RESUMEN
Several independent surveys of yeasts associated with different plant materials and soil led to the proposal of a novel yeast species belonging to the Tremellales clade (Agaricomycotina, Basidiomycota). Analysis of the sequences of the D1/D2 domains and internal transcribed spacer region of the large subunit of the rRNA gene suggested affinity to a phylogenetic lineage that includes Hannaella coprosmaensis, Hannaella oryzae and Hannaella sinensis. Thirty-two isolates were obtained from different sources, including bromeliads, nectar of Heliconia psittacorum (Heliconiaceae), flowers of Pimenta dioica (Myrtaceae), roots and leaves of sugar cane (Saccharum spp.) in Brazil, leaves of Cratoxylum maingayi, Arundinaria pusilla and Vitis vinifera in Thailand, soil samples in Taiwan, and prairie soil in the USA. Sequence analysis of the D1/D2 domains of the large subunit of the rRNA gene showed that the novel species differs from Hannaella coprosmaensis and Hannaella oryzae by 36 and 46 nt substitutions, respectively. A novel species is suggested to accommodate these isolates, for which the name Hannaella pagnoccae sp. nov. is proposed. The type strain is BI118(T) (â=âCBS 11142(T)â=âATCC MYA-4530(T)).
Asunto(s)
Basidiomycota/clasificación , Heliconiaceae/microbiología , Myrtaceae/microbiología , Filogenia , Saccharum/microbiología , Microbiología del Suelo , Secuencia de Bases , Basidiomycota/genética , Basidiomycota/aislamiento & purificación , ADN de Hongos/genética , ADN Espaciador Ribosómico/genética , Flores/microbiología , Datos de Secuencia Molecular , Técnicas de Tipificación Micológica , Hojas de la Planta/microbiología , Raíces de Plantas/microbiología , Análisis de Secuencia de ADN , TaiwánRESUMEN
Yeast isolates from soil samples collected from a latitudinal gradient (>77 degrees S to >64 degrees N) were subjected to multivariate analysis to produce a statistical foundation for observed relationships between habitat characteristics and the distribution of yeast taxa (at various systematic levels) in soil microbial communities. Combinations of temperature, rainfall (highly correlated with net primary productivity), and electrical conductivity (EC) could explain up to ca. 44% of the distribution of the predominant yeast species, rainfall and pH could explain ca. 32% of the distribution of clades in the most common orders (Filobasidiales and Tremellales), whereas vegetation type (trees, forbs, and grass) played the same role for orders. Cryptococcus species with appropriate maximum temperatures for growth predominated in most soils. Cryptococcus species in the Albidus clade of the Filobasidiales predominated in desert soils; Cryptococcus species of other clades in the Filobasidiales and Tremellales predominated in wetter and more-vegetated soils, with Tremellalean species favored in soils of lower pH or higher EC. The predominance of Cryptococcus species in soils has been attributed to their polysaccharide capsules, particularly important when competing with bacteria in arid soils.
Asunto(s)
Ecosistema , Ambiente , Microbiología del Suelo , Levaduras/clasificación , Levaduras/aislamiento & purificación , Biodiversidad , Cryptococcus/clasificación , Cryptococcus/aislamiento & purificación , Cryptococcus/fisiología , ADN Ribosómico/genética , Geografía , Concentración de Iones de Hidrógeno , Análisis Multivariante , Levaduras/fisiologíaRESUMEN
Two new species from Iceland are described on the basis of physiological profiles and sequence data from the D2 region of LSU rDNA: Cryptococcus tephrensis (type ICE99-IToM Y5, ATCC MYA-1765, CBS 8935, GenBank AF317208) and Cryptococcus heimaeyensis (type ICE99-IToM Y8, ATCC MYA-1759, CBS 8933, GenBank AF370717). The two new species are identifiable from sequence data and can be distinguished from their closest relative, Cryptococcus victoriae, by their higher maximum temperatures for growth, failure to utilize nitrate as sole nitrogen source, and utilization of cadaverine and ethylamine as sole nitrogen sources. Cryptococcus tephrensis is distinguishable from C. heimaeyensis by failure to grow on saccharate as sole source of carbon and energy.
Asunto(s)
Cryptococcus/clasificación , Microbiología del Suelo , Cryptococcus/genética , Cryptococcus/fisiología , Medios de Cultivo , ADN de Hongos/análisis , ADN Ribosómico/análisis , Islandia , Datos de Secuencia Molecular , Técnicas de Tipificación Micológica , Filogenia , Análisis de Secuencia de ADNRESUMEN
Cryptococcus antarcticus Vishniac & Kurtzman var. circumpolaris Vishniac and Onofri var. nov. (Filobasidiales, Tremellomycetidae, Hymenomycetes), an anamorphic yeast with ca. 73% nDNA relatedness to Cryptococcus antarcticus var. antarcticus, differs in failure to assimilate raffinose, a lower maximum temperature for growth, fatty acid profile, and in a single nucleotide change in the D2 region of LSU rDNA.