Emendation of the basidiomycetous yeast genus Kondoa and the description of Kondoa aeria sp. nov

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Antonie van Leeuwenhoek 77: 293–302, 2000. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 293 Emendation of the basidiomycetous yeast genus Kondoa and the description of Kondoa aeria sp. nov ´ Alvaro Fonseca 1,* , Jos´ e Paulo Sampaio 1 , João In´ acio 1 & Jack W. Fell 2 1 Biotechnology Unit, Faculty of Sciences & Technology/New University of Lisbon, Caparica, Portugal; 2 Rosenstiel School of Marine & Atmospheric Science, University of Miami, Key Biscayne, FL, USA ( * Author for correspond- ence; E-mail: [email protected]) Received 18 August 1999; accepted 30 November 1999 Key words: Basidiomycetous yeasts, Kondoa aeria sp. nov., ribosomal DNA sequencing, taxonomy Abstract The genus Kondoa Y. Yamada, Nakagawa & Banno was erected to accommodate a single taxon, K. malvinella (Fell & Hunter) Y. Yamada, Nakagawa & Banno, which was transferred from the teliospore-forming genus Rhodospor- idium Banno based on pronounced differences in the 5S and 26S ribosomal RNA (rRNA) nucleotide sequences to R. toruloides Banno. In contrast with the original description, reinvestigation of K. malvinella revealed the formation of transversely septate (auricularioid) basidia that did not arise on teliospores, but formed directly on the dikaryotic mycelium. The four-celled basidia developed sterigmata on which forcibly discharged asymmetric basidiospores (ballistospores) were produced. Additionally, a new taxon emerged from the study of recent isolates, for which the name K. aeria sp. nov. is proposed. This new species produced two-celled auricularioid basidia on hyphae with incomplete clamp connections. Ballistospores arose on the basidia at the tip of sterigmata and, after ejection, germinated by budding. These observations led us to present an emended diagnosis for the genus Kondoa. Analysis of the sequence data from the D1/D2 region of the 26S rRNA gene showed a very close resemblance between K. aeria and K. malvinella in a cluster that also contained several Bensingtonia species. Taxa in this cluster share specific physiological traits and produce characteristic pinkish-cream to mauve colonies; in contrast, formation of ballistoconidia is only observed in the Bensingtonia species. Sequence data supported placement of K. malvinella and K. aeria in the ‘Agaricostilbum clade’ of the Urediniomycetes. Introduction The description of Rhodosporidium malvinellum Fell & Hunter was based on several strains isolated from ocean water in the Antarctic region (Fell 1970) and subsequently this species was reported from a coastal area of the Baltic Sea by Laurenavichene et al. (1989). The species was found to be heterothallic and the life cycle was apparently identical to other Rhodospor- idium species, namely with the formation of a 2-celled phragmometabasidium resulting from the germina- tion of subglobose teliospores (Fell 1970). Based on the comparative analysis of 5S rRNA nucleotide sequences from ca. 50 representative taxa of basidio- mycetes, Gottschalk & Blanz (1985) suggested that R. malvinellum should be placed in a separate genus. Yamada et al. (1989) determined partial sequences of the 18S and 26S rRNA and erected the genus Kondoa to accommodate R. malvinellum due to pronounced differences in nucleotide sequence to R. toruloides, the type species of the genus. The authors based the generic diagnosis on the original description of R. malvinellum and assigned the genus Kondoa to the Filobasidiaceae. The same authors using more rep- resentatives of Rhodosporidium later confirmed the unique phylogenetic position of K. malvinella as in- ferred from sequence analysis (Yamada et al. 1990). However, assignment of Kondoa to the Filobasidi- aceae has been rejected on the basis of cell-wall monosaccharide patterns determined by Prillinger et al. (1993) as well as on the analysis of the D1/D2 region of the 26S rRNA gene by Fell et al. (1992,

Transcript of Emendation of the basidiomycetous yeast genus Kondoa and the description of Kondoa aeria sp. nov

Antonie van Leeuwenhoek77: 293–302, 2000.© 2000Kluwer Academic Publishers. Printed in the Netherlands.

