
PhD student in Ecology and Sustainable Management of Environmental Resources
Cicle: XXXVI
Supervisor: Prof. Laura Selbmann
Thesis title: The Antarctic lichens as evolutionary niches for microbial diversification
Email: stoppiello@unitus.it
Keywords: Antarctica, Lichens, Microbiome, NGS.
Microbiological analysis of environmental samples using both cultural and molecular approaches; management and analysis of big data derived from Next-Generation Sequencing. Proficiency in the analysis of Microbial Ecology, Biostatistics, and Bioinformatics, including expertise in Linux programming language and tools within the R environment. Molecular phylogenetics, utilizing bioinformatic tools such as MAFFT and CIPRES.
Cryptoendolithic microbial communities dominate ice-free rock surfaces in Antarctica. Here, also lichens develop their thalli in very inconspicuous forms hampering a straightforward species recognition but representing an important group of organisms with high percentage of endemism. The traditional dual nature of lichens, i.e. symbiotic associations between biotrophic fungi (mycobiont) and phototrophic microorganisms (photobiont), has been recently challenged. Lichen thalli are open structures housing other non-cyanobacterial prokaryotes, algae and additional microfungi. Phylogenetics, metabarcoding and ‘omics’ analyses, culture experiments and microscopy studies have uncovered in particular the diversity of the lichen-associated fungal and bacterial communities, i.e. the lichen myco- and microbiomes, respectively, under different ecological settings. However, only two researches hint at Antarctic lichens as pivotal niches for the diversification of microfungi in extreme environments. This project aims at capturing the diversity of fungi and bacteria residing within lichen thalli of selected species the endemic Antarctic Acarospora flavocordia, Buellia frigida, Lecanora fuscobrunnea, Lecanora physciella, Lecidea cancriformis, and the cosmopolitan Pleopsidium chlorophanum, Rhizoplaca melanophthalma, Rusavskia elegans. To detect i) the taxa which are characterizing the Antarctic lichen symbioses, ii) the taxa which are peculiar of extreme environmental conditions, developing both endolichenic and endolithic lifestyles, iii) the taxa which are specifically associated with lichen species and can be confirmed complementing symbionts worldwide in same lichen systems. The targeted metabarcoding and culture analyses here proposed will consider both a very ecologically specific (endemic Antarctic species) and an ecologically extended (cosmopolitan species) sampling of lichens, and data obtained from strictly endolithic microbial communities. The results will strengthen the perception that lichen symbioses are characterized by multiple, peculiar and ecologically shaped myco- and microbiomes and are niches where microbial diversification and evolution take place in extreme environments.