Inoculum 63(3) - Mycological Society of America

Several non-aflatoxigenic strains of Aspergillus flavus have been in use
for nearly a decade to inhibit colonization of important food commodities by toxigenic
Aspergilli such as A. flavus and A. parasiticus. Annual application of these
biocontrol strains is necessary because they do not appear to persist in the field.
The reason(s) for this are unknown. One possible mechanism to explain the loss
of an atoxigenic biocontrol competitor strain is that it could be recombining with
the native toxigenic population and reacquiring toxigenic properties. A second
possibility is that aflatoxin production increases the likelihood of survival for toxigenic
strains in the soil, during overwintering, compared to that of an atoxigenic
strain. To test the relative efficacy of these non-aflatoxigenic strains as bio-competitors,
and to assess the reason for the loss of the field inoculum with time (posttreatment),
we transformed six different biocontrol strains with a plasmid containing
DNA for expressing an ‘enhanced green fluorescent protein’ (eGFP) tag.
Competition experiments in petri plates have been set up to test the efficacy of the
transformed biocontrol strains to colonize cotton seed. Tests included: GFP-transformed
biocontrol strains vs non-transformed (homologous and heterologous)
biocontrol strains, and GFP-transformed biocontrol strains vs toxigenic strains of
A. flavus and A. parasiticus. These in vitro studies will test if the GFP tag diminishes
the aggressiveness of the biocontrol strain, as well as the relative abilities of
the individual strains to compete against toxigenic strains. If these tests show
promise in using GFP-tagged strains to track the introduced fungi, subsequent
studies will be done under conditions imitating the growing environment of the
cotton plant in order to track the longevity and recombining potential of these biocontrol
strains.
Morgado, Luis N 1 , Manon Neilen 1 , Machiel E Noordeloos 1 , D Lee Taylor 2 , Ina
Timling 2 , and József Geml 1 . 1 Netherlands Centre for Biodiversity Naturalis, Leiden
University, P.O. Box 9514, Einsteinweg 2, 2300 RA Leiden, The Netherlands,
2 Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks,
AK 99775-7000. Phylogenetic diversity of the ectomycorrhizal genus Cortinarius
(Agaricales, Basidiomycota) in the Arctic
Mycorrhizal associations are abundant and widespread in almost all
ecosystems, and c. 80% of land plant species form associations with mycorrhizal
fungi. They play a particularly important role in the functioning of terrestrial arctic
ecosystems, where arctic plants are highly dependent on mutualistic relationships
with mycorrhizal fungi for survival in these nutrient-poor environments. Ectomycorrhiza
(ECM) is the predominant mycorrhiza type in arctic and alpine
environments, and ECM fungi are crucial for the survival of arctic shrubs (e.g. Betula,
Dryas, Salix). Although recent molecular studies have revealed high diversity
in arctic ECM communities, the systematic treatment of several arctic ECM
genera is still not adequate. Cortinarius is one of the most abundant genera in the
Arctic. Here we present preliminary results on the phylogenetic diversity of the
genus Cortinarius in the North American and European Arctic. We analyzed internal
transcribed spacer (ITS) rDNA sequences from basidiomata and soil samples
collected in northern Alaska and Svalbard using likelihood-based phylogenetic
methods. We detected at least 28 phylogroups, from which 18 matched
sequences from sporocarps deposited in public databases. These included C. umbilicatus,
C. biformis, C. delibutus, C. favrei, C. cinnamomeus, C. aureomarginatus,
C. urbicus, C. fulvescens, among others. The other 8 represent previously
unsequenced taxa that may or may not be newly discovered species. Future
investigations will include multi-gene phylogenetics and morphological analyses.
Morgado, Luis N 1 , Machiel E Noordeloos 1 , Delia Co-David 1 , Yves Lamourex
2 , and József Geml 1 . 1 National Herbarium of the Netherlands, Netherlands
Centre for Biodiversity Naturalis, Leiden University, P.O. Box 9514, Einsteinweg
2, 2300 RA Leiden, The Netherlands, 2 505, Rue Saint-Alexandre, app. 401,
Longueuil (Québec), Canada, J4H3G3. Biogeographic and phylogenetic relationships
of four easily recognizable morphospecies of Entoloma Section Entoloma
(Basidiomycota), inferred from molecular and morphological data
Species from Entoloma section Entoloma are commonly recorded from
both the Northern and Southern Hemispheres and, according to literature, most of
them have, at least, Nearctic-Palearctic distribution. However, all records are
based on morphological analysis, and studies relating morphology, molecular data
and species distribution are lacking. In this study, we selected four morphospecies
from Section Entoloma, to answer specific questions considering species concept
and geographic distribution: E. sinuatum (E. lividum auct.), E. prunuloides (typespecies
of section Entoloma), E. nitidum and the European red-listed E. bloxamii,
with collections from Europe, North America, Australia and New Zealand. We
combined molecular phylogenetics (based on nuclear LSU, ITS and rpb2 and mitochondrial
SSU sequences) with morphological analysis to infer interspecific relationships
and distribution patterns. Our results indicate that most species appear
to have more restricted distribution than previously assumed. None of the collections
studied from North Hemisphere and South Hemisphere proved to be conspecific.