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Emendation of the basidiomycetous yeast genusKondoaand thedescription of Kondoa aeriasp. nov

Alvaro Fonseca1,∗, Jose Paulo Sampaio1, João Inacio1 & Jack W. Fell21Biotechnology Unit, Faculty of Sciences & Technology/New University of Lisbon, Caparica, Portugal;2RosenstielSchool of Marine & Atmospheric Science, University of Miami, Key Biscayne, FL, USA (∗Author for correspond-ence; E-mail: [email protected])

Received 18 August 1999; accepted 30 November 1999

Key words:Basidiomycetous yeasts,Kondoa aeriasp. nov., ribosomal DNA sequencing, taxonomy

Abstract

The genusKondoaY. Yamada, Nakagawa & Banno was erected to accommodate a single taxon,K. malvinella(Fell& Hunter) Y. Yamada, Nakagawa & Banno, which was transferred from the teliospore-forming genusRhodospor-idium Banno based on pronounced differences in the 5S and 26S ribosomal RNA (rRNA) nucleotide sequencesto R. toruloidesBanno. In contrast with the original description, reinvestigation ofK. malvinella revealed theformation of transversely septate (auricularioid) basidia that did not arise on teliospores, but formed directly onthe dikaryotic mycelium. The four-celled basidia developed sterigmata on which forcibly discharged asymmetricbasidiospores (ballistospores) were produced. Additionally, a new taxon emerged from the study of recent isolates,for which the nameK. aeria sp. nov. is proposed. This new species produced two-celled auricularioid basidia onhyphae with incomplete clamp connections. Ballistospores arose on the basidia at the tip of sterigmata and, afterejection, germinated by budding. These observations led us to present an emended diagnosis for the genusKondoa.Analysis of the sequence data from the D1/D2 region of the 26S rRNA gene showed a very close resemblancebetweenK. aeria and K. malvinella in a cluster that also contained severalBensingtoniaspecies. Taxa in thiscluster share specific physiological traits and produce characteristic pinkish-cream to mauve colonies; in contrast,formation of ballistoconidia is only observed in theBensingtoniaspecies. Sequence data supported placement ofK. malvinellaandK. aeria in the ‘Agaricostilbum clade’ of the Urediniomycetes.

Introduction

The description ofRhodosporidium malvinellumFell& Hunter was based on several strains isolated fromocean water in the Antarctic region (Fell 1970) andsubsequently this species was reported from a coastalarea of the Baltic Sea by Laurenavichene et al. (1989).The species was found to be heterothallic and the lifecycle was apparently identical to otherRhodospor-idiumspecies, namely with the formation of a 2-celledphragmometabasidium resulting from the germina-tion of subglobose teliospores (Fell 1970). Basedon the comparative analysis of 5S rRNA nucleotidesequences from ca. 50 representative taxa of basidio-mycetes, Gottschalk & Blanz (1985) suggested thatR. malvinellumshould be placed in a separate genus.

Yamada et al. (1989) determined partial sequences ofthe 18S and 26S rRNA and erected the genusKondoato accommodateR. malvinellumdue to pronounceddifferences in nucleotide sequence toR. toruloides,the type species of the genus. The authors based thegeneric diagnosis on the original description ofR.malvinellumand assigned the genusKondoa to theFilobasidiaceae. The same authors using more rep-resentatives ofRhodosporidiumlater confirmed theunique phylogenetic position ofK. malvinellaas in-ferred from sequence analysis (Yamada et al. 1990).However, assignment ofKondoa to the Filobasidi-aceae has been rejected on the basis of cell-wallmonosaccharide patterns determined by Prillinger etal. (1993) as well as on the analysis of the D1/D2region of the 26S rRNA gene by Fell et al. (1992,

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Table 1. Strains used in this study

Species Strain1 Sexuality2 GenBank #

Agaricostilbum hyphaenesCBS 7811 AF177406

Bensingtonia ciliata CBS 7514T AF189887

B. miscanthii CBS 7282T AF189891

B. phyllada CBS 7169T AF189894

B. subrosea CBS 7283T AF189895

B. yuccicola CBS 7331T AF189897

Kondoa malvinella CBS 6082T Het AF189903

CBS 6083 Het –

K. aeria IGC 5087T Ss AF189901

IGC 5549 Ss AF204055

IGC 5565 Ss AF204054

IGC 5548 Asexual AF189902

Kurtzmanomyces nectaireiCBS 6405T AF177409

Sporobolomyces lactophilusCBS 7527T AF177411

Sterigmatomyces elviae CBS 5922T AF177415

St. halophilus CBS 4609T AF177416

Rhodosporidium CBS 6085T AF070421

diobovatum

R. kratochvilovae CBS 7436T AF071436

R. toruloides CBS 0349 AF070426

1CBS, the Yeast Division of the Centraalbureau voor Schimmel-cultures, Delft, The Netherlands; IGC, Portuguese Yeast CultureCollection, Monte de Caparica, Portugal; T, type strain.2Het, heterothallic; Ss, self-sporulating.

