BOTANICA LITHUANICA 2007, 13(1): 39 44

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1 BOTANICA LITHUANICA 2007, 13(1): CONTRIBUTION TO LITHUANIAN WATER MOULDS. NEW REPORTS OF CRITICAL ACHLYA (SAPROLEGNIACEAE, PERONOSPOROMYCETES) SPECIES Svetlana MARKOVSKAJA Institute of Botany, Laboratory of Mycology, Þaliøjø Eþerø Str. 49, LT Vilnius, Lithuania; Abstract Markovskaja S., 2007: Contribution to the Lithuanian water moulds. New reports of critical Achlya (Saprolegniaceae, Peronosporomycetes) species. [Papildomi duomenys apie Lietuvos dumbliagrybius. Nauji pranešimai apie kritines Achlya (Saprolegniaceae, Peronosporomycetes) rûšis]. Botanica Lithuanica, 13(1): Notes on the occurrence of two new and critical species of straminipilous fungi in fresh waters of Lithuania are presented, and their taxonomy is discussed. Short descriptions, illustrations, and notes on species morphological variability are given, basing on detailed comparative studies of living pure cultures. Keywords: straminipilous fungi, Achlya, fresh water, diversity, taxonomy, Lithuania. INTRODUCTION In , during a study of water moulds in various running and stagnant freshwater habitats of Lithuania new data on occurrence, distribution, and diversity of saprolegniaceous fungi was obtained. Data reported in this paper contributes to the knowledge on the diversity and distribution of Achlya species (MAR- KOVSKAJA, 2004) in Lithuania. The variability of zoospore discharge from the primary sporangia is the basic taxonomically important feature for distinguishing saprolegniaceous genera. Straminipilous fungi recently isolated in Lithuania used to be ascribed to Aplanes and Thraustotheca and are still frequently reported as Aplanes androgynus and Thraustotheca irregularis (ANONYMOUS, 2006). However, basing on detailed morphological studies of living cultures following the primary sporangium concept and taxonomical examination of all published data, JOHNSON et al. (2005) proposed some new combinations in the Saprolegniaceae. As a result, both above-mentioned species were transferred to Achlya because their primary sporangia were found to be achlyoid. In this paper we follow the new changes proposed by JOHNSON et al. (2005). MATERIAL AND METHODS Water moulds were isolated from water samples collected in from various running and stagnant water basins in Lithuania by the standard baiting technique (SEYMOUR, 1970; SEYMOUR & FULLER, 1987). Research methods used in this study were described previously by MARKOVSKAJA (2004). During examination of over 250 living cultures of water moulds about 20 isolates were selected for future morphological studies. To obtain pure, bacteria-free culture, a hyphal tuft was taken from overall culture on hemp seed, washed in 39

