arntz, C., Grammel, N. & Keller, U. (1999) Mol. Gen. Genet. 261, 133-141]. We have cloned a similar peptide synthetase gene from Neotyphodium lolii and inactivated it by gene knockout in Neotyphodium sp. Lp1. The resulting strain retained full compatibility with its perennial ryegrass host plant as assessed by immunoblotting of tillers and quantitative PCR. However, grass-endophyte associations containing the knockout strain did not produce detectable quantities of ergovaline as analyzed by HPLC with fluorescence detection. Disruption of this gene provides a means to manipulate the accumulation of ergovaline in endophyte-infected grasses for the purpose of determining the roles of ergovaline in endophyte-associated traits and, potentially, for ameliorating toxicoses in livestock.
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Affiliation(s)
- D G Panaccione
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506, USA.
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Panaccione DG, Sheets NL, Miller SP, Cumming JR. Diversity of Cenococcum geophilum Isolates from Serpentine and Non-Serpentine Soils. Mycologia 2001. [DOI: 10.2307/3761819] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Annis SL, Panaccione DG. Presence of peptide synthetase gene transcripts and accumulation of ergopeptines in <I>Claviceps purpurea</I> and <I>Neotyphodium coenophialum</I>. Can J Microbiol 1998. [DOI: 10.1139/cjm-44-1-80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Annis SL, Panaccione DG. Presence of peptide synthetase gene transcripts and accumulation of ergopeptines in Claviceps purpurea and Neotyphodium coenophialum. Can J Microbiol 1998; 44:80-6. [PMID: 9546869 DOI: 10.1139/w97-130] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The production of toxic ergopeptine alkaloids by the fungi Claviceps purpurea and Neotyphodium coenophialum involves the activity of one or more nonribosomal peptide synthetases. Claviceps purpurea and N. coenophialum each have several different peptide synthetase genes, fragments of which have been cloned previously. An additional Claviceps purpurea peptide synthetase gene was cloned by hydridization with one of the N. coenophialum peptide synthetase gene fragments. We detected the presence of mRNA from the peptide synthetase genes in cultures of different ages grown under conditions favorable or unfavorable for ergopeptine production. All four peptide synthetase genes from Claviceps purpurea were transcribed under at least some of the experimental conditions. Transcripts from three of the four genes were detected under conditions consistent with their potential involvement in ergopeptine biosynthesis. All three peptide synthetase genes previously identified in N. coenophialum were transcribed during symbiotic growth of this fungus with tall fescue, as well as ergopeptine-producing cultures. The data show that all of the peptide synthetase genes are transcribed, that one of the peptide synthetase genes is dissociated from ergopeptine biosynthesis, and, as a result, prioritize the remaining genes for functional analyses by transformation-mediated gene disruption.
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Affiliation(s)
- S L Annis
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV 26506-6057, USA
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Abstract
The ascomycete fungus Cochliobolus carbonum race 1 is pathogenic on certain genotypes of maize due to the production of HC-toxin, a host-specific cyclic peptide. HC-toxin production is controlled, at least in part, by a duplicated 22-kb region of DNA that is found only in toxin-producing isolates of the fungus. This 22-kb region of DNA is flanked by a repetitive element. We have sequenced the element and found an interrupted reading frame that would encode a product similar to transposases from the fungal transposons Fot1 of Fusarium oxysporum and Pot2 of Magnaporthe grisea. The individual element cloned from C. carbonum is likely to function neither in cis nor trans, as it had a nonsense mutation in frame and several substitutions in its terminal inverted repeats. However, similar elements in the C. carbonum genome may be active, as the putative transposase-encoding region hybridized to mRNA of the size predicted by the reading frame. The element was found in varying copy number in the genomes of all Cochliobolus spp. examined, giving a distinct fingerprint in each species and race tested. The sequence similarity of the C. carbonum repetitive element to other fungal transposons, along with its presence in multiple copies per genome, strongly suggest that the C. carbonum repetitive element is a member of the Fot1 family of fungal transposons.
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Affiliation(s)
- D G Panaccione
- Division of Plant & Soil Sciences, West Virginia University, Morgantown 26506-6057, USA.
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Pitkin JW, Panaccione DG, Walton JD. A putative cyclic peptide efflux pump encoded by the TOXA gene of the plant-pathogenic fungus Cochliobolus carbonum. Microbiology (Reading) 1996; 142 ( Pt 6):1557-1565. [PMID: 8704997 DOI: 10.1099/13500872-142-6-1557] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Race 1 isolates of Cochliobolus carbonum are pathogenic on certain maize lines due to production of a host-selective cyclic tetrapeptide, HC-toxin. Flanking HTS1, which encodes the central enzyme in HC-toxin biosynthesis, a gene was identified and named TOXA. Like HTS1, TOXA occurred only in isolates of the fungus that make HC-toxin and was present as two linked copies in most toxin-producing isolates. HTS1 and TOXA were transcribed in the opposite orientation and their transcriptional start sites were 386 bp apart. The predicted product of TOXA was a 58 kDa hydrophobic protein with 10-13 membrane-spanning regions. The sequence was highly similar to several members of the major facilitator superfamily that confer resistance to tetracycline, methylenomycin, and other antibiotics. Although it was possible to mutate one copy or the other of TOXA by targeted gene disruption, numerous attempts to disrupt both copies in a single strain were unsuccessful, suggesting that TOXA is an essential gene in strains that synthesize HC-toxin. On the basis of its presence only in HC-toxin-producing strains, its proximity to HTS1 and its predicted amino acid sequence, we propose that TOXA encodes an HC-toxin efflux pump which contributes to self-protection against HC-toxin and/or the secretion of HC-toxin into the extracellular milieu.
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Affiliation(s)
- John W Pitkin
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing 48824, USA
| | - Daniel G Panaccione
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing 48824, USA
| | - Jonathan D Walton
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing 48824, USA
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