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Uhlig S, Rangel-Huerta OD, Divon HH, Rolén E, Pauchon K, Sumarah MW, Vrålstad T, Renaud JB. Unraveling the Ergot Alkaloid and Indole Diterpenoid Metabolome in the Claviceps purpurea Species Complex Using LC-HRMS/MS Diagnostic Fragmentation Filtering. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:7137-7148. [PMID: 34148344 DOI: 10.1021/acs.jafc.1c01973] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The plant parasitic fungus Claviceps purpurea sensu lato produces sclerotia containing toxic ergot alkaloids and uncharacterized indole diterpenoids in grasses including cereals. The aim of this study was to detect as many peptide ergot alkaloids and indole diterpenoids in ergot sclerotia as possible by using a liquid chromatography-high-resolution mass spectrometry (LC-HRMS/MS) approach and applying filtering of diagnostic fragment ions for data extraction. The sample set consisted of 66 Claviceps sclerotia from four different geographic locations in southeastern Norway as well as Saskatchewan, Canada. The host plants included both wild grasses and important cereal grains such as rye. DNA sequencing showed that the sclerotia were from three Claviceps species, i.e., Claviceps purpurea sensu stricto (s.s.), Claviceps humidiphila, and Claviceps arundinis (former C. purpurea genotypes G1, G2, and G2a, respectively). All sclerotia from cereal grains were from C. purpurea s.s. Diagnostic fragment filtering was based on detecting specific product ions in MS/MS data sets that are well-conserved across the different ergot alkaloid subgroups and indole diterpenoids of the paspaline/paxilline type. The approach extracted mass spectra from 67 peptide ergot alkaloids (including C-8 epimers and lactam variants) and five indole diterpenoids. In addition, three clavines were detected by using targeted analysis. The sum of the peak areas for ergot alkaloids, which have been assigned as "major" analogues by the European Food Safety Authority (ergometrine, ergosine, ergotamine, α-ergocryptine, ergocornine, ergocristine, and their 8-S epimers), accounted for at least 50% of the extracted total ergot alkaloid metabolome. Univariate and multivariate statistical analyses showed that several of the alkaloids were specific for certain species within the C. purpurea species complex and could be used as chemotaxonomic markers for species assignment.
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Affiliation(s)
- Silvio Uhlig
- Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway
| | | | - Hege H Divon
- Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway
| | - Elin Rolén
- Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway
| | - Kari Pauchon
- Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Science, Universitetstunet 3, 1430 Ås, Norway
| | - Mark W Sumarah
- London Research and Development Center, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada
| | - Trude Vrålstad
- Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway
| | - Justin B Renaud
- London Research and Development Center, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3, Canada
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Dung JKS, Duringer JM, Kaur N, Scott JC, Frost KE, Walenta DL, Alderman SC, Craig AM, Hamm PB. Molecular and Alkaloid Characterization of Claviceps purpurea Sensu Lato From Grass Seed Production Areas of the U.S. Pacific Northwest. PHYTOPATHOLOGY 2021; 111:831-841. [PMID: 33141647 DOI: 10.1094/phyto-07-20-0289-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ergot, caused by Claviceps purpurea sensu lato, is an economically important seed replacement disease of Kentucky bluegrass (Poa pratensis) and perennial ryegrass (Lolium perenne) seed crops. C. purpurea sensu stricto is considered the primary Claviceps species responsible, but genetic diversity and cryptic species within C. purpurea sensu lato have previously been reported. Fifty-six C. purpurea sensu lato isolates collected from P. pratensis (n = 21) and L. perenne (n = 35) in Oregon and Washington between 2010 and 2014 were characterized via random amplified polymorphic DNA (RAPD), partial internal transcribed spacer (ITS), β-tubulin and elongation factor-1α (EF-1α) sequences, conidial size, and ergot alkaloid chemotype. Based on RAPD analysis, seven isolates from P. pratensis and 33 isolates from L. perenne collected in Oregon corresponded to C. purpurea sensu stricto, and 13 isolates collected from P. pratensis in Washington and Oregon were identified as C. humidiphila. Partial ITS, β-tubulin, and EF-1α sequences identified 10 isolates from P. pratensis as C. humidiphila, and seven isolates from P. pratensis and 33 isolates from L. perenne were identified as C. purpurea sensu stricto. Several isolates generated ambiguous RAPD bands or sequences that prevented identification. Ergot alkaloid chemotype profiling found that ergocornine and its epimer were predominant in sclerotia from P. pratensis, whereas ergotamine and its epimer were most abundant in sclerotia from L. perenne. This study confirms the presence of the C. purpurea sensu lato species complex in the U.S. Pacific Northwest and suggests that more research is needed to characterize and mitigate Claviceps spp. infection of grass seed crops in North America.
