Abstract
Cold-stress treated and normally grown rice seedlings were compared by differential screening method. One of the differential clones was characterized as a partial S-adenosylmethionine decarboxylase (SAMDC) cDNA by sequencing analysis and homology search. Two full-length cDNA clones, OsSAMDC1 and OsSAMDC2, were isolated from rice cDNA library with the differential clone as probe. Deduced amino acid sequences of OsSAMDC1 and OsSAMDC2 are identical with those of rice YO7766- and AJ251899-SAMDC released in GenBank databases, respectively. Southern blot analysis with 3'-UTR gene-specific probes indicated that a single-copy of each OsSAMDC gene is present in Yukihikari rice genome. Northern blot analysis with 3'-UTR probes showed that OsSAMDC1 mRNA level is increased in response to cold stress, while OsSAMDC2 mRNA level is increased in response to cold, salt as well as drought stresses. Results on the analysis of polyamines in transgenic rice introduced with OsSAMDC1 was also discussed.
