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Identification and Functional Analysis of a Novel Hydrophobic Protein VdHP1 from Verticillium dahliae. Microbiol Spectr 2022; 10:e0247821. [PMID: 35377232 PMCID: PMC9045179 DOI: 10.1128/spectrum.02478-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Verticillium dahliae could cause destructive vascular wilt disease on hundreds of plant species around the world, including cotton. In this study, we characterized the function of a hydrophobin gene VdHP1 in pathogen development and pathogenicity. Results showed that VdHP1 could induce cell death and activate plant immune responses. The VdHP1 deletion mutants (ΔVdHP1) and the complement mutants (C-ΔVdHP1) were obtained by the homologous recombination method. The VdHP1 deletion mutants exhibited increased hydrophilicity, inhibited microsclerotial formation, and reduced spore smoothness. In addition, the deletion mutants were more sensitive to NaCl, while relatively insensitive to KCl and sorbitol. Mutants also had greater resistance to Congo red, UV radiation, and high temperature, which suggested that ΔVdHP1 strains have stronger resistance to abiotic stress in general. Different carbon source assays showed that the utilization ability of skim milk, cellulose, and starch was greatly enhanced in ΔVdHP1, compared with that of WT and complemented strains. Furthermore, VdHP1 did not affect mycelium penetration on cellophane but contributed to mycelium growth on surface of the living plant cells. The pathogenicity test found that the crude toxin content, colonization, and dispersal of ΔVdHP1 was significantly increased compared with the WT and complementary strains. In addition, cotton seedlings showed more severe wilting symptoms after inoculation with ΔVdHP1 strains. These results suggested that the hydrophobin VdHP1 negatively regulated the virulence of V. dahliae, and played an important role in development, adaptability, and pathogenicity in V. dahliae, which maybe provide a new viewpoint to further understand the molecular mechanisms of pathogen virulence. IMPORTANCE Verticillium dahliae is a soilborne fungal pathogen that causes a destructive vascular disease on a large number of plant hosts, resulting in great threat to agricultural production. In this study, it was illustrated that the hydrophobin VdHP1 could induce cell death and activate plant immune responses. VdHP1 affected the hydrophobicity of V. dahliae, and negatively regulated the strains resistant to stress, and the utilization ability of different carbon sources. In addition, VdHP1 did not affect mycelium penetration on cellophane but contributed to mycelium growth on surface of the living plant cells. The VdHP1 gene negatively regulated the total virulence, colonization, and dispersal of V. dahliae, with enhanced pathogenicity of mutant strains in this gene. These results suggested that the hydrophobin VdHP1 played an importance in development, adaptability, and pathogenicity in V. dahliae, and would provide a new viewpoint to further understand the molecular mechanisms of pathogen virulence.
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Temple B, Horgen PA. Biological roles for cerato-ulmin, a hydrophobin secreted by the elm pathogens,Ophiostoma ulmiandO. novo-ulmi. Mycologia 2019. [DOI: 10.1080/00275514.2000.12061123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Bradley Temple
- Department of Biology, University of Victoria, P.O. Box 1700, Victoria, British Columbia, V9W 2Y2 Canada
| | - Paul A. Horgen
- Department of Botany, University of Toronto at Mississauga, Mississauga, Ontario, L5L 1C6 Canada
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Schoch CL, Crous PW, Wingfield BD, Wingfield MJ. TheCylindrocladium candelabrumspecies complex includes four distinct mating populations. Mycologia 2019. [DOI: 10.1080/00275514.1999.12061019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Conrad L. Schoch
- Department of Plant Pathology, University of Stellenbosch, P. Bag XI, Matieland 7602, South Africa
| | - Pedro W. Crous
- Department of Plant Pathology, University of Stellenbosch, P. Bag XI, Matieland 7602, South Africa
| | | | - Michael J. Wingfield
- Tree Pathology Co-operative Programme, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
