Submitted to: Plant Protein Club 1998 Annual Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/1998
Publication Date: N/A
Technical Abstract: In the last five years bryophytes have become established as model plants for the study of many developmental (cell polarity and plastid development), genetic (homologous recombination) and cellular (calcium signaling) processes. These simple plants offer a wide variety of features that make them ideal for this role. Bryophytes are also ideal models for the study of abiotic stress responses. This is especially true for the study of stress-tolerance mechanisms since many bryophytes exhibit tolerance to extreme environments, e.g., desiccation and freezing. The only cell thickness of most bryophyte leaves allows for the almost instantaneous application of an environmental stress to the protoplasm, and as most are composed of only one major cell type the effect approaches homogeneity. Over the last decade we have developed the moss Tortula ruralis as a model for mechanistic studies into vegetative desiccation-tolerance. Our studies have demonstrated that the moss alters gene expression in response to desiccation and rehydration by alterations in translational controls. Using cDNAs specific to the response we have determined that the formation of mRNPs containing rehydration specific transcripts (rehydrins) during drying plays an important role in the very rapid recovery of these plants from the dry state. We have been able to analyze the desiccation induced formation of these particles using density gradient centrifugation and semi- quantitative RT-PCR and have been successful in purifying them using UV crosslinking, oligo-dT chromatography and FPLC. We are presently attempting to isolate the protein component of these complexes. In addition, we have developed RNA gel mobility shift assays as a separate approach to identifying rehydrin mRNA specific RNA binding proteins.