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Krämer D, Lane FA, Steenkamp ET, Wingfield BD, Wilken PM. Unidirectional mating-type switching confers self-fertility to Thielaviopsis cerberus, the only homothallic species in the genus. Fungal Biol 2021; 125:427-434. [PMID: 34024590 DOI: 10.1016/j.funbio.2020.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 10/01/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 11/29/2022]
Abstract
Sexual reproduction is ubiquitous in nature, and nowhere is this more so than in the fungi. Heterothallic behaviour is observed when there is a strict requirement of contact between two individuals of opposite mating type for sexual reproduction to occur. In contrast, a homothallic species can complete the entire sexual cycle in isolation, although several genetic mechanisms underpin this self-fertility. These can be inferred by characterising the structure and gene-content of the mating-type locus, which contains genes that are involved in the regulation of sexual reproduction. In this study, the genetic basis of homothallism in Thielaviopsis cerberus was investigated, the only known self-fertile species within this genus. Using genome sequencing and conventional molecular techniques, two versions of the mating-type locus were identified in this species. This is typical of species that have a unidirectional mating-type switching reproductive strategy. The first version was a self-fertile locus that contained four known mating-type genes, while the second was a self-sterile version with a single mating-type gene. The conversion from a self-fertile to a self-sterile locus is likely mediated by a homologous recombination event at two direct repeats present in the self-fertile locus, resulting in the deletion of three mating-type genes and one of the repeats. Both locus versions were present in isolates that were self-fertile, while self-sterility was caused by the presence of only a switched locus. This study provides a clear example of the architectural fluidity in the mating-type loci that is common among even closely related fungal species.
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Affiliation(s)
- Daniella Krämer
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Frances A Lane
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - P Markus Wilken
- Department of Biochemistry, Genetics and Microbiology; Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa. http://
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Wilken PM, Steenkamp ET, van der Nest MA, Wingfield MJ, de Beer ZW, Wingfield BD. Unexpected placement of the MAT1-1-2 gene in the MAT1-2 idiomorph of Thielaviopsis. Fungal Genet Biol 2018; 113:32-41. [PMID: 29409964 DOI: 10.1016/j.fgb.2018.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 01/20/2018] [Accepted: 01/29/2018] [Indexed: 01/24/2023]
Abstract
Sexual reproduction in the Ascomycota is controlled by genes encoded at the mating-type or MAT1 locus. The two allelic versions of this locus in heterothallic species, referred to as idiomorphs, are defined by the MAT1-1-1 (for the MAT1-1 idiomorph) and MAT1-2-1 (for the MAT1-2 idiomorph) genes. Both idiomorphs can contain additional genes, although the contents of each is typically specific to and conserved within particular Pezizomycotina lineages. Using full genome sequences, complemented with conventional PCR and Sanger sequencing, we compared the mating-type idiomorphs in heterothallic species of Thielaviopsis (Ceratocystidaceae). The analyses showed that the MAT1-1 idiomorph of T. punctulata, T. paradoxa, T. euricoi, T. ethacetica and T. musarum harboured only the expected MAT1-1-1 gene. In contrast, the MAT1-2 idiomorph of T. punctulata, T. paradoxa and T. euricoi encoded the MAT1-2-1, MAT1-2-7 and MAT1-1-2 genes. Of these, MAT1-2-1 and MAT1-2-7 are genes previously reported in this idiomorph, while MAT1-1-2 is known only in the MAT1-1 idiomorph. Phylogenetic analysis showed that the Thielaviopsis MAT1-1-2 groups with the known homologues of this gene in other Microascales, thus confirming its annotation. Previous work suggests that MAT1-1-2 is involved in fruiting body development, a role that would be unaffected by its idiomorphic position. This notion is supported by our findings for the MAT1 locus structure in Thielaviopsis species. This also serves as the first example of a MAT1-1-specific gene restricted to only the MAT1-2 idiomorph.
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Affiliation(s)
- P Markus Wilken
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa.
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
| | - Magriet A van der Nest
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
| | - Z Wilhelm de Beer
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Pretoria 0028, South Africa
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Mbenoun M, Wilhelm de Beer Z, Wingfield MJ, Wingfield BD, Roux J. Reconsidering species boundaries in the Ceratocystis paradoxa complex, including a new species from oil palm and cacao in Cameroon. Mycologia 2014; 106:757-84. [PMID: 24987122 DOI: 10.3852/13-298] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [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: 11/10/2022]
Abstract
The Ceratocystis paradoxa complex accommodates a group of fungal pathogens that have become specialized to infect mostly monocotyledonous plants. Four species currently are recognized in this group, including C. paradoxa, which has a widespread distribution and broad host range. In this study, multigene phylogenetic analyses involving sequences of the ITS, β-tubulin and TEF-1α gene loci, in combination with phenotypic and mating studies, were used to characterize purported C. paradoxa isolates from Cameroon and to compare them with isolates from elsewhere, including protologs and type specimens of known species. We show that the C. paradoxa complex comprises substantially greater species diversity than previously recognized. One new species in this group is described from Cameroon as Ceratocystis cerberus, while C. paradoxa sensu stricto (s. str.) and four other species are redefined. Lectotypes are designated for C. ethacetica and Endoconidium fragrans (synonym of C. ethacetica), while epitypes are designated for C. paradoxa s. str., C. ethacetica and C. musarum. A neotype is designated for Catenularia echinata (synonym of C. ethacetica) and two species, previously treated in Thielaviopsis, are transferred to Ceratocystis.
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Affiliation(s)
- Michael Mbenoun
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa
| | - Z Wilhelm de Beer
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa
| | - Michael J Wingfield
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa
| | - Brenda D Wingfield
- Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa
| | - Jolanda Roux
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), Private Bag X20, University of Pretoria, Pretoria, 0028, South Africa
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