7453 8824

E4.6. Molecular relationships among hyphaI ascomycetous and yeastlike taxa

C.P. Kurtzman and C.J. Robnett

Abstract: The circumscription of mycelial genera among the ascomycetous yeasts has been controversial because of widely different interpretations of the taxonomic significance of their phenotypic characters. Relationships among species assigned to mycelial genera were determined from extent of divergence in a ca. 600-nucleotide region near the 5' end of the large subunit (26S) ribosomal DNA gene. Phylogenetic analyses showed that Stephanoasclis is distinct from Zygoasclis and that Blastobotrys, Sympodiomyces, and Arxllla represent anamorphs of the Stephanoasclls clade. The analyses demonstrated the following teleomorphic taxa to be congeneric: Ambrosiozyma/HonnoasclIs, Sacclzaromycopsis/ GlIilliennondella/Botryoasclls/Anhroasclls, Dipodasclls/Galactomyces, and Eremotlzecillm/Aslzbya/ Nematospora/Holleya. Species assigned to Dipodasclls comprise two separate clades. New taxonomic combinations are proposed that reflect the phylogenetic relationships determined. Key words: mycelial yeasts, ribosomal rRNA/rDNA, molecular systematics.

Resume: La delimitation des genres myceliens parmi les levures ascomycetes demeure un sujet controverse parce que la signification taxonomique de leurs caracteres phenotypiques est encore I'objet d'interpretations differentes. Les relations entre les especes attribuees aux genres myceliens ont ete determinees sur la base de I'amplitude de divergence dans une region d'environ 600 nucleotides pres de I'extremite 5' du gene de la grande sous-unite (26S) de I'ADN ribosomal. Les analyses phylogenetiques montrent que les Stephanoasclls sont distincts des Zygoasclls et que les Blastobotrys, les Sympodiomyces et les Arxllla representent des anamorphes du clade Steplzanoasclls. Les analyses demontrent que les teleomorphes suivants sont congeneres : Ambrosiozyma/Honnoasclls, Sacclzaromycopsis/Gllilliermondella/ Botryoasclls/Anlzroasclls, Dipodasclis/Galactomyces et Eremotlzecillm/Asbya/Nematospora/Holleya. Les especes attribuees aux Dipodasclls comprennent deux clades distincts. De nouvelles combinaisons taxonomiques sont proposees refletant les relations phylogenetiques determinees. Mots clis : levures myceliennes, rARN/rADN ribosomal, systematique moleculaire. [Traduit par la redaction]

Introduction ascus, Dipodascopsis, and Dipodascus. Descriptors for these taxa include presence or absence of budding or fission, mor­ Phylogenetic analyses of ribosomal RNA / ribosomal DNA phology of ascospores, and type of hyphal septum. The most (rRNA/rDNA) nucleotide sequences have demonstrated the recent taxonomic treatment ofthe , that of Ascomycetes to be comprised ofthree groups: (i) Euascomy­ von Arx and van der Walt (1987), aligned genera primarily cetes, (ii) Hemiascomycetes, a sister group to the Euasco­ on the basis ofascospore shape and their possible relatedness mycetes, and (iii) a polyphyletic assemblage basal to the to members of the Euascomycetes. However, molecular previous two groups and comprised ofsuch genera as Schizo­ studies have provided no support for proposals that represent saccharomyces, Taphrina, Protomyces, Saitoella, and Pneu­ the yeasts as reduced forms of developmentally more com­ mocystis (Bruns et al. 1991; Hausner et al. 1992; Hendriks plex fungi such as Ceratocystis (Hausner et al. 1992; Kurtz­ et al. 1992; Kurtzman 1993; Nishida and Sugiyama 1993; man and Robnett 1994a) and have raised considerable doubt Walker 1985). Nishida and Sugiyama (1994) proposed the about the validity of ascospore shape as a predictor of phylo­ name Archiascomycetes for those taxa in the third group. genetic relatedness (Kurtzman and Robnett 1991, 1994b). From the preceding molecular studies, circumscription of In the present work, we sequenced ca. 600 nucleotides the Hemiascomycetes is now coincident with the Saccharo­ from the 5' end of large subunit rDNAs from a majority of mycetales (= Endomycetales) and is restricted to the budding mycelial taxa assigned to the Saccharomycetales and used yeasts and to yeastlike genera such as Ascoidea, Cephalo- phylogenetic analyses of these sequences to evaluate species assignments to the various genera. Sequences from the 5' end Received August 15, 1994. of the large subunit were examined, because they are suffi­ C.P. Kurtzman and C.J. Robnett. Microbial Properties ciently divergent among yeasts to allow detection of indi­ Research, National Center for Agricultural Utilization vidual species and they appear reliable for determining Research, Agricultural Research Service, U.S. Department of species assignments within genera (Peterson and Kurtzman Agriculture, Peoria, Illinois 61604, U.S.A. 1991; Kurtzman and Robnett 1991). However, intergeneric

