Message - 7th IAL Symposium

Lichen: from genome to ecosystem in a changing world
1I-P
(1I-P3) Submission ID: IAL0124-00002
LINKING FUNCTION WITH BIOTECHNOLOGY: THE POTENTIAL OF LICHEN-ASSOCIATED
BACTERIA TO CONTROL PHYTOPATHOGENS
Berg G. 1 , Zachow C. 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 mini-ecosystems, which harbour highly abundant and diverse bacterial communities [1].
These communities are not only an important structural component of the lichen thallus; also important functions
were identified [2]. One of these is pathogen defense [2]. Due to their long life, lichens have to defend themselves
against a long list of ubiquitous or specifically adapted parasites. Our idea was to use this potential and to
analyze the antagonistic activity of lichen-associated bacteria against Alternaria alternata, Botrytis cinerea, Phytophthora
infestans and Sclerotinia sclerotiorum. The bacteria were isolated from different lichen species (Cladonia
arbuscula, Lecanora polytropa, Lobaria immixta, L. pulmonaria, L. virens, Peltigera canina, Pseudocyphellaria
aurata and Umbilicaria cylindrica) from alpine environments. An impressive spectrum of antagonistic strains
was selected [3]. The highest antagonistic potential was found against the ascomycetous air-borne pathogen B.
cinerea (34.4%). The lichen with the highest overall antagonistic capacity was Pseudocyphellaria aurata; up to
100% of the screened bacterial isolates showed antifungal activity towards P. infestans. In a novel, promising
approach, the bacterial strains were not directly isolated; they were caught from the bacterial community via bait
plants. Using this approach it is possible to enrich plant-competent bacteria and enhance the number of bioactive
isolates.
[1] Grube & Berg (2009) Fungal Biology Reviews 23:72–85
[2] Grube et al. (2009) The ISME J., 3:1105-1115
[3] Berg et al. (2011) IOBC/wprs BULLETIN, in press.
(1I-P4) Submission ID: IAL0140-00004
FLUORESCENCE IN SITU HYBRIDIZATION AND CONFOCAL LASER SCANNING
MICROSCOPY APPROACH TO ANALYSE ALPINE SOIL CRUST LICHENS
Muggia L. 1 , Klug B. 1 , Berg G. 2 , Grube M. 1
1 Institute of Plant Sciences, University of Graz, Graz, Austria
2 Institute of Environmental Biotechnology, Technical University of Graz, Graz, Austria
Biological soil crusts (BSC) are microbially dominated communities inhabiting the uppermost strata of
the soil. Lichens, as distinct and colourful soil crust components of high elevations and subpolar regions, create
niches for other microorganisms. In this contribution we present analyses of the structure of lichen soil crusts by
using microscopic techniques (DNA-FISH and CLSM) and 3D image reconstruction. Lichen thalli were sampled
above the tree-line in open habitats of the Alps, both on siliceous and calcareous substrates. We selected
six squamulose and crustose lichen species for our study: Arthrorhaphis citrinella, Baeomyces placophyllus,
Diploschistes muscorum, Icmadophila ericetorum, Psora decipiens and Trapeliopsis granulosa. We studied the
presence and the distribution of main bacterial groups in lichen thalli and attached soil particles in the hypothallosphere.
Results show that lichen species correlate with patterns of colonisation, suggesting that thalli of lichen
species determine the microbial structure and that lichen soil crust communities are highly complex microbial
metacommunities. Biological soil crusts substantially reduce erosion potential in sensitive habitats and thereby
also contribute to higher quality of water supply.
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