Inoculum 56(4) - Mycological Society of America

MSA ABSTRACTS
at least a year. While the works in Dominican Republic and Puerto Rico have provided
good information on the discomycetes of the region, more studies should be
conducted on other islands, habitats and substrates. symposium presentation
Carpenter, Margaret A.*, Stringer, Alison, Stewart, Alison and Ridgway, Hayley.
National Centre for Advanced Bio-Protection Technologies, Lincoln University,
Canterbury, New Zealand. carpentm@lincoln.ac.nz. Mycoparasitism by Trichoderma
hamatum involves expression of a novel FAD-dependent
monooxygenase.
Biological control of fungal plant diseases by the mycoparasite Trichoderma
hamatum is facilitated by the actions of a range of cell wall degrading enzymes.
As mycoparasitism is a complex process, it is likely that T. hamatumuses
additional mechanisms to attack its hosts. Any unknown genes involved in mycoparasitism
may show changes in expression when T. hamatum makes contact
with a host fungus. Subtractive hybridization was used to target T. hamatum genes
up-regulated during mycoparasitism of the plant pathogen Sclerotinia sclerotiorum.
One of the genes identified encoded an FAD-dependent monooxygenease.
The gene product was 66 % identical to an Aspergillus flavus monooxygenase
which is encoded by a gene that lies adjacent to, and may be part of, a gene cluster
involved in synthesis of a mycotoxin. The T. hamatum monooxygenase gene
was not expressed when T. hamatum was growing alone, nor in dual culture with
itself. However when T. hamatum was grown in dual culture with S. sclerotiorum,
expression of the gene was detected when the two colonies overlapped, but not
prior to contact. Analysis of the promoter region of the gene revealed motifs suggesting
that expression of the gene may be affected by carbon and nitrogen repression,
and by pH. Gene expression in response to these factors has been investigated
by northern blotting. poster
Carris, Lori M. 1 * and Castlebury, Lisa A. 2 . 1 Dept. of Plant Pathology, Washington
State University, Pullman WA 99164, USA, 2 USDA ARS Systematic Botany
and Mycology Lab, 10300 Baltimore Ave., Beltsville, MD 20705, USA. carris@wsu.edu.
Identification of species of Tilletia in U.S. wheat and grass seed
exports.
Tilletia controversa (dwarf bunt of wheat) is a quarantine pest with major
impact on the worldwide movement of wheat and grass seed. Commonly used
identification methods rely on morphological features of teliospores found in seed
washes. However, teliospores of closely related species are difficult to identify
based only on morphological features, and the source of spores in wheat and grass
seed may be contaminating weeds. For example, in 2004 teliospores of T. bromi
from Bromus tectorum (downy brome, cheatgrass), misidentified as T. controversa,
were present in sufficiently high levels in some fields in the Pacific Northwest
to prevent the export of that wheat to China. Similarly, shipments of Kentucky
bluegrass seed (Poa pratensis) have been refused for import to China because
they are contaminated with spores of T. bromi. In contrast, two putative new
species of Tilletia have recently been intercepted by Chinese quarantine officials,
one in seed of Puccinellia distans (alkali grass) from the U.S., and a second in
Festuca rubra (fine fescue) from the U.S. and Lolium perenne (perennial ryegrass)
from Australia. Species of Tilletia commonly encountered in wheat or grass
seed shipments, including the new species from Puccinellia and Festuca/Lolium,
are morphologically characterized and relationships among the weedy grass-infecting
bunts and wheat bunt species are presented. poster
Castlebury, Lisa A. USDA ARS SBML, 10300 Baltimore Ave, Beltsville, MD
20705, USA. castlebury@nt.ars-grin.gov. The Diaporthe vaccinii complex of
fruit pathogens.
Diaporthe vaccinii (anamorph Phomopsis vaccinii) causes twig blight and
upright dieback of Vaccinium corymbosum (blueberry) and V. macrocarpon
(cranberry). However, other species of Diaporthe/Phomopsis have also been reported
on Vaccinium spp. In addition, isolates from a variety of hosts are reported
to be closely related to D. vaccinii. Relationships among this complex of fungi
were characterized with the ITS regions of the nuclear rDNA and intron regions
in the actin and translation elongation factor-1 alpha genes. Four species were resolved:
D. vaccinii, P. fukushii, D. allegheniensis and an as-yet unidentified
species with a broad host range. In this analysis, only D. vaccinii was host specific
and limited to species of Vaccinium. Authentic isolates of P. fukushii, a
pathogen of Pyrus, grouped with isolates from Vaccinium, Chamaecyparis and
Ulmus. Diaporthe allegheniensis from Betula was most closely related to D. vaccinii.
A large group of isolates from a variety of hosts including Vaccinium, Acer,
Rubus, Malus, Corylus, Glycine, Viburnum and Vitis form a separate and wellsupported
species in this complex. Several isolates in this group are from specimens
identified as D. eres, the type species of the genus, which has been reported
to have a broad host range and variable morphology. Results of this study
suggest that although certain pathogenic species in Diaporthe/Phomopsis may be
host specific, many taxa in this genus will have a broad host range. poster
Celio, Gail J. 1 *, Padamsee, Mahajabeen 1 , Detinger, Bryn C. 1 , McLaughlin, David
J. 1 , Hibbett, David S. 2 , Lutzoni, François 3 , Spatafora, Joseph W. 4 , and Vilgalys,
Rytas J. 3 . 1 Dept. of Plant Biology, Univ. of Minnesota, St. Paul, MN 55018, USA,
2 Biology Department, Clark University, Worcester, MA 01610, USA, 3 Dept. of
Biology, Duke University, Durham, NC 27708, USA, 4 Dept. of Botany and Plant
12 Inoculum 56(4), August 2005
Pathology, Oregon State University, Corvallis, OR 97331, USA.
celio001@umn.edu. The Nucleus in the AFTOL Non-Molecular Database.