Can. J. Bot. 73(Suppl. 1): S824-S830 (1995). Printed in Canada / Imprime au Canada E4.6. Kurtzman and Robnett 8825

Table 1. Strain designations and selected phenotypic characters of the species compared.

Strain designationsb Hyphald Budding or SpeciesQ NRRL CBS Co-Qc septum fission"

Acicliloconidium aculeatum (Phaff, Miller & Shifrine) King & Jong [TSp] YB-4298 2282 9 B Ambrosiozyma cicatricosa (Scott & van der Walt) van der Walt Y-17594 6157 DO B Ambrosiozyma monospora (Saito) van der Walt [TSp] Y-1484 2554 7 DO B Ascoidea ajricana Batra & Francke-Grosmann Y-6762 377.68 8? MPER Arthroascus javanensis (Klocker) von Arx [TSp] Y-1483 2555 8 MP B/F Arthroascus schoenii (Nadson & Krasil'nikov) Bab'eva, Vustin, Naumov & Vinovarova Y-17595 7223 B/F? Arxula adeninivorans (Middelhoven, Hoogkamer-Te Niet & Kreger-van Rij) van der Walt, Smith & Yamada Y-17692 8244 9 B/F Arxula terrestris (van der Walt & Johannsen) van der Walt [TSp] Y-l7704 7376 9 MPER B Ashbya goss)pii (Ashby & Nowell) Guilliermond [TSp] Y-1056 109.51 6 Blastobotrys arbuscula de Hoog, Rantio-Lehtimiiki & Smith Y-17585 227.83 MPER B Blastobotrys aristata Marvanova Y-17579 521.75 MPER B Blastobotrys capitlilata de Hoog, Rantio-Lehtimiiki & Smith Y-17573 287.82 MPER Blastobotrys elegans de Hoog, Rantio-Lehtimiiki & Smith Y-17572 530.83 MPER Blastobotrys nivea von Klopotek [TSp] Y-17581 163.67 MPER Blastobotrys proliferans Marvanova Y-17577 522.75 MPER Botryoascus cladosporoides Martinez, Gonzalez, Abarca & Cabaiies Y-17596 7434 B? Botryoascus synnaedendms (Scott & van der Walt) von Arx [TSp] Y-7466 6161 8 MPER B? Botryozyma nematodophila Shann & Smith [TSp] Y-17705 7426 B Cephaloascus albidus Kurtzman Y-7343 389.77 9 MP B Cephaloascus jragrans Hanawa [TSp] Y-6742 121.29 9 CP B Dipodascopsis tothii (Zsolt) Batra & Millner Y-12690 759.85 9 Dipodascopsis uninuc!eata (Biggs) Batra & Millner var. llninucleata [TSp] Y-17583 190.37 9 CP B? Dipodascopsis uninucleata var. wickerhamii Kreger-van Rij Y-2181 741.74 B? Dipodascus aggregatus Francke-Grosmann Y-17564 175.53 F Dipodascus albidus Lagerheim [TSp] Y-12859 766.85 9 F Dipodasclls ambrosiae de Hoog, Smith & Gueho Y-17575 749.85 F Dipodascus annillariae Gams Y-17580 817.71 F Dipodascus australiensis von Arx & Barker Y-17565 625.74 F Dipodasclls capitatus de Hoog, Smith & Gueho Y-17686 197.35 x 580.82 9 F Dipodascus geniculatus de Hoog, Smith & Gueho Y-17628 184.80 F Dipodasclls ingens de Hoog Y-17630 521.90 F Dipodascus macrospoms Madelin & Feest Y-17586 259.82 F Dipodascus magnllsii (Ludwig) von Arx Y-17563 108.12 9 F Dipodascus ovetensis (Pelaez & Ramirez) von Arx Y-17574 192.55 9 F Dipodasclls spicifer de Hoog, Smith & Gueho Y-17578 244.85 F Dipodascus tetraspenna (Macy & Miller) von Arx Y-7288 765.70 F Emericella nidulans (Eidam) Vuillemin 22233 CP decipiens Reess Y-17609 ATCC 11647 F Endomyces scopulamm Helfer Y-17633 131.86 F Eremothecium ashbyi Guilliermond Y-1363 7 Eremothecium cymbalariae Borzi [TSp] Y-17582 270.75 Galactomyces (Butler & Peterson) Redhead & Malloch [TSp] Y-17569 772.71 9 MP F Galactomyces reessii (van der Walt) Redhead & Malloch Y-17566 179.60 F Geotrichum clavatllm de Hoog, Smith & Gueho Y-17570 425.71 F Geotrichum jertlzentans (Diddens & Lodder) von Arx Y-17567 439.83 F Geotrichum jragrans (Berkhout) Morenz ex Morenz Y-17571 152.25 F Geotrichum klebahnii (Stautz) Morenz Y-17568 179.30 F GuilliertllOndella selenospora Nadson & Krasil'nikov [TSp] Y-1357 2562 8 MPER B Holleya sinecauda (Holley) Yamada [TSp] Y-17231 8199 9 B HortllOascus ambrosiae (van der Walt & Scott) van der Walt & von Arx Y-7524 6003 7 DO B HortllOascus philentomus (van der Walt, Scott & van der Klift) van der Walt & von Arx Y-7523 6276 DO B HortllOascus platypodis (Baker & Kreger-van Rij) von Arx [TSp] Y-6732 4111 7 DO B 8826 Can. J. Bot. Vol. 73 (8uppl.1), 1995

