Abstract
Three yeast strains (Hue-1, Hue-8, and Hue-19) with strong heavy metal tolerance were isolated from mangosteen from Hue city, Vietnam. They exhibited identical phenotype and phylogeny.
Sequence analysis of the D1/D2 region of the LSU rRNA gene and the internal transcribed spacer (ITS) region demonstrated that the closest relative of these strains isPapiliotremasp. with 2.12% and 3.55-3.7% divergence in the D1/D2 domain, and ITS domain, respectively. Based on the physiological, biochemical, and molecular data, the three strains belong to a novel species ofPapiliotremagenus, for which the namePapiliotrema huenovsp. nov. is proposed.
These strains are highly tolerant of heavy metals compared to other yeasts, being able to grow in the presence of 2 mM Pb (II), 2 mM Cd (II), and up to 5 mM Ni (II), but no growth was observed in the presence of 1 mM As (III).