Submitted to: International Congress of Plant Molecular Biology
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 1997
Publication Date: N/A
Technical Abstract: Tortula ruralis is a moss capable of surviving drying of its vegetative tissue, i.e. it is considered a dessication-tolerant plant. Several pro- perties of this system lead to the hypothesis that the dessication- tolerance mechanism employed by T. ruralis is based upon rapid repair of cellular damage incurred upon rehydration. It is our working hypothesis that much of the repair of desiccation induced damage results from the activity of rehydrins, a group of proteins whose synthesis is induced upon rehydration. Previous work has demonstrated that the synthesis of these proteins is controlled mainly at the translational level and the tran- scripts for these proteins are not novel to rehydrated and early hydrated phases. During drying, T ruralis accumulates rehydrin mRNAs that are stored in the dried gametophytes ready for use upon rehydration. Our work indicates that this accumulation is a result of increased mRNA stability (formation of mRNPs) along with a presumed increase in transcription. We have isolated and sequenced a number of rehydrin cDNA clones, one of which, Tr288, will be addressed in this poster. During dehydration, Tr288 mRNA associates with the 100,000 xg polysomal pellet and segregates in sucrose and cesium gradients at positoins consistent with the formation of mRNA particles (mRNPs). Upon rehydration the transcripts appear to be released from storage for translation. The resulting Tr288 protein (deduced from translation of the cDNA) exhibits features that are similar to proteins known to be involved in desiccation and water stress responses (e.g., high glycine content and random coil structure) but does not exactly fit any of these groups. We will discuss Tr288 gene structure and expression patterns also.