Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme II: SYSTEMATICS, PHYLOGENY AND EVOLUTION Posters
Rhodocollybia and 18 in Gymnopus. Most represent
previously described tropical - subtropical species like G.
neotropicus, G. lodgeae, G. fibrosipes, and R. turpis
reported from South America and the Caribbean, but some
are considered to be of temperate origin, such as G.
confluens, G. dryophilus, and R. prolixa var. distorta.
Presence of such diverse fungal taxa from the north and
south, especially those associated with oak forests, put
perceivable importance to the biotic exchange that took
place over the Central American Isthmus in recent geologic
times. Sequences from the ITS1-5.8S-ITS2 nuclear
ribosomal DNA region were obtained for most of these
tropical specimens and have been used to generate a
phylogenetic tree. Costa Rican species, including newly
proposed species, are highlighted to show their relationship
to those from temperate locations. Current taxonomic
placement of these taxa based on morphological
characteristics is also analyzed.
727 - Ascomycetous mitosis in basidiomycetous yeasts:
its evolutionary implications
D.J. McLaughlin 1* , R.W. Hanson, Jr. 1 , E.M. Frieders 2 , E.C.
Swann 3 & L.J. Szabo 4
1 University of Minnesota, Dept. of Plant Biology, St. Paul,
MN, U.S.A. - 2 University of Wisconsin, Dept. of Biology,
Platteville, WI, U.S.A. - 3 EMSL Analytical Inc., Plymouth,
MN, U.S.A. - 4 USDA Agricultural Research Service, Cereal
Disease Laboratory, St. Paul, MN, U.S.A. - E-mail:
davem@tc.umn.edu
In budding cells of ascomycetous yeasts, mitosis occurs in
the parent, while in basidiomyceteous yeasts it occurs in
the bud. However, in the basidiomycete Agaricostilbum
pulcherrimum mitosis occurs in the parent and parent-bud
junction. To test whether A. pulcherrimum has a novel
mitotic pattern, investigations of additional yeasts in the
Agaricostilbomycetidae (Urediniomycetes) utilized
immunofluorescence localization of freeze-substituted
material to visualize mitosis. In Bensingtonia yuccicola
mitosis occurred in the bud, as in all other basidiomycetous
yeasts studied to date, but in Stilbum vulgare it occurred in
the parent. Stilbum vulgare also exhibited predominantly
binucleate yeast cells. Nuclear rDNA sequence data
showed that A. pulcherrimum and S. vulgare are more
closely related to each other than to B. yuccicola in the
Agaricostilbomycetidae. Evolutionary implications of these
mitotic patterns will be considered.
728 - Uredo sp. nov., a first rust species on the
Penaeaceae
M. Mennicken * & F. Oberwinkler
University of Tuebingen, Botanical Institute, Systematic
Botany and Mycology, Auf der Morgenstelle 1, D-72076
Tuebingen, Germany. - E-mail:
mechthilde.mennicken@gmx.de
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Book of Abstracts
In the context of our surveying and mapping from rust
fungi within the BIOTA-project Southern Africa, we have
found a new rust fungus in the BIOTA-observatory near
Olifantsbos in the Cape Peninsula National Park. The host
is Saltera sarcocolla (L.) Bullock. Till this day there is no
other rust fungus known neither from the genus Saltera
Bullock, which is endemic in the SW Western Cape, nor
from the family Penaeaceae, which is endemic in the S and
SW Western Cape and S Eastern Cape in South Africa (1,
2). 1. Crous, P. W., Phillips, A. J. L., Baxter, A. P. 2000.
Phytopathogenic fungi from South Africa, 1-358 2.
Bredenkamp, C. L. 2000. Penaeaceae. In O. A. Leistner
(ed.), Seed plants of southern Africa: families and genera.
Strelitzia 10: 440-442.
729 - Ongoing speciation within Cryptococcus
neoformans revealed by global patterns of genetic
variation
W. Meyer 1* , S. Kidd 1 , A. Castaneda 2 , S. Jackson 1 & G.N.
Latouche 1
1 University of Sydney at Westmead Hospital, Molecular
Mycology Laboratory, ICPMR, Level 3, Room 3114A,
Westemead Hospital, Westmead, NSW 2145, Australia. -
2 Grupo de Microbiologia, Instituto Nacional de Salud,
Bogota, Colombia. - E-mail: meyer@angis.usyd.edu.au
Taxonomy within C. neoformans is an open question, with
3 varieties and 5 serotypes currently recognised. Variety
grubii (serotype A), var. neoformans (serotype D) and the
hybrid serotype AD) correspond all to the teleomorph
Filobasidiella neoformans var. neoformans, and var. gattii
(serotypes B, C) corresponds to the teleomorph F. n. var.
bacillispora. A global epidemiological study using PCRfingerprinting
with a minisatellite specific primer (M13)
and RFLP analysis of the orotidine monophosphate
pyrophosphorylase (URA5) and phospholipase (PLB1)
genes revealed ongoing speciation within C. neoformans.
All 3 typing techniques divided over 1000 clinical,
veterinary and environmental isolates from around the
world into 8 molecular types (VNI serotype A, var. grubii;
VNII serotype A, var. grubii; VNIII serotype AD hybrid;
VNIV serotype D (var. neoformans); VGI, VGII, VGIII
and VGIV serotypes B and C, var. gattii. VNIII, AD hybrid
isolates revealed two RFLP patterns one corresponding to
VNI, VNII and VNIV and the other to VNII and VNIV
suggesting different recombination events between var.
grubii and var. neoformans leading to diploid or triploid
strains, having two or three different copies of the
respective genes. The variation found in the PCRfingerprinting
profiles and RFLP patterns lies within a
range comparable to that between established species in
other fungal genera, indicating that evolution and
speciation within the cryptococcal complex is an ongoing
process.
730 - New approach to an old problem - resolving the
Peltigera canina species complex (Peltigeraceae,
lichenized Ascomycota)