Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2015
Publication Date: 3/12/2015
Citation: Kurtzman, C.P., Robnett, C.J. 2015. Occultifur kilbournensis f.a. sp. nov., a new member of the Cystobasidiales associated with maize (Zea mays) cultivation. Antonie Van Leeuwenhoek. 107(5):1323-1329.
Interpretive Summary: In a study to examine the ecology of microorganisms associated with maize cultivation and their effect on plant health, we isolated and characterized yeasts from maize plants and from surrounding soil in fields located in south-central Illinois. In addition to isolation of yeasts during the growing season, yeasts were isolated from overwintered stalks, cobs, and surrounding soil. Predominant among isolates were several species of Cryptococcus and a red yeast that D1/D2 LSU rRNA gene sequence analysis revealed to be a new species of the basidiomycete yeast genus Occultifur. The species is being described as Occultifur kilbournensis, named in recognition of the small agricultural community of Kilbourne, Illinois, which is the location of field plots examined in this study. Remarkably, the new species reached high population numbers only on overwintered maize residue. In continuing research, O. kilbournensis will be examined for protection of young maize plants against fungal pathogens during cool, early spring growth and for ability to degrade mycotoxins that are commonly produced by mold pathogens of maize.
Technical Abstract: During a study of microorganisms associated with maize (Zea mays) cultivation, yeasts were isolated from overwintered stalks, cobs and surrounding soil, which were collected from an agricultural field in south-central Illinois, USA. Predominant among isolates were two species of Cryptococcus (Cr. flavescens, Cr. magnus) and a red yeast that D1/D2 LSU rRNA gene sequences revealed to be a new species of the basidiomycete yeast genus Occultifur. The species, which was not detected in the same field during the growing season, is described here as Occultifur kilbournensis (MycoBank number MB 811259; type strain NRRL Y-63695, CBS 13982, GenBank numbers, D1/D2 LSU rRNA gene, KP413160, ITS, KP413162; allotype strain NRRL Y-63699, CBS 13983). Mixture of the type and allotype strains resulted in formation of hyphae with clamp connections and a small number of apparent basidia following incubation on 5 % malt extract agar at 15 °C for 2 months. In view of the uncertainty of the life cycle, the new species is being designated as forma asexualis. From analysis of D1/D2 and ITS nucleotide sequences, the new species is most closely related to Occultifur externus.