ISSN 1022-7954, Russian Journal of Genetics, 2017, Vol. 53, No. 5, pp. 561–567. © Pleiades Publishing, Inc., 2017.
Original Russian Text © E.S. Naumova, Ch.-Fu Lee, V.I. Kondratieva, A.Zh. Sadykova, G.I. Naumov, 2017, published in Genetika, 2017, Vol. 53, No. 5, pp. 562–569.
Molecular Genetic Polymorphism of Soil Yeasts
of the Genus Williopsis from Taiwan Island
E. S. Naumova
, Ch.-Fu Lee
, V. I. Kondratieva
, A. Zh. Sadykova
, and G. I. Naumov
State Research Institute for Genetics and Selection of Industrial Microorganisms, Moscow, 117545 Russia
Department of Applied Science, National Tsing Hua University, Hsinchu, 30014 Taiwan
Received June 30, 2016
Abstract⎯Comparative molecular genetic study of Williopsis yeasts isolated in different world regions reveals
some peculiarities of species content in Taiwan. Some Williopsis yeasts may represent novel species. In Tai-
wan, four of the five known Williopsis species are documented: W. s a t u r n u s , W. s u a v eo l e n s , W. m r a k i i , and
W. s u b s u f f i c i e n s . The W. sa t u r n u s yeasts predominate in Taiwanese soils, while W. s u a v e o l e n s is more fre-
quently isolated in Europe.
Keywords: soil yeast Williopsis, phylogenetic analysis, biological species, Taiwan, killer toxins
Over the last decade, the gene pool of yeast used in
fundamental and applied research was considerably
expanded. In modern science and practice, great
attention is paid to unconventional non-Saccharomy-
ces yeasts that are able to produce various physiologi-
cally active substances and to function as biological
agents suppressing the development of harmful fungi.
In this connection Taiwan, which possesses endemic
flora and fauna, is of relevance for studies of yeast bio-
diversity. Geographical isolation and tropical climate
are obviously important factors that affect evolution of
Taiwanese yeasts. Ascomycetous yeasts Williopsis are
commonly found in soils and other natural environ-
ments in Taiwan . Strains capable of producing
broad-spectrum killer toxins (mycocins) are common
among these yeasts [2–5]. Williopsis yeasts can be used
in agriculture as biocontrolling microorganisms for
protection of plants and damp grain from fungi infec-
tions and in medicine and veterinary science for
mycosis treatment [6, 7].
The modern classification of ascomycetous yeasts
is based on phylogenetic analysis of a number of
molecular markers, most importantly the D1/D2
domain of the 26S rRNA gene [8, 9]. Additionally,
analysis of the 5.8S-ITS fragment that comprises the
5.8S rRNA gene and internal transcribed spacers ITS1
and ITS2 is used to identify the phylogenetic relation-
ship of closely related species. This region is character-
ized by a significant interspecific divergence and a low
level of intraspecific polymorphism. The length of the
ITS region is constant among strains of the same spe-
cies ; however, the sequence can vary [11, 12]. The
following Williopsis species were identified by genetic
and molecular analysis: W. s a t u r n u s , W. m r a k i i , W. s a r -
gentensis, W. s u a v eo l e n s , and W. subsufficiens [13–15].
W. beijerinckii, which was identified via genetic analysis,
was assigned as synonym of W. s a t u r n u s on the basis of a
high level of total DNA-DNA reassociation .
The goal of the present study was to perform a phy-
logenetic analysis of Williopsis yeasts isolated in Tai-
wan and other regions of the world, as well as a genetic
hybridization analysis of putative novel species.
MATERIALS AND METHODS
Media and Strains
The studied strains of genus Williopsis and their
origins are listed in Table 1. The yeasts were cultivated
at 28°С on complete agar medium YPD of the follow-
ing composition (g/L): glucose, 20; peptone, 10; yeast
extract, 10; agar, 20. The composition of the minimal
medium (g/L): yeast nitrogen base without amino
acids (Difco, United States), 6.7; glucose, 20; agar, 20.
The composition of the sporulation medium (g/L):
sodium acetate, 10; potassium chloride, 5; agar, 20.
Polymerase Chain Reaction (PCR)
PCR was performed on a Tercyc DNA thermocy-
cler (DNA-Technology, Russia) directly on yeast cells
using NL-1 (5'-GCATATCAATAAGCGGAG-
GAAAG-3') and NL-4 (5'-GGTCCGT-
GTTTCAAGACGG-3') primers for the D1/D2
domain or ITS1 (5'-TCCGTAGGTGAACCTG-
CGG) and ITS4 (5'-TССTCCGCTTATTGA-