A molecular phylogenetic reappraisal of theGraphiumcomplex based on 18S rDNA sequences

Abstract

Based on nuclear encoded small subunit (18S) rDNA sequences, a taxonomic reappraisal of Graphium (anamorphic fungi) was undertaken using neighbour-joining (NJ) and fast DNA maximum likelihood (fastDNAml) methods and compared with traditional classifications. In common with Graphium putredinis, Graphium penicillioides (the lectotype species) was found to be related to the Microascales, not the Ophiostomatales as previously believed. Both species might be heterogenous and should be treated as species aggregates. The representative mode of conidiogenesis for these two species was nodular-annellidic, rather than the dense-annellidic mode characteristic of the synnematous ophiostomatalean anamorphs. Graphium is emended to be restricted to G. penicillioides, G. putredinis, and related synnematous anamorphs of Petriella and Pseudallescheria, and a nomenclator for the nine species presently accepted in Graphium is presented. Pesotum, originally characterized mainly by sympodial conidiogenesis, is emended to include synnematous anamorphs of Ophiostoma species formerly included in a variety of genera with sympodial to dense-annellidic conidiogenesis. Eight new combinations in Pesotum are included in a nomenclator for the 26 species currently known. Three new combinations from Ceratocystis to Ophiostoma are proposed for species with Pesotum anamorphs. The holomorph of Graphium calicioides has affinities to the black yeasts and should be classified in the Chaetothyriales. However, the critical morphological, loculoascomycetous characters of the teleomorph are not completely documented. Interpreted from the molecular context, the morphological similarities between these three groups of anamorphs are homoplasies and examples of convergent evolution.Key words: Chaetothyriales, Graphium, Microascales, Ophiostomatales, Pesotum, 18S (SSU) rDNA sequences.

Parascedosporium and its relatives: phylogeny and ecological trends

“…Sequences compromised those downloaded from GenBank (Jacobs et al 2003, Okada et al 1998, Paciura et al 2010 supplemented with sequences generated from material in the CBS collection of fungus cultures and other sequences from CBS not yet incorporated into the public collection.…”

Molecular methods as ways of dealing with terminological difficulties in fungal ecology

“…Cooke and Massee revealed to be the anamorph of Chaetosphaeria sp. (Okada et al 1998). Resolving the problem described above is not be possible without the use of molecular techniques.…”

“…This can be misleading and make us misinterpret the observed changes in DNA sequence, as our knowledge about the relation between genotype and expressed phenotype is still very modest. Still, when it goes to recognizing species of fungi in nature, phylogenetic concept gives best results out of all the aforementioned; phylogenetic methods helped to resolve relationships in many systematic groups (Okada et al 1998), not only fungal (Paszko 2002).…”

“…(for example see Sung et al 2007), it has to be said though that those methods alone cannot be treated as a sufficient tool for taxonomy. A combination of phenotypic, ecological and molecular data should be used together with the knowledge about the group of interest and intuition of the researcher (Okada et al 1998). One should also keep in mind that speciation is a dynamic process; species arise, "live" their history, split, hybridize and go extinct all the time (Cracraft 1992).…”

Graphium basitruncatumFungemia in a Patient with Acute Leukemia

“…Graphium-like species having affinities to the family Ophiostomatales are placed in the genus Pesotum (10). Okada et al determined that Graphium penicillioides, the type species, was a species aggregate and that Stilbum basitruncatum was morphologically and phylogenetically distinct (10,11). They proposed a new combination as G. basitruncatum (Mats.)…”