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Affiliation(s)
- Jeremiah K S Dung
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research and Extension Center, Oregon State University, Madras, OR 97741
| | - Jennifer M Duringer
- Department of Environmental and Molecular Toxicology, College of Agricultural Sciences, Oregon State University, Corvallis, OR 97331
| | - Navneet Kaur
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston, OR 97838
| | - Jeness C Scott
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research and Extension Center, Oregon State University, Madras, OR 97741
| | - Kenneth E Frost
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston, OR 97838
| | - Darrin L Walenta
- Department of Crop and Soil Science, Oregon State University Extension Service, La Grande, OR 97850
| | - Stephen C Alderman
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331
| | - A Morrie Craig
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331
| | - Philip B Hamm
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston, OR 97838
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Tooley PW, Goley ED, Carras MM, Frederick RD, Weber EL, Kuldau GA. Characterization ofClavicepsspecies pathogenic on sorghum by sequence analysis of the β-tubulin gene intron 3 region and EF-1α gene intron 4. Mycologia 2019. [DOI: 10.1080/00275514.2001.12063186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Paul W. Tooley
- USDA-ARS, Foreign Disease—Weed Science Research Unit, 1301 Ditto Ave., Ft. Detrick, Maryland 21702-5023
| | - Erin D. Goley
- USDA-ARS, Foreign Disease—Weed Science Research Unit, 1301 Ditto Ave., Ft. Detrick, Maryland 21702-5023
| | - Marie M. Carras
- USDA-ARS, Foreign Disease—Weed Science Research Unit, 1301 Ditto Ave., Ft. Detrick, Maryland 21702-5023
| | - Reid D. Frederick
- USDA-ARS, Foreign Disease—Weed Science Research Unit, 1301 Ditto Ave., Ft. Detrick, Maryland 21702-5023
| | - Erin L. Weber
- USDA-ARS, Foreign Disease—Weed Science Research Unit, 1301 Ditto Ave., Ft. Detrick, Maryland 21702-5023
| | - Gretchen A. Kuldau
- USDA-ARS, Russell Research Center, P. O. Box 5677, Athens, Georgia 30604
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4
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Panaccione DG, Sheets NL, Miller SP, Cumming JR. Diversity of Cenococcum geophilum isolates from serpentine and non-serpentine soils. Mycologia 2019. [DOI: 10.1080/00275514.2001.12063196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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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Dung JKS, Scott JC, Cheng Q, Alderman SC, Kaur N, Walenta DL, Frost KE, Hamm PB. Detection and Quantification of Airborne Claviceps purpurea sensu lato Ascospores from Hirst-Type Spore Traps using Real-Time Quantitative PCR. PLANT DISEASE 2018; 102:2487-2493. [PMID: 30256180 DOI: 10.1094/pdis-02-18-0310-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The U.S. Pacific Northwest states of Oregon and Washington are major producers of cool-season grass seed. Ergot, caused by fungi in the Claviceps purpurea sensu lato group, is an important seed replacement disease of grass worldwide. Microscopic methods that are currently used to quantify airborne Claviceps ascospores captured by spore traps are not currently rapid enough to allow for detecting and reporting of spore numbers in a timely manner, hindering growers from using this information to help manage ergot. We developed a SYBR Green real-time quantitative polymerase chain reaction (qPCR)-based assay for fast and efficient detection and quantification of C. purpurea sensu lato ascospores from Hirst-type spore traps. Species-specificity of the qPCR assay was confirmed against 41 C. purpurea sensu lato isolates collected from six hosts and six other Claviceps spp. Significant relationships were observed between cycle threshold (Ct) values and standard curves of serial dilutions of DNA ranging from 1 pg to 10 ng (R2 = -0.99; P = 0.0002) and DNA extracted from a conidial suspension representing 8 to 80,000 conidia (R2 = -0.99; P = 0.0004). Ct values from qPCR were significantly correlated with results from microscopic examination of spore trap samples from the field (r = -0.68; P < 0.0001) and the procedure was able to detect a single ascospore from spore trap tape samples. The qPCR procedure developed in this study provided a means for quantifying airborne Claviceps ascospores that was highly specific and useful over a wide range of spore densities, and could be performed in a matter of hours instead of days. The qPCR assay developed in this study could be part of an integrated pest management approach to help grass seed growers make risk-based fungicide application decisions for ergot management in grass grown for seed.