1995). These later authors showedR. malvinellumtobe closely related to severalBensingtoniaspecies andonly distantly related to other members ofRhodospor-idium. Swann & Taylor (1995a) suggested thatK.malvinellais a member of the ‘Agaricostilbum clade’of the Urediniomycetes based on partial sequences ofthe 18S rRNA gene. In the 4th edition of ‘The Yeasts’monograph, Fell & Statzell-Tallman (1998) chose tomaintain the taxonomic binomialR. malvinellumsincethey felt there was not sufficient physiological andmorphological evidence to support the molecular data.Here we report additional morphological evidence thatconfirmsKondoaas a distinct genus, the descriptionof a new species,K. aeria, to accommodate 4 strainsrecently isolated in Portugal, and the emendation ofthe diagnosis of the genusKondoa.

Methods

Strains studied. Table 1 lists the strains used in thisstudy and their respective sources. Yeast strains weremaintained on potato-dextrose agar (PDA) slants at4 ◦C.

Characterization of the strains.Micromorphologywas investigated using light microscopy and phasecontrast optics. The identification methods followedstandard protocols (Yarrow 1998). In addition to as-sessing the utilization of standard carbon compoundsin liquid media, 6 aldaric acids (Fonseca 1992) and11 aromatic compounds (Sampaio 1994) were testedusing the techniques of Yarrow (1998). The only dif-ference resided in the concentrations used for thearomatic compounds – 0.1% (w/v) – since some ofthe compounds can be toxic for yeasts. Results from68 physiological tests (listed in Table 2) were inte-grated using numerical taxonomy. This analysis usedthe Simple Matching coefficient and the UPGMAclustering method. Determination of molar content ofG+C in genomic DNA (nDNA) – thermal denatura-tion method; four determinations; reference: nDNA ofCandida parapsilosisCBS 604 (mol % G+C = 40.2) –followed Giménez-Jurado et al. (1990). DNA isolationand PCR amplification for sequencing were performedusing standard protocols (Kurtzman & Robnett 1998).The DNA was amplified with universal fungal primersITS 5 (5′ GGA AGT AAA AGT CGT AAC AAG G)and LR6 (5′ CGC CAG TTC TGC TTA CC) usingMJ Research Thermal Cyclers. The resulting ampliconwas purified with the QIAquick PCR purification kit.The sequence from the D1/D2 600-650 base pair re-gion at the 5′ end of the 26S rDNA was obtained witha Li-Cor Automated Sequencer (LI-COR Inc., USA)using standard protocols (Fell et al. 1999). Cycle se-quencing employed forward primer F63 (5′ GCA TATCAA TAA GCG GAG GAA AAG) and reverse primerLR3 (5′ GGT CCG TGT TTC AAG ACG G). Phylo-genetic trees were computed from aligned nucleotidesequences according to the procedures described byFell et al. (1999). The nucleotide sequence for strainsIGC 5087, IGC 5548, IGC 5549 and IGC 5565, de-termined in this study, were deposited in GenBankunder accession numbers listed in Table 1. All othersequences are available at GenBank (Table 1).

Results

Re-investigation ofKondoa malvinella

The life cycle of K. malvinella was examined bylight microscopy. After mixing compatible matingtypes (CBS 6082 and CBS 6083) on corn meal agar(CMA) plates incubated at 15–18◦C, cell-cell conjug-ation and the subsequent formation of dikaryotic my-celium with clamp connections were readily observed

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Table 2. Physiological characteristics ofKondoa aeriasp. nov.

