Abstract
Clonostachys (Bionectriaceae, Hypocreales) species are common soil-borne fungi, endophytes, epiphytes, and saprotrophs. Sexual morphs of Clonostachys spp. were placed in the genus Bionectria, which was further segregated into the six subgenera Astromata, Bionectria, Epiphloea, Myronectria, Uniparietina, and Zebrinella. However, with the end of dual nomenclature, Clonostachys became the single depository for sexual and asexual morphtypified species. Species of Clonostachys are typically characterised by penicillate, sporodochial, and, in many cases, dimorphic conidiophores (primary and secondary conidiophores). Primary conidiophores are mononematous, either verticillium-like or narrowly penicillate. The secondary conidiophores generally form imbricate conidial chains that can collapse to slimy masses, particularly on sporodochia. In the present study, we investigated the species diversity within a collection of 420 strains of Clonostachys from the culture collection of, and personal collections at, the Westerdijk Fungal Biodiversity Institute in Utrecht, the Netherlands. Strains were analysed based on their morphological characters and molecular phylogeny. The latter used DNA sequence data of the nuclear ribosomal internal transcribed spacer regions and intervening 5.8S nrDNA (ITS) and partial 28S large subunit (LSU) nrDNA and partial protein encoding genes including the RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-alpha (TEF1) and β-tubulin (TUB2). Based on these results, the subgenera Astromata, Bionectria, Myronectria and Zebrinella are supported within Clonostachys. Furthermore, the genus Sesquicillium is resurrected to accommodate the former subgenera Epiphloea and Uniparietina. The close relationship of Clonostachys and Sesquicillium is strongly supported as both are inferred phylogenetically as sister-genera. New taxa include 24 new species and 10 new combinations. Recognition of Sesquicillium distinguishes species typically forming a reduced perithecial stroma superficially on plant tissue from species in Clonostachys often forming well-developed, through bark erumpent stromata. The patterns of observed perithecial wall anatomies, perithecial wall and stroma interfaces, and asexual morph diversifications described in a previously compiled monograph are used for interpreting ancestral state reconstructions. It is inferred that the common ancestor of Clonostachys and Sesquicillium may have formed perithecia superficially on leaves, possessed a perithecial wall consisting of a single region, and formed intercalary phialides in penicilli of conidiophores. Character interpretation may also allow hypothesising that diversification of morphs occurred then in the two genera independently and that the frequently stroma-linked Clonostachys morphs evolved together with the occupation of woody host niches and mycoparasitism.
Original language | English |
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Pages (from-to) | 205-266 |
Number of pages | 62 |
Journal | Studies in Mycology |
Volume | 105 |
DOIs | |
Publication status | Published - Jun 2023 |
Bibliographical note
Publisher Copyright:© 2023 Westerdijk Fungal Biodiversity Institute.
Funding
support to L.Z. (CSC student number: 202006510014) and the Slovenian Research Agency (ARRS) for financial support to H.-J.S. (grant no. P4-0072; Agrobiodiversity program). P.W.C. is grateful to the European Union’s Horizon 2020 research and innovation program (RISE) under the Marie Skłodowska-Curie grant agreement No. 101008129, project acronym ‘Mycobiomics’, and the Dutch NWO Roadmap grant agreement No. 2020/ ENW/00901156, project ‘Netherlands Infrastructure for Ecosystem and Biodiversity Analysis – Authoritative and Rapid Identification System for Essential biodiversity information’ (acronym NIEBA-ARISE) for funding. The authors are grateful to Dr Gary J. Samuels, who collected most of the holomorphs included in this study. Without his forward sight to deposit specimens and cultures in international biological resource centres, this study would not have been possible. We would like to thank the China Scholarship Council (CSC) for financial
Funders | Funder number |
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Horizon 2020 Framework Programme | |
H2020 Marie Skłodowska-Curie Actions | 101008129, 2020/ ENW/00901156 |
Javna Agencija za Raziskovalno Dejavnost RS | P4-0072 |
China Scholarship Council |
Keywords
- Biocontrol
- Bionectriaceae
- multi-locus
- mycoparasitism
- new taxa
- phylogeny
- soil-borne
- taxonomy