Guyanagaster, a New Wood-Decaying Sequestrate Fungal Genus Related to Armillaria (Physalacriaceae, Agaricales, Basidiomycota)
Abstract
Premise of the study : Sequestrate basidiomycete fungi (e. g. "gasteromycetes") have
foregone ballistospory and evolved alternative, often elaborate mechanisms of basidiospore
dispersal with highly altered basidioma morphology. Sequestrate fungi have independently
evolved in numerous Agaricomycete lineages, confounding taxonomic arrangements of
these fungi for decades. Understanding the multiple origins and taxonomic affinities
of sequestrate fungi provides insight into the evolutionary forces that can drastically
alter basidioma morphology. In the neotropical rainforests of the Guiana Shield, we
encountered a remarkable sequestrate fungus fruiting directly on decaying hardwood
roots. The fungus 'singular combination of traits include a wood-decaying habit; black,
verrucose peridium; reduced stipe; and gelatinized basidiospore mass. Methods : Guyanagaster
necrorhiza gen. et sp. nov. is described. Macro-and micromorphological characters
were assessed and compared to most similar taxa. To determine the phylogenetic affinities
of the fungus, DNA sequence data were obtained for the 18S, ITS, and 28S rDNA, RBP2,
and EF1 alpha regions and subjected to single-and multi-gene analyses. DNA sequences
from fungal vegetative organs growing on decaying woody roots confirmed the wood-inhabiting
lifestyle of Guyanagaster. Key results : Guyanagaster is morphologically unique among
sequestrate fungi worldwide. Phylogenetic evidence places Guyanagaster in close relation
to the wood-decaying mushroom genus Armillaria in the Physalacriaceae (Agaricales,
Agaricomycetes, Basidiomycota). Conclusions : Guyanagaster represents an independently
evolved sequestrate form within the Physalacriaceae. Although molecular data confirm
that Guyanagaster is closely related to Armillaria, the unusual features of this fungus
suggest a case of radically divergent morphological evolution.
Type
Other articleSubject
agaricomycetesbasidiomycetes
fungal taxonomy
gasteromycete syndrome
guyana
neotropics
rdna systematics
sequestrate fungi
statismosporic fungi
molecular phylogenetics
sequences
evolution
diversification
russulaceae
mushrooms
inference
boletales
truffle
primers
plant sciences
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https://hdl.handle.net/10161/4195Published Version (Please cite this version)
10.3732/ajb.1000097Citation
Henkel,Terry W.;Smith,Matthew E.;Aime,M. Catherine. 2010. Guyanagaster, a New Wood-Decaying
Sequestrate Fungal Genus Related to Armillaria (Physalacriaceae, Agaricales, Basidiomycota).
American Journal of Botany 97(9): 1474-1484.
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