AgaricussectionXanthodermatei: a phylogenetic reconstruction with commentary on taxa

Abstract

Agaricus section Xanthodermatei comprises a group of species allied to A. xanthodermus and generally characterized by basidiomata having phenolic odors, transiently yellowing discolorations in some parts of the basidiome, Schaeffer's reaction negative, and mild to substantial toxicity. The section has a global distribution, while most included species have distributions restricted to regions of single continents. Using specimens and cultures from Europe, North America, and Hawaii, we analyzed DNA sequences from the ITS1+2 region of the nuclear rDNA to identify and characterize phylogenetically distinct entities and to construct a hypothesis of relationships, both among members of the section and with representative taxa from other sections of the genus. 61 sequences from affiliated taxa, plus 20 from six (or seven) other sections of Agaricus, and one Micropsalliota sequence, were evaluated under distance, maximum parsimony and maximum likelihood methods. We recognized 21 discrete entities in Xanthodermatei, including 14 established species and 7 new ones, three of which are described elsewhere. Four species from California, New Mexico, and France deserve further study before they are described. Type studies of American taxa are particularly emphasized, and a lectotype is designated for A. californicus. Section Xanthodermatei formed a single clade in most analyses, indicating that the traditional sectional characters noted above are good unifying characters that appear to have arisen only once within Agaricus. Deep divisions within the sequence-derived structure of the section could be interpreted as subsections in Xanthodermatei; however, various considerations led us to refrain from proposing new supraspecific taxa. The nearest neighbors of section Xanthodermatei are putatively in section Duploannulati.

Agaricus section Brunneopicti: a phylogenetic reconstruction with descriptions of four new taxa

“…It remains also to confirm that the phenol-like odor is really due to the presence of this component as this has been done for the species of section Xanthodermatei (Gill and Strauch 1984;Petrova et al 2007). Moreover the phenol is likely responsible for the poisoning (gastrointestinal symptoms) following consumption of these species (Kerrigan et al 2005;Petrova et al 2007).…”

“…It will be interesting to see to what extent future volatile organic compound analysis and odor panel tests would support this viewpoint applied to almond and phenol odors in section Brunneopicti. According to Callac et al (2005) the phenolic substances would derive from an evolutionary ancestral biochemical shift and its maintaining all along the evolution of section Xanthodermatei indicates that this trait could represent a defense mechanism as for example a feeding barrier. In the tree of Zhao et al (2011) section Brunneopicti appeared as the more ancient among the described section of the genus.…”

“…Species identification in Agaricus however, remains problematic due to a limited number of taxonomically relevant morphological features (Challen et al 2003;Zhao et al 2011). However, the circumscription of species and sections has been improved by exploiting the polymorphism of the nuclear ribosomal ITS (Internal transcribed spacer) DNA sequences (Challen et al 2003;Kerrigan et al 2005Kerrigan et al , 2008. Compared with temperate areas, knowledge of species diversity is less-developed in tropical regions.…”

The first record of Agaricus iodosmus (Agaricaceae) in Ukraine

“…з ме тою з'ясування їх ви до во го скла ду та по ши рен ня в різ них рос лин нихуг ру по ван няхре гіо ну.Уходідо слі дженьнами був ви яв ле ний Agaricus iodosmus Heinem., но вий для те ри то рії Ук ра ї ни вид. Він на ле жить до сек ції Xanthodermatei Singer роду Agaricus L. (Kerrigan et al, 2005). Зазначимо, що на початку 70х років минулогостоліттяцейгриббуввдругеописанийяк різновидність A. xanthodermus (var.…”

OCCURRENCE OF MUSHROOM SPECIES BELONGING TO THE GENUS AGARICUS (AGARICACEAE, BASIDIOMYCETES) IN SOME REGIONS OF UZBEKISTAN

“…Genus Agaricus have been divided into several sections that were Agaricus, Arvense, Сhitonioides, Sanguinoletti, Xanthodermatei, Spissicaules, and Duploannulatae [5,12].…”