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Sequencing and annotation of the Ophiostoma ulmi genome. BMC Genomics 2013; 14:162. [PMID: 23496816 PMCID: PMC3618308 DOI: 10.1186/1471-2164-14-162] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/28/2013] [Indexed: 02/02/2023] Open
Abstract
Background The ascomycete fungus Ophiostoma ulmi was responsible for the initial pandemic of the massively destructive Dutch elm disease in Europe and North America in early 1910. Dutch elm disease has ravaged the elm tree population globally and is a major threat to the remaining elm population. O. ulmi is also associated with valuable biomaterials applications. It was recently discovered that proteins from O. ulmi can be used for efficient transformation of amylose in the production of bioplastics. Results We have sequenced the 31.5 Mb genome of O.ulmi using Illumina next generation sequencing. Applying both de novo and comparative genome annotation methods, we predict a total of 8639 gene models. The quality of the predicted genes was validated using a variety of data sources consisting of EST data, mRNA-seq data and orthologs from related fungal species. Sequence-based computational methods were used to identify candidate virulence-related genes. Metabolic pathways were reconstructed and highlight specific enzymes that may play a role in virulence. Conclusions This genome sequence will be a useful resource for further research aimed at understanding the molecular mechanisms of pathogenicity by O. ulmi. It will also facilitate the identification of enzymes necessary for industrial biotransformation applications.
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Carresi L, Comparini C, Bettini PP, Pazzagli L, Cappugi G, Scala F, Scala A. Isolation of the orthologue of the cerato-ulmin gene in Ophiostoma quercus and characterization of the purified protein. ACTA ACUST UNITED AC 2008; 112:1245-55. [PMID: 18783930 DOI: 10.1016/j.mycres.2008.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 04/30/2008] [Accepted: 05/01/2008] [Indexed: 11/30/2022]
Abstract
Ophiostoma quercus is an ophiostomatoid fungus strictly related to the Ophiostoma's (O. ulmi, O. novo-ulmi, and O. himal-ulmi) that cause Dutch elm disease (DED). O. quercus has a number of morphological characteristics in common with the DED pathogens, and is a well-known and economically important sapstaining fungus occurring worldwide on hardwoods and commercially produced pines, and causes typical cankers on oak stems. In elm trees O. quercus can survive for months without causing any disease symptoms. DED fungi produce cerato-ulmin (CU), a class II hydrophobin, which is generally considered as the main toxin potentially involved in various phases of the DED pathogenesis. In the present work we isolated and sequenced the orthologue of the cu gene in the O. quercus isolates H988, H1042, and H2053. Moreover the CU protein from O. quercus isolate H988 was also purified and characterized. Sequence analysis showed that there is a pronounced difference between the whole cu gene region of O. quercus and the homologous fragments of the DED-causing species O. ulmi, O. novo-ulmi, and O. himal-ulmi. It also appeared that differences in the structural conformation of the promoter were unlikely to play a role in the modulation of the transcript level and that, for O. quercus, differences in CU production did not result from the potential different regulation levels. Clear differences were shown in the transcriptional unit of the cu genes and in the amino acid sequences among all the CUs. The purified O. quercus CU was separated using matrix-assisted laser desorption ionization/time of flight (MALDI-TOF) spectrometry into seven forms of increasing molecular weight from 7190 to 7724Da. The hydrophobicity profiles indicated that two regions of the O. quercus CU protein were more hydrophobic than the corresponding regions of the CUs of the DED fungi. The O. quercus CUs had theoretical isoelectric point values similar to those of the DED fungi. Finally, the contradiction between the consistent differences between these four Ophiostoma species in the cu gene region and in the CU proteins and their strict phylogenetic relationship is discussed.
