Project description:We used raw RNA-Seq data from the lichen Lobaria pulmonaria to analyze changes in gene expression in response to ultraviolet-B (UV-B) treatment. The aim of the present work was to unravel the UV-B-induced defense response in the lichen Lobaria pulmonaria based on physiological traits and transcriptional profiling. Here we analyzed gene expression in mycobionts (Lobaria pulmonaria) and photobionts (Symbiochloris reticulata) after 80 min daily application of UV-B treatment of Lobaria pulmonaria thalli for two weeks. Special attention was paid to the UV-B-induced expression of the genes encoding stress tolerance proteins (heat shock proteins, antioxidants, etc.) and enzymes involved in the biosynthesis of photoprotective metabolites.
Project description:The Lobaria pulmonaria holobiont consists of algal, fungal, cyanobacterial, and integrated diverse bacterial components and thrives in undisturbed, humid forests. We set out to investigate the role of the microbiome of L. pulmonaria in the adaptation of this ecologically sensitive lichen species to diverse climatic conditions. Our central hypothesis posited that microbiome composition and functionality aligns with continental-scale climatic parameters related to temperature and precipitation. In addition, we tested whether short-term weather dynamics, sampling season, and the genotypes of the fungal and algal partners influenced the variation in the lichen microbiome. Insights into compositional and functional changes within the microbiome were obtained using metaproteomics. Comparative examinations between Sub-Atlantic Lowland (SAL) and Alpine (ALP) regions unveiled the distinct impact of climate on microbiome functions.
Project description:UNLABELLED: PREMISE OF THE STUDY:Microsatellite loci were developed for the threatened haploid lichen fungus Lobaria pulmonaria to increase the resolution to identify clonal individuals, and to study its population subdivision. • METHODS AND RESULTS:We developed 14 microsatellite markers from 454 DNA sequencing data of L. pulmonaria and tested for cross-amplification with L. immixta and L. macaronesica. The number of alleles per locus ranged from two to 23. Nei's unbiased gene diversity, averaged over loci, ranged from 0.434 to 0.517 in the three studied populations. • CONCLUSIONS:The new markers will increase the genetic resolution in studies that aim at disentangling clones in L. pulmonaria and may be useful for closely related species within Lobaria sect. Lobaria.
Project description:Rhizobiales (Alphaproteobacteria) are well-known beneficial partners in plant-microbe interactions. Less is known about the occurrence and function of Rhizobiales in the lichen symbiosis, although it has previously been shown that Alphaproteobacteria are the dominating group in growing lichen thalli. We have analyzed the taxonomic structure and assigned functions to Rhizobiales within a metagenomic dataset of the lung lichen Lobaria pulmonaria L. One third (32.2%) of the overall bacteria belong to the Rhizobiales, in particular to the families Methylobacteriaceae, Bradyrhizobiaceae, and Rhizobiaceae. About 20% of our metagenomic assignments could not be placed in any of the Rhizobiales lineages, which indicates a yet undescribed bacterial diversity. SEED-based functional analysis focused on Rhizobiales and revealed functions supporting the symbiosis, including auxin and vitamin production, nitrogen fixation and stress protection. We also have used a specifically developed probe to localize Rhizobiales by confocal laser scanning microscopy after fluorescence in situ hybridization (FISH-CLSM). Bacteria preferentially colonized fungal surfaces, but there is clear evidence that members of the Rhizobiales are able to intrude at varying depths into the interhyphal gelatinous matrix of the upper lichen cortical layer and that at least occasionally some bacteria also are capable to colonize the interior of the fungal hyphae. Interestingly, the gradual development of an endosymbiotic bacterial life was found for lichen- as well as for fungal- and plant-associated bacteria. The new tools to study Rhizobiales, FISH microscopy and comparative metagenomics, suggest a similar beneficial role for lichens than for plants and will help to better understand the Rhizobiales-host interaction and their biotechnological potential.