Sequences of psychrophilic fungi amplified from glacier-preserved ascolichens

Abstract

Ribosomal DNA sequences were amplified from subfossils of the ascolichen Umbilicaria cylindrica (L.) Delise ex Duby collected at the ablating edges of Greenland glaciers. Surprisingly, phylogenetic analysis indicated that the amplified rDNA sequences were not closely related to those of the lichen-forming fungus but rather represented two groups of psychrophilic basidiomycetes (orders Cystofilobasidiales and Sporidiales) and one group of ascomycetes (order Leotiales). Two of these groups, the Sporidiales and the Leotiales, include other fungi previously detected in DNA extracted from the grass clothing of the Tyrolean Iceman desiccated and frozen for over 3000 years and also in 2000-and 4000-year-old ice core samples from northern Greenland. Large subunit ribosomal DNA sequences representing the group Cystofilobasidiales were nearly identical to those of the basidioyeast saprobe Mrakia frigida. The adjacent internal transcribed spacer sequence was more than 98% similar to those from three samples of U. cylindrica from different sites that had been subjected to ice burial for various lengths of time, suggesting they also were Mrakia sequences. Although ancient contamination of multiple U. cylindrica specimens with fungi such as Mrakia cannot be ruled out, it is more probable that saprobic colonization of the subfossil tissues by psychrophilic fungi proceeded during recent ice melt.Key words: ancient DNA, small subunit ribosomal DNA, 18S ribosomal DNA, phylogenetic analysis, psychrophilic fungi, lichen-forming fungi.Résumé : Les auteurs ont amplifié les séquences de l'ADN ribosomal provenant de subfossiles de l'ascolichen, Umbilicaria cylindrica (L.) Delise ex Duby, récoltés sur les marges d'ablation de glaciers, au Groenland. De façon surprenante, les analyses phylogénétiques indiquent que les séquences de rADN amplifiées ne sont pas étroitement apparentées avec celles du champignon formant ce lichen, mais représente plutôt deux groupes de champignons basidiomycètes psychrophiles (ordre des Cystofilobasidiales et des Sporidiales) et un groupe d'ascomycètes (ordre des Léo-tiales). Deux de ces groupes, les Sporidiales et les Léotiales, incluent d'autres champignons préalablement décelés dans l'ADN extrait des habits constitués d'herbes portés par l'homme des glaces Tyroléen desséché et congelé depuis plus de 3000 ans, ainsi que de carottes de glaces âgée de 2000 et 4000 ans, échantillonnées au nord du Groenland. Les grandes sous-unités des séquences d'ADN représentant le groupe des Cystofilobasidiales sont presqu'identiques à celles de la basidiolevure saprophyte, le Mrakia frigida. La séquence de l'espaceur interne transcrit adjacent ressemble à plus de 98% à celles provenant de trois échantillons de l'U. cylindrica récoltés sur différents sites ayant été soumis au recouvrement par la glace pendant différentes périodes de temps, ce qui suggère qu'il s'agirait également de séquences du Mrakia. Bien qu'on ne puisse exclure la possibilité de contamination des spécimens multiples de l'U. cylindrica par des c...

Yeasts from macroalgae and lichens that inhabit the South Shetland Islands, Antarctica

“…Mrakia spp. have been found in different cold environments, such as Greenland (DePriest et al ., ), sediment and ice from Italian Alps (Thomas‐Hall et al ., ), and Antarctic lake sediment and soil surrounding lakes (Tsuji et al ., ). According to Thomas‐Hall et al .…”

Cold-adapted yeasts from Antarctica and the Italian Alps—description of three novel species: Mrakia robertii sp. nov., Mrakia blollopis sp. nov. and Mrakiella niccombsii sp. nov.

“…Group 1, Mrakia robertii composed of CBS 8912 T , CBS 8918, CBS 8919, DBVPG 4728, DBVPG 4752, DBVPG 4775 and DBVPG 4782 (differed from CBS 8912 T by 3 or 4 nt) and 2 uncultured basidiomycetous strains from Greenland lichens (Depriest et al 2000a , b ) that showed 4 and 6 different base pairs from CBS 8912 T . Group 2, Mrakia gelida constituted of CBS 5272 T , CBS 5917, and CBS 8914 and CBS 8922 and two uncultured basidiomycetes isolates from Greenland lichens (Depriest et al 2000a , b ) differed from CBS 5272 T by 1 and 5 nt, respectively. Group 3, Mrakia psychrophila consisted of only the type strain AS 2.1971 T .…”

“…Strains belonging to the genera Mrakia and Mrakiella have been found in many cold climates throughout the world, such as Antarctica (Di Menna 1966a ; Xin and Zhou 2007 ); glacier-preserved ascolichens in Greenland (Depriest et al 2000a , b ), central Russia (Maksimova and Chernov 2004 ), Western Siberia and Alaska (Poliakova et al 2001 ); the Alps from glacier cryoconite, glacial sediment, ice and melting water (Margesin et al 2002 ; Turchetti et al 2008 ); glaciers of Argentina (de García et al 2007 ) and frozen fish in Japan (Komagata and Nakase 1965 ). Di Menna ( 1966b ) found Mrakia to be the dominant yeast genus in soil of Antarctica, representing 24% of the yeast species isolated in that study.…”

Biodiversidade de leveduras derivadas de ecossistemas antárticos marinhos e terrestres e prospecção de lipases.

“…Representantes do gênero Mrakia têm sido encontrados em diferentes ambientes frios, tais como liquens da região da Groelândia (DEPRIEST et al, 2000), água da região da patagônia argentina (GARCIA et al, 2007), sedimento, gelo e água de região dos Alpes italianos (THOMAS-HALL et al, 2010…”

“…No ambiente Antártico ocorre as três formas de liquens, sendo os liquens crustáceos aqueles com maior prevalência (Figura 3).Antártica Buellia frigida encontrada na região do Vales secos de McMurdo 78 °S (SANCHO; GREEN;PINTADO, 2007). Devido ao crescimento lento e a sensibilidade a poluentes ambientais, os liquens muitas vezes são utilizados como indicadores de mudança climática ambientais(GREEN et al, 2012).Em comparação as funções bem conhecidas dos fungos filamentosos e das algas, pouco se conhece acerca das funções de bactérias e leveduras associadas aos liquens(DEPRIEST et al, 2000;GRUBE et al, 2015). A diversidade bacteriana associada a liquens tem sido recentemente abordada…”