Assimilation of carbon compounds1:

D-Glucose + Inulin − Aldaric acids:

D-Galactose +, D Soluble starch + L-tartaric acid −L-Sorbose −, D Glycerol + D-tartaric acid −D-Glucosamine − Erythritol − meso-tartaric acid −D-Ribose − Ribitol + Saccharic acid −D-Xylose +, D Xylitol +, D Mucic acid −L-Arabinose −, D D-Glucitol + Aromatic compounds:

D-Arabinose −, D D-Mannitol + Protocatechuic acid +

L-Rhamnose − Galactitol −, D Vanillic acid +

Sucrose + Inositol − Veratric acid −Maltose + Glucono-δ-lactone − Ferulic acid −α,α-Trehalose + D-Gluconate −, D p-Hydroxybenzoic acid +, D

Methyl-α-glucoside − D-Glucuronate − m-Hydroxybenzoic acid −Cellobiose +, D D,L-lactic acid D Gallic acid −Salicin +, D Succinic acid + Salicylic acid −Melibiose − Citric acid + Gentisic acid −Lactose − L-malic acid W, D Catechol −Raffinose W, D Methanol − Phenol −Melezitose − Ethanol −

Utilization of nitrogen sources1:

Potassium nitrate D Ethylamine − Cadaverine W, D Creatinine −Sodium nitrite −, D L-Lysine − Creatine −

Other tests:

Growth in vitamin-free medium: Absent

Growth at 25◦C: +

Growth at 30◦C: −Formation of extracellular starch-like compounds: Absent

Growth in the presence of 0.01% cycloheximide: Absent

Urea hydrolysis: Present

Colour reaction with Diazonium Blue B: Present

1Test results: +, positive; D, delayed positive; W, weak, WD, delayed weak; -, negative.

within less than a week, as reported in the originaldescription (Fell 1970). In the following 6 weeks,periodic inspections did not reveal the presence ofteliospores. Instead, thin-walled chlamydospore-likecells were sometimes observed (Figures 1a, b). Thesecells differed from typicalRhodosporidiumteliosporesby the absence of a thick wall and a clamp connectionat the base, and the rapid loss of cytoplasmic materialwithout the formation of a metabasidium. Moreover,after ca. two months we detected the formation of auri-cularioid basidia directly on the dikaryotic mycelium.The basidia 3.5–4.5× 25–40µm were four-celled(rarely three-celled) and produced allantoid ballisto-spores 3.5–4.5× 10–15µm at the end of sterigmata

(Figures 1c, d, e & 3a). Sometimes endospores couldbe seen in basidial cells. However, we could not findteliospores or the two-celled phragmometabasidia re-ported in the original description of this species (Fell1970).

Description ofKondoa aeriasp. nov.

The examination of several recent isolates led to therecognition of a second taxon of the genusKondoa,for which the nameK. aeriasp. nov. is proposed. Thedescription is presented below.

Latin diagnosis ofKondoa aeriaFonseca, Sampaio& Fell sp. nov.

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Figure 1. Micrographs ofK. malvinellaCBS 6082× CBS 6083: (a, b) chlamydospore-like cells; (c, d) 4-celled basidia; (e) ballistosporesattached to basidium. Culture conditions: CMA, 18◦C, after ca. 1 month (a, b) or after ca. 2 months (c–e). Insert bar: 10µm (scale bar is thesame for all micrographs).

Species dimorpha. In stadio filamentoso hyphisfibulis imcompletis crescit. Basidia transverse septatacompartimentis duobus, lateraliter vel terminaliter ehyphis orientia. Basidiosporae a sterigmatibus partae

coniciuntur compartimentis basidii evacuatis; gemma-tione germinantes. Nonnumquam conidia non coniect-abilia (sporidia) abstringuntur.

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Figure 2. Micrographs ofK. aeria: (a) vegetative cells (IGC 5087); (b) mycelium with incomplete clamp connection (IGC 5087); (c) youngbasidium (IGC 5565) (CMA; 20◦C); (d, e) empty 2-celled basidia (IGC 5087); (f) germinating basidiospore (IGC 5087). Culture conditions:YM broth, 20◦C, after 5 days (a); CMA, 20◦C, after ca. 2 months (b–f). Insert bar: 10µm (scale bar is the same for all micrographs).

