Yeasts isolated from plant-associated beetles and other insects: seven novel Candida species near Candida albicans

Yeasts related to Candida albicans were isolated from the digestive tracts of beetles in eight families and various orders of insects such as earwigs, crickets, and roaches, most of which were caught at light traps or in a few cases directly from plant materials. Based on comparisons of DNA sequences and other taxonomic characteristics, a total of 41 isolates were identified as Candida orthopsilosis, Candida pseudorhagii, Candida maltosa, Candida parapsilosis, Candida tropicalis, Candida neerlandica, Lodderomyces elongisporus, and seven new Candida species. The new species and type strains are designated as Candida gigantensis NRRL Y-27736T, Candida bohiensis NRRL Y-27737T, Candida alai NRRL Y-27739T, Candida buenavistaensis NRRL Y-27734T, Candida frijolesensis NRRL Y-48060T, Candida labiduridarum NRRL Y-27940T, and Candida tetrigidarum NRRL Y-48142T. A phylogeny based on SSU and LSU rRNA gene sequences indicated that most of the new species were closely related to members of the C. albicans/L. elongisporus clade, such as C. albicans, Candida dulbliniensis, C. neerlandica, Candida chauliodes, and Candida corydali. Candida alai was placed near this clade, but no closely related sister taxon was identified. The ecology of the insect-associated yeasts is discussed and compared with the results from other studies.     

Multilocus phylogenetic study of the Scheffersomyces yeast clade and characterization of the N-terminal region of xylose reductase gene

Many of the known xylose-fermenting (X-F) yeasts are placed in the Scheffersomyces clade, a group of ascomycete yeasts that have been isolated from plant tissues and in association with lignicolous insects. We formally recognize fourteen species in this clade based on a maximum likelihood (ML) phylogenetic analysis using a multilocus dataset. This clade is divided into three subclades, each of which exhibits the biochemical ability to ferment cellobiose or xylose. New combinations are made for seven species of Candida in the clade, and three X-F taxa associated with rotted hardwood are described: Scheffersomyces illinoinensis (type strain NRRL Y-48827(T) = CBS 12624), Scheffersomyces quercinus (type strain NRRL Y-48825(T) = CBS 12625), and Scheffersomyces virginianus (type strain NRRL Y-48822(T) = CBS 12626). The new X-F species are distinctive based on their position in the multilocus phylogenetic analysis and biochemical and morphological characters. The molecular characterization of xylose reductase (XR) indicates that the regions surrounding the conserved domain contain mutations that may enhance the performance of the enzyme in X-F yeasts. The phylogenetic reconstruction using XYL1 or RPB1 was identical to the multilocus analysis, and these loci have potential for rapid identification of cryptic species in this clade.     

Metschnikowia noctiluminum sp. nov., Metschnikowia corniflorae sp. nov., and Candida chrysomelidarum sp. nov., isolated from green lacewings and beetles

Fourteen yeast isolates belonging to the Metschnikowia clade were isolated from the digestive tracts of lacewings (Neuroptera: Chrysopidae), soldier beetles and leaf beetles (Coleoptera: Cantharidae and Chrysomelidae), and a caddisfly (Trichoptera: Hydropsychidae). The insect hosts were associated with sugary substances of plants, a typical habitat for yeasts in this clade. Based on DNA sequence comparisons and phenetic characters, the yeasts were identified as Candida picachoensis, Candida pimensis, and four undescribed taxa. Among the undescribed taxa, three yeasts were distinguished from one another and from other described taxa by nucleotide differences in the ribosomal DNA repeat, which were sufficient to consider them as new species. Two of the novel yeast species are described as Metschnikowia noctiluminum (NRRL Y-27753^T) and M. corniflorae spp. nov. (NRRL Y-27750^T) based in part on production of needle-shaped ascospores, which are found in most Metschnikowia species. Sexual reproduction was not observed in the third new yeast, Candida chrysomelidarum sp. nov. (NRRL Y-27749^T). A fourth isolate, NRRL Y-27752, was not significantly distinct from Metschnikowia viticola and Candida kofuensis to be described as a new species. Phylogenetic analysis of the D1/D2 loop sequences placed M. noctiluminum within the M. viticola clade, while C. chrysomelidarum was a sister taxon of Candida rancensis. Metschnikowia corniflorae was phylogenetically distinct from other new species and fell outside of the large-spored Metschnikowia group.     

