title: Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics.
abstract: Symbioses represent a frequent and successful lifestyle on earth and lichens are one of their classic examples. Recently, bacterial communities were identified as stable, specific and structurally integrated partners of the lichen symbiosis, but their role has remained largely elusive in comparison to the well-known functions of the fungal and algal partners. We have explored the metabolic potentials of the microbiome using the lung lichen Lobaria pulmonaria as the model. Metagenomic and proteomic data were comparatively assessed and visualized by Voronoi treemaps. The study was complemented with molecular, microscopic and physiological assays. We have found that more than 800 bacterial species have the ability to contribute multiple aspects to the symbiotic system, including essential functions such as (i) nutrient supply, especially nitrogen, phosphorous and sulfur, (ii) resistance against biotic stress factors (that is, pathogen defense), (iii) resistance against abiotic factors, (iv) support of photosynthesis by provision of vitamin B12, (v) fungal and algal growth support by provision of hormones, (vi) detoxification of metabolites, and (vii) degradation of older parts of the lichen thallus. Our findings showed the potential of lichen-associated bacteria to interact with the fungal as well as algal partner to support health, growth and fitness of their hosts. We developed a model of the symbiosis depicting the functional multi-player network of the participants, and argue that the strategy of functional diversification in lichens supports the longevity and persistence of lichens under extreme and changing ecological conditions.
authors: Institute of Plant Sciences, Karl-Franzens-University, Graz, Austria.
authors: Martin
authors: M
authors: Grube
authors: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
authors: Tomislav
authors: T
authors: Cernava
authors: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
authors: Jung
authors: J
authors: Soh
authors: Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
authors: Stephan
authors: S
authors: Fuchs
authors: 1] Institute of Plant Sciences, Karl-Franzens-University, Graz, Austria [2] Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
authors: Ines
authors: I
authors: Aschenbrenner
authors: Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
authors: Christian
authors: C
authors: Lassek
authors: Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
authors: Uwe
authors: U
authors: Wegner
authors: Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
authors: Dörte
authors: D
authors: Becher
authors: Institute of Microbiology, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
authors: Katharina
authors: K
authors: Riedel
authors: Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
authors: Christoph W
authors: CW
authors: Sensen
authors: Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria.
authors: Gabriele
authors: G
authors: Berg
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000502:physiology*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D000460:Chlorophyta / Q000235:genetics; D008011:Lichens / Q000382:microbiology*; D054892:Metagenome; D056186:Metagenomics; D064307:Microbiota; D010788:Photosynthesis; D020543:Proteome; D040901:Proteomics; D013559:Symbiosis / Q000235:genetics
chemical_list: D020543:Proteome