Table 1 (concluded).

Strain designationsb Hyphald Budding or Species a NRRL CBS Co-Qc septum fission e

Nematospora coryli Peglion [TSp] Y-12970 2608 5,6 B Neurospora crassa Shear & Dodge 13141 Oosporidium miirgaritiferum Stautz [TSp] Y-1519 2531 B Pichia humboldtii Rodrigues de Miranda & Torok Y-10929 6787 B/F Saccharomycopsis capsularis Schionning [TSp] Y-17639 2519 8 MPER B Saccharomycopsis crataegensis Kurtzman & Wickerham Y-5902 6447 8 MPER B/F Saccharomycopsis fibuligera (Lindner) Klocker Y-2388 2521 8 MPER B/F Saccharomycopsis malanga (Dwidjoseputro) Kurtzman, Vesonder & Smiley Y-7175 6267 8 MPER B Saccharomycopsis vini (Kreger-van Rij) van der Walt & Scott Y-7290 4110 8 MPER B Schizoblastosporion starkeyi-henrici Ciferri [TSp] YB-3963 2159 6 B Schizosaccharomyces pombe Lindner [TSp] Y-12796 356 10 F Stephanoascus ciferrii Smith, van der Walt & Johannsen [TSp] Y-10943 5295 9 MPER B Stephanoascus farinosus de Hoog, Rantio-Lehtimiiki & Smith Y-17593 140.71 B Sympodiomyces parvus Fell & Statzell [TSp] Y-10004 6147 9 B Yarrowia lipolytica (Wickerham, Kurtzman & Herman) van der Walt & von Arx [TSp] YB-423 6124 9 MP B/F Zygoascus helleniclls Smith [TSp] Y-6591 4099 9 MP B

