МАТИЦА СРПСКА ОДЕЉЕЊЕ ЗА ПРИРОДНЕ НАУКЕ ЗБОРНИК МАТИЦЕ СРПСКЕ ЗА ПРИРОДНЕ НАУКЕ MATICA SRPSKA DEPARTMENT OF NATURAL SCIENCES PROCEEDINGS FOR NATURAL SCIENCES Покренут 1951 / First published in 1951. Published as Научни зборник, серија природних наука until the tenth issue (1955), as the Series for Natural Science from the eleventh issue (1956) — Зборник за pриродне науке, and under its present title since the sixty-sixth issue (1984) Главни уредници / Editors-in-Chief Miloš Jovanović (1951), Branislav Bukurov (1952—1969), Lazar Stojković (1970—1976), Slobodan Glumac (1977—1996), Rudolf Kastori (1996—) 120 Уредништво / Editorial Board Consulting Editors S. GAJIN A. ATANASSOV, Bulgaria L. DOVNIKOVIĆ P. HOCKING, Australia D. KAPOR A. RODZKIN, Belorusija R. KASTORI M. SIMMONDS, UK L. LEPŠANOVIĆ S. STOJILKOVIC, USA I. MAKSIMOVIĆ G. SCHILING, Germany V. MARIĆ GY. VARALLYAY, Hungary S. PETROVIĆ S. ĆURČIĆ Главни и одговорни уредник / Editor-in-Chief RUDOLF KASTORI YU ISSN 0352-4906 UDK 5/6 (05) MATICA SRPSKA PROCEEDINGS FOR NATURAL SCIENCES 120 NOVI SAD 2011 SCIENTIFIC BOARD OF THE THIRD SCIENTIFIC MEETING MYCOLOGY, MYCOTOXICOLOGY AND MYCOSES Academician Čedomir Popov, President of Matica Srpska Professor Ferenc Balaž, Ph.D. Professor Faruk Bozoglu, Ph.D. Academician Dragutin Djukic Professor Nina Gunde Cimerman, Ph.D. Professor Georgios Karaoglanidis, Ph.D. Academician Rudolf Kastori Professor Dzoko Kungulovski, Ph.D. Professor Antonio Logrieco, Ph.D. Professor Peter Raspor, Ph.D. Professor Alexei Smirnov, Ph.D. Professor Marija Skrinjar, Ph.D. ORGANIZATION BOARD OF THE THIRD SCIENTIFIC MEETING MYCOLOGY, MYCOTOXICOLOGY AND MYCOSES Professor Marija Skrinjar, Ph.D., President Assistant Professor Ferenc Bagi, Ph.D. Dr Slavica Veskovic Moracanin, Ph.D. Professor Jelena Vukojevic, Ph.D. Academician Dragutin Djukic Mirjana Zrnic, Secretary Dr Dobrila Jakic Dimic, Ph.D. Jelena Levic, Ph.D. Professor Ida Leskosek-Cukalovic, Ph.D. Professor Antonio Logrieco, Ph.D. Professor Milan Matavuly, Ph.D. Professor Stevan Masirevic, Ph.D. Professor Hrvoje Pavlovic, Ph.D. Professor Smiljka Simic, Ph.D. The papers published in this Collection of Papers will be presented at The 4th International Scien tific Meeting Mycology, Mycotoxicology and Mycoses, on April 20—22 2011, in Matica Srpska and are also the results of the research in the project Mycotoxins in Foodstuffs financed by The Ministry of Science and En vironmental protection of Republic of Serbia and Provincial Secretariate of Science and Technological Development Зборник Матице српске за природне науке / Proc. Nat. Sci, Matica Srpska Novi Sad, № 120, 7—18, 2011 UDC 632.4.06 DOI: 10.2298/ZMSPN1120007Z Janja Zajc1 , Polona Zalar1 , Kristina Sepčič1 and Nina Gunde-Cimerman 1,2,† 1 University of Ljubljana, Biotechnical Faculty, Biology Department, Večna pot 111, SI-1000 Ljubljana, Slovenia 2 Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova 39, SI-1000 Ljubljana, Slovenia † Corresponding author: Nina Gunde-Cimerman, Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, SI-1000 Ljubljana, Slovenia; e-mail: [email protected]; Tel: +386 1 320 34 00, Fax: + 386 1 257 33 90 XEROPHILIC FUNGAL GENUS WALLEMIA – BIOACTIVE INHABITANTS OF MARINE SOLAR SALTERNS AND SALTY FOOD ABSTRACT: Wallemia is a genus of cosmopolitan xerophilic fungi, frequently in- volved in food spoilage of particularly sweet, salty, and dried food. Until recently, only a single species, Wallemia sebi, was recognized in the genus. When a large group of strains globally collected in salterns and other different ecological niches was analyzed on the level of physiological, morphological and molecular characteristics, a new basidiomycetous class, Wallemiomycetes, covering an order of Wallemiales was proposed and three Walle- mia species were recognized: W. ichthyophaga, W. sebi and W. muriae. Wallemia ichthy- ophaga was recognized as the most halophilic eukaryote known, thus representing an ap- propriate eukaryotic model for in depth studies of adaptation to hypersaline conditions. Our preliminary studies indicated that all three Wallemia species synthesized a yet undescribed haemolytic compound under, surprisingly, low water activity conditions. Due to the taxo- nomic status w hich was unrevealed only recently, there were so far no reports on the pro- duction of any bioactive compounds by the three newly described species. The article aims to present the taxonomy, ecology, physiology and so far described molecular mechanisms of adaptations to life at low water activity, as well as bioactive potential of the genus Wal- lemia, a phylogenetically