Message - 7th IAL Symposium

Lichen: from genome to ecosystem in a changing world
2I-P
2I: Adaptation and morphological evolution
(2I-P1) Submission ID: IAL0057-00008
EVOLUTION OF VAGRANCY IN THE “MANNA LICHENS”
Sohrabi M. 1
1 Botanical Museum, Department of Mycology, University of Helsinki, Helsinki, Finland
The vagrant growth form of lichenized fungi has evolved in several distantly related fungal lineages,
including Lecanoraceae (Rhizoplaca), Megasporaceae (Circinaria), Parmeliaceae (Cetraria, Masonhalea and
Xanthoparmelia) and Verrucariaceae (Dermatocarpon). This research is focused on the evolution of vagrancy
among the ‘manna lichens’ as the most famous exemplar of the vagrant growth form. ‘Manna lichens’ comprise
c. 17 accepted species previously treated under the genus Aspicilia but recently the group was entirely moved to
the newly resurrected genus Circinaria. Therefore, no vagrant member was left in the genus Aspicilia (Megasporaceae)
in its traditional sense. With current circumscription, the genus Circinaria is found to be heteromorphic,
with numerous strictly saxicolous, and some true vagrant or semivagrant species. Within the ‘manna lichens’
some species are obligatorily unattached (truly vagrant), growing and reproducing without proper attachment to
a substrate. Some other species are “erratic”, i.e., facultatively unattached (vagrant-crustose or semivagrant);
these taxa often persist in two different growth forms, initially attached to soil or rocks and later developing a
vagrant growth form. In this study, a comprehensive sampling of the genus Circinaria was made (c. 100 specimens),
including both truly crustose and truly vagrant or semivagrant taxa. The nuITS, nuLSU and mtSSU rDNA
were used as molecular markers. The datasets were analysed using parsimony and Bayesian methods. Some
conclusions could be made about the relationships between truly crustose and vagrant taxa in the genus Circinaria.
The occurrence of the vagrant growth form in several apparently unrelated lineages in the genus Circinaria
shows interesting patterns of convergent evolution and ecological adaptation. Despite these insights, the reasons
behind the high plasticity in external morphology of vagrant species still remain largely unknown.
(2I-P2) Submission ID: IAL0140-00002
ARE LONG-LIVING LICHEN THALLI AN ARENA FOR PHOTOBIONT VARIATION?
Muggia L. 1 , Vancourova L. 2 , škaloud P. 2 , Peksa O. 2 , Wedin M. 3 , Grube M. 1
1 Institute of Plant Science, University of Graz, Graz, Austria
2 Department of Botany, Charles University in Prague, Faculty of Science, Prague, Czech Republic
3 Cryptogamic Botany, Swedish Museum of Natural History, Stockholm, Sweden
Previous studies of symbiont selectivity in lichens often relied on the uniformity of the algal partner in
individual thalli. Fingerprinting analyses of whole thallus DNA extractions, however, reveal presence of multiple
Trebouxia strains within individuals of different species. A mixture of algal genotypes may be an adaptive advantage,
because their different physiological performances can mediate tolerance to varying environmental
conditions. We studied intrathalline variation of Trebouxia photobionts the cosmopolitan crustose lichen Protoparmeliopsis
muralis, which has a broad ecological tolerance. We hypothesize that the lichen thallus could be
an arena for combinations of the mycobiont with several algal strains, in order to promote longevity, robustness
and fertility of this lichenized fungal species. We compared the photobiont diversity of marginal lobes and regenerative
central outgrowths in two ecologically different localities. The single strand conformation polymorphism
analysis (SSCP) and the haplotype analyses reveal the presence of different Trebouxia strains in the thalli. The
majority of them were identified as T. incrustata and as “uncultured” Trebouxia strains, which is present as two
different taxa in Czech Republic and Austria.
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