Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme II: SYSTEMATICS, PHYLOGENY AND EVOLUTION Posters
texture and color of mycelial mats and in fruitage ability.
Some of the Lentinellus hyphal structures like clamps,
gloeocystidiaes, chlamydospores, conidias, hyphal
swellings, rings and incrustations were species-specific.
Strains of all studied species could produce laccase,
whereas tyrosinase was determined only for L. micheneri,
L. ursinus and L. castoreus.
755 - Group I intron evolution as mobile and nonmobile
elements within the lichen-forming fungal
family Acarosporaceae
V. Reeb 1* , P. Haugen 2 , D. Bhattacharya 2 & F. Lutzoni 1
1 Duke University - Biology, Box 90338, Durham NC
27705, U.S.A. - 2 University of Iowa - Biological Sciences,
Iowa City IOWA 52242, U.S.A. - E-mail: vreeb@duke.edu
Autocatalytic group I introns in the nucleus are found only
in ribosomal DNA genes. These genetic elements are most
commonly inherited vertically although their widespread
and often sporadic distribution suggests their ability to
integrate in novel rDNA sites. Two models exist for group
I intron spread: 1) intron homing facilitated by an
endonuclease encoded in the intron, and 2) reversesplicing.
It seems that many organellar group I introns rely
primarily on homing for spread, whereas virtually none of
the rDNA introns contain endonucleases. To date only
eight endonucleases have been reported in algae, nonlichenized
ascomycetes, and amoeboflagellates. In this
paper, we study the evolution of group I introns within the
lichenized ascomycete family Acarosporaceae. Group I
introns are well known in the ascomycetes and are
particularly abundant in the Acarosporaceae (128 in 2.5 Kb
of rDNA in 35 taxa). The family Acarosporaceae appears
to be one of the most basal divergences within the
lichenized ascomycetes, therefore, the study of its introns is
of particular interest to better understand the evolution of
lichen introns. We provide evidence for both relatively
ancient and recently acquired group I intron lineages within
the Acarosporaceae. Furthermore, we report for the first
time in lichenized ascomycetes, the presence of a homing
endonuclease in members of the Acarosporaceae. These
endonucleases may facilitate the lateral transfer of some
ascomycete group I introns.
756 - The rust genus Hemileia - Monograph and
collection of the characteristics in a DeltaAccess
database
A. Ritschel * , R. Berndt & F. Oberwinkler
Chair of Special Botany/Mycology, University of Tübingen,
Auf der Morgenstelle 1, D-72076 Tübingen, Germany. - Email:
anja.ritschel@uni-tuebingen.de
The genus Hemileia is phytoparasitic mainly on hosts
belonging to the families Rubiaceae, Apocynaceae and
Asclepiadaceae. The species are distributed tropically to
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Book of Abstracts
subtropically, probably originally in Africa and Asia. By
the cultivation of coffee, however, members of the genus
occur nowadays pantropically. Regarding the life cycle, so
far only those for uredinia and telia are known. Hitherto, 53
species of Hemileia have been described. Some of these
species were described upon the uredinial stage and require
nomenclatural revision. The type species Hemileia
vastatrix represents one of the most important pathogens
world-wide in the cultivation of coffee and thus has great
economical importance. Although there have been
numerous studies on the morphology and the parasitism of
several Hemileia species, no monograph of the genus exists
up to now. Therefore, an investigation of all Hemileia
species is carried out by means of light and electron
microscopy. The work is based on extensive herbarium
material. The morphological data gathered are entered into
a database. This database was developed within the
framework of the GLOPP-project and is designed to
register rust fungus biodiversity, morphological features
and to allow the identification of the pathogens. Our final
aim is to make this database available on the internet.
757 - Molecular identification of Taphrina species
parasitic on Prunus
M.G. Rodrigues * & A. Fonseca
CREM, SABT, Universidade Nova de Lisboa, Quinta da
Torre, 2829-516 Caparica, Portugal. - E-mail:
manuel.jg.rodrigues@clix.pt
The dimorphic ascomycete genus Taphrina comprises ca.
100 species recognised by their filamentous parasitic stage
on several vascular plants. Infection symptoms may
develop on leaves, fruits, shoots and flowers. Most species
parasitise a single host and/or cause a specific infection
symptom. The best known species is Taphrina deformans,
causal agent of peach leaf curl, a disease with a pronounced
impact on peach growing areas worldwide. Other
economically important species of the genus Prunus are
also potential Taphrina hosts, such as almond, cherry and
plum trees. The present work focuses on the
characterisation of Taphrina spp. on Prunus using
molecular techniques: PCR-fingerprinting (MSP-PCR),
sequencing of rDNA (ITS and D1/D2 regions) and DNA-
DNA hybridizations. MSP-PCR proved to be a quick and
reproducible method for species differentiation, allowing
the selection of strains for sequencing. The D1/D2 region
was too conserved to differentiate the Taphrina studied.
The ITS regions were more useful for this purpose, and
phylogenetic clustering of Taphrina spp. correlated with
the host, geographic origin and/or the type of infection
symptom. Intraspecific variability in the ITS regions was
evaluated by comparison with the results of MSP-PCR and
hybridization experiments. The conventional identification
of the Taphrina species studied was re-evaluated in the
light of the results of the molecular techniques employed.