The diversity of yeast species collected from the bromeliad tanks of Vriesea minarum, an endangered bromeliad species, and their ability to produce extracellular enzymes were studied. Water samples were collected from 30 tanks of bromeliads living in a rupestrian field site located at Serrada Piedade, Minas Gerais state, Brazil, during both the dry and rainy seasons. Thirty-six species were isolated, representing 22 basidiomycetous and 14 ascomycetous species. Occultifur sp., Cryptococcus podzolicus and Cryptococcus sp. 1 were the prevalent basidiomycetous species. The yeast-like fungus from the order Myriangiales, Candida silvae and Aureobasidium pullulans were the most frequent ascomycetous species. The diversity of the yeast communities obtained between seasons was not significantly different, but the yeast composition per bromeliad was different between seasons. These results suggest that there is significant spatial heterogeneity in the composition of populations of the yeast communities within bromeliad tanks, independent of the season. Among the 352 yeast isolates tested, 282 showed at least one enzymatic activity. Protease activity was the most widely expressed extracellular enzymatic activity, followed by xylanase, amylase, pectinase and cellulase activities. These enzymes may increase the carbon and nitrogen availability for the microbial food web in the bromeliad tank of V. minarum. Sequence analyses revealed the existence of 10 new species, indicating that bromeliad tanks are important sources of new yeasts. The novel species Occultifur brasiliensis, f.a., sp. nov., is proposed to accommodate the most frequently isolated yeast associated with V. minarum. The type strain of O. brasiliensis, f.a., sp. nov. is UFMG-CM-Y375(T) (= CBS 12687(T)). The Mycobank number is MB 809816.

Six novel yeast species, Starmerella camargoi f.a., sp. nov., Starmerella ilheusensis f.a., sp. nov., Starmerella litoralis f.a., Starmerella opuntiae f.a., sp. nov., sp. nov., Starmerella roubikii f.a., sp. nov. and Starmerella vitae f.a, sp. nov. are proposed to accommodate 19 isolates recovered from ephemeral flowers or bees in Brazil, Costa Rica and Belize. Sequence analysis of the ITS-5.8S region (when available) and the D1/D2 domains of the large subunit of the rRNA gene showed that the six novel yeasts are phylogenetically related to several species of the Starmerella clade. The type strains are Starmerella camargoi f.a., sp. nov. UFMG-CM-Y595 (=CBS 14130; Mycobank number MB 822640), Starmerella ilheusensis f.a., sp. nov. UFMG-CM-Y596 (=CBS CBS14131; MB 822641), Starmerella litoralis f.a., sp. nov. UFMG-CM-Y603 (=CBS14104; MB 822642), Starmerella opuntiae f.a., sp. nov. UFMG-CM-Y286 (=CBS 13466; MB 822643), Starmerella roubikii f.a., sp. nov. UWOPS 01-191.1 (=CBS 15148; MB 822645) and Starmerella vitae f.a., sp. nov. UWOPS 00-107.2 (=CBS 15147; MB 822646). In addition, 25 species currently assigned to the genus Candida are reassigned formally to the genus Starmerella.

Six yeast strains representing two novel Wickerhamiella species were isolated from plants and insects collected in Costa Rica, Brazil, and French Guiana. They belong to a subclade containing Wickerhamiella domercqiae and Wickerhamiella bombiphila, and differ by approximately 12 % in the D1/D2 sequences of the large subunit rRNA gene from these species. The intergenic spacer (ITS) regions of the two novel species differ by around 19 and 27 %, respectively, from those of W. domercqiae. The novel species exhibit 5 % divergence in the D1/D2 sequences among them (around 4 % in the ITS). The names Wickerhamiella dianesei f.a., sp. nov. and Wickerhamiella kurtzmanii f.a., sp. nov. are proposed to accommodate these species, for which a sexual cycle has not been observed. Wickerhamiella dianesei was isolated from the stingless bee, Trigona fulviventris, collected in an Asteraceae flower in Costa Rica, and from leaves of Sabicea brasiliensis (Rubiaceae) and a flower of Byrsonima crassifolia (Malpighiaceae) in Brazil. Wickerhamiellsa kurtzmanii was isolated from a flower of Ipomoea batatoides (Convolvulaceae) in Costa Rica, the surface of a fruit of B. crassifolia in Brazil, and flowers in French Guiana. The type strains are Wickerhamiella dianesei UWOPS 00-107.1 (=CBS 14185=NRRL Y-63789; Mycobank number MB 827008) and Wickerhamiella kurtzmanii UWOPS 00-192.1 (=CBS 15383=NRRL Y-63979; MB 827011).

Two isolates representing a new species of Scheffersomyces were isolated from rotting wood samples collected in an Amazonian forest ecosystem in Brazil. Analysis of the sequences of the D1/D2 domains showed that this new species is phylogenetically related to Scheffersomyces NYMU 15730, a species without a formal description, and the two are in an early emerging position with respect to the xylose-fermenting subclade containing Scheffersomyces titanus and Scheffersomyces stipitis. Phylogenomic analyses using 474 orthologous genes placed the new species in an intermediary position between Scheffersomyces species and the larger genus Spathaspora and the Candida albicans/Lodderomyces clade. The novel species, Scheffersomyces stambukii f.a., sp. nov., is proposed to accommodate these isolates. The type strain of Scheffersomyces stambukii sp. nov. is UFMG-CM-Y427 (=CBS 14217). The MycoBank number is MB 824093. In addition, we studied the xylose metabolism of this new species.

