A comparison between ITS phylogenetic relationships and morphological species recognition within Mycena sect. Calodontes in Northern Europe

Article (PDF Available)inMycological Progress 9(3):395-405 · August 2010with160 Reads
DOI: 10.1007/s11557-009-0648-7
The members of Mycena sect. Calodontes (Tricholomataceae s.l., Basidiomycota) are characterised by a collybioid aspect and more or less purplish to reddish colours and a distinct raphanoid odour. In Europe, nine species have been recognised though some of these based on somewhat dubious morphological differences. Historically, most were assigned to Mycena pura. However, since Mycena pura displays one of the most striking colour variabilities within European agarics, many attempts have been made to subdivide it into independent entities, and several forms, varieties and species have been split from Mycena pura s.l. based largely on differences in colouration, gross macromorphology or other phenetic traits. We developed a large sample of ITS sequences of all species of sect. Calodontes known from Europe for which vouchers exist. Furthermore, partial LSU data were developed and additional sequences downloaded from GENBANK to assess the relationship of Calodontes with other Mycena spp. We show that most Calodontes form a monophyletic group including a few North and South American collections, but that this cannot be conclusively shown when an additional North American sequence is added. For all other species than M. pura and M. diosma, we found morphological species recognition to be in agreement with the ITS data. Several significantly different clades can be recognised within the M. pura morphospecies, none of which can be linked to the observed (and described by proxy) colour varieties/forms. Indications of a possible environmental basis of the colour differentiation in the M. pura morphospecies are discussed. KeywordsBasidiomycete phylogenetics-Morphological species recognition-Cryptic speciation

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Available from: Christoffer Bugge Harder
    • "Most M. pura colour varieties (e.g. multicolor, ianthina, violacea ) were earlier found to have no phylogenetic basis (Harder et al. 2010). However, the addition of tEF and RPB1 suggest that M. pura var. "
    [Show abstract] [Hide abstract] ABSTRACT: Phylogenetic analyses of Mycena sect. Calodontes using ITS previously suggested ten cryptic monophyletic ITS lineages within the Mycena pura morphospecies. Here, we compare ITS data (645 bp incl. gaps) from 46 different fruit bodies that represent the previously described ITS diversity with partial tEF-1-α (423 bp) and RNA polymerase II (RPB1) (492 bp) sequence data to test the genealogical concordance. While neither of the markers were in complete topological agreement, the branches differing between the tEF and RPB1 trees had a low bootstrap (<50) support, and the partition homogeneity incongruence length difference (ILD) tests were not significant. ILD tests revealed significant discordances between ITS and the tEF and RPB1 markers in several lineages. And our analyses suggested recombination between ITS1 and ITS2, most pronounced in one phylospecies that was identical in tEF and RPB1. Based on the agreement between tEF and RPB1, we defined 11 mutually concordant terminal clades as phylospecies inside the M. pura morphospecies; most of them cryptic. While neither of the markers showed an unequivocal barcoding gap between inter- and intraspecific diversity, the overlap was most pronounced for ITS (intraspecific diversity 0-3.5 %, interspecific diversity 0.4 %-8.8 %). A clustering analysis on tEF separated at a 1.5 % level returned all phylogenetic species as Operational Taxonomic Units (OTUs), while ITS at both a 1.5 % level and at a 3 % threshold level not only underestimated diversity as found by the tEF and RPB1, but also identified an OTU which was not a phylogenetic species. Thus, our investigation does not support the universal suitability of ITS for species recognition in particular, and emphasises the general limitation of single gene analyses combined with single percentage separation values.
    Full-text · Article · Nov 2013
    • "Cryptic species can be detected across barriers such as geography (e.g. within Mycena pura, Harder et al. 2010; within Laccaria amethystina, Vincenot et al. 2011 ) and there may well be a geographical component to some of the cryptic species detected in this study. The three phylogenetic species (LAT2, SPE2, SPB2) collected from the Australian Capital Territory, which was the most northern site included, were phylogenetically distinct from other collections assigned on morphology to L. lateritia, L. sp. "
    [Show abstract] [Hide abstract] ABSTRACT: Laccaria (Hydnangiaceae, Agaricales, Basidiomycota) is one of the more intensively studied ectomycorrhizal genera; however, species boundaries within Laccaria and the closely related Hydnangium and Podohydnangium in Australia have not yet been examined with molecular sequence data. Based on morphological characters, eight native species of Laccaria are currently recognized in Australia, as well as three Hydnangium species and the monotypic Podohydnangium australe. Sequences of the internal transcribed spacer region of nuclear rDNA (ITS), RNA polymerase beta subunit II (rpb2) and translation elongation factor 1 alpha (tef-1α) were generated from 77 collections of Laccaria, Hydnangium and Podohydnangium from Australia. Ten phylogenetic species and a further 11 potential species (represented by singletons) of Laccaria in Australia are delimited from sequence analyses. Most of the morphological species contained cryptic phylogenetic species, but these species were always nested entirely within a given morphological species, although not always as sister taxa. The rpb2 locus performed best as a species barcode with pairwise and patristic distance measures. The ITS sequence region returned the least resolved gene tree of the three regions examined and was the least useful as a barcode region. Based on the phylogenetic topology, there appears to have been multiple gains and/or losses of the ectomycorrhizal association of some species with the myrtle beech, Nothofagus cunninghamii as well as of sequestrate basidiocarps and two-spored basidia.
    Article · Feb 2013
    • "We added 12 ITS sequences from Calodontes, some of which were from selected North American Mycena aff. pura specimens with morphologically interesting similarities to European M. pearsoniana (Table 1), to the 78 ITS sequences analyzed in Harder et al. (2010). Additionally, the ITS sequence of Matheny´s Mycena aff. "
    [Show abstract] [Hide abstract] ABSTRACT: In Mycena sectio Calodontes with otherwise amyloid spores, the inamyloid spores of Mycena pearsoniana Dennis ex Singer were a distinguishing feature for this species and its subsection Violacella. Although the original concept of this species was European, Singer chose to typify it with material collected in Mexico. The name has since been applied to all European collections with inamyloid spores and decurrent lamellae. Our phylogenetic analysis of 91 ITS sequences from European, North and South American Calodontes collections shows that European collections identified as M. pearsoniana fall into two well-supported sibling clades together with both inamyloid and weakly amyloid North American collections. Since the holotype of M. pearsoniana is in an advanced state of decay, we have selected an epitype from a North American locality with a climate comparable to the Mexican type locality. Our results show weakly and inamyloid spore reactions to be homoplastic in Calodontes, and furthermore that spores of M. pearsoniana can show either amyloid or inamyloid reactions interchangeably. This raises doubt about the taxonomic value of this trait in Mycena systematics.
    Full-text · Article · Aug 2011
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