Efficient transgene expression in chrysanthemum, Dendranthema grandiflorum (Ramat.) Kitamura, by using the promoter of a gene for chrysanthemum chlorophyll-a/b-binding protein

Abstract

We investigated the usefulness of the promoter of a gene for chrysanthemum chlorophyll-a/b-binding protein (Cab) for transgene expression in the chrysanthemum Dendranthema grandiflorum (Ramat.) Kitamura. We used the promoter region of a Cab gene isolated from the chrysanthemum-wild species D. japonicum Makino. The 35S promoter of cauliflower mosaic virus (CaMV) or the Cab promoter was fused to the β-glucuronidase gene (gus) and introduced into the chrysanthemum. We obtained 300 putative transformants (115 with 35S/gus and 185 with Cab/gus). GUS assay of the leaves of the in vitro plants revealed that 9. 6% (11/115) of the putative plants to which 35S/gus had been introduced and 24.3% (45/185) of the putative plants to which Cab/gus had been introduced were GUS-positive. Southern blot analysis showed that even the GUS-negative plants harbored the gus gene in their genomes. The Cab promoter expressed the transgene more efficiently than the 35S promoter and could be used for transgene expression in chrysanthemum leaf tissues.