In medio liquido cum dextroso et peptono etextracto levedinis et extracto malti post dies 5 ad20 ◦C cellulae sunt ellipsoideae ad cylindratae 3–6 × 5–9 µm, singulae vel binae. Reproductiovegetativa gemmatione enteroblastica. Sedimentumadest. Cultura in agaro cum dextroso et pep-tono et extracto levedinis et extracto malti postdies 7 ad 25◦C, cremea, glabra, nitida, butyr-acea, margo integer. In agaro farina Zeae maydis

confecto post dies 7 ad 20◦C, mycelium verumformatur. Glucosum non fermentatur. Glucosum,galactosum (lente), D-xylosum (lente), L-arabinosum(variabiliter), D-arabinosum (variabiliter), saccharum,maltosum, trehalosum, cellobiosum (lente), salicinum(lente), raffinosum (exigue, lente), amylum, glycer-olum, ribitolum, xylitolum (lente), D-glucitolum, D-mannitolum, galactitolum (variabiliter), acidum DL-lacticum (lente), acidum succinicum, acidum citricum

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et acidum L-malicum (lente, exigue) assimilanturat non D-glucosaminum, L-sorbosum, D-ribosum,L-rhamnosum,α-methyl-D-glucosidum, melibiosum,lactosum, melezitosum, inulinum, erythritolum, inos-itolum, glucono-δ-lactonum, acidum D-gluconicum,acidum D-glucuronicum, acidum L-tartaricum, eth-anolum nec methanolum. Assimilatio kallii nitrati(lente), sodii nitrosi (variabiliter) et cadaverini (lente,exigue) ad non ethylamini, L-lysini, creatini nec creat-inini. Vitamina externa ad crescentiam necessaria sunt.Maxima temperatura crescentiae: 25–30◦C. Materiaamyloidea non formatur. Ureum finditur. Diazoniumcaeruleum B positivum. Proportio molaris guaniniplus cytosini in acido deoxyribonucleico: 52.4±0.5per centum (typus). Typus: IGC 5087, ex aere inLusitania isolatus, exsiccatus et vivus in collectionezymotica lusitanica et vivus in collectione zymoticaDelphis Batavorum (CBS 8352) praeservatus.

Growth in glucose (1%), peptone (0.5%), yeast ex-tract (0.3%), malt extract (0.3%) (YM) broth.After5 days at 20◦C the cells are ellipsoidal to cylindrical3–6 × 6–9 µm, and occur singly or in pairs (Fig-ure 2a). Vegetative reproduction is by enteroblasticconidiogenesis. No capsules are present. Sediment ispresent.

Growth on YM agar. After 1 week the colonies arecream-coloured to pinkish-cream, the surface is glossyand smooth, the texture is soft to butyrous and the mar-gins are entire. The pinkish-tinge is more conspicuouson PDA in at least 2-week old cultures. True myceliumdevelops into the agar.

Dalmau plate culture on corn meal agar.After 1week at 20◦C, true mycelium develops from singlecells in all strains except IGC 5548. After 1 month,hyphae with incomplete clamp connections are ob-served (Figure 2b). After 2 months, two-celled basidia3–5× 30–50µm develop laterally or terminally onthe hyphae (Figure 2c). Single allantoid ballistospores4.5–6.0× 10.5–16.5µm arise on sterigmata and thebasidial cells become empty (Figures 2d, e & 3b). En-dospores are occasionally observed in the basal cellof a few basidia. Empty and often distorted basidiaremain visible in cultures more than 2 months old andare found mainly on the agar surface. The ballisto-spores germinate by budding (Figure 2f). Strain IGC5549 also produced two-celled basidia that formedmultiple sessile basidiospores (sporidia) (Figure 3b);these basidia did not become empty and were observed

Figure 3. Line drawings of basidia and basidiospores ofKondoamalvinellaandK. aeria: (a) K. malvinellaCBS 6082× CBS 6083(CMA, 18 ◦C, after ca. 2 months); (b)K. aeria IGC 5549 (CMA,20◦C, after ca. 2 months); note that the basidium on the left did notdevelop sterigmata and produced sporidia instead of ballistospores.Insert bars: 5µm.

only on the hyphae growing into the agar. Strain IGC5548 did not produce filaments.

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Figure 4. Phenogram ofK. aeria and related species based on the responses of selected strains to 68 physiological tests (Simple-Matchingcoefficient, UPGMA cluster method).

Physiological characteristics ofKondoa aeriasp.nov. are listed in Table 2. Fermentation of glucose wasnot observed. Growth in liquid media was often slowand cell density never reached more than 2+ (resultscoring after Yarrow 1998).