"[TSpJ, Type species of the . bNRRL, ARS Culture Collection, National Center for Agricultural Utilization Research, Peoria, Ill. CBS, Centraalbureau voor Schimmelcultures, Baarn/Delft, The Netherlands. ATCC, American Type Culture Collection, Rock-ville, Md. cCo-Q, number of isoprene units on the side chain of coenzyme Q or ubiquinone. Data from Barnett et al. (1990) and Yamada et al. (1987). dDO, dolipore-like; CP, central pore; MP, micropore; MPER, multiperforate.

Fig. 1. A phylogenetic tree derived from maximum parsimony analysis depicting the mycelial ascomycetous yeasts, yeastiike fungi, and various reference species. The phylogram was calculated from nucleotide divergence in the 5' end of the large subunit rRNA gene (positions 63 -680). Branch lengths are proportional to nucleotide differences and the numbers given on branches are the percentage of frequencies with which a given branch appeared in 100 bootstrap replications. Branches with frequencies of less than 50% were collapsed. The letters A- J refer in the text to specific areas of the tree.

A

8 82

100 c

D

E

86

F 100

G 100

58

79

96 91 H

-- Ashbya gossypii Nematospora coryli 100 Holleya sillecauda Eremothecium cymbalariae 60 Eremothecium ashbyi Elldomyces scopularum 100 Neurospora crassa ,..---- Oosporidium margaritiferum J .....---- Emericella llidulalls 1..- Schizosaccharomyces pombe

determined from the program PADP 3.1.1 (Swofford 1993) heuristic search with the random addition option of PADP. using the general heuristic search option followed by boot­ Sequences for the strains listed in Table 1 have been strap analysis (100 replications). An alternative analysis used deposited in GenBank. S828 Can. J. Bot. Vol. 73 (SuppI.1), 1995

