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-27653T), C. tritomae (NRRL Y-27650T), C. panamensis (NRRL Y-27657T), C. lycoperdinae (NRRL Y-27658T), C. atbi (NRRL Y-27651T), C. barrocoloradensis (NRRL Y-27934T), C. aglyptinia (NRRL Y-27935T), C. stri (NRRL Y-48063T), and C. gatunensis (NRRL Y-48064T). 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.
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We thank undergraduate students Cennet Erbil, Melissa Spera, Jonathan Lo, and Aurash Khoobehi for their very competent help in all phases of this study. We are extremely grateful for the expert identification of basidiomycetes by Clark Ovrebo and by participants of an ATBI foray in GSMNP lead by Karen Hughes and Ron Petersen and supported by their grant NSF DEB-0338699. We also appreciate the hospitality and logistical support of Hughes and Petersen. Our colleague in a joint study, Joseph V. McHugh, helped to collect and identify the beetles. Donald Windsor and Oris Acevedo graciously helped with the logistics for collecting at the Smithsonian Tropical Research Institute, Barro Colorado Island, Panama. Jean Euzeby and Richard Warga gave advice on Latin names and descriptions. We acknowledge the curators and culture collections that preserve the germ plasm derived from and used in our studies: NRRL (Cletus Kurtzman) and CBS (Teun Boekhout and Vincent Robert) and use of the GenBank public database. This work was supported in part by National Science Foundation Grants DEB-0072741 and REU supplements to M. B. and Joseph V. McHugh and NSF DEB-0417180 to M. B., J. V. M., and S.-O. S., and the Boyd Professor Fund at LSU. We also acknowledge the use of the DNA sequencing facility supported by NSF Multiuser Equipment Grant (DBI-0400797) to Robb Brumfield.
- Molecular systematics
- New Candida species
- Ribosomal DNA