Plant Molecular Biology 33: 897–909, 1997.
1997 Kluwer Academic Publishers. Printed in Belgium.
Structural organization, expression and promoter activity of a
cold-stress-inducible gene of potato (Solanum tuberosum L.)
, Jochen van Berkel, Heike Glaczinski, Francesco Salamini and
e-Weg 10, D-50829 K
oln, Germany (
Current address: Department of Biochemistry, University of Arizona, Biological Sciences
West, Tucson, AZ 85721, USA
Received 8 March 1996; accepted in revised form 8 December 1996
Key words: cold storage, gene regulation, Solanum tuberosum, stress response, transgenic plants
Cold storage of potato tubers at 4
C is associated with the accumulation of several cold-induced transcripts. By
using a previously characterized cDNA (CI7) as probe, we isolated and sequenced the corresponding ci7 gene.
The putative promoter of ci7 contains sequence elements that have been shown to mediate expression of stress-
responsive genes of Arabidopsis thaliana. CI7 transcripts were differentially induced in response to cold, drought,
high salt or exogenous ABA treatment in potato tubers and leaves. Whereas accumulation of CI7 transcript during
cold storage occurred within days, induction of CI7 transcript in response to drought, ABA and salt occurred rapidly
within few hours. In tubers, accumulation of CI7 protein in response to abiotic stresses and ABA was small when
compared to transcript levels. In leaves, the CI7 protein was undetectable after all treatments tested. 3 kb of the
-ﬂanking ci7 promoter region were fused to the GUS reporter gene and introduced into S. tuberosum plants. The
analysis of tubers of independent transgenic lines did not reveal signiﬁcant induction of enzymatic GUS activity in
response to low temperature. When RNA gel blotting was used to analyze the level of induction of the GUS gene
driven by the ci7 promoter, the heterologous GUS fusion was, however, strongly responsive to low temperature.
Nuclear run-on transcription studies of the ci7 gene, in comparison with RNA gel blot analyses of the transgenic
plants, indicated that most of the temperature-regulated expression of the ci7 gene in tubers may be accounted for
by post-transcriptional control mechanisms.
Plant response to low temperature leads to alteration
of the cellular metabolism and is correlated with signi-
ﬁcant changes in gene expression (for reviews see [20,
51, 7]). Cold-regulated genes have been isolated and
characterized in several plant species, including alfalfa
[38, 58], Arabidopsis [21, 30, 43, 18, 31, 34, 35], spin-
ach , tomato , barley [6, 11] and wheat 
but not in the cultivated potato.
Several low temperature regulated genes analyzed
so far are also responsive to abscisic acid (ABA)
The nucleotidesequence data reportedwill appear in the EMBL,
GenBank and DDBJ Nucleotide Sequence Databases under the
accession number U69633.
and drought [7, 52]. Moreover, both transcription-
al and post-transcriptional control mechanisms have
been reported for cold-regulated gene expression [21,
58, 12]. The structural and functional promoter ana-
lysisof low temperature-responsive genes has provided
information on cis-acting elements involved in the reg-
ulation of cold-responsive gene expression [24, 44,
60, 61, 3]. Yamaguchi-Shinozaki and Shinozaki 
analyzed the Arabidopsis rd29a promoter and iden-
tiﬁed a novel cis-acting, dehydration-responsive ele-
ment (DRE) that contained the sequence TACCGA-
CAT involved in the induction of rd29a by drought,
high salt and low temperature but not in response to
Pips nr. 128913 BIO2KAP
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