Results and discussion within clades, and many of the clades coincide with accepted genera. Intergeneric relationships are not well resolved but Phylogenetic analyses spe~i~s assignments to clades are strongly supported by The phylogeny of mycelial yeasts as estimated from rDNA statIstIcal analysis (bootstrap values, 82 - 100%). sequence divergence is shown in Fig. 1. Of the 618 nucleo­ tides sequenced (corresponding to positions 63 - 680 of Sac­ Stepharzoascus/Arxula/Blastobotrys/Sympodiomyces charomyces cerevisiae) , there were 411 variable sites of From morphological similarities, de Hoog et al. (1985) sug­ whic~ 342 w~r~ phylogenetically informative. A ph~lo­ gested a teleomorph-anamorph connection between Stephano­ genetic analySIS Implemented by the heuristic search option ascus and Blastobotrys, and this prediction is confirmed from of PAUP found in excess of 100 equally parsimonious trees of rDNA sequence analysis (Fig. IB). Smith and Batenburg­ 2256 steps (consistency index (CI) = 0.348, retention index van der Vegte (1985) showed by transmission electron (RI) = 0.688). .Schizosaccharomyces pombe was the desig­ m~croscopy that Stephanoascus ciferrii forms hyphal septa nated outgroup m the analyses. The heuristic search with the wIth several randomly placed micropores, whereas Stephan­ random addition option gave identical results. Because there oascus farinosus has a single, centrally placed micropore is considerable nucleotide variability at the 3' end of the (Table 1). Kreger-van Rij (l984c) proposed that cono-eneric region sequenced, inaccurate sequence alio-nment could species exhibit the same type of septal pore, but the ~resent markedly impact estimates of phylogenetic °relationships. analysis suggests that some variation in septum ultrastructure The sequences were reanalyzed following deletion of 242 may be found within a genus. Two additional species of ?ucleotides from the 3' ends. Resulting trees were essentially Stephanoascus (Traquair et al. 1988) were examined in the Identical to analyses that included all nucleotides. The one present study. However, nucleotide sequences from avail­ exception was a statistically weak (bootstrap value 61 %) able cultures of Stephanoascus jlocculosus Traquair, Shaw, association between Zygoascus and Dipodascopsis not seen and Jarvis (CBS 167.88, NRRL Y-17627) and Stephanoascus when all nucleotides were analyzed. The stability of species rugulosus Traquair et al. (CBS 170.88, NRRL Y-17626) rel~tionships within a clade was further examined by com­ proved to be basidiomycetous. panng members of each clade with an outgroup species Zygoascus hellenicus shares many phenotypic properties selected from an adjacent clade. For example, species of the with species of Stephanoascus (Table 1). However the Saccharomycopsis clade were analyzed with Ambrosiozyma divergent position of Zygoascus (Fig. 1) suggests it to' be a monospora as the designated outgroup. Such comparisons separate genus. resulted in only minor shifts of species within a clade and The placement of Sympodiomyces and Ar.xula in the each clade showed a much higher CI (range for all clades, Stephanoascus clade was not predicted. Blastobotrys was 0.621-0.862) than obtained when all species were included originally described as a hyphomycete, whereas Sympodi­ in th~ same heuristic.search. Earlier, we compared the type omyces and Arxula were considered yeasts. Van der Walt speCIes of all genera mcluded in the present study from their et al. (1990) pointed out in their description of Ar;rula that divergence in three different regions of 300 nucleotides each the genus is unique because of marked xerotolerance, multi­ (Kurtzman and Robnett 1994a). One region corresponded to perforate septa, and ability to utilize certain purines. How­ the 3' end of the sequences examined in the present study, ever, these authors did note that Stephanoascus ciferrii has the second to a more conserved region in the laro-e subunit similar properties. From our analysis, Blastobotrys, An:ula, (positions 1520- 1819), and the third to a conser~ed reo-ion and Sympodiomyces represent the same anamorphic genus. in the small subunit (positions 1313-1612). Phyloo-e;etic Blastobotrys has taxonomic priority, but we refrain from relationships among species common to the two studi:S were proposing new combinations at this time, because the type nearly identical when all three regions were analyzed together strain of Candida chiropterol11l11 Grose & Marinkelle is also and when the combined sequences ofthe two more conserved a member of this clade (data not shown), thus suggesting regions were compared. other nomenclatural possibilities.

