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- Riess, Kai, et al.
(författare)
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The origin and diversification of the Entorrhizales : deep evolutionary roots but recent speciation with a phylogenetic and phenotypic split between associates of the Cyperaceae and Juncaceae
- 2019
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Ingår i: Organisms Diversity & Evolution. - : SPRINGER HEIDELBERG. - 1439-6092 .- 1618-1077. ; 19:1, s. 13-30
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Tidskriftsartikel (refereegranskat)abstract
- Fungi belonging to the Entorrhizales (Entorrhizomycota) comprise biotrophic pathogens associated with roots of theCyperaceae and Juncaceae plant species. They are nearly globally distributed but rarely studied due to a hidden lifestyle without causing visible effects on host plants. Therefore, the evolutionary origin and phylogenetic relationships of the group are still poorly understood and it is not known whether species diversification was the result of co-evolution with their hosts or the result of host jumps. To infer hypotheses about the evolutionary history of the Entorrhizales, divergence times were estimated and plant-fungal tanglegrams calculated. Relaxed molecular clock analyses suggest that the Entorrhizomycota originated around the Neoproterozoic-Palaeozoic and diverged during the Late Cretaceous-Paleogene into the extant orders Entorrhizales and Talbotiomycetales. The split of the major lineages within the Entorrhizales took place in the Eocene, somewhat later than the divergence of the host families Cyperaceae and Juncaceae. Topology- and distance-based co-phylogenetic analyses of the fungi and their hosts revealed a large number of co-speciation and lineage sorting events in early fungal speciation, which resulted in a phylogenetic split corresponding to species infecting Cyperaceae or Juncaceae. Given that this split is congruent with spore differences, Entorrhiza s. str. is emended for species infecting hosts in the Cyperaceae, and a new genus Juncorrhiza is described for species restricted to hosts in the Juncaceae. Additionally, three new species are described: Entorrhiza fuirenae, Juncorrhiza maritima and J. oxycarpi.
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| 2. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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