|Cushman, John -|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: September 21, 2009
Publication Date: N/A
Technical Abstract: Desiccation tolerance (DT) is defined as the equilibration of protoplasmic water potential with that of the surrounding air (generally dry) without loss of viability upon rehydration. Vegetative DT is widespread amongst mosses and lichens, but is relatively rare in vascular plants (0.15%). Recent studies of selected resurrection species indicate that while resurrection plants might have evolved unique adaptive proteins, enzymes, and antioxidants, the molecular genetic basis of DT lies in the unique orchestration of transcriptional and posttranscriptional regulatory programs that operate during drying and rehydration. DT requires signaling pathways and regulatory mechanisms, aspects of which resemble developmental programs present in orthodox seeds, which result in the accumulation of oligosaccharides, stress adaptive proteins, antioxidants, reactive oxygen scavenging enzymes, as well as alterations in the composition and structure of membrane lipids. Functional genomics studies using transcriptome, proteome, and metabolome analyses are just beginning to unravel the system complexity required to orchestrate the metabolic symphony that is DT. The status of current gene discovery efforts is summarized along with major transcriptome technologies available currently to conduct desiccation sensitive versus tolerant species comparisons. These strategies, integrated with large-scale proteomic and metabolomic investigations currently in progress, promise to revolutionize our understanding of the mechanistic basis of desiccation tolerance in resurrection plants.