Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Sat, 03 Nov 2018 00:48:18 Species reassignment of Geotrichum bryndzae, Geotrichum phurueaensis, Geotrichum silvicola and Geotrichum vulgare based on phylogenetic analyses and mating compatibility Marizeth Groenewald, 1 Teresa Coutinho, 2 Maudy Th. Smith 1 and J. P. van der Walt 2 3 Correspondence Marizeth Groenewald m.groenewald@cbs.knaw.nl 1 CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands 2 Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa The present classification of Galactomyces and its anamorph, Geotrichum, is based on various studies that used morphology, ecology, biochemistry, DNA–DNA reassociation comparisons and gene sequencing. In this study, the identities of strains of the Centraalbureau voor Schimmel- cultures yeast culture collection, as well as seven strains from South Africa, were examined by analyses of the nucleotide divergence in the internal transcribed spacer regions of the nuclear rRNA gene (nrRNA) operon, the D1/D2 domains of the 26S rRNA gene and partial actin gene sequences as well as compatibility studies. The South African strains were assigned to species in the genus Galactomyces. The phylogenetic analyses and mating studies revealed that Geotrichum silvicola and Geotrichum bryndzae are synonyms of Galactomyces candidus and that Geotrichum vulgare is a synonym of Galactomyces pseudocandidus. INTRODUCTION The present classification of the arthroconidial teleomorph genus Galactomyces and its anamorph Geotrichum (de Hoog & Smith, 2011a, 2011b) is a result of previous studies dealing with morphology and ecology (Redhead & Malloch, 1977; von Arx, 1977), biochemistry (Weijman, 1979), DNA–DNA association comparisons (Gue ´ho et al., 1985; Smith et al., 1995), and more recently with gene sequencing (Kurtzman & Robnett, 1995; Ueda-Nishimura & Mikata, 2000; de Hoog & Smith, 2004). Both hetero- thallic and homothallic species are present in Galactomyces. To date, the only exclusively homothallic species is Galactomyces reessii; Butler & Petersen (1972) reported that self-sterile forms of this species do not exist in nature. The first report on the occurrence of heterothallism in Galactomyces was by Butler & Petersen (1970). Two self- fertile cultures, Pr-11 T (5CBS 772.71 T ) and Pr-47 (5CBS 773.71), showing typical morphology of the anamorph species Geotrichum candidum, were isolated from soil in which unidentified grasses were growing. From these two self-fertile cultures, the authors isolated compatible self- sterile clones labelled Pr-11A 1 , Pr-11A 2 and Pr-47A 1, Pr- 47A 2, respectively, reporting that Pr-11A 1 was compatible with Pr-47A 2 (5CBS 775.71) and Pr-11A 2 with Pr-47A 1 (5CBS 774.71). Butler & Petersen (1972) described this teleomorph state of Geo. candidum as Endomyces geotri- chum. However, on the basis of morphological features, Redhead & Malloch (1977) designated this species as the type species of the novel genus Galactomyces. Revising the genus Geotrichum and its teleomorphs and using strains CBS 774.71 and CBS 775.71 of Galactomyces geotrichum as test strains, de Hoog et al. (1986) determined the mating types of nine strains identified as Geo. candidum. However, in that study, the authors used a different mating type nomenclature from Butler et al. (1988), listing CBS 774.71 as mating type A (mt A) and CBS 775.71 as mating type a (mt a). Four strains had the latter mating type and five strains had mating type A. A second heterothallic species described was Galactomyces citri-aurantii (Butler et al., 1988). This species was introduced to accommodate Geo. candidum-like isolates that cause sour rot of citrus species. Determining the mating types within these Geo. candidum- like isolates, Butler et al. (1988) assigned mt A 1 to strain 220 (5CBS 175.89 IT ) and mt A 2 to strain 178 (5CBS 176.89 T ) of Abbreviations: ITS, internal transcribed spacer; LSU, large subunit. The GenBank/EMBL/DDBJ accession numbers for the sequences reported in this paper are JN974262–JN974293 and JQ793921– JQ793944 (see supplementary material for further details). A supplementary figure and supplementary material are available with the online version of this paper. 3Johannes P. van der Walt passed away during the review process of this manuscript. Due to his original contribution to this manuscript we still acknowledge him as one of the co-authors. International Journal of Systematic and Evolutionary Microbiology (2012), 62, 3072–3080 DOI 10.1099/ijs.0.038984-0 3072 038984 G 2012 IUMS Printed in Great Britain