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

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-CdVSA09-2T = CBS 13649T = NRRL Y-63721T; MycoBank no. MB809688; allotype EBD-CdVSA10-2A = CBS13650A = NRRL Y-63720A) 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-CdVSA08-1T = CBS 13651T = NRRL Y-63722T; MycoBank no. MB809689; allotype EBD-CdVSA57-2A = CBS 13729A = NRRL Y-63723A) 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.

Candida metrosideri pro tempore sp. nov. and Candida ohialehuae pro tempore sp. nov., two antifungal-resistant yeasts associated with Metrosideros polymorpha flowers in Hawaii

“…Flowers have been increasingly recognized as unexplored reservoirs of yeast diversity due to the production of nutrient-rich exudates, such as floral nectar or stigmatic secretions, in which microbes can thrive [1][2][3]. Study of yeast diversity in flowers has led during the last decade to the discovery of more than 50 new species of ascomycetes yeasts, dispersed across different continents [2,[4][5][6][7][8][9][10][11][12][13][14]. Additionally, the taxonomic status of several flower-inhabiting yeast species still remains unclear because their phylogenetic affiliation is not yet satisfactorily resolved by available multilocus sequences, and/or they seem unable to produce sexual structures under standard laboratory conditions, making accurate classification challenging.…”

Characterization of a novel yeast species Metschnikowia persimmonesis KCTC 12991BP (KIOM G15050 type strain) isolated from a medicinal plant, Korean persimmon calyx (Diospyros kaki Thumb)

“…The genus Metschnikowia of the family Metschnikowiaceae (Order Saccharromycetales ) comprises single-celled species that reproduce via budding of vegetative cells and is characterized by the presence of one or two needle-shaped ascospores on elongated asci (Mendonca-Hagler et al 1993 ; Pretorius 2000 ; Marinoni et al 2006 ; Kuan et al 2016 ). A total of 35 Metschnikowia species have been described to date in a wide range of hosts, including flowers, fruits, flower-pollinating insects, and lacewings (Mendonca-Hagler et al 1993 ; Lachance et al 2005 ; Guzmán et al 2013 ; De Vega et al 2014 ; Kuan et al 2016 ; Álvarez-Pérez et al 2016 ). Yeasts provide a variety of unique bioactive metabolites that have medicinal importance (Mager and Winderickx 2005 ; VanderMolen et al 2013 ).…”

A stable phylogeny of the large‐spored Metschnikowia clade

“…proteae or M . drakensbergensis and other species, but the two formed abundant sterile asci when crossed with each other (de Vega et al ., , ).…”

“…Last (de Oliveira Santos et al ., ) is a tree inferred from the entire rRNA gene cluster for the sensu stricto and arizonensis subclades. The inclusion of the unassigned strain M2Y3 (cla a , Table ) is warranted by the placement suggested by D1/D2 phylogenies used in two recent species descriptions (de Vega et al ., , ).…”