Metschnikowia drakensbergensis sp. nov. and Metschnikowia caudata sp. nov., endemic yeasts associated with Protea flowers in South Africa

Clara de Vega, Beatriz Guzmán, Sandy-Lynn Steenhuisen, Steven D. Johnson, Carlos M. Herrera, Marc-André Lachance

¹Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Avenida de Américo Vespucio s/n, 41092 Sevilla, Spain

²Real Jardín Botánico, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain

³Department of Biological Sciences, University of Cape Town, P/Bag, Rondebosch 7701, South Africa

⁴School of Life Sciences, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg 3209, South Africa

⁵Department of Biology, University of Western Ontario, London, Ontario N6A 5B7, Canada

Correspondence
Clara de Vega cvega{at}ebd.csic.es

International Journal of Systematic and Evolutionary Microbiology 2014; 64(Pt 11):3724–3732 · https://doi.org/10.1099/ijs.0.068445-0

Abstract

In a taxonomic study of yeasts recovered from nectar of flowers and associated insects in South Africa, 11 strains were found to represent two novel species. Morphological and physiological characteristics and sequence analyses of the large-subunit rRNA gene D1/D2 region, as well as the actin, RNA polymerase II and elongation factor 2 genes, showed that the two novel species belonged to the genus Metschnikowia. Metschnikowia drakensbergensis sp. nov. (type strain EBD-CdVSA09-2^T = CBS 13649^T = NRRL Y-63721^T; MycoBank no. MB809688; allotype EBD-CdVSA10-2^A = CBS13650^A = NRRL Y-63720^A) was recovered from nectar of Protea roupelliae and the beetle Heterochelus sp. This species belongs to the large-spored Metschnikowia clade and is closely related to Metschnikowia proteae, with which mating reactions and single-spored asci were observed. Metschnikowia caudata sp. nov. (type strain EBD-CdVSA08-1^T = CBS 13651^T = NRRL Y-63722^T; MycoBank no. MB809689; allotype EBD-CdVSA57-2^A = CBS 13729^A = NRRL Y-63723^A) was isolated from nectar of Protea dracomontana, P. roupelliae and P. subvestita and a honeybee, and is a sister species to Candida hainanensis and Metschnikowia lopburiensis. Analyses of the four sequences demonstrated the existence of three separate phylotypes. Intraspecies matings led to the production of mature asci of unprecedented morphology, with a long, flexuous tail. A single ascospore was produced in all compatible crosses, regardless of sequence phylotype. The two species appear to be endemic to South Africa. The ecology and habitat specificity of these novel species are discussed in terms of host plant and insect host species.