2 sterilized distilled water and inoculated into malt extract agar (MEA). The pure cultures from single hyphal tips on sterile halves of hemp seeds grown in sterile distilled water were used for future detailed microscopical examination of morphological features. Observations of discharge from primary zoosporangia were made on less than 48 h old intact colonies freely floating in water as recommended by PADGETT & JOHNSON (2004). After critical examination and identification of the selected living pure cultures, specimens on glass slides with lacto-phenol were used for permanent preservation in the fungal collection at the Herbarium of the Institute of Botany, Vilnius (BILAS). RESULTS AND DISCUSSION Achlya androgyna (W. Archer) Johnson et Seymour, Mycotaxon, 92: Fig.1. Saprolegnia androgyna W. Archer, Quart. J. Microscop. Soc. (N.S.), 7: Aplanes androgynus (W. Archer) Humphrey, Trans. Amer. Phil. Soc. (N.S.), 17: Achlya treleaseana (Humphrey) Kauffman, 8 Rep. Michigan Acad. Sci., Arts, Ltrs., 8: Aplanes treleaseanus (Humphrey) Coker, J. Elisha Mitchell Sci. Soc., 42: (For comprehensive list of synonyms see JOHNSON et al., 2005) Material examined: Tauragë distr., Vieðvilë Strict Nature Reserve, Lake Glitis, April 27, 2005; Ðvenèionys distr., Lake Arkliaðûdis, September 16, 2005; Jonava distr., Lake Ilgasis, September 8, 2005 and May 16, Short morphological description: Mycelium extensive, diffuse. Zoosporangia fusiform or cylindrical, renewed sympodially, x ìm. Zoospores discharge achlyoid or rarely aplanoid. Zoospores ìm in diam. Gemmae abundant, fusiform, pyriform or cylindrical, terminal and intercalary, single and catenulate. Oogonia terminal, intercalary or lateral, predominantly catenulate, fusiform, naviculate or cylindrical, ( 90) ìm. Oogonial wall pitted, smooth or rarely with some papillae. Terminal oogonia often with conical spine-like projection. Oospores subcentric or centric, (20 )28 34 ìm in diam.; 10 30( 40) in number, filling the oogonium. Antheridial branches androgynous, semihypogynous or monoclinous, 1 3 in number, branched, attached by projections or laterally appressed. Fertilization tubes not observed. Remarks. The taxonomic concept of this fungus has been changed several times. Originally it was described as Saprolegnia androgyna by ARCHER (1867), but later was transferred by HUMPHREY (1893) to Aplanes, and this name was employed till present time. The similar taxon described by HUMPHREY (1893) as Saprolegnia treleaseana, later transferred to Achlya (KAUFFMAN, 1906) and afterwards to Aplanes (COKER, 1927), but now they all are placed among synonyms of Achlya androgyna (JOHNSON et al., 2005). Basing on molecular and morphological studies, SPENCER et al. (2002) proposed to place Aplanes androgynus to monophyletic Newbya clade with new genus Newbya (for 10 subcentric Achlya s. str. species) together with Aplanopsis spinosa, the Calyptralegnia and Aplanes genera. Thus, according to propositions of SPENCER et al. (2002), Aplanes androgynus may be also placed to Newbya. Taxonomical position of this fungus is still questionable because the pattern of primary zoospores behaviour and its morphological characters are instable and especially varying in oogonial wall ornamentation. The detailed taxonomical discussion with comprehensive list of synonyms was presented in JOHNSON et al. (2005). Our observations support the data presented by JOHNSON et al. (2005) that variability in oogonial wall ornamentation is not taxonomically significant and probably depends on the environmental conditions: fungal colonies growing in water containing living plants of Sphagnum sp. as a rule produce achlyoid type of zoosporangia. All Lithuanian isolates were collected from the lakes overgrown by Sphagnum sp. and were characterized predominantly by achlyoid sporangia and only very rarely by aplanoid. Oogonial wall ornamentation is a very variable character, but Lithuanian isolates were predominantly smooth or sparsely papillate. Sometimes semihypogynous antheridial branches were observed in Lithuanian isolates, but never diclinous, meanwhile JOHN- SON et al. (2005) in their description also mentioned diclinous antheridial branches. Achlya androgyna is widespread in Europe, Asia, North America, Central America, South America, Africa (JOHNSON, 1956; PYSTINA, 1994; RIETHMÜLLER, 2000; JOHNSON et al., 2005), and most probably it is not rare in freshwaters of Lithuania. Achlya irregularis (Coker et M. W. Ward) Johnson et Seymour, Mycotaxon, 92: Fig. 2. Thraustotheca irregularis Coker et M. W. Ward, in Ward, J. Elisha Mitchell Sci. Soc., 55: Material examined: Panevëþys distr., Geguþinë environs, River Istra, October 6, Short morphological description: Mycelium dense, hyphae slender. Zoosporangia cylindrical and clavate, fusiform and irregular, renewed sympodially, ìm. Zoospores discharge achlyoid or rarely thraus- 40

3 a b 100 µm Fig. 1. Achlya androgyna: a zoosporangia with zoospores and oogonia, b hyphae bearing oogonia with subcentric oospores and androgynous antheridial branches 41

4 a b 100 µm Fig. 2. Achlya irregularis: a zoosporangia and zoospores, b hyphae bearing oogonia with not maturing or eccentric oospores and diclinous antheridial branches 42

