Acquisition of Desiccation Tolerance by Cultured Carrot Cells upon Ectopic Expression of C-ABI3, a Carrot Homolog of ABI3

To obtain direct evidence for the involvement of C-ABI3, a carrot (Daucus carota L.) homolog of VP I/ABI3, seed-specific transcription factor, in the acquisition of desiccation tolerance, we prepared transgenic carrot non-embryogenic cells (NC) in which the C-ABI3 gene was expressed ectopically. Non-transgenic NC, in which expression of C-ABI3 was not detected, did not exhibit desiccation tolerance even after treatment with abscisic acid (ABA). In transgenic NC that expressed C-ABI3, embryo-specific ABA-inducible genes (ECP genes) were expressed upon ABA-treatment. Furthermore, the transgenic NC became desiccation-tolerant upon ABA-treatment, bur did not tolerate desiccation without ABA-treatment.