The ectomycorrhizal status of Calostoma cinnabarinum determined using isotopic, molecular, and morphological methods

Abstract

Calostoma cinnabarinum Corda belongs to the suborder Sclerodermatineae (Boletales), which includes many well-known ectomycorrhizal basidiomycetes, but the genus Calostoma has been described as saprotrophic. This study combines isotopic, molecular, and morphological techniques to determine the mode of nutrition of C. cinnabarinum. δ13C and δ15N measurements were compared among co-occurring C. cinnabarinum, ectomycorrhizal fungi, saprotrophic fungi, and ectomycorrhizal plants. Isotopic profiles of C. cinnabarinum resembled those of ectomycorrhizal fungi but not those of saprotrophic fungi. For molecular analyses, ectomycorrhizal root tips were extracted from soil cores collected beneath C. cinnabarinum fruit bodies. Nuclear ribosomal internal transcribed spacer (nrITS) sequences were obtained from ectomycorrhizal root tips using fungal-specific primers and screened against C. cinnabarinum nrITS sequences. Ectomycorrhizal root tips had nrITS sequences that matched C. cinnabarinum fruiting bodies. Root tips colonized by C. cinnabarinum were also described morphologically. Several morphological characters were shared between fruiting bodies and ectomycorrhizal root tips of C. cinnabarinum. Results of isotopic, molecular, and morphological analyses indicate that C. cinnabarinum is ectomycorrhizal. Molecular analysis and observations of plant associations suggest that C. cinnabarinum forms ectomycorrhizae with Quercus .

Elucidating the nutritional dynamics of fungi using stable isotopes

“…Such predictions could form the basis for research hypotheses about the evolution of the ECM and SAP habit (Hobbie et al. 1999, 2001) and be combined in a phylogenetic context (e.g., Wilson et al. 2007).…”

Ectomycorrhizal diversity and community structure in stands of Quercus oleoides in the seasonally dry tropical forests of Costa Rica

“…Root tips of each morphotype were frozen at −80°C and lyophilized, after which DNA was extracted using Qiagen DNeasy Plant Mini Kit (Qiagen USA, Valencia, California) following manufacturer's instructions. Polymerase chain reaction (PCR) amplification of the internal transcribed spacer region using primers ITS1F (Gardes and Bruns 1993) and ITS4 (White et al 1990) was attempted for all samples using the protocol of Wilson et al (2007). Successful amplifications, i.e., single amplicons, were cleaned and cycle sequenced using BigDye v3.1 on an Applied Biosystems 3730 DNA sequencer (Applied Biosystems, Foster City CA).…”

Diversity and evolution of ectomycorrhizal host associations in the Sclerodermatineae (Boletales, Basidiomycota)

“…Most Sclerodermatineae are considered to be ectomycorrhizal (Binder & Hibbett, 2006; Wilson et al. , 2007).…”

“…Astraeus , Calostoma , Pisolithus and Scleroderma have been conclusively shown to form ectomycorrhizas with angiosperms and gymnosperms through synthesis studies (Molina, 1981; Molina & Trappe, 1982a; Danielson, 1984) and molecular analyses (Tedersoo et al. , 2007; Wilson et al. , 2007).…”