Comparative genome analysis of lichen-forming fungi and partner algae
S. PARK (1), H. Song (2), J. Kim (1), J. Choi (2), J. Jeon (3), Y. Lee (2), J. Hur (1) (1) Korean Lichen Research Institute, Sunchon National University, Korea; (2) Fungal Bioinformatics Laboratory and Center for Fungal Genetic Resources, Seoul National University, Korea; (3) School of Biotechnology, Yeungnam University, Korea

Lichens are symbiotic organisms, composed of a fungal partner (the mycobiont) and at least one eukaryotic algal or cyanobacterial species (the photobiont). As demonstrated by the world-wide distribution of lichens in various kinds of habitats from the tropics to the Polar regions, lichen symbiosis seems to be a highly successful adaptation to a diverse range of environmental conditions. To get insight in the genetic features linked to the symbiosis in both fungi and algae, whole-genome sequences of five lichen-forming fungal isolates and two algal isolates were determined. For the five sequenced fungal genomes, average size and the number of predicted genes were 36.05 Mb and 97,468, respectively, and two sequenced algal genomes, average size and the number of predicted genes were 55.14 Mb and 8,995, respectively. We explored genomic features including genes encoding small secreted proteins (SSPs), polyketide synthesis genes, carbohydrate active enzyme-related genes, cytochrome P450 genes, and transcription factor genes. In addition, genome and proteome conservation analysis revealed that the lichen-forming fungal genomes share the majority of genetic materials in common, when compared in a pairwise manner. To gain a better understanding of the molecular determinants of symbiosis, we performed RNA-seq and analyzed gene expression during resynthesis between fungus and alga. We reveal that a number of genes encoding SSPs are involved in symbiosis during the resynthesis. The availability of both fungal and algal genomes will provide an opportunity to decipher an understanding of the processes by which symbionts interact between both organisms. Our study will enhance our understanding of the adaptive evolution of the lichen-forming fungi with the algae to their ecological niches.

Abstract Number: P2-43
Session Type: Poster