Six new anamorphic ascomycetous yeasts near Candida tanzawaensis

Six new species of the yeast genus Candida are described from their unique nucleotide sequences in the D1/D2 domain of 26S rDNA. Five of these species form a clade with Candida tanzawaensis, and the sixth is basal to this group. The new species and their sources of isolation are the following: Candida ambrosiae (type strain NRRL YB-1316, CBS 8844), from insect frass, rotted wood and mushroom fruiting bodies; Candida canberraensis (type strain NRRL YB-2417, CBS 8846), from soil; Candida caryicola (type strain NRRL YB-1499, CBS 8847), from a pignut hickory tree; Candida prunicola (type strain NRRL YB-869, CBS 8848), from exuded gum of a black cherry tree; Candida pyralidae (type strain NRRL Y-27085, CBS 5035), from insect frass; Candida xylopsoci (type strain NRRL Y-27066, CBS 6037), from insect frass.     

Three new species of Candida from apple cider: C. anglica, C. cidri and C. pomicola

Three new anamorphic ascomycetous yeasts are described: Candida anglica (type strain NRRL Y-27079, CBS 4262), Candida cidri (type strain NRRL Y-27078, CBS 4241), and Candida pomicola (type strain NRRL Y-27083, CBS 4242). These three species were isolated from cider produced in the United Kingdom, and their identification was determined from unique nucleotide sequences in the species-specific D1/D2 domain of large subunit (26S) ribosomal DNA. Phylogenetic analysis of D1/D2 sequences placed C. anglica near Candida fragi, C. cidri near Pichia capsulata, and C. pomicola in the Pichia holstii clade.     

Eleven new species of Sugiyamaella and Candida from forest habitats

Eleven new yeasts from forest habitats are described from nucleotide sequence analysis of the nearly entire large subunit rRNA gene, ITS1-5.8S-ITS2 rRNA gene, mitochondrial small subunit rRNA gene, and the cytochrome oxidase II gene. All are members of the Sugiyamaella clade. Three are heterothallic species of Sugiyamaella and eight species are assigned to Candida. The Sugiyamaella species are: Su. americana sp. nov., type strain NRRL YB-2067 (CBS 10352), mating type a, and isotype NRRL YB-4197 (CBS 10353), mating type alpha; Su. chiloensis sp. nov., type strain NRRL Y-17646 (CBS 8168), mating type a, and isotype NRRL Y-27101 (CBS 5927), mating type alpha, anamorph Ca. bertae; Su. japonica sp. nov., type strain NRRL YB-2788 (CBS 10354), diploid, NRRL YB-2764 (CBS 10355), mating type a, and NRRL YB-2799 (CBS 10356), mating type alpha. The Candida species with type strains are: Ca. boreocaroliniensis sp. nov. NRRL YB-1835 (CBS 10344), Ca. floridensis sp. nov. NRRL YB-3827 (CBS 10350), Ca. grinbergsii sp. nov. NRRL Y-27117 (CBS 5924), Ca. lignohabitans sp. nov. NRRL YB-1473 (CBS 10342), Ca. marilandica sp. nov. NRRL YB-1847 (CBS 10346), Ca. marionensis sp. nov. NRRL YB-1336 (CBS 10341), Ca. neomexicana sp. nov. NRRL YB-2450 (CBS 10349), and Ca. pinicola sp. nov. NRRL YB-2263 (CBS 10348).     

Candida hyderabadensis sp. nov., a novel ascomycetous yeast isolated from wine grapes

Three ascomycetous yeast strains were isolated from decaying green wine grapes, collected from Hyderabad city in India. Two strains, YS9 and YS21, were identified as Kodamaea ohmeri and Candida fermentati, respectively. The third strain, YS12(T), differs from Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis, the nearest phylogenetic neighbours, by 1.6-1.9% with respect to the nucleotide sequence of the D1/D2 domain of the 26S rRNA gene and by 1.4-9.2% with respect to the nucleotide sequence of the internal transcribed spacer 1 (ITS1)-5.8S rRNA gene-ITS2 region. YS12(T) also differs from C. parapsilosis, C. metapsilosis and C. orthopsilosis by some phenotypic characteristics. Thus, based on the phenotypic differences and phylogenetic analysis, strain YS12(T) is assigned the status of a new species of Candida, for which the name C. hyderabadensis sp. nov. is proposed. The type strain is YS12(T) (NRRL Y-27953(T)=CBS10444(T)=IAM15334(T)).     