Recognition of species and genera from extent of Cephaloascus rRNA/rDNA divergence The two known species of Cephaloascus are closely related Comparisons of species defined from genetic crosses (Fig. lC) despite marked differences in hyphal septum ultra­ have demonstrated that the extent of substitutions in laro-e s~ructure. Cephaloascus fragrans has septa with a pronounced subunit region 330-630 does not generally exceed 1% amo~o­ smgle central pore similar to many euascomycetes, whereas conspecific strains and is often less (Peterson and Kurtzma~ septa of Cephaloascus albidus have a single central micro­ 1991; Kurtzman and Robnett 1991). Recognition of genera pore (Kurtzman 1977). This observation, along with the from molecular comparisons is less well understood. Yeast heterogeneity of septum structure seen in the Stephanoascus genera that appear monophyletic show 3- 20 %divero-ence in clade, is another example that septum ultrastructure can vary large subunit region 330-630 (Kurtzman 1993). H~wever, among species of a genus. it needs to be determined whether these genera represent well separated clades or whether they intergrade. Ambrosiozyma/Honnoascus In the present study, the clades recognized in our analysis Species ofthis clade (Fig. ID) are unique among the filamen­ are treated as genera. Not all show the same extent of nucleo­ tous members ofthe yeasts because they form inflated hyphal tide substitutions. This may reflect differing times of diver­ septa that have been termed doliporelike. The genus Hor­ gence, differing rates of substitution, or both. The most moascus was described for nitrate-assimilating members of divergent clade (H) in the present study has 20 % substitu­ Ambrosiozyma (Ambrosiozyma ambrosiae, Ambrosiozyma tions. Interclade divergence is generally twice that found philentoma, and Ambrosiozyma platypodis) (von Arx 1972), E4.6. Kurtzman and Robnett 8829 but this reassignment was not accepted by Kreger-van Rij Kurtzman & Robnett, comb.nov. Basionym: Endo­ (1984a). Our analysis shows the species to be monophyletic myces schoenii Nadson & Krasil'nikov. Dokl. Akad. and closely related, leading us to consider Hormoascus a Nauk SSSR, 13: 313. 1932. synonym ofAmbrosioz:yma. "Honnoascus" ambrosiae differs 8. Saccharomycopsis selenospora (Nadson & Krasil'ni­ from "Hormoascus" platypodis by just two nucleotides kov) Kurtzman & Robnett, comb.nov. Basionym: (0.3 %) and is considered a synonym of the latter species. Guilliennondella selenospora Nadson & Krasil'nikov. Compt. Rend. 187: 307. 1928. SaccharomycopsislArthroascuslBotryoascusl 9. Saccharomycopsis synnaedendra Scott & van der Guilliennondella Walt. Members of this clade (Fig. IE) show considerable species­ 10. Saccharomycopsis vini (Kreger-van Rij) van der Walt specific variation in the shape oftheir ascospores. Morpholo­ & Scott. gies may be hat-shaped (galeate) or spheroidal to elongate, and with or without equatorial ledges or short polar append­ DipodascuslEndomyceslGeotrichum ages. Asci are generally spheroidal to ellipsoidal and either On the basis ofrDNA sequence analysis, species ofDipodas­ free or attached to hyphae. Arthroascus and Guilliermondella cus separate into two clades (Fig. 1, G and H). Both clades are distinguished from one another by ascospore morphology are characterized by Geotrichum anamorphs. Species in the and from the remainder of the taxa in this clade by the mor­ Dipodascus ingens clade (Fig. IG) are characterized by asci phology of their asci, which are typically converted hyphal producing one to four ascospores, whereas Dipodascus spe­ cells (Kreger-van Rij 1984b, 1984c). Many of the other cies in the Dipodascus albidus clade have asci that produce species occasionally form ascospores in hyphal cells. The in excess of four ascospores. However, the two species of hyphal septa of Arthroascus exhibit a single central micro­ Galactomyces that are members of this latter clade form one pore, but septa of other taxa in the clade are multiperforate. or two ascospores per ascus, thus obscuring any distinction A majority of the species in this clade were formerly of the two clades from ascospore numbers. assigned to Endomycopsis. However, van der Walt and Scott The delimitation of Endomyces from Dipodascus and (1971) pointed out that Endomycopsis was an obligate syno­ Saccharomycopsis and its synonyms has been controversial, nym of Saccharomycopsis resulting in the reassignment of because Endomyces decipiens, the type species of the order some species to Saccharomycopsis, Guilliermondella, Endo­ Endomycetales, is known only from the drawings of Brefeld myces (Saccharomycopsis fibuligera), and Endomycopsella (von Arx 1972). In an effort to preserve nomenclatural (Saccharomycopsis crataegensis and Saccharomycopsis vini), stability, Redhead and Malloch (1977) designated as neotype and to