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-27753T) and M. corniflorae spp. nov. (NRRL Y-27750T) 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-27749T). 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.
Bibliographical noteFunding Information:
We thank Cletus Kurtzman (NRRL) and Teun Boekhout and Vincent Robert (CBS) for providing reference yeast cultures and for placing the yeast isolates from this study in culture collections under their care. We also thank Catherine Tauber and Michael Ferro for identifying the lacewing and caddisfly hosts, respectively, and John Morse for references on adult caddisfly biology. We acknowledge Glenda Newman, principal, North Corbin Elementary School, Walker, LA, USA, for permission to collect at the school. Some collections were made with Joseph V. McHugh at the Smithsonian Tropical Research Institution, Barro Colorado Research Station, Panama, and we thank him and the Smithsonian staff for logistical support in obtaining accommodations and permits. The staff of the M. D. Socolofsky Sciences Microscopy Facility, Louisiana State University, graciously assisted with microscopic expertise during this study. The GenBank public database is also acknowledged. This research was supported by the National Science Foundation, Biodiversity Surveys and Inventories Program (DEB-0072741 and DEB-0417180), including REU Supplements, and a Howard Hughes Medical Institute grant through the Undergraduate Biological Sciences Education Program to Louisiana State University. We also acknowledge the use of the DNA sequencing facility supported by NSF Multiuser Equipment Grant (DBI-0400797) to Robb Brumfield.
Copyright 2008 Elsevier B.V., All rights reserved.
- Insect-fungus interactions
- Molecular phylogeny