Isolation and characterization of a novel cis-acting sequences regulating root-specific gene from Daucus carota L.

Aquaporins are ubiquitous channel proteins that facilitate the transport of water across cell membranes. Most of aquaporins are represent in more than one tissues, but some of them performed highest in roots. They are be- lived to participate in water transport. DcRB7, a member of the aquaporin family, was isolated from somatic embryos of carrot and identified as a homologous gene of TobRB7. Further studies showed that the expression of DcRB7 was particular in carrot root. To investigate the transcription regulation of DcRB7, a 650-bp upstream sequence of DcRB7 was isolated by inverse PCR, and was fused to the β-glucuronidase (GUS) report gene. After the recombined vectors were transformed into tobacco, the expression pat- tern was performed by histochemical staining and the quan- titative analysis of GUS activity. The results indicated that the cis-acting element of DcRB7 gene directs GUS expression not only as root-specific but also as drought inducible.