From metagenome and proteome to biocontrol: analysis of moss- and lichen-associated microbial communities

Bryophytes and lichens represent interesting bioresources; their tight interaction with microorganisms is only partly understood. Recently it was shown that both groups of crypotgams are colonized at high abundance with special microbial communities, which functionally contribute to the the vitality of moss plantlets and lichen symbioses. To characterize biodiversity of associated microbial communities, we applied combination of methods; phylogenetic diversity, spatial organization and specificity were described by establishment of the clone libraries, fluorescence in situ hybridization (FISH) and SSCP fingerprinting. Furthermore, metagenomic and proteomic data sets were explored. In addition, isolates were investigated regarding their interaction with plants. According to our results, cryptogam-associated microbial communities comprise a unique pool of highly diverse, mostly uncultivable and host-specific microorganisms. Structure of the communities strongly depends on abiotic and biotic factors. Associated bacteria have a function for nutrient supply and pathogen defense. Knowledge about diversity and function was used to isolate bacteria for biotechnological applications. A high proportion of isolates showed antifungal activities and a remarkable plant growth promotion by nitrogen fixation, phosphate solubilisation and production of phytohormons as well as an extraordinary high biocontrol potential.