Molar%G+C of nuclear DNA (Tm): 52.4±0.4(IGC 5087); 50.9±0.2 (IGC 5549); 50.5±0.2 (IGC5548).

rDNA partial sequencing: Nucleotide sequencesfrom the D1/D2 region of 26S rDNA for strains IGC5087, IGC 5548, IGC 5549 and IGC 5565 were de-posited at GenBank (Table 1). All four strains hadidentical D1/D2 sequences.

Physiological and molecular comparisons ofKon-doa aeriawith closely related species are illustrated inFigures 4 & 5, respectively.

Etimology. The specific epithetaeria refers to theapparent airborne origin of the propagules of themajority of strains.

Origin of the strains studied. Strains IGC 5087 (June1993), IGC 5548 (May 1994) and IGC 5565 (Nov.1996) were isolated as single colonies that appearedas contaminants on YM or CMA agar plates at differ-ent locations: Oeiras (IGC 5087) and Caparica (IGC

5548 and IGC 5565), Portugal. Strain IGC 5549 (Nov.1996) was isolated from a decayed basiodiocarp of adacrymycetaceous fungus using the ballistospore-fallmethod (Caramulo, Portugal). All strains are main-tained at the Portuguese Yeast Culture Collection (Ca-parica, Portugal), living and as lyophilised material.IGC 5087 was designated as the type strain and wasalso deposited at the Yeast Division of the Centraalbur-eau voor Schimmelcultures, Delft, The Netherlands(CBS 8352).

Emendation of the genusKondoa

As a result of the re-examination ofK. malvinellaandof the recognition ofK. aeriasp. nov., we propose anemended diagnosis of the genusKondoa.

KondoaYamada, Nakagawa & Banno emend. Fon-seca, Sampaio & Fell.

Genus is dimorphic and basidiocarps are lack-ing. Hyphae with or without clamp connections.Teliospores are absent. Transversely septate basidiaarise directly on the mycelium. Single, forcibly dis-charged basidiospores (ballistospores) arise at the tipof sterigmata on the basidial cells. Basidiospores ger-minate by budding. Multiple, passively abstrictedbasidiospores (sporidia) may also be present. En-

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Figure 5. One of three most parsimonious trees based on the analysis of sequences from the D1/D2 region of the 26S rRNA gene (ca. 600bp) of selected basidiomycetous species of the ‘Agaricostilbum clade’ using PAUP 4.0 (heuristic search, random step-wise addition, treebisection-reconnection). Species ofRhodosporidiumwere used as the outgroup. Branch lengths are proportional to the number of nucleotidedifferences and the numbers given on branches are the frequencies (>50%) with which a given branch appeared in 1000 bootstrap replications.

dospores may form in the basidia. Yeast coloniesare pinkish-cream to mauve. Starch-like compoundsare not produced. Inositol and D-glucuronate are notassimilated. GenusKondoabelongs to the ‘Agaricos-tilbum clade’ of the Urediniomycetes (sensuSwann &Taylor 1995b).

Species accepted:Kondoa malvinella (Fell &Hunter) Yamada, Nakagawa & Banno, basionym:Rhodosporidium malvinellumFell & Hunter;KondoaaeriaFonseca, Sampaio & Fell sp. nov.

Discussion

Re-investigation ofK. malvinellaby light microscopyrevealed that basidia formed directly on the dikaryoticmycelium, were of the auricularioid type and gave riseto ballistospores (Figure 3a). Globose chlamydospore-like cells were observed, but neither teliospores northe two-celled phragmometabasidia reported in theoriginal description of this species (Fell 1970) werefound in the present study. These observations werenot previously reported and, as far as we are aware,this type of basidium had not been observed in basi-

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Table 3. Selected characteristics ofKondoa aeriaandK. malvinella

Species Selected physiological characteristics1 Morphological characteristics2

L-ara Rha Rib mHB Lys (N) Cad (N) 25◦C Clamps Basidia Pigment.