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Affiliation(s)
- Lara Carresi
- Dipartimento Biotecnologie Agrarie-sezione Patologia Vegetale, University of Florence, via della Lastruccia, 10 50019 Sesto Fiorentino, Italy
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Klimes A, Dobinson KF. A hydrophobin gene, VDH1, is involved in microsclerotial development and spore viability in the plant pathogen Verticillium dahliae. Fungal Genet Biol 2006; 43:283-94. [PMID: 16488633 DOI: 10.1016/j.fgb.2005.12.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 12/02/2005] [Accepted: 12/19/2005] [Indexed: 11/26/2022]
Abstract
The wilt fungus Verticillium dahliae Kleb. produces desiccation- and cold-tolerant resting structures, known as microsclerotia, which are the primary source of disease inoculum in the field. In an exploration of the molecular mechanisms involved in the development of these important structures, we have identified in V. dahliae a differentially expressed, class II hydrophobin gene (VDH1). vdh1 mutants generated through targeted gene disruption show a severe reduction in microsclerotia production, indicating that the gene is important for this type of development. Although vdh1 mutants do produce normal conidiophores and spores, desiccation-tolerance of the spores is reduced. The VDH1 gene is not, however, needed for normal disease development in tomato. VDH1's functions are multi-faceted, and seem generally relevant to long-term survival in V. dahliae.
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MESH Headings
- Amino Acid Sequence
- Blotting, Northern
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- Fungal Proteins/genetics
- Fungal Proteins/physiology
- Gene Deletion
- Gene Expression Regulation, Fungal
- Genetic Complementation Test
- Introns/genetics
- Solanum lycopersicum/microbiology
- Microscopy
- Molecular Sequence Data
- Morphogenesis/genetics
- Mutagenesis, Insertional
- Plant Diseases/microbiology
- RNA, Fungal/analysis
- RNA, Messenger/analysis
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Spores, Fungal/genetics
- Verticillium/cytology
- Verticillium/genetics
- Verticillium/growth & development
- Virulence
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Affiliation(s)
- Anna Klimes
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford St., London, Ont., Canada N5V 4T3
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Gibb EA, Hausner G. Optional mitochondrial introns and evidence for a homing-endonuclease gene in the mtDNA rnl gene in Ophiostoma ulmi s. lat. ACTA ACUST UNITED AC 2005; 109:1112-26. [PMID: 16279406 DOI: 10.1017/s095375620500376x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Strains of Ophiostoma ulmi, O. novo-ulmi subsp. americana, O. novo-ulmi subsp. novo-ulmi and O. himal-ulmi were examined for optional introns/insertions within the following mitochondrial genes: small subunit RNA gene (rns), large ribosomal subunit gene (rnl) and the cytochrome oxidase subunit I gene (coxI). Insertions were noted in the rns and coxI genes in strains of O. ulmi, the less aggressive species, but absent in strains of the more aggressive O. novo-ulmi subsp. americana. Strains of all species examined had a group I intron present in the U11 region of the mitochondrial-rnl gene. In all but two strains of O. novo-ulmi subsp. americana, this rnl-U11 intron was about 1.5 kb in length whereas a 2.6 kb version of this element was present in all strains representing O. ulmi, O. novo-ulmi subsp. novo-ulmi, and Ophiostoma himal-ulmi. Irrespective of size, this intron based on RNA folds is a class IA1 group I intron and it encodes a putative ORF for the rps3 ribosomal protein. The size variation of the rnl-U11 intron was examined in detail for two strains of O. novo-ulmi subsp. americana and sequence data suggests the presence of a complex ORF within the 2.6 kb version of this intron; here a homing endonuclease-like gene has been inserted in frame and fused to the carboxyl-terminus of the putative rps3 coding region. The mitochondrial optional introns/insertions in combination with nuclear markers might be useful in distinguishing among the various species and subspecies of the O. ulmi s. lat. complex.