ancient taxon and a taxonomic maverick within Basidiomycota. Key words: fungi, Wallemia spp., taxonomy, low water activity, xerophiles, halo- philes, osmoadaptation, secondary metabolites Abbreviations AAS, atomic absorption spectroscopy; aw, water activity; EPS, extracel- lular polysaccharides; GPD1, glycerol-3-phosphate dehydrogenase; HPLC, high performance liquid chromatography; ITS rDNA, internal transcribed spacer regions ribosomal deoxyribonucleic acid; NMR, nuclear magnetic res- 7 onance; PTS2, peroxisomal targeting sequence; SSU rDNA, small subunit ribosomal deoxyribonucleic acid; UV, ultraviolet. INTRODUCTION Water, with its central role in biological processes, is the key life-limiting parameter. Therefore, low amount of biologically available water (low water activity [aw]) represents one of the most pervasive stresses for biological sys- tems, as only specially adapted organisms can thrive at such conditions. Tol- erance of low water-activity is apparent in only ten out of 140 known orders of fungi, most of them belonging to the Ascomycota (d e H o o g , Z a l a r et al., 2005), while xerotolerance is rare in the phylum Basidiomycota. Xerophilic fungi are capable of growth at water activity below 0.85, corresponding to 17% NaCl, or 50% glucose added to the growth medium (G u n d e - C i m e r - m a n , O r e n et al., 2005). Fungi are not only being capable of growing at low aw, but they also show preferences for certain chemical nature of the sol- ute lowering the aw (de Hoog, Zala r et al., 2005; Gu nde - Ci mer- m a n and P l e m e n i t a š , 2006), as xerophilic fungi are able to live in the environments rich in sugar, while halophilic live in the environments rich in salt. Halotolerance and extreme halotolerance describe the salt-adaptable fun- gi that do not necessarily require salt (NaCl) for viability, but are able to sus- tain a range of different salt concentrations, even across the whole salinity range – from fresh water to NaCl saturation (G u n d e - C i m e r m a n and P l e m e - n i t a š 2006). An obligate halophilic character is possessed by only few fun- gal species that exhibit superior growth on media with NaCl as controlling solute (W h e e l e r , H o c k i n g et al., 1988; Z a l a r , d e H o o g et al., 2005; K r a l j K u n č i č , K o g e j et al., 2010). Xerophilic fungi were first only known as domestic extremophiles that contaminate food preserved by the reduction of biologically available water by means of drying, freezing or adding solutes (P i t t and H o c k i n g 1977; P i t t and H o c k e r i n g , 2009). Natural saline and hypersaline environ- ments, where high concentrations of NaCl are prevailing, were believed to be populated almost exclusively by bacteria, archaea and eukaryotic alga Dunaliella salina (Rodriguez-Valera, Ruiz-Berraquero et al., 1981; Schiew- e r , 1991; O r e n , 2005), until fungi as active inhabitants of solar salterns were first reported (G u n d e - C i m e r m a n , Z a l a r et al., 2000). Later numerous halotolerant and extremely halotolerant fungi (Z a l a r , d e H o o g et al., 1999; G u n d e - C i m e r m a n , Z a l a r et al., 2000; B u - tinar, Santos et al., 2005; Zalar, de Hoog et al., 2007; Zalar, F r i s v a d et al., 2008; Z a l a r , G o s t i n c a r et al., 2008), and only two halophilic representatives, both from genus Wallemia (Z a l a r , d e H o o g et al., 2005) were isolated from hypersaline water of the Sečovlje solar salterns (Adriatic coast, Slovenia). Since the first discovery of fungi in salterns, nu- merous fungal species thriving in extremely saline environments around the 8 globe have been described, amongst them xerophilic and halophilic species of the genus Wallemia, and are in the focus of the above review. Ecology of the Wallemia spp. Fungi from genus Wallemia are frequently involved in food spoilage of particularly sweet, salty, and dried food (S a m s o n , H o e k s t r a et al., 2002), and are also often isolated from indoor or outdoor air (Ta k a h a s h i , 1997), soil (D o m s c h , G a m s et al., 1990) and sea salt (D a s S a r m a , K l e b a h n et al., 2010). Until recently (Z a l a r , d e H o o g et al., 2005), a single cosmopolitan species, W. sebi, that was isolated from jams, dates, bread, cakes, salted beans, maize flour, crystalline sugar, fish, bacon, fruits, soil, hay and textiles around the globe (E d u a r d , L a c e y et al., 1990; H a n h e l a , L o u h e l a i n e n et al., 1995; Z e n g , W e s t e r m a r k et al., 2004; Z a l a r , d e H o o g et al., 2005), have been recognized in the genus.