During studies of the yeast diversity associated with rotting wood in Brazil and fruits, plants and insects in French Guiana, three strains of a new species were isolated. Analysis of the sequences of the internal transcribed spacer (ITS)-5.8S and D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the genus Hyphopichia and its closest relative is Candida homilentoma. These species differ by 44 nucleotide substitutions in D1/D2 sequences. A new species Hyphopichia buzzinii f. a., sp. nov., is proposed to accommodate these isolates. The type strain of Hyphopichia buzzinii sp. nov. is CLIB 1739 (=CBS 14300 = UFMG-CM-Y6121; MycoBank number is MB 815609). In addition, we isolated 11 strains of C. homilentoma from rotting wood, leaf surfaces, and water bodies in Brazil, and these strains when crossed among one another and with the type strain (CBS 6312) of this species, produced hat-shaped ascospores typical of the genus Hyphopichia. We describe the teleomorph of C. homilentoma as a new combination, Hyphopichia homilentoma comb. nov. (type strain CBS 6312; MycoBank number is MB 820009). We also propose to transfer the other six Candida species of the Hyphopichia clade to this genus as new combinations. Hyphopichia homilentoma produced ethanol and xylitol from D-xylose whereas H. buzzinii was only able to convert this pentose to xylitol.

Yeast communities associated with cacti were studied in three ecosystems of Southeast, Central and North Brazil. A total of 473 yeast strains belonging to 72 species were isolated from 190 samples collected. Cactophilic yeast species were prevalent in necrotic tissues, flowers, fruits and insects of cacti collected in Southeast and North Brazil. Pichia cactophila, Candida sonorensis and species of the Sporopachydermia complex were the most prevalent cactophilic species in Southeast and Central regions. Kodamaea nitidulidarum, Candida restingae and Wickerhamiella cacticola were frequently associated with cactus flowers and fruits. The diversity of yeasts associated with the substrates studied was high. Twenty-one novel species were found. One is described here as Kluyveromyces starmeri sp. nov. based on 21 isolates obtained from necrotic tissues, flowers, fruits and associated insects of the columnar cacti Cereus saddianus, Micranthocereus dolichospermaticus and Pilosocereus arrabidae in two different ecosystems in Brazil. Phylogenetic analyses of sequences encoding the gene of the small subunit (SSU) rRNA gene, the internal transcribed spacer, the 5.8S rRNA gene and the D1/D2 domains of the large subunit (LSU) rRNA showed that the species is related to Kluyveromyces dobzhanskii, Kluyveromyces lactis and Kluyveromyces marxianus. Phylogenomic analyses based on 1264 conserved genes shared among the new species and 19 other members of the Saccharomycetaceae confirmed this phylogenetic relationship. The holotype is K. starmeri sp. nov. CBS 16103 T (=UFMG-CM-Y3682 T). The Mycobank number is MB 836817.

The enigmatic species Ustilago tillandsiae is the only known smut fungus associated with Bromeliaceae. Its generic position is evaluated by morphological, physiological, and molecular phylogenetic analyses using large subunit rDNA sequences. Phylogenetic analyses resolved U. tillandsiae as a member of the Ustilaginales in a sister relationship to the lineage containing Tranzscheliella species. However, U. tillandsiae differs from Tranzscheliella species by the development of sori in flowers, a different structure of sori and a different type of spore ornamentation. Consequently, a new genus Pattersoniomyces is described to accommodate U. tillandsiae. The new combination Pattersoniomyces tillandsiae is substantiated. In the sexual stage (teleomorph), this species infects bromeliads: Tillandsia flabellata, Tillandsia leiboldiana, and Tillandsia sp. in Central America between southern Mexico and Costa Rica. The yeast stage (anamorph) of P. tillandsiae was found associated with the phylloplane of Canistrum improcerum and in water tanks (phytotelmata) of Vriesea minarum, two bromeliads occurring in northeast and southeast Brazil, respectively. The link between the teleomorph and anamorphic strains is supported by identical sequences of the D1/D2 domains of the large subunit rDNA. Pattersoniomyces represents the tenth endemic smut genus to the Americas, but the only one that occurs in both North and South America, being a truly neotropical genus. The host plant families of Ustilaginales are extended to the Bromeliaceae. As far as we know, Pattersoniomyces represents the single event of a host jump from Cyperaceae or Poaceae to Bromeliaceae, apparently without further species radiation on multiple bromeliad species and genera growing in South America.

Two independent surveys of yeasts associated with different bromeliads in different Brazilian regions led to the proposal of a novel yeast species, Bullera vrieseae sp. nov., belonging to the Tremellales clade (Agaricomycotina, Basidiomycota). Analysis of the sequences in the internal transcribed spacer (ITS) region and D1/D2 domain of the LSU rRNA gene suggested affinity to a phylogenetic lineage that includes Bullera miyagiana and Bullera sakaeratica. Six isolates of the novel species were obtained from different bromeliads and regions in Brazil. Sequence analysis of the D1/D2 domains of the large subunit of the rRNA gene showed that the novel species differs from B. miyagiana and B. sakaeratica by 85 and 64 nt substitutions, respectively and by more than 75 nt substitutions in the ITS region. Phenotypically, Bullera vrieseae sp. nov. can be distinguished from both species based on the assimilation of meso-erythritol, which was negative for B. vrieseae sp. nov. but positive for the others, assimilation of d-glucosamine, which was positive for B. vrieseae sp. nov. but negative for B. miyagiana and of l-sorbose, which was negative for B. vrieseae sp. nov. but positive for B. sakaeratica. The novel species Bullera vrieseae sp. nov. is proposed to accommodate these isolates. The type strain of Bullera vrieseae sp. nov. is UFMG-CM-Y379T (BRO443T; ex-type CBS 13870T).