Simulated atmospheric N deposition alters fungal community composition and suppresses ligninolytic gene expression in a northern hardwood forest.

High levels of atmospheric nitrogen (N) deposition may result in greater terrestrial carbon (C) storage. In a northern hardwood ecosystem, exposure to over a decade of simulated N deposition increased C storage in soil by slowing litter decay rates, rather than increasing detrital inputs. To understand the mechanisms underlying this response, we focused on the saprotrophic fungal community residing in the forest floor and employed molecular genetic approaches to determine if the slower decomposition rates resulted from down-regulation of the transcription of key lignocellulolytic genes, by a change in fungal community composition, or by a combination of the two mechanisms.

Slowed decomposition is biotically mediated in an ectomycorrhizal, tropical rain forest.

Bacteria and fungi drive the cycling of plant litter in forests, but little is known about their role in tropical rain forest nutrient cycling, despite the high rates of litter decay observed in these ecosystems. However, litter decay rates are not uniform across tropical rain forests. For example, decomposition can differ dramatically over small spatial scales between low-diversity, monodominant rain forests, and species-rich, mixed forests.

Phylogenetic similarity and structure of Agaricomycotina communities across a forested landscape.

The Agaricomycotina are a phylogenetically diverse group of fungi that includes both saprotrophic and mycorrhizal species, and that form species--rich communities in forest ecosystems. Most species are infrequently observed, and this hampers assessment of the role that environmental heterogeneity plays in determining local community composition and in driving beta-diversity. We used a combination of phenetic (TRFLP) and phylogenetic approaches [Unifrac and Net Relatedness Index (NRI)] to examine the compositional and phylogenetic similarity of Agaricomycotina communities in forest floor and surface soil of three widely distributed temperate upland forest ecosystems (one, xeric oak--dominated and two, mesic sugar maple dominated).

Isolation of fungal cellobiohydrolase I genes from sporocarps and forest soils by PCR.

Cellulose is the major component of plant biomass, and microbial cellulose utilization is a key step in the decomposition of plant detritus. Despite this, little is known about the diversity of cellulolytic microbial communities in soil. Fungi are well known for their cellulolytic activity and mediate key functions during the decomposition of plant detritus in terrestrial ecosystems.

Inter- and intraspecific resolution of nrDNA TRFLP assessed by computer-simulated restriction analysis of a diverse collection of ectomycorrhizal fungi.

An assessment of the inter- and intraspecific resolution of 5' nrDNA ITS TRFLP was conducted by computer-simulated restriction analysis of 316 ectomycorrhizal GenBank sequences. Generally, sequences with a similarity of < 90 % could be distinguished with two to three independent enzyme digests, although sequences with similarity > 95 % were likely to remain unresolved. Choice of restriction enzyme strongly influenced resolution, especially when less than three enzymes were used.

Nitrogen availability alters macrofungal basidiomycete community structure in optimally fertilized loblolly pine forests.

•  We investigated the effect of an optimal nutrition strategy designed to maximize loblolly pine (Pinus taeda) growth on the rank abundance structure and diversity of associated basidiomycete communities. •  We conducted both small- and large-scale below-ground surveys 10 years after the initiation of optimal nutrition, and used TRFLP of selectively PCR-amplified nrDNA ITS to determine the distribution and abundance of macrofungal basidiomycete species in c. 200 soil samples collected from optimally fertilized and unfertilized treatments at the SETRES loblolly pine experimental site, North Carolina, USA.