09.01.2013 Views

Message - 7th IAL Symposium

Message - 7th IAL Symposium

Message - 7th IAL Symposium

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

The 7 th International Association for Lichenology <strong>Symposium</strong> 2012<br />

(3B-2-P11) Submission ID: <strong>IAL</strong>0189-00001<br />

GEOGRAPHICAL ASPECTS OF SYMBIONT DIVERSITY IN THE GENUS NEPHROMA<br />

Fedrowitz K. 1 , Kaasalainen U. 2 , Rikkinen J. 2<br />

1 Department of Ecology, Swedish University of Agricultural Sciences (SLU) Uppsala, Sweden<br />

2 Department of Biosciences, University of Helsinki, Helsinki, Finland<br />

Patterns of symbiont diversity in cyanolichens are important for the deeper understanding of ecological<br />

processes affecting these species, such as dispersal, establishment, and symbiont selectivity. We studied<br />

the diversity of Nephroma (Peltigerales, Ascomycota) mycobionts within a global, phylogenetic framework and<br />

investigated the genetic diversity of their associated Nostoc photobionts. Fungal genotypes were based on the<br />

Internal Transcribed Spacer region (ITS) of ribosomal DNA (rDNA), while cyanobacterial diversity was based on<br />

nucleotide differences in the tRNALeu (UAA) intron. The full data set included over 250 mycobiont and over 350<br />

photobiont sequences, of which over 140 were obtained from the same lichen specimen, respectively. Our sampling<br />

was focused on the northern hemisphere, but we also included some material from South America and New<br />

Zealand. The study illustrates the phylogenetic structure for the genus Nephroma in the northern hemisphere<br />

and shows that several clades are variable and likely consist of several species. Our results provide evidence<br />

that several lichen-forming fungi of the genus Nephroma associate with sequence identical Nostoc haplotypes<br />

over a global scale (Europe – Asia, or Europe – North America). All bipartite species share Nostoc genotypes<br />

with one or more species, while tripartite species are not monophyletic within Nephroma but use entirely different<br />

photobiotic strains. Geographic mosaic patterns in symbiont selectivity were identified for two species, showing<br />

relatively higher selectivity locally compared to globally. Such patterns indicate habitat preferences of particular<br />

symbiont combinations but also a possible founder effect. We conclude that species of the genus Nephroma are<br />

selective in their association with symbiotic partners. Particular symbiont associations are linked to geographical<br />

areas, and several lichen-forming fungi of this genus share sequence identical photobionts over a global scale.<br />

More studies on photobiont sharing in lichen communities are needed to further identify how and where lichen<br />

species acquire their symbiotic partners.<br />

175<br />

3B-2-P

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!