Message - 7th IAL Symposium

4B-O
Lichen: from genome to ecosystem in a changing world
(4B-O3) Submission ID: IAL0211-00001
PHOTOBIONT DIVERSITY AND RICHNESS IN LECIDEOID ANTARCTIC LICHENS FROM
AN ECOLOGICAL POINT OF VIEW
Ruprecht U. 1 , Brunauer G. 1 , Printzen C. 2
1 Organismic Biology, University of Salzburg, Salzburg, Austria
2 Botanik und Molekulare Evolutionsforschung, Forschungsinstitut Senckenberg, Frankfurt, Germany
As part of a comprehensive study on lecideoid lichens in Antarctica, we also investigated the photobiont
diversity and abundance in our sample set. A phylogeny of these photobiont ITS sequences in combination with
samples from Arctic, Alpine and other temperate regions reveals the presence of five, possibly even six major
Trebouxia clades in Antarctic lecideoid lichens. Two clades are formed by members of the T. jamesii and T. impressa
aggregates but for all other clades no close match of any known Trebouxia species could be found in the
sequence databases. One genetically uniform and well supported Trebouxia clade was only found in the climatically
unique cold desert regions of the Antarctica (preliminarily named Trebouxia sp. URa1). Trebouxia sp. URa2
and URa3 are widely distributed and abundant in the investigated areas. None of the analysed mycobionts is
restricted to a particular Trebouxia species. Trebouxia sp. URa1 is preferably associated with the highly adapted
Antarctic endemic lichen L. cancriformis. Our analysis revealed differences in the species composition of locally
available photobiont pools which is clearly influenced by habitat ecology. Trebouxia sp. URa1 may represent an
endemic photobiont species since it seems to be restricted to the Antarctic cold deserts, a habitat that has no
ecological counterpart elsewhere in the world.
(4B-O4) Submission ID: IAL0097- 00001
HOW DO CHANGING ENVIRONMENTAL CONDITIONS AFFECT POLAR AND TEMPERATE
HAPLOTYPES OF CETRARIA ACULEATA?
Domaschke S. 1 , Vivas M. 2 , Sancho L. 2 , Printzen C. 1
1 Botany and Molecular Evolution, Senckenberg Research Institute, Frankfurt, Germany
2 Biología Vegetal II, Fac. de Farmacia, Universidad Complutense, Madrid, Spain
Lichens are highly specialized symbiotic organisms which are able to colonize habitats with extreme environmental
conditions. Our model organism Cetraria aculeata is common in the maritime Antarctic and throughout
the Arctic. At the same time, it grows in places where competition from vascular plants is low and it can be
found in arid grassland areas, maritime dunes or woodlands in temperate regions. This distribution makes it a
suitable object to study ecophysiological adaptation mechanisms on an intraspecific level. Previous studies have
shown that polar and temperate photobionts of Cetraria aculeata belong to two different genetical haplotype
groups (Fernández-Mendoza et al., 2011). Here we aim at assessing the ecophysiological differences between
polar and temperate populations of C. aculeata and to check whether they are correlated with different photobiont
haplotype groups within the species. We performed gas exchange measurements at different temperatures and
photon flux densities with samples collected from Antarctica, Spitsbergen, Germany and Spain. Furthermore,
we transplanted thalli from these populations to Spain and Norway. By comparing photosynthetic performance,
weight increase, chlorophyll content and the number of photobiont cells before and after transplantation we were
able to observe physiological reactions of different genetic haplotypes to changing environmental situations.
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