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Affiliation(s)
- Jeremiah K S Dung
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research Center, Oregon State University, Madras
| | - Jeness C Scott
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research Center, Oregon State University, Madras
| | - Qunkang Cheng
- Department of Botany and Plant Pathology, Central Oregon Agricultural Research Center, Oregon State University, Madras
| | - Stephen C Alderman
- National Forage Seed Production Research Center, United States Department of Agriculture-Agricultural Research Service, Corvallis, OR
| | - Navneet Kaur
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston
| | - Darrin L Walenta
- Union County Extension Service, Oregon State University, La Grande
| | - Kenneth E Frost
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston
| | - Philip B Hamm
- Department of Botany and Plant Pathology, Hermiston Agricultural Research and Extension Center, Oregon State University, Hermiston
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Negård M, Uhlig S, Kauserud H, Andersen T, Høiland K, Vrålstad T. Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex. Toxins (Basel) 2015; 7:1431-56. [PMID: 25928134 PMCID: PMC4448156 DOI: 10.3390/toxins7051431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/24/2022] Open
Abstract
The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability.
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Affiliation(s)
- Mariell Negård
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway.
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
| | - Silvio Uhlig
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway.
- Department of the Chemical and Biological Working Environment, National Institute of Occupational Health, P.O. Box 8149 Dep, 0033 Oslo, Norway.
| | - Håvard Kauserud
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
| | - Tom Andersen
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
| | - Klaus Høiland
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
| | - Trude Vrålstad
- Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway.
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
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7
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Abstract
An update on new developments in the field of ergot alkaloid biosynthesis since 2011 is highlighted.
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Affiliation(s)
- Dorota Jakubczyk
- The John Innes Centre
- Department of Biological Chemistry
- Norwich NR4 7UH, UK
| | - Johnathan Z. Cheng
- The John Innes Centre
- Department of Biological Chemistry
- Norwich NR4 7UH, UK
| | - Sarah E. O'Connor
- The John Innes Centre
- Department of Biological Chemistry
- Norwich NR4 7UH, UK
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8
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Belesky DP, Bacon CW. Tall fescue and associated mutualistic toxic fungal endophytes in agroecosystems. TOXIN REV 2009. [DOI: 10.1080/15569540903082143] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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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] [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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10
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Douhan GW, Smith ME, Huyrn KL, Westbrook A, Beerli P, Fisher AJ. Multigene analysis suggests ecological speciation in the fungal pathogen Claviceps purpurea. Mol Ecol 2008; 17:2276-86. [PMID: 18373531 PMCID: PMC2443689 DOI: 10.1111/j.1365-294x.2008.03753.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Claviceps purpurea is an important pathogen of grasses and source of novel chemical compounds. Three groups within this species (G1, G2 and G3) have been recognized based on habitat association, sclerotia and conidia morphology, as well as alkaloid production. These groups have further been supported by Random Amplification of Polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers, suggesting this species may be more accurately described as a species complex. However, all divergent ecotypes can coexist in sympatric populations with no obvious physical barriers to prevent gene flow. In this study, we used both phylogenetic and population genetic analyses to test for speciation within C. purpurea using DNA sequences from ITS, a RAS-like locus, and a portion of beta-tubulin. The G1 types are significantly divergent from the G2/G3 types based on each of the three loci and the combined dataset, whereas the G2/G3 types are more integrated with one another. Although the G2 and G3 lineages have not diverged as much as the G1 lineage based on DNA sequence data, the use of three DNA loci does reliably separate the G2 and G3 lineages. However, the population genetic analyses strongly suggest little to no gene flow occurring between the different ecotypes, and we argue that this process is driven by adaptations to ecological habitats; G1 isolates are associated with terrestrial grasses, G2 isolates are found in wet and shady environments, and G3 isolates are found in salt marsh habitats.
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Affiliation(s)
- G W Douhan
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521, USA.
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11
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Tooley PW, Bandyopadhyay R, Carras MM, Pazoutová S. Analysis of Claviceps africana and C. sorghi from India using AFLPs, EF-1alpha gene intron 4, and beta-tubulin gene intron 3. ACTA ACUST UNITED AC 2006; 110:441-51. [PMID: 16563714 DOI: 10.1016/j.mycres.2005.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Revised: 11/14/2005] [Accepted: 12/16/2005] [Indexed: 10/24/2022]
Abstract
Isolates of Claviceps causing ergot on sorghum in India were analysed by AFLP analysis, and by analysis of DNA sequences of the EF-1alpha gene intron 4 and beta-tubulin gene intron 3 region. Of 89 isolates assayed from six states in India, four were determined to be C. sorghi, and the rest C. africana. A relatively low level of genetic diversity was observed within the Indian C. africana population. No evidence of genetic exchange between C. africana and C. sorghi was observed in either AFLP or DNA sequence analysis. Phylogenetic analysis was conducted using DNA sequences from 14 different Claviceps species. A multigene phylogeny based on the EF-1alpha gene intron 4, the beta-tubulin gene intron 3 region, and rDNA showed that C. sorghi grouped most closely with C. gigantea and C. africana. Although the Claviceps species we analysed were closely related, they colonize hosts that are taxonomically very distinct suggesting that there is no direct coevolution of Claviceps with its hosts.
