Differential regulation of two ABA-inducible genes from Craterostigma plantagineum in transgenic Arabidopsis plants.

In Craterostigma plantagineum the CDeT-6-19 and CDeT-27-45 genes are expressed following desiccation and/or ABA treatment. Their promoters were fused to the beta-glucuronidase reporter gene (GUS) and tested in transgenic Arabidopsis. GUS activity was measured in mature Arabidopsis seeds, and the responsiveness to ABA in vegetative tissue was found to be limited to the early developmental stages. When transgenic plants were crossed with plants over-expressing the ABI3 gene, it was observed that ABI3 is not required for ABA induction of the CDeT-6-19 promoter, whereas it is crucial for expression of the CDeT-27-45 promoter.