Submitted to: Annual International Meeting for Moss Research
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2002
Publication Date: N/A
Technical Abstract: Much of our understanding of vegetative desiccation-tolerance in plants comes from the study of two model plants that differ extensively in the mechanism by which they achieve this remarkable capability. These models are the dicot Craterostigma plantagineum and the widespread moss Tortula (or Syntrichia) ruralis. Our studies have centered upon the bryophyte model that appears to utilize a mechanism for tolerance that includes a constitutive cellular protection component coupled to an inducible cellular repair process. From an evolutionary standpoint this type of mechanism is thought to be the primitive state and as such could provide important clues as to the identity of genes critical to ability to survive severe water deficits. As part of our continuing efforts to understand the mechanisms of vegetative desiccation tolerance we have recently taken a functional genomics approach that includes Tortula ruralis. We have establish two Subtractive Suppression Hybridization (SSH) libraries for Tortula in conjunction with a collection of 10,000 ESTs that are currently under analysis and annotation. A Bacterial Artificial Chromosome (BAC) library is also under construction for physical mapping purposes. Our initial efforts into functional genomics are concentrated on a microarray-based expression analysis, using both the EST collection and the SSH libraries, to establish the identity of those genes that are central to the response. These genes will then form the focus of functional studies in both bryophytes and angiosperm modes. The results of our efforts in this area will be presented and discussed. We have also taken a proteomics level approach to unravel the intricacies of a translational control mechanism we have established as critical to the response of Tortula to desiccation and rehydration. 2-D gel analysis of polysomal fractions have identified proteins we believe are involved in the formation of messenger ribonucleic acid particles (mRNPs) during a slow desiccation event. These mRNPs selectively sequester rehydrin transcripts and we are interested in the identity, function, and selective binding properties of these proteins. In collaboration with William Hurkman at the ARS Western Region laboratory in Albany, Calfornia, we are attempting to microsequence these proteins in order to expand our abilities to investigate their properties. The results from these studies will also be presented in order to give an overview of our research program in volving Tortula ruralis.