Phylogenetic classification of peltigeralean fungi (Peltigerales, Ascomycota) based on ribosomal RNA small and large subunits

Abstract

To provide a comprehensive molecular phylogeny for peltigeralean fungi and to establish a classification based on monophyly, phylogenetic analyses were carried out on sequences from the nuclear ribosomal large (LSU) and small (SSU) subunits obtained from 113 individuals that represent virtually all main lineages of ascomycetes. Analyses were also conducted on a subset of 77 individuals in which the ingroup consisted of 59 individuals representing six families, 12 genera, and 54 species potentially part of the Peltigerineae/Peltigerales. Our study revealed that all six families together formed a strongly supported monophyletic group within the Lecanoromycetidae. We propose here a new classification for these lichens consisting of the order Peltigerales and two suborders-Collematineae subordo nov. (Collemataceae, Placynthiaceae, and Pannariaceae) and Peltigerineae (Lobariaceae, Nephromataceae, and Peltigeraceae). To accommodate these new monophyletic groups, we redefined the Lecanorineae, Pertusariales, and Lecanorales sensu Eriksson et al. (Outline of Ascomycota-2003, Myconet 9: 1-103, 2003). Our study confirms the monophyly of the Collemataceae, Lobariaceae, Nephromataceae, and Peltigeraceae, and the genera Nephroma, Sticta, and Peltigera. However, Leptogium, Lobaria, Pseudocyphellaria, and Solorina were found to be nonmonophyletic genera. Reconstruction of ancestral symbiotic states within the Peltigerales, using maximum likelihood (ML) and a Bayesian approach to account for phylogenetic uncertainty, revealed an evolutionary scenario in which bimembered associations with cyanobacteria were ancestral, followed by multiple independent acquisitions of green algae to form tripartite symbioses and rare subsequent losses of the cyanobiont to form bimembered symbioses with green algae.

Cardinal characters on a slippery slope – A re-evaluation of phylogeny, character evolution, and evolutionary rates in the jelly lichens (Collemataceae s. str)

“…In a traditional circumscription the members of the Collemataceae were also characterized by a similar ascoma development, a disc-shaped proper wall (exciple), and asci with an internal amyloid tube structure (Henssen, 1965;Henssen, 1981 Degelius, 1954). This was also supported by several early studies of Peltigerales phylogeny, where the included Collema and Leptogium representatives did not form monophyletic groups (Wiklund and Wedin, 2003;Miadlikowska and Lutzoni, 2004;Wedin and Wiklund, 2004; Miadlikowska et al, 2006). Two recent studies focussing more specifically on Collemataceae in the old, wide sense confirmed this reciprocal non-monophyly (Wedin et al, 2009; Otálora 6 et al, 2010), which was also supported by later studies on Peltigerales (Muggia et al, 2011;Spribille and Muggia, 2012).…”

Analysis of the Peltigera membranacea metagenome indicates that lichen-associated bacteria are involved in phosphate solubilization

“…P. membranacea is a cyanolichen, with Nostoc cyanobacteria as photobiont (Miadlikowska & Lutzoni, 2004). A metagenomic library was constructed from a collection of lichen thalli and the bacterial microbiota were analysed in terms of phylogenetic diversity and functional gene composition.…”

Lichen-symbiotic cyanobacteria associated withPeltigerahave an alternative vanadium-dependent nitrogen fixation system

“…The most common type of cyanobacterial lichen photobiont is Nostoc (Nostocaceae) (Antoine, 2004;Nash, 2008a), which is the symbiont associated with members of the lichen-forming fungal genus Peltigera (Tschermak-Woess, 1988;Miadlikowska & Lutzoni, 2004;O'Brien et al, 2005;Hodkinson et al, 2012a), the group that is the focus of our research (Fig. 1).…”