Kondoa aeria − − + − − − + Inc. 2-cell Pinkish cream

Kondoa malvinella + + − + + + − Comp. 4-cell Mauve

1Assimilation of: L-arabinose, L-ara; L-rhamnose, Rha; ribitol, Rib; m-hydroxybenzoic acid, mHB; L-lysine (N-source), Lys (N);Cadaverine (N-source), Cad (N); growth at 25◦C.2Morphological characteristics: clamp connections (incomplete, inc.; complete, comp.); pigmentation of colonies (pigment.).

diomycetous yeasts. In fact, presently recognizedteleomorphic yeast species that produce auricularioid(meta)basidia also produce teliospores (probasidia)and their basidiospores are passively abstricted (c.f.Leucosporidium, Rhodosporidium, SakaguchiaandSporidiobolus) (Boekhout et al. 1998). However,among simple-pored, parasitic and/or basidiocarp-producing heterobasidiomycetes this type of basidiawas found in various orders, e.g. Platygloeales andSeptobasidiales (Boekhout et al. 1998). Recently,Sampaio et al. (1999) describedOccultifur externus,a dimorphic species that, like theKondoaspecies, wasisolated in the yeast phase and produced dikaryoticmycelium that developed auricularioid basidia withballistospores. Physiological and molecular data ledthe authors to assign the new taxon to the ‘Naohideaclade’ of the Urediniomycetes, thus phylogeneticallydistant fromKondoa.

According to 18S rDNA sequence data (Swann &Taylor 1995a),K. malvinellabelongs to the ‘Agaricos-tilbum clade’ that also contains the teleomorphic spe-ciesAgaricostilbum hyphaenes(Har. & Pat.) Oberw.& Bandoni andMycogloea macrospora(Berk. & Br.)McNabb. Both species produce auricularioid basidiathat do not arise from teliospores, a characteristicshared byKondoa. The morphology of the sexualstructures evidenced by the present study give ad-ditional support to the separation ofKondoa fromRhodosporidiumat the genus level, which was basedprimarily on sequence data.

The basidia ofKondoa aeria exhibited similarcharacteristics to those ofK. malvinella, i.e. theydid not originate from teliospores, possessed sterig-mata and produced forcibly discharged basidiospores.However,K. aeria differed fromK. malvinellaby thepresence of incomplete clamp connections and of two-celled basidia (Figure 3). In addition to morphology,the results of physiological characterization and therDNA sequence data from the new isolates supportthe assignment of strains IGC 5087, IGC 5565 and

IGC 5549 to a single species that is distinct fromK. malvinella (Figure 4). Although we did not ob-serve filamentous structures in strain IGC 5548, thephysiological profile as well as sequence data (Fig-ure 5) suggested that this strain represents the ana-morph ofK. aeria. Table 3 contains a selected list ofphysiological and morphological characteristics thatdifferentiate the twoKondoaspecies. The two speciesalso differ in their ecological distribution:K. malv-inella was isolated from seawater, whereasK. aeriawas found in terrestrial habitats and the dispersion ap-pears to be by airborne propagules. Since the yeastphase failed to produce ballistoconidia, the airbornecells may be the basidiospores. Additional isolatesmust be obtained to ascertain if the basidia are associ-ated with basidiocarps of other fungi, as might be thecase of strain IGC 5549. Analysis of the nucleotidesequences from the D1/D2 region of the 26S rDNAshowedK. aeriasp. nov. to be the closest relative ofK.malvinella(6 nucleotide differences) (Figure 5). Thisanalysis also revealed that the twoKondoa speciesbelong to the ‘Agaricostilbum lineage’, in agreementwith the results from the 18S rDNA of Swann &Taylor (1995a). TheKondoaclade contained severalrepresentatives of the anamorphic genusBensingtonia(B. miscanthii, B. phyllada, B. subroseaandB. yucci-cola), but not the type species (B. ciliata). The formerBensingtoniaspecies, which appear to be physiologic-ally related toKondoa(Figure 4), displayed similarmacromorphological characteristics, namely pinkish-cream colonies on PDA. However, vegetative cells ofthe Kondoaspecies did not produce ballistoconidia.We expect that a possible teleomorph of theBensing-tonia species in theKondoaclade will have similarcharacteristics to the ones displayed by theKondoaspecies.

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Acknowledgements

This research was supported in part by ‘Fundação paraa Ciência e Tecnologia’ (Praxis/PCNA/C/BIA/174/96,Portugal). J. Inácio was a recipient of a grantfrom ‘Fundação para a Ciência e Tecnologia’ (GGPXXI/BICJ/3855/96, Portugal). Funding for J.W. Fellwas provided by the National Science Foundation,Division of Ocean Sciences (USA). The authors are in-debted to Dr. Michael Weiss (University of Tübingen,Germany) for reviewing the latin diagnosis ofKondoaaeria.

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