Black fungi in lichens from seasonally arid habitats

Abstract

We present a phylogenetic study of black fungi in lichens, primarily focusing on saxicolous samples from seasonally arid habitats in Armenia, but also with examples from other sites. Culturable strains of lichen-associated black fungi were obtained by isolation from surface-washed lichen material. Determination is based on ITS rDNA sequence data and comparison with published sequences from other sources. The genera Capnobotryella, Cladophialophora, Coniosporium, Mycosphaerella, and Rhinocladiella were found in different lichen species, which showed no pathogenic symptoms. A clade of predominantly lichen-associated strains is present only in Rhinocladiella, whereas samples of the remaining genera were grouped more clearly in clades with species from other sources. The ecology of most-closely related strains indicates that Capnobotryella and Coniosporium, and perhaps also Rhinocladiella strains opportunistically colonise lichens. In contrast, high sequence divergence in strains assigned to Mycosphaerella could indicate the presence of several lichen-specific species with unknown range of hosts or habitats, which are distantly related to plant-inhabitants. Similar applies to Cladophialophora strains, where the closest relatives of the strains from lichens are serious human pathogens.

Keywords: Aridity; Chaetothyriomycetidae; Dothideomycetidae; black fungi; phylogeny; symbioses.

Fig 1.

MP phylogenetic hypotheses based on ITS sequences of the black fungal genera Capnobotryella (a), Cladophialophora (b), Coniosporium (c), Mycosphaerella (d), and Rhinocladiella (e). Sequences obtained in this study are shown in bold, the isolation sources are written in parentheses, and yellow ellipses highlight the clades they form. Trees are unrooted, bootstrap cut-offs higher then 75% are reported.

Fig 1.

MP phylogenetic hypotheses based on ITS sequences of the black fungal genera Capnobotryella (a), Cladophialophora (b), Coniosporium (c), Mycosphaerella (d), and Rhinocladiella (e). Sequences obtained in this study are shown in bold, the isolation sources are written in parentheses, and yellow ellipses highlight the clades they form. Trees are unrooted, bootstrap cut-offs higher then 75% are reported.

Fig 1.

MP phylogenetic hypotheses based on ITS sequences of the black fungal genera Capnobotryella (a), Cladophialophora (b), Coniosporium (c), Mycosphaerella (d), and Rhinocladiella (e). Sequences obtained in this study are shown in bold, the isolation sources are written in parentheses, and yellow ellipses highlight the clades they form. Trees are unrooted, bootstrap cut-offs higher then 75% are reported.

Fig 1.

MP phylogenetic hypotheses based on ITS sequences of the black fungal genera Capnobotryella (a), Cladophialophora (b), Coniosporium (c), Mycosphaerella (d), and Rhinocladiella (e). Sequences obtained in this study are shown in bold, the isolation sources are written in parentheses, and yellow ellipses highlight the clades they form. Trees are unrooted, bootstrap cut-offs higher then 75% are reported.

Fig 1.

MP phylogenetic hypotheses based on ITS sequences of the black fungal genera Capnobotryella (a), Cladophialophora (b), Coniosporium (c), Mycosphaerella (d), and Rhinocladiella (e). Sequences obtained in this study are shown in bold, the isolation sources are written in parentheses, and yellow ellipses highlight the clades they form. Trees are unrooted, bootstrap cut-offs higher then 75% are reported.

Fig 2.

A. Co-culture on LB medium of Rhinocladiella sp. and Trebouxia sp. both isolated from Lecanora muralis, Bar = 1 mm; B. Thallus of Lecanora muralis showing symptoms of black fungal infection, Bar = 1 mm.