Lichinodium is a new lichenized lineage in the Leotiomycetes

Maria Prieto,Ibai Olariaga,Mats Wedin,Matthias Schultz

doi:10.1007/s13225-018-0417-5

Maria Prieto, Ibai Olariaga + Show 2 more

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https://doi.org/10.1007/s13225-018-0417-5

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Abstract

Here, we show that Lichinodium (Lichinaceae, Lichinomycetes, Ascomycota) constitutes a formerly unrecognized lineage within the Leotiomycetes, thus being the first lichenized lineage recognized in the superclass Sordariomyceta (Leotiomycetes, Laboulbeniomycetes and Sordariomycetes). To infer the position of Lichinodium, we constructed two multilocus phylogenies based on six and five gene regions (nuLSU rDNA, nuSSU rDNA, mtSSU rDNA, RPB1, RPB2 and MCM7) including main Pezizomycotina groups in the first analysis and focusing secondly on a comprehensive selection of Sordariomyceta. The results show that Lichinodium is sister to Leotiaceae. We discuss the morphological and ecological similarities between Lichinodium and other Leotiomycetes, and describe the new order Lichinodiales and family Lichinodiaceae. The sister relationship between Sordariomycetes and Laboulbeniomycetes is here supported as it is the relationship between this clade and the Leotiomycetes. The results also support the polyphyly of Helotiales, the recognition of the Leotiales in a strict sense or the inclusion of the Triblidiales in Leotiomycetes. The photobionts of Lichinodium were sequenced for two genetic markers (rbcLX and 16S rDNA) and identified as Rhizonema, a recently described genus of filamentous cyanobacteria belonging to Nostocaceae. TEM studies revealed that the mycobiont-cyanobiont interface in Lichinodium does not produce haustoria, thus differing from a typical Lichinomycete (e.g. Ephebe).

Highlights

Lichenization, the symbiotic process in which fungi utilize green algal or cyanobacterial photobionts for the provision of carbohydrates, is a very common and successful lifestyle among Ascomycota, where currently more than 19,000 lichenized species (27% of the known Ascomycota) are Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.difficult (Hawksworth 1988; Grube and Hawksworth2007)
Here, we show that Lichinodium (Lichinaceae, Lichinomycetes, Ascomycota) constitutes a formerly unrecognized lineage within the Leotiomycetes, being the first lichenized lineage recognized in the superclass Sordariomyceta (Leotiomycetes, Laboulbeniomycetes and Sordariomycetes)
The first investigated the overall relationships of Lichinodium, based on a matrix including a wide representation of main groups of Pezizomycotina and including six genes

Summary

Introduction

There are very few filamentous lichens, but they appear in several classes of Ascomycota, and represent fungi associated with a number of different photobionts. They can be found in the Lecanoromycetes (e.g. Polychidium and Spilonema with cyanobacteria in Peltigerales and Coenogonium with Trentepohlia in Ostropales), in Dothideomycetes (Cystocoleus and Racodium with Trentepohlia in Capnodiales), in Eurotiomycetes (Pyrenothrix in Chaetothyriales with Scytonema) and in the Lichinomycetes (e.g. Ephebe with Stigonema, Thermutis and Zahlbrucknerella with Scytonema (Henssen 1963; Herrera-Campos et al 2005; Muggia et al 2008; Hawksworth et al 2011). Two more filamentous species associated with Trentepohlia have been described, their phylogenetic and taxonomic position is not clear (i.e. Physolinum monile, Davis et al 1989 and Racoleus, the latter suggested as ‘‘? Capnodiales (incertae sedis)’’ in Hawksworth et al 2011)

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