Abstract
Previously we produced transgenic rice plants over-expressing ipt gene from Agrobacterium. In the transgenic regenerants with multiple shoots, a high-level expression of a D-type cyclin gene (provisionally named OsCYCD) was observed. The OsCYCD expression, however, was not so obvious in dedifferentiated rice calli without such ectopic expression of the ipt gene. Though these results implied that OsCYCD expression might be regulated by cytokinins, addition of various phytohormones including BA did not increase the transcripts. For more detailed analyses of OsCYCD expression, transgenic plants carrying OsCYCD::gus reporter gene were produced via Agrobacterium. GUS staining of these transgenic plants and in situ hybridization showed that OsCYCD was transcribed in the limited areas expected to be leaf primordia and vascular bundles, but not in root tips. Moreover, ectopic expression of OsCYCD caused abnormal shapes in the leaves. These results suggested that function of this D-type cyclin is related to leaf formation.
