Message - 7th IAL Symposium

3B-1-P
Lichen: from genome to ecosystem in a changing world
(3B-1-P4) Submission ID: IAL0264-00001
CHARACTERIZATION OF THE MATING-TYPE LOCI IN LOBARIA PULMONARIA
AND IMPLICATIONS FOR CONSERVATION
Singh G. 1 , Dal Grande F. 1 , Cornejo C. 1 , Werth S. 1 , Scheidegger C. 1
1 Biodiversity and Conservation Biology, WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
A large proportion of lichen-forming ascomycetes are known to reproduce sexually. One key factor governing
the sexual reproductive mode in ascomycetes is the presence or absence of mating-type (MAT) genes
represented by two alternative idiomorphs, Mat1-1 and Mat1-2 genes. However, in fungi other than ascomycetes
more than two idiomorphs may be present. The genes encoded by the MAT locus are putative transcription factors
thought to control sexual development and to regulate the expression of downstream, mating-type-specific
genes. Although there is little sequence similarity among MAT genes from different genera, the encoded DNA
binding proteins have conserved motifs, e.g., the α box in Mat1-1 and the HMG domain in Mat1-2. In spite of
the high occurrence of sexual reproduction, mating systems of lichens remain poorly understood. However, a
detailed study of sexual reproductive strategies is required for understanding evolutionary traits and population
genetics of lichen-forming fungi. The aim of the present study was to determine the organization of the MAT locus
in the putatively heterothallic species Lobaria pulmonaria L. (Hoffm.) in order to gain insights into the genetic
basis of its reproductive strategies and sexuality. Targeting conserved motifs of MAT genes with degenerate PCR
followed by inverse PCR and TAIL-PCR, we identified MAT genes and their flanking regions in L. pulmonaria. Our
study further included the development of real-time PCR to detect MAT loci in European and Asian L. pulmonaria
populations. These markers were used to infer the relation between fertility, genetic diversity and the occurrence
of MAT genes, especially in strongly fragmented and geographically isolated populations where the low numbers
of ascomata could be due to lack of mating partners.
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