ROLB EXPRESSION PATTERN IN THE EARLY STAGES OF CARROT SOMATIC EMBRYOGENESIS

The pattern of expression of the rolB gene, derived from the T-DNA of the plant pathogen Agrobacterium rhizogenes, has been investigated dur ing the early stages of somatic embryo formation in suspension culture s of carrot (Daucus carota L.). The reporter gene GUS (Escherichia col i beta-glucuronidase), under transcriptional control of full-length ro lB promoter region, has been utilized in order to evaluate both qualit ative and quantitative variations in the expression pattern. Fluorimet ric measurements point to the developmental regulation of the gene, wh ile results from histochemical analysis indicate that the promoter of rolB is firstly activated in the central (core) region of the globular embryos. (C) 1997 Academic Press Limited.