A particularly interesting group of fungi, for which we still
have too little genetic information, is that represented by
lichenicolous taxa. Lichenicolous fungi are species with inconspicuous
and often melanized mycelia that inhabit lichen
thalli and develop diverse degrees of specificity and parasitic
behaviour towards their hosts (Lawrey & Diederich 2003).
They are usually recognized by phenotypic symptoms and
their sexual or asexual spore-producing structures on the lichen
hosts. Lichenicolous fungi have been classified according
to morpho-anatomical characters, but molecular data are still
lacking for the majority of the described species, estimated at
over 1800 worldwide (Lawrey & Diederich 2015). It is likely that
the very narrow host ranges of certain species and their strict
dependence on their host are responsible for the failure of
many lichenicolous fungi to grow in axenic cultures. Attempts
to isolate lichenicolous fungi are usually performed by inoculating
spores or tiny fragments of the fruiting bodies (apothecia,
perithecia or conidiomata) on media. However, the
production of reproductive structures in culture has only
been observed for the two successfully isolated genera Lichenoconium
(Lawrey et al. 2011) and Phoma (Lawrey et al. 2012).