March 2008 - Mycological Society of America

o@ucok.edu. A new species of Tricholoma from Costa Rica. Collections
of an undescribed species of Tricholoma sect. Genuina were
made in the oak forests of Costa Rica. The fungus is characterized by
the light yellowish brown, viscid pileus, very pale yellow lamellae and
stipe, and by crowded lamellae. DNA was extracted using a modified
CTAB buffer followed by alcohol precipitation. Primers ITS1F and
ITSF4 were used for PCR of the ribosomal RNA ITS region. Dideoxy
sequencing was primed with ITS5 in the forward direction and ITS4 in
the reverse direction with alignment and trimming done manually. Parsimony
analysis was performed in PAUP using 1000 bootstrap replicates.
A monophyletic clade of nine Tricholoma collections resulted. A
second clade appeared as a sister to the first clade, the latter containing
two collections deposited in GenBank as Tricholoma ustale and T.
ustaloides respectively, but with poor bootstrap support. Two additional
collections comprise a third clade which is basal to the putative T.
ustale/T. ustaloides clade. Collections in the first clade represent a hitherto
unnamed species of Tricholoma apparently related to the second
white-gilled clade from California. Collections in the third clade differ
in ITS sequence from the first clade by only 1.52%. The third clade
may represent a sibling species or all three clades may represent a single
large species complex which has diverged over distance and time.
Poster
Padamsee, Mahajabeen 1 *, Matheny, P. Brandon 2 and McLaughlin,
David J. 11 Dept. of Plant Biology, University of Minnesota, St. Paul,
MN 55108, USA, 2 Biology Department, Clark University, Worcester,
MA 01610. USA. pada0003@umn.edu. Rocking the coprinoid boat:
a phylogenetic study of the little brown mushroom genus Psathyrella.
The first broad phylogenetic study of the mushroom genus
Psathyrella was based on 132 sequences from the nuclear ribosomal
large subunit gene and parsimony and Bayesian analyses. For this study
Psathyrella sequences were generated and analyzed to represent approximately
one tenth of the known species worldwide, and most subgeneric
subdivisions. Representatives of the coprinoid genera (Parasola,
Coprinopsis, and Coprinellus) were included to evaluate
relationships in Psathyrellaceae with Coprinus in the outgroup.
Psathyrella was found to be polyphyletic, with representatives in seven
clades. Most species of Psathyrella, including its type species P. gracilis,
formed a large clade with Coprinellus. Generic limits of Parasola,
Lacrymaria, and Coprinopsis are affected. Morphological characters
traditionally used to subdivide Psathyrella and the two major
taxonomic systems are evaluated based on phylogenetic analyses. Contributed
Presentation
Palencia, Edwin R. 1 *, Klich, Maren 2 and Bacon, Charles W. 31 University
of Georgia, Plant Pathology Department, Athens, GA 30604, USA,
2 USDA, ARS, SRRC, New Orleans, LA 70124, USA, 3 USDA, ARS,
Russell Research Center, Athens, GA 30604, USA.
edwin.palansia@ars.usda.gov. Molecular differentiation of species
within the Aspergillus section Nigri by using an automated repetitive-PCR
method. Some species in the Aspergillus section Nigri, are
known for their production of mycotoxins, including ochratoxin A, a
chlorinated cyclic polyketide compound. Ochratoxin A has been classified
as possible carcinogenic to humans by the International Agency
for Research on Cancer, and the evidence suggests nephrotoxic, teratogenic
and carcinogenic activities in laboratory animals. The accurate
classification and identification of ochratoxigenic species within the A.
niger aggregate has been elusive since the morphology of most of the
members is very similar. Molecular biology techniques have been developed
in order to differentiate species within this aggregate, however
most of them are impractical for routine identification and they required
too much time. In this work, we report the use of an automated
repetitive-sequence-based DNA fingerprinting method which reduces
the time and labor required by other molecular methods. We used 27
Aspergillus section Nigri species and strains that were previously identified
by microscopy and our results indicated a high concordance between
the automated DNA fingerprinting system and morphology.
Poster
32 Inoculum 59(2), March 2008
Palmer, Jonathan M. *, Perrin, Robyn M. and Keller, Nancy P. Plant
Pathology Department, University of Wisconsin, Madison, WI 53706,
USA. palmer3@wisc.edu. Chromatin remodeling mutants affect
development and secondary metabolism in Aspergillus fumigatus.
