March 2008 - Mycological Society of America

distinctive but no probe-level sequence is identified that is not shared
with other taxa, a set of probes are designed to a combination of regions
on the operon that taken together do not exist in any other taxa. The selected
probes will each be paired with a control probe containing a central
mismatch to reduce the effects of non-specific hybridization and
synthesized on a NimbleGen platform. This microarray could greatly
advance our knowledge of the role fungi play in important matters such
as bioremediation, carbon sequestration and human diseases in addition
to providing a monitoring tool to assess the health of an ecosystem.
Symposium Presentation
Dewsbury, Damon R. 1 * and Moncalvo, Jean-Marc. 2 1 Department of
Ecology and Evolutionary Biology, University of Toronto, ON M5S
3B2, Canada, 2 Department of Natural History, Royal Ontario Museum,
ON M5S 2C6, Canada. damondewsy@yahoo.com. A molecular phylogeny
of Eastern North American morels (genus Morchella) focusing
on the “Carolinian” forest zone. Members of the genus Morchella
are easily identified in the field but species boundaries are
problematic given the limited morpho-characters. DNA sequences of
the ITS, LSU, RPB2 and EF-1 alpha regions are being obtained from
many specimens sampled from four Maryland national parks and southern
Ontario. Most of these specimens were collected in the “Carolinian”
forest zone, which is characterized by a particular suite of flora dominated
by Tuliptrees (Liriodendron tulipifera). The Tuliptree belongs to
the Magnoliaceae and thus is quite distinct from other dominant tree
species in Eastern North America. It has been noted anecdotally that
there is a correlation between these trees and morel fruitings. Sequence
data will be used to elucidate a molecular phylogeny to answer several
questions. Of the four morphotaxa that can be distinguished in the field,
do any mask multiple phylogenetic species? Do Southern Ontario
morels from the Carolinian zone cluster with Maryland collections, following
the tree host/forest ecotype, or with geographically closer taxa
from forests with more northern floral elements such as maple (Acer
genus) and pine (Pinus genus)? Lastly, this study will begin to address
whether there is a need for a taxonomic revision of the genus in eastern
North America to provide formal names for morels that are phylogenetically
distinct from their European counterparts. Poster
Dianese, José Carmine* and Pereira-Carvalho, Rita C. Departamento de
Fitopatologia, Universidade de Brasília, 70910-900 Brasília, Distrito
Federal, Brazil. jcarmine@unb.br. Fungal conservation with the Rio
Convention: the experience of Brazil. Mycology in Brazil suffered a
long period of stagnation mainly after the deaths of Augusto Chaves
Batista, Ahmés Pinto Viégas in the 1960s, and more recently the loss of
Alcides Teixeira. However, coinciding with the signature of “The Convention
on Biodiversity”, a few people woke up for the need of fungal
conservation starting with a systematic description of our mycodiversity.
Thus major projects involving the study of savanna (cerrado) microfungi,
fungi of the “caatinga” (semi-arid Northeast region), survey and
description of endomycorrhizal fungi, microfungi of interest to biocontrol
of insects and plant diseases, and description of important fractions
of the Boletales and other macrofungi, were all initiated after 1992 in
Brazil. These efforts, in some instances based upon cooperation with
American and European mycologists, although conducted by isolated
groups deserve consideration and an effort to present an overview of the
mycological progress in our Country in the last 15 years. It must be emphasized
that in Brazil the preservation of fungi “ex-situ” in culture collections
is clearly left aside with money destined to collections being
funneled to collateral activities even in institutions whose primary mission
is exactly that of preserving germplasm. With the establishment of
the “Centro de Biotecnologia da Amazônia” (Amazonian Biotechnology
Center) in Manaus by the Federal Government it is expected that the
first step will be the organization of a unique mycological collection,
and the same must become real for the cerrado where Embrapa is giving
the first steps in the same direction. On the other hand several frustrated
experiences led to difficulties in motivating the financing agents
to invest in culture collections, treasure still unexplored. Data will be
gathered and presented to permit an evaluation of the mycological
progress in Brazil post-Rio 92. Symposium Presentation
14 Inoculum 59(2), March 2008
Dianese, J. C.* and Pereira-Carvalho, R.C. Departamento de Fitopatologia,
Universidade de Brasília, 70910-900 Brasília, Distrito Federal,
Brazil. jcarmine@unb.br. A new hyphomycete genus based on Alternaria
qualeae. A re-examination suggested by Dr. Emmory Simmons
(personal communication) of the type material of Alternaria
qualeae Dornelo-Silva & Dianese, deposited in Herbarium UB, led to
the conclusion that the specimen does not really belong in an Alternaria
species but indeed belongs in a new genus to be published soon. The
specimen can not be included in Alternaria because of the the presence
of a stroma produced by the fungus on the abaxial face of the host
leaves, and the fact that a careful examination of the conidial base and
the conidiogenous cells revealed scars but not the characteristic tretic
condition needed to characterize an alternarian species. Finally, a close
observation of the conidiogenous cells revealed their annellidic condition.
