Large genetic divergence of new, morphologically similar species of sterile lichens from Europe (Lepraria, Stereocaulaceae, Ascomycota): concordance of DNA sequence data with secondary metabolites

Abstract

Lichenized fungi of the genus Lepraria are known for their paucity of morphological characters. Species identification is therefore largely based on secondary chemistry. We investigated different chemotypes of the morphologically highly similar L. jackii species complex by internal transcribed spacer (ITS) sequencing. In phylogenetic analyses including all available Lepraria species, samples belonging to different chemotypes of the L. jackii agg. corresponded to four highly divergent clusters. While true L. jackii was genetically uniform, the other three clades represented previously unrecognized species. They originated from different major speciation events, and two of them were not closely related to any other species. Assessment of intraspecific genetic variability revealed four different patterns with respect to geographic scale. ITS sequences proved to be the most reliable and distinctive characters for species recognition in the Lepraria jackii complex and were in accordance with chemical and ecogeographic data. Frequent occurrence of long branches, relatively few resolved relationships despite high genetic variability, and the discovery and description of a considerable part of the Lepraria species within the last 10 years suggest that the genus is probably much larger than currently known. The diversification of this asexual group in the potential absence of recombination is discussed.

Molecular analyses uncover the phylogenetic placement of the lichenized hyphomycetous genusCheiromycina

“…However, some species-rich genera are exceptionally represented by only asexual species, such as Lepraria , which have also evolved strikingly diverse array of secondary metabolites (Ekman and Tønsberg 2002; Elix and Tønsberg 2004; Kukwa 2006; Nelsen and Gargas 2008; Flakus et al 2011; Lendemer 2013). Whether speciation in Lepraria has occurred in the absence of recombination is still a debated question (Fehrer et al 2008). Although parasexual processes may play a crucial role in lineages of lichen-forming fungi, it is very difficult to demonstrate and it might be speculated that they act in the successful distribution of the species and their genetic diversity.…”

Lichen Systematics: The Role of Morphological and Molecular Data to Reconstruct Phylogenetic Relationships

“…Because morphological characters used to distinguish lichens are often scarce or too variable, chemical differences are used to delimit taxa and identify otherwise similar species. Especially within sterile groups, such as Lepraria, secondary compounds have become important characters to distinguish species (Fehrer et al 2008). Before molecular data provided independent evidence, it was difficult to assess whether chemical differences reflected infraspecific variability or isolation of phylogenetic lineages (see Hawksworth 1976;Lumbsch 1998).…”

The genus Lepraria (Stereocaulaceae, lichenized Ascomycota) in Belarus

“…Since then, much attention has been paid to the taxonomy and chemistry of this group, and six species have been newly described, namely Orange and L. toensbergiana Bayerová & Kukwa (Tønsberg, 2002;Slavíková-Bayerová & Orange, 2006;Slavíková-Bayerová & Fehrer, 2007). However, the systematic position of the latter taxon has been briefly discussed (Bayerová & Haas, 2005;Baruffo et al, 2006;Fehrer et al, 2008;Tretiach et al, 2009;Saag et al, 2009), and a new combination L. jackii var. toensbergiana (Bayerová & Kukwa) Kukwa has been proposed (Śliwa & Kukwa, 2012).…”