the newly described genera Arthroascus, Botryoascus, a specimen of Endomyces decipiens found on Agaricus and Yarrowia (von Arx 1972; van der Walt and von Arx melleus. In the present study, we sequenced living cultures 1980). The history of these taxonomic changes was briefly that had been designated as Endomyces decipiens and Endo­ reviewed by von Arx (1972) and von Arx and Yarrow myces scopulanll1z (Table I). The strain identified as (1984). Endomyces decipiens is a member of the Dipodascus albidus Our analysis of the taxa discussed above places all except clade, whereas Endomyces scopulanmz is a member of the Yarrowia lipolytica, which is quite divergent, in a single euascomycete clade (Fig. 11). clade and suggests that they are congeneric. This interpreta­ Although species assigned to Endomyces are typically tion is consistent with our study of type species from the described as having hat-shaped ascospores, these taxa may above genera in which partial sequences of large subunit still be closely related to Dipodascus because they charac­ (two regions) and small subunit (one region) rRNAs were teristically form arthrospores. Consequently, the phylogeny compared (Kurtzman and Robnett 1994a). In the present and nomenclatural status of Endomyces need to be resolved work, Saccharomycopsis fibuligera and Botryoascus clado­ before taxonomic changes can be made that reflect the phylo­ sporoides were found to differ by two nucleotides, and we genetic diversity found among species placed in Dipodascus. consider the latter taxon a synonym of the former. The controversy of Endomyces can be settled by sequencing We propose assignment of the following species to the the species with hat-shaped spores that are found on agarics. genus Saccharomycopsis Schionning. Four of the species are Although the Endomyces from agarics may not grow in pure new combinations. culture (Redhead and Malloch 1977), sequencing should still 1. Saccharomycopsis capsularis Schionning. be possible through use of taxon-specific primers and PCR­ 2. Saccharomycopsis crataegensis Kurtzman & based technology. Wickerham. 3. Saccharomycopsisjennentans (Lee, Lee, Hsu & Phaff) AshbyalEremotheciumlHolleyalNematospora Kurtzman & Robnett, comb.nov. Basionym: Arthro­ The four genera in this clade (Fig. II) are phylogenetically ascus jermentans Lee, Lee, Hsu & Phaff. Int. J. Syst. and morphologically similar. Kurtzman (1995) has proposed Bacteriol. 44: 305. 1994. that the taxa are congeneric and all should be assigned to 4. Saccharomycopsis fibuligera (Lindner) Klocker. Eremothecium. 5. Saccharomycopsis javanensis (Klocker) Kurtzman & Robnett, comb.nov. Basionym: Endomyces javanen­ SchizoblastosporionlBotryozymalAciculoconidiuml sis Klocker. C.R. Trav. Lab. Carlsberg, 7: 267. Oosporidium 1909. The teleomorphic states of these four monotypic genera are 6. Saccharomycopsis malanga (Dwidjoseputro) Kurtz­ unknown, and all exhibit unusual cellular morphologies. man, Vesonder & Smiley. rDNA analysis places Schizoblastosporion, Botryozyma, and 7. Saccharomycopsis schoenii (Nadson & Krasil'nikov) Aciculoconidium in the yeast clade but shows Oosporidium 8830 Can. J. Bot. Vol. 73 (8uppI.1). 1995 to be a euascomycete. Aciculoconidium is phylogenetically Kurtzman, c.P. 1995. Relationships among the genera Ashbya. near Yarrowia lipolytica and might be expected to have a Eremothecium, Holleya and Nematospora determined from similar teleomorph. rDNA sequence divergence. J. Ind. Microbiol. In press. Kurtzman, C.P., and Robnett, C.J. 1991. Phylogenetic relationships among species of Saccharomyces, Conclusions Schizosaccharomyces, Debaryomyces, and Schwanniomyces Phenotypic characters such as ascospore morphology and determined from partial ribosomal RNA sequences. Yeast, 7: 61-72. septum ultrastructure are often useful for recognition of indi­ Kurtzman, c.P., and Robnett, c.J. 1994a. Orders and families vidual species, but the comparisons presented in this study of ascosporogenous yeasts and yeast-like taxa compared from demonstrate that they are poor predictors of phylogenetic ribosomal RNA sequence similarities. In Ascomycete relatedness. Some of the relationships reported here were not systematics: problems and perspectives in the nineties. unexpected, but others, such as the deep division within Edited by D.L. Hawksworth. Plenum Press, New York. Dipodascus, proved surprising. The results of our study pp. 249-258. argue for continued application of molecular comparisons if Kurtzman, c.P., and Robnett, C.J. 1994b. Synonymy of the is to be based on phylogeny. yeast genera Wingea and Debaryomyces. Antonie Leeuwenhoek. 66: 337-342. Nishida, H., and Sugiyama, J. 1993. Phylogenetic relationships Acknowledgment among Taphrina, Saitoella, and other higher fungi. Mol. BioI. Evo!. 10: 431-436. Larry W. 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