Subcellular characters relating to polar structures and nuclear division have
been useful for inferring evolutionary relationships since the 1960s. Nuclear division
features are shared by all eukaryotes. The long evolutionary history of the
Fungi has permitted diversification of nuclear division and related processes. In
motile fungal cells polar structures include centrioles, while in other fungi they appear
as electron-opaque spindle pole bodies (SPBs). SPBs vary among taxa in
shape, position relative to the nuclear envelope, and timing of replication, migration,
and spindle initiation. The nuclear envelope may remain intact, become disrupted,
or disperse completely and reappear at various times during nuclear division.
Several patterns of nucleolus behavior are observed during the cell cycle.
Perinuclear endoplasmic reticulum and/or spindle pole body caps may be associated
with dividing nuclei. The database currently contains 17 characters and 67
character states from 81 species of the estimated 85,000 species of fungi. Compilation
of data from published nuclear division studies reveals the need for comprehensive
examination of representative species. poster
Charlton, Nikki D. 1 , Carbone, Ignazio 1 , Tavantzis, Stellos M. 2 and Cubeta, Marc
A. 1 *. 1 Dept. of Plant Pathology, North Carolina State University, Raleigh, NC
27695-7616, USA, 2 Dept. of Biological Sciences, University of Maine, Orono,
ME 04469-5722, USA. marc_cubeta@ncsu.edu. Genetic diversity and genealogical
history of the M2 dsRNA mycovirus in a field population of Rhizoctonia
solani anastomosis group 3.
Populations of the soil fungus Rhizoctonia solani anastomosis group 3 (AG-
3) (teleomorph= Thanatephorus cucumeris are genetically diverse and can harbor
double stranded RNA (dsRNA) mycoviruses. Recently, Tavantzis and colleagues
have demonstrated that isogenic strains of R. solani AG-3 that possess the 3.6 kb
dsRNA (M2) exhibited reduced virulence on potato stems. In this study, a sample
of 115 isolates from a field population of R. solani AG-3 was examined for the
M2 dsRNA with reverse transcription PCR (RT-PCR). The M2 dsRNA was detected
in approximately 48% of the sample. Three regions consisting of 3248 bp
of the M2 dsRNA from a subsample of 11 isolates were sequenced to examine
the genetic diversity and to reconstruct the genealogical history of the M2 dsRNA.
Ten haplotypes were inferred for each of the three regions and mutation rates were
not significantly different between these three regions. A preliminary site compatibility
analysis performed using SNAP Workbench for all putative clades in
the M2 mycovirus strict consensus tree identified recombination events among
the clades. M2 dsRNA haplotypes and clades will be examined further to determine
their relationship with phenotypic characteristics of the fungus and to design
transmission experiments. contributed presentation
Chatasiri, Sinchai 1 * and Ono, Yoshitaka 2 . 1 Graduate School of Science and Engineering,
Ibaraki University, 2 College of Education, Ibaraki University, 2-1-1
Bunkyo, Mito, Ibaraki 310-8512, Japan. herb-iba@mx.ibaraki.ac.jp. Taxonomy
and phylogeny of the Puccinia hemerocallidis species complex.
Puccinia hemerocallidis is a pathogen of daylily rust native of East Asia;
and it has recently invaded and established in North America and Australia. The
fungus has long been believed to cause plantainlily rust as well. However, P.
hemerocallidis and a pathogen of plantainlily rust, once named as P. funkiae, are
found distinct in host specificity in their macrocyclic life cycle and urediniospore
morphology; thus, the two fungi are taxonomically separated. Puccinia patriniae
and P. melanoplaca are microcylic, producing only telia/teliospores on different
species of Patrinia, a spermogonial- aecial host genus of P. hemerocallidis and P.
funkiae. Puccinia patriniae and P. melanoplaca are similar to P. hemerocallids
and P. funkiae in teliospore morphology. These suggest monophyly of the four
species and evolutionary derivation of either one of the two or both microcyclic
species from either P. hemerocallids or P. funkiae. To determine possible phylogenetic
relationships of the four species, ITS regions including 5.8S gene of small
subunit rDNA were amplified by a PCR method, sequenced and analyzed. During
the course of the study, P. melanoplaca was deleted from the consideration
due to failure of rDNA amplification. The results show that the three species are
monophyletic as indicated by their host specificity and teliospore morphology and
indicate that P. hemerocallidis and P. funkiae had derived from a hypothetical
common ancestor and P. patriniae had branched off from a hypothetical common
ancestor shared by P. hemerocallidis. symposium presentation
Chavarria, Allan* and González, Maria C. Departamento de Botanica, Instituto de
Biologia, UNAM, Mexico. acchs2002@yahoo.com.mx. Some freshwater mitosporic
fungi from Xochimilco, Mexico City.
New records of freshwater mitosporic fungi from Xochimilco, Mexico City,
are described and illustrated. Sixty wood blocks (Pinus sp.) were submerged during
2 months in two canals and one lagoon. All the samples were placed in plastic
bags and returned to the laboratory. Collected material was washed in tap water
and placed in sterile plastic boxes containing paper towels and the samples were
incubated at laboratory conditions. Woody substrates were examinated periodically
for the presence of fungal structures. The common recorded genera were
Arthrobotrys, Phoma, Taeniollela, and Trichocladium. The present study is the
Continued on following page