Message - 7th IAL Symposium

Lichen: from genome to ecosystem in a changing world
1I-O
(1I-O3) Submission ID: IAL0276-00001
MICROBIAL COMMUNITY IN ANTARCTIC LICHENS
Park C.H. 1 , Kim K. 2 , Chun J. 3 , Jeong G. 3 , Hong S. 1
1 Division of Polar Life Science, Korea Polar Research Institute, Incheon, Korea
2 Korean Bioinformation Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
3 School of Biological Science, Seoul National University, Seoul,Korea
Lichens are symbiotic association of fungal (mycobiont) and photosynthetic algal or cyanobacterial
(photobiont) partners. Contribution of the two major partners has been well known, but composition and role
of other components of lichen ecosystems has not been evaluated carefully. Recently, microbial community in
the lichen thalli has been revealed by cultivation of microorganisms, FISH imaging, and sequence analyses. It
was also suggested that bacteria, archaea and microfungi associated with lichens (microbiont) have important
roles in lichen ecosystem by biodiversity and meta-proteome analyses. In the current study, microbial community
composition in Cladonia, Umbilicaria, Usnea, and 3 crustose lichens from King George Island, Antarctica
was analyzed by pyrosequencing of bacterial 16S rDNA, eukaryotic LSU rDNA, and algal ITS region of nuc
rDNA. Proteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes in bacterial community and Dothideomycetes,
Eurotiomycetes and Lecanoromycetes in lichen-associated fungal community were the major phyla
in the Antactic lichen ecosystems. Microbial phylotype composition from the same or related lichen species
were more closely related than those of different lichen species. Sequencing results of LSU and ITS regions of
nuclear rDNA and plastid 16S rDNA of algal species indicated that each lichen thalli contain diverse photobionts.
In most cases a major photobiont constituted higher than 97% of total photobiont community, but in some cases,
the second major photobiont comprised upto 20% of total photobiont community. These results imply that lichen
thalli is a complex ecosystem composed of lichenized fungi, diverse photobionts and microbionts such as bacteria
and microfungi. It also suggests that studies for all partners of lichens are required to understand ecology
and physiology of lichens.
(1I-O4) Submission ID: IAL0124-00001
THE MICROBIOME OF LICHENS: STRUCTURAL AND BIOGEOGRAPHIC DIVERSITY
Berg G. 1 , Cardinale M. 1 , Grube M. 2
1 Institute of Environmental Biotechnology, University of Technology, Graz, Austria
2 Institute of Plant Sciences, Karl-Franzens University, Graz, Austria
Lichens are traditionally considered as mutualisms between fungi and photoautotrophic species. New
molecular and microscopic techniques revealed progress in the understanding of the lichen-associated microbiome.
Our research during the last years revealed lichens as mini-ecosystems, which harbour highly abundant
and diverse bacterial communities [1]. The analyses of samples from three lichen species (Cladonia arbuscula,
Lecanora polytropa and Umbilicaria cylindrica) from alpine environments by a polyphasic approach showed
biofilm-like structures and a high degree of species specificity [2]. Lichen-associated microbial communities consist
of diverse taxonomic groups. The majority of bacteria in growing parts belong to Alphaproteobacteria [3] but
there are also diverse new phylogenetic lineages as well as new species [4]. As an important driver of bacterial
community the age of the thallus parts was identified: the younger growing parts of the lichens hosted bacterial
communities that significantly differ from those of the older/senescing portions at the basis of the thalli. The
substrate type and, to a lower extent, the exposition to the sun also affected the bacterial community structures
significantly [3]. Moreover, the structure of the bacterial community was influenced by biogeographic aspects.
The variation of the always dominant Alpaproteobacteria correlated with geography, whereas this effect could
not be observed for Burkholderia or functional genes for nitrogen fixation (nif).
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