ISSN 1021-4437, Russian Journal of Plant Physiology, 2006, Vol. 53, No. 5, pp. 698–701. © MAIK “Nauka /Interperiodica” (Russia), 2006.
Original Russian Text © P.E. Drobyazina, E.E. Khavkin, 2006, published in Fiziologiya Rastenii, 2006, Vol. 53, No. 5, pp. 786–789.
For several decades, the effects of day length and
temperature on ﬂowering and tuber formation in potato
L.) are enticing plant physiolo-
gists who put forward several hypotheses for the envi-
ronmental and hormonal control of potato development
[1–5]. On the other hand, the genetic regulation of these
processes has not been sufﬁciently explored .
Among the genes that control transition to ﬂowering
and tuberization in potato, the most likely candidate is
the putative homolog of the
, the key gene in the photoperiodic reg-
ulation of ﬂowering . Under the short-day inductive
conditions, the constitutive expression of
in potato leaves impaired photoperiod-controlled tuber-
Within the family Solanaceae, the homologs of
have been already cloned from potato and
L.) plants [9, 10]; how-
ever, only the sequences of three tomato homologs are
presently available. Two of them (
) are controlled by the circadian clock
does not seem to be involved
in the control of ﬂowering time, the overexpression of
in arabidopsis plants delayed their tran-
sition to ﬂowering .
cDNA from Japa-
nese morning glory (
), the species system-
atically related to the Solanaceae, complemented the
mutants; in addition, the transition of
transformed plants to ﬂowering occurred much earlier
than in the wild-type plants .
Our goal was to characterize the
homologs in potato and its wild relatives that differ in
their photoperiodic responses. The present paper
describes a potato genome fragment closely resembling
the homologs of
MATERIALS AND METHODS
Potato tubers (
, cv. Bastoneza, K-7580) were
obtained from the Vavilov Institute of Plant Industry
(St. Petersburg). This cultivar comes from Chile and is
adapted to the long-day conditions. Plants were grown
under continuous light and room temperature. Genomic
DNA was isolated from young leaves using a modiﬁed
CTAB protocol .
Cloning a potato genome fragment and assessing its
Genomic DNA was ampliﬁed by
polymerase chain reaction using the forward (F) and
reverse (R) primers CGTTTACTGTCGGGCGGATT
these primers were designed on the basis of the tomato
, GenBank accession
no. AY490251) to amplify the genome fragment corre-
sponding to the 68–2095 bp stretch of this gene (Fig. 1).
The ampliﬁcation protocol included a preliminary
1-min denaturation at
followed by 35 cycles as
for 45 s for denaturing DNA,
45 s for annealing primers, and
for 100 s for syn-
thesizing the complementary DNA chains, and the con-
cluding synthesis at
for 5 min. The subsequent
steps of separation, visualization, elution, ligation,
cloning, and sequencing followed the previously
described protocols .
A Structural Homolog of
P. E. Drobyazina and E. E. Khavkin
Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Timiryazevskaya ul. 42, Moscow, 127550
fax: 7 (495) 977-0947; e-mail: email@example.com
Received March 29, 2006
—A 2-kb genome fragment cloned from potato cv. Bastoneza closely resembles
, the ara-
bidopsis gene for the photoperiodic control of ﬂowering, and its homologs in tomato, cottonwood, and barley.
The potato homolog is immediately related to tomato
; their exons and introns were 94 and 82%
identical. Within the most variable middle region of CONSTANS protein and its homologs, asparagine- and
glutamine-rich motifs are of particular interest as they are probably involved in transcription regulation.
Key words: Solanum tuberosum - Solanum lycopersicum -
- photoperiodic control - asparagine-
and glutamine-rich motifs
; PCR—polymerase chain reaction.