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Affiliation(s)
- Paul W Tooley
- USDA-ARS, Foreign Disease-Weed Science Research Unit, 1301 Ditto Avenue, Fort Detrick, MD 21702-5023, USA.
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12
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Chutrakul C, Peberdy JF. Isolation and characterisation of a partial peptide synthetase gene fromTrichoderma asperellum. FEMS Microbiol Lett 2006; 252:257-65. [PMID: 16214297 DOI: 10.1016/j.femsle.2005.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 08/28/2005] [Accepted: 09/02/2005] [Indexed: 11/23/2022] Open
Abstract
Many species of Trichoderma have attracted interest as agents for the biological control of soil borne fungal pathogens of a range of crop plants. Research on the biochemical mechanisms associated with this application has focused on the ability of these fungi to produce enzymes which lyse fungal cell walls, and antifungal antibiotics. An important group of the latter are the non-ribosomal peptides called peptaibols. In this study Trichoderma asperellum, a strain used in biological control in Malaysia, was found to produce the peptaibol, trichotoxin. This type of peptide molecule is synthesised by a peptide synthetase (PES) enzyme template encoded by a peptide synthetase (pes) gene. Using nucleotide sequences amplified from adenylation (A-) domains as probes, to hybridise against a lambda FIXII genomic library from T. asperellum, 25 clones were recovered. These were subsequently identified as representative of four groups based on their encoding properties for specific amino acid incorporation modules in a PES. This was based on analysis of their amino acid sequences which showed up to 86% identity to other PESs including TEX 1.
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Affiliation(s)
- Chanikul Chutrakul
- Microbiology Group, School of Biology, University of Nottingham, University Park, UK
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13
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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] [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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14
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Moffitt MC, Neilan BA. The expansion of mechanistic and organismic diversity associated with non-ribosomal peptides. FEMS Microbiol Lett 2000; 191:159-67. [PMID: 11024258 DOI: 10.1111/j.1574-6968.2000.tb09334.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Non-ribosomal peptides are a group of secondary metabolites with a wide range of bioactivities, produced by prokaryotes and lower eukaryotes. Recently, non-ribosomal synthesis has been detected in diverse microorganisms, including the myxobacteria and cyanobacteria. Peptides biosynthesized non-ribosomally may often play a primary or secondary role in the producing organism. Non-ribosomal peptides are often small in size and contain unusual or modified amino acids. Biosynthesis occurs via large modular enzyme complexes, with each module responsible for the activation and thiolation of each amino acid, followed by peptide bond formation between activated amino acids. Modules may also be responsible for the enzymatic modification of the substrate amino acid. Recent analysis of biosynthetic gene clusters has identified novel integrated, mixed and hybrid enzyme systems. These diverse mechanisms of biosynthesis result in the wide variety of non-ribosomal peptide structures and bioactivities seen today. Knowledge of these biosynthetic systems is rapidly increasing and methods of genetically engineering these systems are being developed. In the future, this may lead to rational drug design through combinatorial biosynthesis of these enzyme systems.
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Affiliation(s)
- M C Moffitt
- School of Microbiology and Immunology, University of New South Wales, 2052, NSW, Sydney, Australia
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15
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Johnson RD, Johnson L, Itoh Y, Kodama M, Otani H, Kohmoto K. Cloning and characterization of a cyclic peptide synthetase gene from Alternaria alternata apple pathotype whose product is involved in AM-toxin synthesis and pathogenicity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2000; 13:742-753. [PMID: 10875335 DOI: 10.1094/mpmi.2000.13.7.742] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Afternaria afternata apple pathotype causes Alternaria blotch of susceptible apple cultivars through the production of a cyclic peptide host-specific toxin, AM-toxin. PCR (polymerase chain reaction), with primers designed to conserved domains of peptide synthetase genes, amplified several products from A. alternata apple pathotype that showed high similarity to other fungal peptide synthetases and were specific to the apple pathotype. Screening of a Lambda Zap genomic library with these PCR-generated probes identified overlapping clones containing a complete cyclic peptide synthetase gene of 13.1 kb in length with no introns. Disruption of this gene, designated AM-toxin synthetase (AMT), by transformation of wild-type A. afternata apple pathotype with disruption vectors resulted in toxin-minus mutants, which were also unable to cause disease symptoms on susceptible apple cultivars. AM-toxin synthetase is therefore a primary determinant of virulence and specificity in the A. alternata apple pathotype/apple interaction.
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Affiliation(s)
- R D Johnson
- Laboratory of Plant Pathology, Faculty of Agriculture, Tottori University, Japan.
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