Expression of CaMV35S-GUS gene in transgenic rice plants

Summary To understand the properties of the cauliflower mosaic virus (CaMV) 35S promoter in a monocotyledonous plant, rice (Oryza sativa L.), a transgenic plant and its progeny expressing the CaMV35S-GUS gene were examined by histochemical and fluorometric assays. The histochemical study showed that -glucuronidase (GUS) activity was primarily localized at or around the vascular tissue in leaf, root and flower organs. The activity was also detected in the embryo and endosperm of dormant and germinating seeds. The fluorometric assay of various organs showed that GUS activity in transgenic rice plants was comparable to the reported GUS activity in transgenic tobacco plants expressing the CaMV35S-GUS gene. The results indicate that the level of expression of the CaMV 35S promoter in rice is similar to that in tobacco, a dicotyledonous plant, suggesting that it is useful for expression of a variety of foreign genes in rice plants.