Grants and Contracts Details
Salt stress, one of the major causes of crop yield losses, evokes a complex set of responses both at the cellular and organismal levels. One of the primary responses to salt stress is the rapid depolymerization of cortical microtubules (MTs) followed by the formation of a new MT network better suited for surviving high salinity. The main process underlying the reorganization of MT networks is dynamic instability (i.e., MT growth and shrinkage) that is predominantly regulated by MT associated proteins (MAPs). We have recently shown that the cellular level of SPIRAL1 (SPR1), an MT-stabilizing MAP, is regulated by 26S proteasome-dependent proteolysis that is accelerated under salt stress conditions. Furthermore, we showed that SPR1 destabilization is required for the salt stress-induced depolymerization of cortical MTs and for salt stress tolerance. In the proposed one-year project, we will investigate the salt stress-induced SPR1 degradation by identifying SPR1’s intrinsic destabilizing residues. Prior to their degradation, 26S proteasome target proteins are labeled by the attachment of a polyubiquitin chain to one or more lysines. SPR1 is a small protein, and it contains just a few lysines that potentially serve as destabilizing residues. We propose to generate a set of single and double lysine-to-arginine mutants, and introduce them into the Arabidopsis spr1-3 mutant. The ease and speed of generating transgenic Arabidopsis lines will allow us to analyze the effects of the mutations both on SPR1 stability and on salt stress sensitivity within the one-year time frame. The envisioned outcome of this project is the isolation of SPR1 versions with altered stability. These SPR1 mutants will be instrumental in dissecting the salt stressregulated SPR1 degradation mechanism that is expected to offer new tools for the improvement of salt stress tolerance in crop species. Key words: 26S proteasome, cortical microtubules, microtubule-associated proteins, plant development, salt tolerance. Areas of expertise: Ubiquitin-dependent proteolysis, Arabidopsis research, plant stress physiology, plant cytoskeleton, salt stress mechanisms.
|Effective start/end date||7/1/12 → 6/30/14|
- KY Science and Technology Co Inc: $49,482.00
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