The specimen could not be fitted in any of the known genera of
dematiaceous hyphomycetes. Poster
Didukh, Maryna* and Moncalvo, Jean-Marc. Department of Ecology
and Evolutionary Biology, University of Toronto, and Department of
Natural History, Royal Ontario Museum, Toronto, Canada. maryna.didukh@gmail.com.
DNA barcoding Pleurotus species (Agaricales,
Basidiomycota). DNA barcoding is an approach designed to increase
the efficiency of recovering and documenting species across
different kingdoms of life. In numerous groups of animals, a short, ca.
600 bp segment of the cytochrome oxidase 1 gene (CO1) was shown
to very be effective for that purpose, and this gene has been proposed
as a possible universal marker. However, the utility of CO1 as a
species marker in fungi still remains to be tested. Primary disputes
over CO1 involve fundamental issues like accuracy (intraspecific variation
and interspecific divergence) and the proposed use of singlegene
thresholds as an initial step in species discovery. Prior to the barcoding
initiative, information on the organization and variation of
CO1 in fungi was scarce and restricted mostly to model organisms in
the Ascomycota. In this study, over 40 strains of seven species of the
genus Pleurotus as well as representatives of other agaricoid taxa were
used to assess variation in the target CO1 region and to compare its
performance with more widely used nuclear markers: nuclear ribosomal
DNA internal transcribed spacer (nrDNA ITS) region and elongation
factor-1 alpha (EF-1 alpha). Pleurotus strains were further used
to compare cDNA vs. genomic sequences for CO1 and EF-1 alpha in
order to retrieve information on nuclear gene organization. Contributed
Presentation
DiMarco, Michael J. and Silliker, Margaret E.* Department of Biology,
DePaul University, 2325 N. Clifton Avenue, Chicago, IL 60614,
USA. msillike@depaul.edu. RNA editing of Didymium iridis atp8
and nad4L mitochondrial genes. Mitochondrial genomics has provided
evolutionary insights, however, in some organisms, the mitochondrial
DNA genes appear to be scrambled; functional genes arise
after the mRNA undergoes an editing process. In the Myxogastria
(plasmodial slime molds) editing is primarily by cytosine-base insertions
that alter the transcript to remove stop codons. We characterized
editing events in two mitochondrial genes, atp8 and nad4L of Didymium
iridis. Total RNA was isolated, reverse transcribed, cloned, sequenced,
and aligned with the genomic DNA sequences to reveal the
editing sites. Nad4L was edited evenly throughout by C-insertions,
while atp8 was predominantly edited at the beginning of the transcript.
Editing sites were downstream of a purine-pyrimidine dinucleotide
67% of the time. Given the base composition of the genes, A-T dinucleotides
are predicted to occur in 16% of the sequence, however, this
dinucleotide pair was found immediately upstream at 57% of all the upstream
pur-pyr editing sites. The C-base insertions were preferentially
inserted in the 3rd position (wobble position) of the codon to create a
correct reading frame. Editing sites were conserved 63% and 85% in
atp8 and nad4L, respectively, between D. iridis and Physarum polycephalum,
a related Myxogastria. In both organisms a similar mechanism
of RNA editing appears to be responsible for maintaining protein
function. Poster
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