The phylogeny of the cactophilic yeasts based on the 18S ribosomal RNA gene sequences: The proposals of Phaffomyces antillensis and Starmera caribaea, new combinations

The complete sequences of the 18S rRNA gene fragments of the type strains o f the cactophilic yeast species, Pichia antillensis, Pichia caribaea, Phaff omyces opuntiae, Phaffomyces thermotolerans, Starmera amethionina var. amet hionina, and Starmera amethionina var. pachycereana were determined and com pared. The type strain of Phaffomyces opuntiae had two kinds of the 18S rRN A gene sequences of which base differences were counted to be 15 and of whi ch the percent similarity was calculated to be 99.1. The type strains of P. antillensis, P. caribaea, and Starmera amethionina var. pachycereana had t he Q-7 system. The phylogenetic analyses showed that the genera Phaffomyces and Starmera were monophyletic and distant from each other and from the ot her species examined of the ascogenous teleomorphic genera, and that P, ant illensis and P. caribaea were included within the clusters of the genera Ph affomyces and Starmera, respectively. The two Pichia species were transferr ed to the genera Phaffomyces and Starmera as the new combinations, Phaffomy ces antillensis and Starmera caribaea, The new family Phaffomycetaceae was proposed as the type genus Phaffomyces.