The pck1 promoter from Urochloa panicoides (a C-4 plant) directs expression differently in rice (a C-3 plant) and maize (a C-4 plant)

摘要

A chimeric Lyme using beta-glucuronidase (GUS) as a reporter gene under the control of a 1.3 kb 5'-flanking region of pck1 (involved in C-4 photosynthesis in Urochloa panicoides) was introduced into rice and maize. GUS activity was detected in leaf blades, leaf sheaths and roots of transgenic rice plants and was detected at high levels in leaf blades and at low levels in leaf sheaths and roots of transaenic maize plants. The pck1 promoter drove the expression of GUS activity in transgenic maize following 6 h of illumination. In contrast, GUS activity was not induced in transgenic rice even after 24 h illumination. Histochemical analysis revealed that GUS staining was localized to bundle sheath cells and vascular bundles of both rice and maize transformants and GUS activity in bundle sheath cells of transgenic maize was induced by light. These results suggest that the 1.3 kb pck1 promoter contains cis-acting elements for preferential and abundant expression in bundle sheath cells of the leaf blade with light dependence in maize but rice lacks some trans-acting elements required for the expression controlled by pck1.