Biology

Conservation of biotrophy in hygrophoraceae inferred from combined stable isotope and phylogenetic analyses

Document Type

Article

Abstract

The nutritional modes of genera in Hygrophoraceae (Basidiomycota: Agaricales), apart from the ectomycorrhizal Hygrophorus and lichen-forming taxa, are uncertain. New δ 15N and δ 13C values were obtained from 15 taxa under Hygrophoraceae collected in central Massachusetts and combined with isotopic datasets from five prior studies including a further 12 species using a data standardization method to allow cross-site comparison. Based on these data, we inferred the probable nutritional modes for species of Hygrophorus, Hygrocybe, Humidicutis, Cuphophyllus and Gliophorus. A phylogeny of Hygrophoraceae was constructed by maximum likelihood analysis of nuclear ribosomal 28S and 5.8S sequences and standardized δ 15N and δ 13C values were used for parsimony optimization on this phylogeny. Our results supported a mode of biotrophy in Hygrocybe, Humidicutis, Cuphophyllus and Gliophorus quantitatively unlike that in more than 450 other fungal taxa sampled in the present and prior studies. Parsimony optimization of stable isotope data suggests moderate conservation of nutritional strategies in Hygrophoraceae and a single switch to a predominantly ectomycorrhizal life strategy in the lineage leading to Hygrophorus. We conclude that Hygrophoraceae of previously unknown nutritional status are unlikely to be saprotrophs and are probably in symbiosis with bryophytes or other understory plants. © 2011 by The Mycological Society of America.

Publication Title

Mycologia

Publication Date

3-2011

Volume

103

Issue

2

First Page

280

Last Page

290

ISSN

0027-5514

DOI

10.3852/10-195

Keywords

Cuphophyllus, ecology, Gliophorus, Humidicutis, Hygrocybe, Hygrophorus, nutritional status

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