Cryptococcus terrestris sp. nov., a tremellaceous, anamorphic yeast phylogenetically related to Cryptococcus flavescens

Abstract

Cryptococcus terrestris sp. nov. (Basidiomycota, Agaricomycotina, Tremellomycetes, Tremellales) is typified by CJDX4 Y23 T (5CBS 10810 T 5NRRL Y-48451 T ), isolated from forest soil in Oklahoma, USA. This species is most readily identified by the sequence of the D1/D2 domain region of the 26S rDNA and ITS (internal transcribed spacer) region. Additional strains from Oklahoma (C107DX4 Y11 5CBS 10813 5NRRL Y-48452) and Brazil (Ep11c 5CBS 10812 5NRRL Y-48454; 56e 5CBS 10811 5NRRL Y-48453) either had identical sequences or differed minimally. C. terrestris differs physiologically from the most closely related species, Cryptococcus flavescens, by the weak or delayed assimilation of ribose and salicin, and differs from Cryptococcus aureus by the utilization of nitrate and nitrite and growth in vitamin-free medium.Members of the genus Cryptococcus are found in a wide variety of habitats, and are difficult to identify by traditional methods. The genus is polyphyletic and is distributed throughout the class Tremellomycetes, with representatives in all orders (Tremellales, Filobasidiales and Cystofilobasidiales) (Scorzetti et al., 2002;Hibbett et al., 2007). Independent yeast surveys in Oklahoma (USA) and Rio Grande do Sul (Brazil) produced four isolates with very similar physiological profiles and sequences of the D1/D2 domain of the 26S rDNA and internal transcribed spacer (ITS) region. Sequences differed significantly from those of any previously described yeast species, and the isolates formed a discrete clade close to Cryptococcus flavescens. This study deals with the description of this novel species, for which the name Cryptococcus terrestris sp. nov. is proposed.The Oklahoman strains CJDX4 Y23 T and C107DX4 Y11 were isolated from a sandy loam (sand 67.5 %, silt 28.7 %, clay 3.8 %) Konawa series soil collected in the rhizosphere of a mixed hardwood (mainly Quercus spp.) forest in Payne County, Oklahoma, on 6 July 2006 (35 u 59.9869 N 97 u 05.0899 W) and 27 January 2007 (35u 59.9499 N 97u 05.0509 W), respectively. A subsample of the surface to 2 cm layer was incubated overnight in 50 ml M3C (Vishniac, 2002) plus an antibiotic mixture on a New Brunswick Gyrotary shaker and then sampled by spreading 0.1 ml of appropriate dilutions on M3C plus antibiotic agar. The antibiotic mixture included 160 mg penicillin G potassium salt and 100 mg streptomycin sulfate ml 21 for the July sample, augmented by the addition of 32 mg gentamicin sulfate ml 21 for the January sample. The Brazilian strains Ep11c and 56e were isolated during an epidemiological study of yeasts associated with a case of cryptococcal meningitis in a worker from a timber factory at Cachoeira do Sul in Rio Grande do Sul state in southern Brazil (30 u 00.4709 S 52 u 54.8659 W). The factory dealt mostly with wood of Pinus spp. trees, but also processed Ficus and some Eucalyptus trees. Both strains were collected within the factory area. Strain Ep11c was isolated on 26 September 2005 from dry pigeon droppings that were lying on the grass. Strain 56e was isolated ...

Phylogenetic Analysis of Phenotypically Characterized Cryptococcus laurentii Isolates Reveals High Frequency of Cryptic Species

“…It is likely that the delayed recognition of C. terrestris and C. flavescens hindered the recognition of divergent phenotypic traits now recognized as important species characteristics. C. terrestris can be differentiated phenotypically from C. flavescens by delayed and/or weak assimilation of ribose and salicin [13], [44]. Our analysis supports the previous reported genetic differentiation; C. flavescens diverged from C. terrestris by 1.2–1.6% (6–10 polymorphisms) and 0.5–2.5% (2–10 polymorphisms) in the 28S-LSU and ITS regions, respectively.…”

“…C. flavescens has only recently been differentiated as a sibling species of C. terrestris [13] with the advancements in multi-locus sequence analysis. It is likely that the delayed recognition of C. terrestris and C. flavescens hindered the recognition of divergent phenotypic traits now recognized as important species characteristics.…”

“…More recently, Cryptococcus terrestris (CBS 10810), the cryptic species of C. flavescens , was isolated and described from soil in Brazil [13].…”

Biodiversity of cactophilic microorganisms in western Argentina: community structure and species composition in the necroses of two sympatric cactus hosts

“…It is possible that these isolates were in fact Y. deformans. On the other hand, C. terrestris has been recently described from isolates recovered from samples of soil in a forest in Oklahoma and the surroundings of a timber factory in Brazil (Crestani et al, 2009). Our survey is the first to indicate that this organism exploits saprotrophic niches, as well as showing its association with decaying cacti.…”

Papiliotrema leoncinii sp. nov. and Papiliotrema miconiae sp. nov., two tremellaceous yeast species from Brazil

“…After 3 weeks in Dalmau plate culture on cornmeal agar, pseudohyphae and true hyphae are not formed. Sexual reproduction is (Takashima et al, 2003); 5, P. terrestris (Crestani et al, 2009); 6, P. baii (Yurkov et al, 2015); 7, P. ruineniae (Yurkov et al, 2015); 8, P. wisconsinensis (Sylvester et al, 2015 In YPD broth after 5 days at 25 uC, the yeast cells are oval to ellipsoid and occur singly or in pairs (3.2-8.1| 2.4-7.8 mm) (Fig. 2c).…”