Testing the "one-log-one-genet" hypothesis: methodological challenges of population sampling for the Hawaiian wood-decay fungus Rhodocollybia laulaha.

We test our "one-log-one-genet" sampling method for the Hawaiian mushroom Rhodocollybia laulaha that posits all R. laulaha mushrooms collected from a single log represent a single genet. We also examine the potential expansion of single genets beyond the confines of one log and the temporal persistence of genets in nature.

Fungal communities influence root exudation rates in pine seedlings.

Root exudates are hypothesized to play a central role in belowground food webs, nutrient turnover, and soil C dynamics in forests, but little is known about the extent to which root-associated microbial communities influence exudation rates in trees. We used a novel experimental technique to inoculate loblolly pine (Pinus taeda L.) seedlings with indigenous forest fungi to examine how diverse fungal communities influence exudation.

Ectomycorrhizal iconoclasts: the ITS rDNA diversity and nitrophilic tendencies of fetid Russula.

Fetid Russula are frequently dominant ectomycorrhizal fungi, and some appear to be especially nitrophilic. However, little is known about their phylogenetic relationships or how common nitrophilic traits are in this group. This study addresses this gap and presents a phylogenetic analysis of ITS rDNA sequences and a meta-analysis of studies that examine ectomycorrhizal fungi response to nitrogen increase.

Investigating the allelic evolution of an imperfect microsatellite locus in the Hawaiian mushroom Rhodocollybia laulaha.

The evolutionary mechanisms that give rise to microsatellite alleles remain poorly understood in general and are especially understudied for fungal microsatellite loci. The unusual G28 microsatellite locus was developed from the Hawaiian mushroom Rhodocollybia laulaha. Here, we employ a novel approach to test for allele size homoplasy and examine competing mechanistic models of microsatellite evolution in the context of biogeographic expectations for this locus based on Hawaiian geologic history.

A 'dirty' business: testing the limitations of terminal restriction fragment length polymorphism (TRFLP) analysis of soil fungi.

Terminal restriction fragment length polymorphism (TRFLP) is an increasingly popular method in molecular ecology. However, several key limitations of this method have not been fully examined especially when used to study fungi. We investigated the impact of spore contamination, intracollection ribosomal DNA internal transcribed spacer (ITS) region variation, and conserved restriction enzyme recognition loci on the results produced by TRFLP to characterize soil fungal communities.

The response of ectomycorrhizal fungal inoculum to long-term increases in nitrogen supply.

The inoculum of ectomycorrhizal (EM) fungi was examined in a 16 y long nitrogen fertilization experiment maintained in a temperate oak savanna. To measure EM fungal inoculum, bur oak seedlings were grown in three types of bioassays: (i) intact soil cores that measure inoculum such as spores, mycelia and mycorrhizal roots; (ii) resistant propagule bioassays that measure inoculum types resistant to soil drying; and (iii) previously mycorrhizal root bioassays that measure the ability of EM fungi to colonize new roots from mycorrhizal roots. Colonization of bur oak seedlings was characterized by morphotyping and where necessary by restriction analysis and internal transcribed spacer (ITS) sequencing.

Long-term increase in nitrogen supply alters above- and below-ground ectomycorrhizal communities and increases the dominance of Russula spp. in a temperate oak savanna.

•  Here we examine the effects of increased nitrogen (N) supply on the ectomycorrhizal fungal communities of a temperate oak savanna. •  In a 16-yr N-addition experiment in which replicate 1000 m plots received 0, 5.4 or 17 g N m  yr , ectomycorrhizal sporocarp production was measured in the 14th, 15th and 16th year of fertilization.

Good-Enough RFLP Matcher (GERM) program.

A spreadsheet-based program (Good-Enough RFLP Matcher or GERM) is presented that matches unknown restriction fragment length polymorphism (RFLP) patterns of ectomycorrhizal fungi to a database of known ectomycorrhizal fungi. The program uses three simple methods to determine whether a sample matches a known: (1) Forward Matching: whether every band in the unknown is present in a known sample within a given error range; (2) Backward Matching: whether every band in the known sample is present in the unknown within a given error range; (3) Sum of Bands: whether the sum of all bands in the known and unknown are similar within a given error range. The program is available through the web page of this journal.