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Affiliation(s)
- Ewan A Gibb
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
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Tadesse Y, Bernier L, Hintz WE, Horgen PA. Real time RT-PCR quantification and Northern analysis of cerato-ulmin ( CU) gene transcription in different strains of the phytopathogens Ophiostoma ulmi and O. novo-ulmi. Mol Genet Genomics 2003; 269:789-96. [PMID: 14513363 DOI: 10.1007/s00438-003-0890-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2003] [Accepted: 06/13/2003] [Indexed: 10/26/2022]
Abstract
Cerato-ulmin is a surface protein that belongs to the class of fungal proteins known as hydrophobins. This class II hydrophobin is produced throughout the life cycle and in all developmental stages of Ophiostoma novo-ulmi and O. ulmi; the aggressive and non-aggressive pathogens responsible for Dutch elm disease. Since yeast/mycelial transitions are often important to pathogenesis in dimorphic fungi such as Ophiostoma, we have examined the levels and abundance of cu mRNA in the yeast and mycelial stages of this fungus. The fungus contains one copy of the cu gene per haploid genome, located on chromosome IV. Our studies have been done using phosphoimager-based Northern analysis and real-time quantitative RT-PCR (qRT-PCR) to measure levels of cu mRNA. These measurements were made in both yeast-like and mycelial stages of the pathogen. Two wild-type, aggressive, strains of O. novo-ulmi (VA30 and H327) and one wild type non-aggressive strain of O. ulmi (H5) were analysed. As controls, we have utilized two types of mutants that we had previously generated, the null cu mutants THEK5-8 and THEK5-8-1, and a cu over-expression mutant, H5-tf16. Data generated by both Northern hybridization and real-time qRT-PCR analyses demonstrate that there is no cu mRNA transcription in the null mutants. The Northern analysis clearly showed that the over-expressing mutant H5-tf16 produces much more cu mRNA than the non-aggressive or aggressive strains. The quantitative data generated using qRT-PCR demonstrated that mycelium generally had 20-60% more cu mRNA than the yeast form. The non-aggressive strain of O. ulmi (H5) produces one-tenth as much cu mRNA as the aggressive strains (VA30 and H327). When transformed with additional copies of the cu gene, this same non-aggressive strain (H5-tf16) expressed about 20 times more cu mRNA than the wild type H5 strain. These data were consistently generated in multiple real-time qRT-PCR experiments with different RNA preparations, clearly demonstrating that the quantitative abundance values obtained were reproducible. Our study represents the first report on the use of real-time qRT-PCR to compare and quantify gene transcription in different growth phases of a fungal pathogen.
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Affiliation(s)
- Y Tadesse
- Department of Botany, University of Toronto at Mississauga, Mississauga, Ontario, L1L 1C6, Canada.
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de Beer ZW, Wingfield BD, Wingfield MJ. The Ophiostoma piceae complex in the Southern Hemisphere: a phylogenetic study. MYCOLOGICAL RESEARCH 2003; 107:469-76. [PMID: 12825520 DOI: 10.1017/s0953756203007445] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Ophiostoma piceae species complex incorporates several economically important species, including serious tree pathogens and agents of bluestain. The species in the complex are morphologically similar, but can be distinguished from each other based on morphology, biology, mating type studies and molecular data. At present, all the species in the complex are considered to be native to the Northern Hemisphere, most of them with a very wide distribution. Only a few sporadic reports of members of the complex are available from the Southern Hemisphere, where they are believed to have been introduced, including New Zealand, Australia, Chile, Brazil and Uruguay. This study aims to confirm the identity of isolates resembling O. piceae originating from three Southern Hemisphere countries, using mating compatibility and rDNA sequencing. Our results show that O. quercus is widely distributed throughout South Africa on both native and exotic hardwoods. O. quercus is also reported for the first time from Brazil, again from a native host. O. floccosum is reported for the first time from South Africa, but from an exotic Pinus sp. These results suggest that species of the O. piceae complex are common in the Southern Hemisphere, and that current views on the origins of especially O. quercus need to be reconsidered.
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Affiliation(s)
- Z Wilhelm de Beer
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa.