Three new beetle-associated yeast species in the Pichia guilliermondii clade

New yeasts in the Pichia guilliermondii clade were isolated from the digestive tract of basidiocarp-feeding members of seven families of Coleoptera. A molecular phylogeny and unique traits placed eight isolates in Candida fermentati and three undescribed taxa in the genus Candida. The new species and type strains are C. smithsonii (type strain NRRL Y-27642^T), C. athensensis (type strain NRRL Y-27644^T), and C. elateridarum (type strain NRRL Y-27647^T). Based on comparison of small-and large-subunit rDNA sequences, C. smithsonii and C. athensensis form a statistically well-supported subclade with P. guilliermondii, C. xestobii, and C. fermentati; C. elateridarum is basal to this subclade.     

New species and new combinations in the yeast genera Kregervanrija gen. nov., Saturnispora and Candida

Analysis of nucleotide sequences from the domains 1 and 2 of the large-subunit rDNA demonstrated species of the Pichia fluxuum clade to be phylogenetically isolated, and domains 1 and 2 and internal transcribed spacer rDNA sequence analyses of strains phenotypically identified as P. fluxuum resulted in the discovery of three new species. From this work, the following new genus, new species, and new combinations are proposed: Kregervanrija gen. nov.; type species Kregervanrija fluxuum comb. nov. (type strain NRRL YB-4273, CBS 2287); Kregervanrija delftensis comb. nov. (type strain NRRL Y-7119, CBS 2614); Kregervanrija pseudodelftensis sp. nov. (type strain NRRL Y-5494, CBS 10105); Saturnispora besseyi comb. nov. (NRRL YB-4711, CBS 6343); Saturnispora mendoncae sp. nov. (type strain NRRL Y-11515, CBS 5620); and Candida abiesophila sp. nov. (type strain NRRL Y-11514, CBS 5366).     

Two new species in the Pichia guilliermondii clade: Pichia caribbica sp. nov., the ascosporic state of Candida fermentati, and Candida carpophila comb. nov

Pichia caribbica sp. nov. (type strain DBVPG 4519, NRRL Y-27274, CBS 9966) is described as the ascosporic state of Candida fermentati, and Candida guilliermondii var. carpophila (type strain DBVPG 7739, NRRL Y-17905, CBS 5256) is elevated to species status as Candida carpophila comb. nov. These new taxa, which are indistinguishable on the basis of conventional taxonomic criteria, differ from one another and from Pichia guilliermondii by low DNA base sequence relatedness, different electrophoretic karyotypes, and nucleotide divergence in domains D1/D2 of 26S rDNA. Pichia caribbica produces one, rarely two, saturn-shaped ascospores in persistent asci. On the basis of molecular criteria, C. carpophila comb. nov., C. fukuyamaensis, and C. xestobii are conspecific, with the name C. carpophila having taxonomic priority.     

Three new asexual arthroconidial yeasts, Geotrichum carabidarum sp. nov., Geotrichum histeridarum sp. nov., and Geotrichum cucujoidarum sp. nov., isolated from the gut of insects

Twenty arthroconidial yeasts were isolated from the digestive tract of basidiome-feeding beetles and lepidopteran larvae. All of the yeasts reproduced only asexually by arthroconidia and some by endo- or blastoconidia as well. Based on the comparisons of sequences in ribosomal RNA genes and other taxonomic characteristics, the yeasts were identified as three unknown Geotrichum species. The three new species are described as Geotrichum carabidarum (NRRL Y-27727^T), G. histeridarum (NRRL Y-27729^T), and G. cucujoidarum (NRRL Y-27731^T). Phylogenetic analyses from ribosomal DNA sequences showed that members of the genus Geotrichum and related arthroconidial yeast taxa were divided into two major clades: (1) Dipodascus and Galactomyces with Geotrichum anamorphs including all the new species; and (2) Magnusiomyces with Saprochaete anamorphs. G. cucujoidarum formed a subclade with G. fermentans and Geotrichum sp. Y-5419, while the two closely related species, G. carabidarum and G. histeridarum, represent a new basal subclade in the clade of Geotrichum and its teleomorphs.     

New anamorphic yeast species: Candida infanticola sp. nov., Candida polysorbophila sp. nov., Candida transvaalensis sp. nov. and Trigonopsis californica sp. nov

Three new species of Candida and a new species of Trigonopsis are described based on their recognition from phylogenetic analysis of gene sequences from large subunit ribosomal RNA, ITS1/ITS2 rRNA, mitochondrial small subunit rRNA and cytochrome oxidase II. Candida infanticola sp. nov. (type strain NRRL Y-17858, CBS 7922) was isolated from the ear of an infant in Germany and is closely related to Candida sorbophila. Candida polysorbophila sp. nov. (type strain NRRL Y-27161, CBS 7317) is a member of the Zygoascus clade and was isolated in South Africa as a contaminant from an emulsion of white oil and polysorbate. Candida transvaalensis sp. nov. (type strain NRRL Y-27140, CBS 6663) was obtained from forest litter, the Transvaal, South Africa, and forms an isolated clade with Candida santjacobensis. Trigonopsis californica sp. nov. (type strain NRRL Y-27307, CBS 10351) represents a contaminant from wine in California, and forms a well-supported clade with Trigonopsis cantarellii, Trigonopsis variabilis and Trigonopsis vinaria.     

