Abstract
Arabidopsis thaliana RD20, isolated from dehydrated plants is highly responsive to dehydration, high salinity and ABA treatment as a target of many stress-responsive transcription factors such as RD26 (NAC) and AREB1 (bZIP). Histochemical analysis showed that RD20 is expressed in all vegetative tissue during dehydration. Promoter region of RD20 including ABRE motifs was required for ABA response of RD20 and further upstream region including no known cis motif was required for response to dehydration.
RD20 encodes a calcium- binding EF-hand protein that have been shown to possess Ca2+ binding activity. Transient expression of GFP:RD20 fusion protein in onion epidermal cells revealed that RD20 is localized to granular structures, likely to be oil bodies. To analyze biological function of RD20, we constructed RD20 overexpressor and RNAi plants. Phenotypes of the transgenic plants will be shown and the role of RD20 in stress-response of plant will be discussed.