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Pipe ND, Brasier CM, Buck KW. Two natural cerato-ulmin (CU)-deficient mutants of Ophiostoma novo-ulmi: one has an introgressed O. ulmi cu gene, the other has an O. novo-ulmi cu gene with a mutation in an intron splice consensus sequence. MOLECULAR PLANT PATHOLOGY 2000; 1:379-382. [PMID: 20572985 DOI: 10.1046/j.1364-3703.2000.00042.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Summary The nucleotide sequences of the cerato-ulmin (cu) genes of two naturally occurring pathogenic CU-deficient mutants, PG470 and MAFf8, of the Dutch elm disease fungus, Ophiostoma novo-ulmi, were determined. The PG470 cu gene sequence was identical to that of CU-secreting isolates of O. novo-ulmi, except for a G to A mutation in the GT splice consensus sequence at the start of intron 1, suggesting that the CU deficiency was due to a splicing defect in the premRNA. In contrast, the MAFf8 cu gene showed a 99.1% sequence identity with cu genes of O. ulmi isolates, but only 92.8% sequence identity with cu genes of CU-secreting isolates of O. novo-ulmi, and in a dendrogram clustered with cu gene sequences of O. ulmi isolates with 100% bootstrap support. Restriction fragment length polymorphisms of the ribosomal RNA region, random amplified polymorphic DNA markers, and many biological properties of MAFf8, including pathogenicity, were typical of O. novo-ulmi. It is therefore likely that the cu gene of MAFf8 has been introgressed from O. ulmi, probably as a result of rare hybrid formation between O. ulmi and O. novo-ulmi, followed by backcrossing of the hybrid with O. novo-ulmi. The presence of an O. ulmi-like cu gene in MAFf8 is consistent with its CU deficiency, since the O. ulmicu gene is known to be poorly expressed and O. ulmi isolates secrete little or no CU in culture.
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Affiliation(s)
- N D Pipe
- Department of Biology, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK
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Rare interspecific hybrids in natural populations of the Dutch elm disease pathogens Ophiostoma ulmi and O. novo-ulmi. ACTA ACUST UNITED AC 1998. [DOI: 10.1017/s0953756297004541] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Temple B, Horgen PA, Bernier L, Hintz WE. Cerato-ulmin, a hydrophobin secreted by the causal agents of Dutch elm disease, is a parasitic fitness factor. Fungal Genet Biol 1997; 22:39-53. [PMID: 9344630 DOI: 10.1006/fgbi.1997.0991] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dutch elm disease is caused by the aggressive Ophiostoma novo-ulmi and the nonaggressive O. ulmi. Both secrete the protein cerato-ulmin (CU). To determine what role CU plays in the pathology of Dutch elm disease, we constructed a CU overexpression mutant of the nonaggressive O. ulmi H5. Stable integration of a single copy of the cu gene from the aggressive O. novo-ulmi into the genome of the nonaggressive isolate resulted in increased secretion of CU protein. Trials with American elm, Ulmus americana, suggested no alteration of virulence of this overexpressing transformant. Using aggressive and nonaggressive wild types, the cu overexpressing mutant, and our cu- mutant (Bowden et al., 1996), we have demonstrated that CU production is correlated with an altered phenotype and more hydrophobic and adherent yeast-like cells. Our results also demonstrate that CU has a role in protecting infectious propagules from desiccation. These biological roles for CU would affect transmission of Dutch elm disease, and we therefore propose that this hydrophobin acts as a parasitic fitness factor.
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Affiliation(s)
- B Temple
- Department of Botany, University of Toronto at Mississauga, Mississauga, Ontario, L5L 1C6, Canada
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Comparison of the cerato-ulmin (cu) gene sequences of the Himalayan Dutch elm disease fungus Ophiostoma himal-ulmi with those of O. ulmi and O. novo-ulmi suggests that the cu gene of O. novo-ulmi is unlikely to have been acquired recently from O. himal-ulmi. ACTA ACUST UNITED AC 1997. [DOI: 10.1017/s0953756296002754] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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