Abstract:
As the world’s second saltiest lake, Urmia Lake is
the main source of halotolerant
unicellular microalga,
Dunaliella,
in Iran. Recently, this lake and, consequently, it
s
biodiversity are being threatened environmentally.
Hence collecting, preserving, and
identification of indigenous microorganisms of the
lake are of great importance. The
objective of the present study was the molecular sc
reening of
Dunaliella
isolates in Urmia
Lake. For this purpose, 32 samples were taken from
different geographical regions of the
lake. Then, their molecular pattern was examined ba
sed on
18S rDNA
gene and intron-
sizing method. Results based on conserved and speci
es-specific primers of
18S rDNA
illustrated that, depending on the various parts of
the lake, the genetic variation of
Dunaliella
population differs. The amplified pattern for indi
vidual isolates was similar to
that previously described for
D. tertiolecta
,
D. bardawil
and
Dunaliella sp.
ARIINW
-M1/2
.
Also,
18S rDNA
sequencing and phylogenetic analysis of five index
isolates showed that the
isolates
Dunaliella sp
. ABRIINW
-Ch5, -Sh6.3 and -U1/1 were grouped with different
intron lacking species of
Dunaliella
, ABRIINW
-Ch3.1 was clustered with
Dunaliella sp
.
ABRIINW
-M1/2, while the isolate
Dunaliella sp
. ABRIINW
-S1.5 was clustered with
intron-harboring species of
D. bardawil
,
D. parva,
and
D. viridis
. The results indicated that
Urmia Lake is composed of isolates with different
18S rDNA
profiles with various intron
arrangement.
Keywords:
18S rDNA
, Halotolerant unicellular microalga, Molecular scr
eening.