Cryptococcus bestiolae and Cryptococcus dejecticola, two new yeast species isolated from frass of the litchi fruit borer Conopomorpha sinensis Bradley

Two new yeast species, Cryptococcus bestiolae and Cryptococcus dejecticola, were discovered in the frass of the litchi fruit borer Conopomorpha sinensis Bradley. The yeasts utilize inositol, hydrolyze urea, produce starch-like substance, and contain CoQ10. Phylogenetic analyses of D1/D2 26S rDNA and internal transcribed spacer (ITS) sequences indicate that the yeasts are closely related to Bullera dendrophila and an undescribed species of Cryptococcus (strain CBS 8507). The two new species differed from each other by 17 nucleotides in the D1/D2 region and by 68 nucleotides in the ITS region. Cryptococcus bestiolae is a sister species to Cryptococcus sp. CBS 8507, from which it differs by eight nucleotides in the D1/D2 region and 59 nucleotides in the ITS region. Cryptococcus dejecticola and B. dendrophila differed by 13 nucleotides in the D1/D2 and 57 nucleotides in the ITS region. Cryptococcus bestiolae and Cr. dejecticola formed with B. dendrophila a well defined clade consisting of insect associated species. The type strain of Cr. bestiolae is TH3.2.59 (=CBS 10118=NRRL Y-27894), and the type strain of Cr. dejecticola is Litch 17 (=CBS 10117=NRRL Y-27898).     

Three new ascomycetous yeasts from insect-associated arboreal habitats

A new species of Pichia and two new species of Candida are described and were determined to be genetically isolated from all other currently recognized ascomycetous yeasts from their sequence divergence in the species-variable D1/D2 domain of large subunit (26S) ribosomal DNA. The three species were primarily isolated from the frass of wood-boring insects living in pine and spruce trees. The new species and their type strains are the following: Pichia ramenticola NRRL YB-1985 (CBS 8699), mating type alpha (NRRL YB-3835, CBS 8700, mating type a), Candida piceae NRRL YB-2107 (CBS 8701), and Candida wyomingensis NRRL YB-2152 (CBS 8703). Pichia ramenticola and C. piceae assimilate methanol as a carbon source; P. ramenticola is the first known heterothallic ascomycetous yeast to utilize this compound.     

A yeast clade near Candida kruisii uncovered: nine novel Candida species associated with basidioma-feeding beetles

Yeasts similar to Candida kruisii were isolated repeatedly from the digestive tracts of basidioma-feeding beetles, especially nitidulids inhabiting and feeding on a variety of agarics in the southeastern USA and Barro Colorado Island, Panama. Based on the identical sequences of the D1/D2 domains of the LSU rRNA gene (rDNA) and host beetle information, the isolates were grouped into 19 genotypes which varied from C. kruisii by up to 38 nucleotide differences in the D1/D2 region. Phylogenetic analysis of rDNA sequences and phenotypic traits placed the isolates in C. kruisii and in nine undescribed taxa. The new species and type strains are designated as Candida pallodes (NRRL Y-27653^T), C. tritomae (NRRL Y-27650^T), C. panamensis (NRRL Y-27657^T), C. lycoperdinae (NRRL Y-27658^T), C. atbi (NRRL Y-27651^T), C. barrocoloradensis (NRRL Y-27934^T), C. aglyptinia (NRRL Y-27935^T), C. stri (NRRL Y-48063^T), and C. gatunensis (NRRL Y-48064^T). A phylogeny based on analysis of a combined database of sequences of SSU and LSU rDNA and the ITS region showed that the nine new species formed a novel sister clade to C. kruisii that was strongly supported by bootstrap analysis. Candida pallodes, C. tritomae, C. panamensis, and C. lycoperdinae formed one subclade, while C. atbi, C. barrocoloradensis, C. aglyptinia, C. stri, and C. gatunensis formed a second distinct subclade within the larger clade. Candida pallodes and C. atbi showed a strong host specificity to beetle species in the genus Pallodes (Coleoptera: Nitidulidae) collected from a variety of agarics. On the other hand, C. panamensis, C. tritomae, and C. lycoperdinae were associated with several unrelated beetles in Erotylidae, Scarabaeidae, Tenebrionidae, and Curculionidae as well as Lycoperdina ferruginea (Nitidulidae). Candida pallodes, C. tritomae, C. lycoperdinae, and C. atbi have been isolated repeatedly in the USA, while the other five new species have been found only at Barro Colorado Island, Panama.     

