Lichenized Fungi and the Evolution of Symbiotic Organization

Abstract

Lichen symbioses comprise a fascinating relationship between algae and fungi. The lichen symbiotic lifestyle evolved early in the evolution of ascomycetes and is also known from a few basidiomycetes. The ascomycete lineages have diversified in the lichenized stage to give rise to a tremendous variety of morphologies. Their thalli are often internally complex and stratified for optimized integration of algal and fungal metabolisms. Thalli are frequently colonized by specific nonlichenized fungi and occasionally also by other lichens. Microscopy has revealed various ways these fungi interact with their hosts. Besides the morphologically recognizable diversity of the lichen mycobionts and lichenicolous (lichen-inhabiting) fungi, many other microorganisms including other fungi and bacterial communities are now detected in lichens by culture-dependent and culture-independent approaches. The application of multi-omics approaches, refined microscopic techniques, and physiological studies has added to our knowledge of lichens, not only about the taxa involved in the lichen interactions, but also about their functions.

Biodiversity Patterns and Ecological Preferences of the Photobionts Associated With the Lichen-Forming Genus Parmelia

“…In general, mycobionts which show a high specificity for algal partners tend to accept only single algal lineages (Piercey-Normore and DePriest, 2001;O'Brien et al, 2013;Leavitt et al, 2015;Magain et al, 2017;Kosecka et al, 2020;Mark et al, 2020;Pino-Bodas and Stenroos, 2020;Garrido-Benavent et al, 2021), while mycobionts which are generalist can associate with many different algal lineages (Wirtz et al, 2003;Muggia et al, 2013;Sadowska-Deś et al, 2014); this has also been reported for photobionts and their preference toward fungal partners (Peksa and Škaloud, 2011). Specific or generalist associations among lichen symbionts are not random, but rather are modulated by ecological, environmental and evolutionary factors (Beck et al, 2002;Miadlikowska et al, 2006;Leavitt et al, 2015;Grube and Wedin, 2016;Chagnon et al, 2019), which have significant impacts on the structure of lichen communities and species distribution (Muggia et al, 2014;Sork and Werth, 2014;Steinová et al, 2019). Many analyses have pointed out that climatic conditions are the most important factor shaping phycobiont distribution patterns (Kroken and Taylor, 2000;Helms et al, 2003;Fernández-Mendoza et al, 2011;Peksa and Škaloud, 2011;Řídká et al, 2014); however, the influence of factors such as phylogenetic and evolutionary specialization, reproductive strategy, the presence of compatible phycobionts as well as ecological factors should not be overlooked (Yahr et al, 2006;Muggia et al, 2013;Printzen et al, 2013;Singh et al, 2017;Ertz et al, 2018;Pardo-De la Hoz et al, 2018;…”

Biosynthetic Gene Content of the ‘Perfume Lichens’ Evernia prunastri and Pseudevernia furfuracea

“…They impact various community processes, also because of their rich and diverse secondary chemistry [3,4]. Recent studies have shown that lichens represent complex multi-species symbiotic assemblages, forming microhabitats and harbouring a high diversity of other eukaryotic and prokaryotic microorganisms [5,6,7]. High-throughput sequencing technologies have revealed the presence of multiple fungal and algal species, along with hyper-diverse bacterial communities, within individual lichen thalli [7,8,9,10,11,12,13].…”

Do Aerial Nitrogen Depositions Affect Fungal and Bacterial Communities of Oak Leaves?

“…Taxa with a lichen-forming mycobiont strategy characterized the majority of symbiotrophic. Fungi associated with lichen symbiosis are usually combined with green algal species and a smaller number of Cyanobacteria (Grube and Wedin, 2016). A possible explanation of the increase of lichen-associated fungi could be related to a direct increase of algae cells on the leaf surface due to the increased N availability.…”