PLANT PHYSIOLOGY , Vol 113, Issue 2 335-345, Copyright © 1997 by American Society of Plant Biologists
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GENE REGULATION AND MOLECULAR GENETICS |
Expression Patterns and Promoter Activity of the Cold-Regulated Gene ci21A of Potato
A. Schneider, F. Salamini and C. Gebhardt
Max-Planck-Institut fur Zuchtungsforschung, Carl-von-Linne-Weg 10, D-50829 Cologne, Germany
Storage of potato (Solanum tuberosum) tubers at 4[deg]C is associated with
the accumulation of several transcripts. DNA sequence analysis of cDNA
clone CI21, which corresponds to one of the cold-induced transcripts,
revealed high homology to transcripts of tomato (Lycopersicon esculentum)
and wild potato (Solanum chacoense) induced by ripening and water stress.
Two homologous, nonallelic genes, ci21A and ci21B, were isolated and
sequenced. Northern blot analysis showed that CI21 transcripts were present
at the highest levels in cold-stored tubers, at lower levels in stems and
roots, and at the lowest levels in leaves and tubers stored at room
temperature. Treatment with abscisic acid, heat, and a high concentration
of salt had no marked effect on CI21 transcript levels in tubers and
leaves. Drought was the only stress treatment that induced CI21 transcripts
in leaves, but it did not do so in tubers. Western blot analysis detected
CI21 protein only in tubers. Chimeric gene constructs between the putative
ci21A promoter region and the uidA reporter gene were tested in transgenic
potato plants for induction of [beta]-glucuronidase activity by low
temperature. A 2-fold increase of [beta]-glucuronidase activity in response
to tuber storage at 4[deg]C was observed for fragments between 380 and 2000
bp of the ci21A promoter region.
