Molecular Characterization of the Rehydration Process in the Resurrection Plant Craterostigma plantagineum.

The resurrection plant Craterostigma plantagineum is unique among higher plants because it is able to survive a desiccation treatment. For this reason it has been used as a model system for the analysis of the molecular mechanisms of desiccation tolerance. Many transcripts and proteins are expressed de novo during dehydration. This paper describes the molecular events that occur during the rehydration process of dried C. plantagineum plants. Changes in gene expression patterns were first analyzed by in vivo labeling and in vitro translation experiments. In a second set of experiments steady-state mRNA levels were monitored using specific cDNA clones. The experiments indicated three major changes on the molecular level during rehydration: the dehydration-specific gene products disappeared during an early phase of rehydration, a small number of rehydration-specific transcripts were synthesized around 12 to 15 h after the onset of rewatering, and hydration-related gene products appeared concomitantly. The gene expression patterns during rehydration are discussed with respect to the possible roles of the gene products.