Entoloma sinuatum and E. nitidum contain phylogeographical groups
that are partly recognizable using morphological characters. Entoloma bloxamii is
paraphyletic, falling apart into 3 distinct lineages, one represented in Europe, a
34 Inoculum 63(3), June 2012
second restricted to North America, and a third represented in both these continents.
The European and North American E. prunuloides appear to be conspecific.
Furthermore the accepted taxa appear to belong to two distinct clades, (1) Entoloma
clade, with E. sinuatum, E. subsinuatum, E. whiteae, E. flavifolium, and
(2) Prunuloides clade, with E. prunuloides, E. bloxamii and E. nitidum.
Morgenstern, Ingo 1,2 , Justin Powlowski 1,3 , and Adrian Tsang 1,2 . 1 Centre for
Structural and Functional Genomics, Concordia University, 7141 Sherbrooke
Street West, Montreal, Quebec, Canada, 2 Department of Biology, Concordia
University, 3 Department of Chemistry and Biochemistry, Concordia University.
Transcriptional activity of “GH61”-encoding genes from various fungal
species grown on straws
The efficient degradation of lignocellulosic biomass using microbial enzymes
is considered a key step for the production of second generation biofuel
and value-added by-products. Efforts to improve commercial cellulase mixtures
include the spiking with auxiliary enzymes. Recently, members of the so-called
glycosyl hydrolase family 61 (GH61) have attracted much interest due to their cellulase-enhancing
properties in enzyme mixtures. Copies for GH61 encoding
genes are present in the majority of fungal genomes; however, the copy number
of GH61s differs tremendously among the investigated genomes, exceeding thirty
copies in some species. Currently, it is not known whether this is merely an example
of high redundancy or how far functional differences are present among
GH61 paralogs. We are examining the transcriptional profile of “GH61s” both
from ascomycete and basidiomycete species grown on alfalfa and/or barley straw
as substrate and are interpreting the results in a phylogenetic context.
Morrison, Eric W 1 , Serita D Frey 2 , W Kelley Thomas 3 , and Anne Pringle 4 1
.
Department of Molecular, Cellular and Biomedical Sciences, University of New
Hampshire, Durham, NH, 2 Department of Natural Resources and the Environment,
University of New Hampshire, Durham, NH, 3 Hubbard Center for Genome
Studies, University of New Hampshire, Durham, NH, 4 Organismic and Evolutionary
Biology, Harvard University, Cambridge, MA. Diversity and composition
of soil fungal communities under long-term nitrogen enrichment
Nitrogen (N) deposition from fossil fuel burning has the potential to affect
ecosystem processes such as the decomposition and storage of soil organic matter.
The Harvard Forest Chronic Nitrogen Addition experiment (HFCN) was established
in 1989 to test the effects of long-term N fertilization on ecosystem
processes in a northeastern mixed-hardwood forest. Three plots receive one of
three treatments: ambient N deposition (control), 50 kg N ha -1 yr -1 (low N), or
150 kg N ha -1 yr -1 (high N). Researchers at this site have observed an accumulation
of soil C in the N fertilized plots and a decrease in fungal biomass, ligninolytic
enzyme activity, and rates of litter decay. Soil fungi are the primary decomposers
of lignin in these communities. We hypothesized that decreased
decomposition rates in N fertilized plots may be due to decreased diversity and
changes in the composition of the fungal community. We performed a marker
gene study of the fungal community in the organic soil horizon using 454 sequencing
of three loci: ITS1, ITS2, and rDNA large subunit D2-D3 region. The
dominant fungal family in soils under ambient N deposition was the Russulaceae.
This family underwent a significant decrease in relative abundance in N treated
soils. Unknown fungi dominated N treated soils. Control soils had significantly
fewer unknown OTUs. High N soils had higher numbers of OTUs and singleton
OTUs then control soils and low N soils, and had higher predicted richness. Fungal
communities in high N soils had different community structure than control
and low N soils as predicted with OTU based and phylogenetic beta-diversity
metrics. Differences in community composition and higher numbers of unknown
OTUs in high N soil fungal communities may suggest that a previously uncatalogued
portion of the community is released by the decline of the dominant Russulaceae.
Mueller, Olaf 1 , Scott Baker 3 , Guillaume Blanc 2 , Frank Collart 3 , Fred Dietrich 1 ,
Peter Larsen 3 , Jon Magnuson 3 , Francis Martin 4 , Emmanuelle Morin 4 , François
Lutzoni 1 , and Daniele Armaleo 1 . 1 Department of Biology, Duke University,
Durham, NC 27708 USA, 2 Information Génomique et Structurale (IGS), CNRS-
UPR2589, IFR-88, Marseille, 3 Argonne National Laboratory, 9700 S. Cass Avenue,
Argonne, IL 60439, 4 IUMR 1136, INRA-Nancy University, Interactions
Arbres/Microorganismes, INRA-Nancy, 54280 Champenoux, France. Insights
from comparative genomics in lichen symbiosis
Mutual recognition and response among plants and fungi are central to either
pathogenic or symbiotic associations. Genomes of the lichen-forming ascomycete
Cladonia grayi (mycobiont) and its photoautotrophic symbiont, the single-celled
green alga Asterochloris sp. (photobiont), were sequenced and
analyzed to identify genes specific for the establishment and maintenance of
lichen symbiosis. Annotated gene models of C. grayi and Asterochloris were
compared to reference genomes representing related Ascomycota taxa (Euro-
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