Black fungal extremes - CBS

available online at www.studiesinmycology.orgdoi:10.3114/sim.2008.61.01St u d i es in My c o l o g y 61: 1–20. 2008.Drought meets acid: three new genera in a dothidealean clade of extremotolerantfungiL. Selbmann 1 *, G.S. de Hoog 2,3 , L. Zucconi 1 , D. Isola 1 , S. Ruisi 1 , A.H.G. Gerrits van den Ende 2 , C. Ruibal 2 , F. De Leo 4 , C. Urzì 4 andS. Onofri 11DECOS, Università degli Studi della Tuscia, Largo dell’Università, Viterbo, Italy; 2 CBS Fungal Biodiversity Centre, P.O. Box 85167, NL-3508 AD Utrecht, The Netherlands;3Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Kruislaan 315, NL-1098 SM Amsterdam, The Netherlands; 4 Dipartimento di Scienze Microbiologiche,Genetiche e Molecolari, Università di Messina, Salita Sperone 31, I-98166 Messina, Italy*Correspondence: Laura Selbmann, selbmann@unitus.itAbstract: Fungal strains isolated from rocks and lichens collected in the Antarctic ice-free area of the Victoria Land, one of the coldest and driest habitats on earth, were foundin two phylogenetically isolated positions within the subclass Dothideomycetidae. They are here reported as new genera and species, Recurvomyces mirabilis gen. nov., sp.nov. and Elasticomyces elasticus gen. nov., sp. nov. The nearest neighbours within the clades were other rock-inhabiting fungi from dry environments, either cold or hot. PlantassociatedMycosphaerella-like species, known as invaders of leathery leaves in semi-arid climates, are also phylogenetically related with the new taxa. The clusters are alsorelated to the halophilic species Hortaea werneckii, as well as to acidophilic fungi. One of the latter, able to grow at pH 0, is Scytalidium acidophilum, which is ascribed here tothe newly validated genus Acidomyces. The ecological implications of this finding are discussed.Key words: Acidophilic fungi, Antarctica, black fungi, extremotolerance, halophilic fungi, ITS, lichens, phylogeny, rock-inhabiting fungi, SSU, taxonomy.Taxonomic novelties: Recurvomyces Selbmann & de Hoog, gen. nov.; Recurvomyces mirabilis Selbmann & de Hoog, sp. nov.; Elasticomyces Zucconi & Selbmann, gen. nov.;Elasticomyces elasticus Zucconi & Selbmann, sp. nov.; Acidomyces Selbmann, de Hoog & De Leo, gen. nov.; Acidomyces acidophilus (Sigler & J.W. Carmich.) Selbmann, deHoog & De Leo, comb. nov.INTRODUCTIONContrary to expectations, bare rocks in arid and semi-arid climatesmay harbour a bewildering biodiversity of black fungi. Many specieshave been reported from the Mediterranean basin (Sterflinger et al.1997, Wollenzien et al. 1997, Bogomolova & Minter 2003, De Leoet al. 1999, 2003, Bills et al. 2004, Ruibal et al. 2005, Ruibal et al.2008). These extremotolerant fungi live and even thrive on surfacesthat are too harsh to support growth of competing microorganisms;they shelter in small depressions in the marble surface, calledmicropits (Sterflinger 1998). Similar extremotolerant fungi werediscovered in the extremely cold and ice-free McMurdo Dry Valleys,a desert area in the Antarctic (Nienow & Friedmann 1993), wheretemperatures are only occasionally above zero, dropping to about–50 °C in winter. Onofri et al. (1999) and Selbmann et al. (2005)even reported on the existence of possibly endemic genera,Friedmanniomyces Onofri and Cryomyces Selbmann, de Hoog,Mazzaglia, Friedmann & Onofri in these habitats, which apparentlyshow active evolution under conditions of near-permanent frost andextreme dryness (Friedmann et al. 1987). These fungi may escapeprohibitive environmental conditions by colonising air spaces inrocks, living in association with lichens and algae in cryptoendolithiccommunities (Friedmann & Ocampo 1976, Friedmann 1982).In the present paper we describe three new fungal genera andspecies; their novelty is supported by molecular phylogeny, taking aclearly separate position within the Dothideomycetidae. One genusincludes two strains isolated from rocks in the Antarctic desert, onestrain from rocks collected in Monte Rosa in the Alps, Italy, and anunidentified rock fungus from Puebla de la Sierra, Spain; the othergenus includes three strains isolated from different thalli of Antarcticlichens, one from cryptoendolithic Antarctic communities and onefrom rocks collected in Aconcagua in the Argentinian Andes. Incontrast to most rock-inhabiting black fungi, which are generallyscarcely differentiated, they show peculiar and distinguishedmorphological traits.Fungi may also be encountered in extremely acidicenvironments. Some are able to grow at pH values down to pH 0(Starkey & Waksman 1943, Harrison et al. 1966, Gould et al. 1974,Ivarsson & Morita 1982, Gimmler et al. 2001). Sigler & Carmichael(1974) compared four strains from an acidic soil (pH 1.4–3.5) withthe ones previously isolated by Starkey & Waksman (1943) andIvarsson & Morita (1982), referring them to the genus ScytalidiumPesante on the basis of scarcely differentiated brown arthroconidia.Our SSU and ITS comparison proved these fungi also to bemembers of a clade within the Dothideomycetidae, amidst rockinhabitingfungi from cold and semi-arid climates.MATERIALS AND METHODSStrainsBlack fungi were isolated from rock samples harbouring acryptoendolithic lichen-dominated community and from epilithiclichens collected in different locations of Northern and SouthernVictoria Land, Antarctica, in the framework of the Italian expeditionCopyright 2008 CBS Fungal Biodiversity Centre, P.O. Box 85167, 3508 AD Utrecht, The Netherlands.You are free to share - to copy, distribute and transmit the work, under the following conditions:Attribution:You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).Non-commercial: You may not use this work for commercial purposes.No derivative works: You may not alter, transform, or build upon this work.For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you getpermission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights.1