5 tothecoid. Zoospores ìm in diam. Gemmae abundant, variable in shape and size. Oogonia obpyriform or spherical (50 )80 86( 100) ìm in diam., lateral or terminal (in our material they are larger than reported by JOHNSON et al. (2005), description (20 )40 55( 72) ìm). Oogonial wall pitted, smooth. Oospores spherical, aborting or oospheres not maturing, mature oospores eccentric, ìm in diam., (6 )8 10 in number, usually not filling the oogonium. Antheridial branches diclinous, long and slender, branched, clasping the oogonium, (1 )2 4 in number, laterally appressed. Fertilization tubes not observed. Remarks. JOHNSON et al. (2005), basing mainly on achlyoid nature of the primary sporangia, transferred Thraustotheca irregularis to Achlya. COKER (1927), WARD (1939) and JOHNSON et al. (2005) noted that wall of achlyoid sporangia could be deliquesced entirely or in part after the zoospores are released. In Lithuanian isolates the achlyoid sporangia predominated, but sometimes partly deliquesced sporangia as in Thraustotheca were also observed. I support the opinion of placing this taxon to Achlya because the primary sporangia are predominantly achlyoid. Such feature as achlyoid or sometimes thraustothecoid discharge of zoospores may be observed also in some other species of Achlya, for example Achlya dubia (JOHNSON, 1956; MARKOVSKAJA, 2004). Achlya irregularis is a rather rare species known from Europe, North America, Central America and South America (WARD, 1939; JOHNSON et al., 2005); it is also rare in freshwaters of Lithuania. ACKNOWLEDGEMENTS The author is grateful to anonymous reviewers for valuable comments. Financial support of this study by the Lithuanian State Science and Studies Foundation is kindly acknowledged. REFERENCES ANONYMOUS, 2006: Index fungorum. COKER W. C., 1927: Other watermolds from the soil. J. Elisha Mitchell Sci. Soc., 42: HUMPHREY J. E., 1893: The Saprolegniaceae of the United States, with notes on other species. Trans. Amer. Phil. Soc. (N.S.), 17: JOHNSON JR. T. W., 1956: The Genus Achlya: Morphology and Taxonomy. Michigan. JOHNSON JR. T. W., SEYMOUR R. L., PADGETT D. E., 2005: Systematics of the Saprolegniaceae: new combinations. Mycotaxon, 92: KAUFFMAN C. H., 1906: Unreported Michigan fungi from Petoskey, Detroit, and Ann Arbor for Rep. Michigan Acad. Sci., Arts, Ltrs., 8: MARKOVSKAJA S., 2004: Saprolegniaceae (Peronosporomycetes) in Lithuania. I. The genera Achlya and Newbya. Botanica Lithuanica, 10(2): PADGETT D. E., JOHNSON JR. T. W., 2004: Zoosporangial discharge in a Protoachlya hypogyna (Saprolegniaceae) isolate from southeastern North Carolina. Mycologia, 96(2): PYSTINA K. A., 1994: Opredelitel gribov Rossii. Class Oomycetes. Vypusk 1. Poriadki Saprolegniales, Leptomitales, Lagenidiales. Sankt-Peterburg. RIETMÜLLER A., 2000: Morphologie, Ökologie und Phylogenie aquatischer Oomyceten. Biblioth. Mycol., 185: SEYMOUR R. L., 1970: The genus Saprolegnia. Nova Hedwigia, 19: SEYMOUR R. F., FULLER M. S., 1987: Collection and isolation of water molds (Saprolegniaceae) from water and soil. In: FULLER M. S., JAWORSKI A. (eds.), Zoosporic fungi in teaching and research: Athens. SPENCER M. A., VICK M. C., DICK M. W., 2002: Revision of Aplanopsis, Pythiopsis, and subcentric Achlya species (Saprolegniaceae) using 18S rdna and morphological data. Mycol. Res., 106(5): WARD M. W., 1939: Observations on a new species of Thraustotheca. J. Elisha Mitchell Sci. Soc., 55:

6 PAPILDOMI DUOMENYS APIE LIETUVOS DUMBLIAGRYBIUS. NAUJI PRANEÐIMAI APIE KRITINES ACHLYA (SAPROLEGNIACEAE, PERONOSPOROMYCETES) RÛÐIS Svetlana MARKOVSKAJA Santrauka Straipsnyje skelbiami nauji duomenys apie dvi straminopiliniø grybø rûðis, ðiuo metu priskiriamas Achlya genèiai. Pateikiami pagrindiniai rûðiø sinonimai, trumpai apraðoma jø morfologija, paplitimas Lietuvoje ir pasaulyje, trumpai aptariami taksonomijos klausimai ir grybø morfologijos ypatumai. Straipsnis iliustruotas originaliais pieðiniais. 44