Metschnikowia santaceciliae,Candida hawaiiana,and Candida kipukae,three new yeast species associated with insects of tropical morning glory

A new haplontic heterothallic species of Metschnikowia and two related asexual yeast species were discovered in morning glory flowers and associated insects. Metschnikowia santaceciliae came from Conotelus (Coleoptera: Nitidulidae) and other insect species associated with flowers of Ipomoea indica (purple morph) in Costa Rica. Candida hawaiiana and Candida kipukae were found in I. indica (syn. I. acuminata) and its insects in Hawai'i, and the former was also isolated in a specimen of Conotelus collected on Merremia tuberosa (Convolvulaceae) in Costa Rica. The three species have nearly identical physiological profiles, typical of the genus Metschnikowia. The sequences of the D1/D2 domains of their large subunit ribosomal DNA confirm that the species belong to the Metschnikowia clade, even though they share a very low degree of inter-relatedness. M. santaceciliae is a sister species to Metschnikowia continentalis. C. kipukae is a basal member of the large-spored Metschnikowia subclade, and C. hawaiiana has a weak affinity to Metschnikowia agaves. Two of the three species appear to be endemic. The type cultures are: Metschnikowia santaceciliae, strains UWO(PS)01-517a1=CBS 9148=NRRL Y-27475 (h(+, holotype) and UWO(PS)01-520a1=CBS 9149=NRRL Y-27476 (h-, isotype); Candida hawaiiana, strain UWO(PS)91-698.3=CBS 9146=NRRL Y-27473; Candida kipukae, strain UWO(PS)00-669.2=CBS 9147=NRRL Y-27474.     

Metschnikowia arizonensis and Metschnikowia dekortorum,two new large-spored yeast species associated with floricolous beetles

Two new haplontic heterothallic species of Metschnikowia were discovered in flowers and associated beetles. Metschnikowia arizonensis was recovered from flowers of cholla cactus (Opuntia echinocarpa) and a specimen of Carpophilus sp. (Coleoptera: Nitidulidae) found in these flowers, in Arizona. Metschnikowia dekortorum was isolated in specimens of the nitidulid beetle Conotelus sp. captured in flowers of two species of Ipomoea in northwestern Guanacaste Province, Costa Rica. The sexual cycle of these yeasts is typical of the large-spored Metschnikowia species, but the asci and spores are intermediate in size between these and other members of the genus. The physiology is consistent with that of most Metschnikowia species except that both species fail to utilize lysine as sole nitrogen source. Also, M. arizonensis utilizes fewer carbon compounds than most species and exhibits considerable variability among strains at this level. Partial ribosomal DNA large-subunit (D1/D2) sequences suggest that M. arizonensis and M. dekortorum are moderately related sister species whose positions are intermediate between the large-spored species Metschnikowia and Metschnikowia hibisci. The type cultures are: M. arizonensis, strains UWO(PS)99-103.3.1=CBS 9064=NRRL Y-27427 (h(+), holotype) and UWO(PS)99-103.4=CBS 9065=NRRL Y-27428 (h(-), isotype); and M. dekortorum, strains UWO(PS)01-142b3=CBS 9063=NRRL Y-27429 (h(+), holotype) and UWO(PS)01-138a3=CBS 9062=NRRL Y-27430 (h(-), isotype).     

<Emphasis Type="Italic">Trichomonascus petasosporus</Emphasis> sp. nov. and <Emphasis Type="Italic">Sympodiomyces indianaensis</Emphasis> sp. nov., two new members of the Saccharomycetales

Two new yeasts are described that were recognized as novel from nucleotide divergence in domains D1/D2 of 26S rDNA. The new species and their type strains are the following: Trichomonascus petasosporus NRRL YB-2092T (CBS 9602T), mating type a, NRRL YB-2093 (CBS 9603), mating type alpha, and Sympodiomyces indianaensis NRRL YB-1950T (CBS 9600T). Phylogenetic analysis placed the two new taxa, which are sister species, in the Sympodiomyces clade near Blastobotrys/Stephanoascus farinosus. Placement of Trichomonascus in the Saccharomycetales resolves the earlier uncertainties surrounding the classification of this morphologically unusual genus.