The worldwide frequency and the profile of patients at risk for invasive
aspergillosis (IA) continues to expand, owing to increased numbers of
immunocompromised patients including those afflicted with
HIV/AIDS, malignancy, and organ dysfunction. Over 90% of IA cases
are caused by Aspergillus fumigatus. Despite the recent steady increases
in IA, new and effective treatments have not been discovered in part
because little is know about virulence attributes of A. fumigatus. Like
other aspergilli, A. fumigatus produces various secondary metabolites,
including gliotoxin, an immunotoxin that has been implicated in contributing
to virulence. However, disruption of a few components of the
gliotoxin biosynthetic gene cluster does not reduce virulence in a
mouse model, but gliotoxin does appear to be involved in apoptosis.
Therefore, gliotoxin may be contributing to virulence but is not acting
alone. Recent studies have implicated the importance of a global regulator
of toxin production, LaeA, in IA development. Because chromatin
remodeling is important for genetic regulation and has been implicated
in LaeA control of secondary metabolism gene clusters, we are exploring
the possibility that A. fumigatus chromatin remodeling mutants
could be affected in both fungal and IA development. We constructed
gene disruption mutants of dimE, a methyltransferase of histone 3 lysine
9 (H3K9) and lsdA, a de-methylase of H3K4. Both mutants show
alterations in development and/or secondary metabolite profiles. Contributed
Presentation
Pereira-Carvalho, Rita C. and Dianese, José Carmine. Departamento de
Fitopatologia, Universidade de Brasília, 70910-900 Brasília, DF,
Brazil. jcarmine@unb.br. An Actinocymbe species on Alibertia sessilis
from the cerrado. A fungus belonging in family Chaetothyriaceae
was for the first time found on leaves of Alibertia sessilis, and identified
as a new species of Actinocymbe, a rare epiphytic ascomycete previously
known from India. The fungus shows colonies epiphytic;
mycelium septate, superficial, thin; ascomata 216-300-444 µm, dimidiate-discoidal,
textura meandriformis, setose, ostiolate; setae 153,6-324
x 4,8 - 9,6 (7,2) µm, septate, brown, with a wider 12-48 (24) µm base;
asci 35 -47,5- 57 x 12-20-20 µm, prostate, bitunicate; ascospores 13-
19-41 x 3-5-8 µm, 1-2-4 septate. Poster
Pérez-Martínez, José M. 1 * and Piepenbring, Meike. 2 1 Tropical Research
and Education Center, University of Florida, 18905 SW 280th
Street, Homestead, FL 33031, USA, 2 Botanisches Institut, J. W.
Goethe-Universität Frankfurt am Main, D-60054 Frankfurt am Main,
Germany. jperezma@ufl.edu. New records and new hosts of smut
fungi (Ustilaginomycetes) from Cuba. Field work yielded new data
on smut fungi in Cuba. Ustilago chrysopogonis is recorded for the first
time for Cuba and the Neotropics on the new host plant Schizachyrium
hirtiflorum. Sporisorium bicornis known from Brazil and Colombia is
found for the first time in Cuba. Sporisorium ellisii known only from
USA and Mexico is now reported on the new host Andropogon glomeratus
from five localities for this country. The presence of Sporisorium
andropogonis is confirmed. Descriptions, illustrations, and notes on
distribution and ecology of the new records are provided. Poster
Perry, Brian A. 1 *, Desjardin, Dennis E. 1 and Moncalvo, Jean-Marc. 2
1 Department of Biology, San Francisco State University, San Francisco,
CA 94132, USA, 2 Center for Diversity and Conservation Biology,
Royal Ontario Museum and Department of Botany, University of
Toronto, Toronto, ON M5S 2C6, Canada.
brian_perry@post.harvard.edu. Molecular systematics of the
mycenoid fungi (Mycena and allied genera). Our research focuses on
phylogenetic systematics in the mushroom genus Mycena s.l. and allied
mycenoid fungi (Tricholomataceae, Euagarics). With over 1880
species epithets published in Mycena alone, the mycenoid fungi represent
one of the most diverse groups of saprotrophic mushrooms.
Mycenoid taxa play major roles in litter decomposition, nutrient recy-
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