STRP, a novel Arabidopsis protein with a protective role against abiotic stresses

Title : STRP, a novel Arabidopsis protein with a protective role against abiotic stresses

Abstract:

Plants, as sessile organisms, are constantly exposed to critical environmental conditions such as drought, extreme temperatures, and salinity that negatively affect their growth and development, reducing crop productivity. To cope with these abiotic stressors, plants have evolved a repertoire of physiological and biochemical responses that involve multiple processes, including hormone signaling, metabolism alteration, and activation of gene expression. Understanding the complex mechanisms underlying the plant responses to abiotic stresses represents a major goal for developing crop varieties that can adapt well to adverse environmental conditions. STRP (Salt-Tolerance Related Protein) is an Arabidopsis thaliana poorly characterized protein initially proposed to be involved in the plant response to salt stress based on the hypersensitivity to salt stress displayed by the loss-of-function Arabidopsis mutant. In a proteomic study aimed to identify temperature stress-responsive proteins, STRP was found rapidly accumulate during short-term cold exposure, suggesting its involvement in the plant response to cold stress. In this study, we characterized STRP protein and investigated its role in the plant response to cold and salt stresses. Our experiments demonstrated that low-temperature exposure and salt stress caused STRP accumulation and that this was due to the inhibition of its proteasome-mediated degradation. The strp knockout mutant was more susceptible to oxidative damages induced by cold and salt stresses compared to wild-type plants. Furthermore, the analysis of the abscisic acid effects on growth and development evidenced that strp plants displayed a reduced sensitivity towards the hormone. STRP shares common features with the Late Embryogenesis Abundant (LEA) proteins (a family of highly hydrophilic and intrinsically disordered proteins identified in a wide range of organisms) which in plants accumulate at high levels in embryos before seed desiccation and in vegetative tissues under various stress conditions. LEA proteins were proposed to play a protective role by stabilizing cellular structures. STRP is a hydrophilic and largely unstructured protein that remains highly soluble after boiling and can prevent enzyme inactivation after freezing, similar to LEA proteins. Localization studies performed with protoplast transiently transformed with the 35S::STRP-YFP construct showed that STRP is localized in the cytosol and nucleus and associated with the plasma membrane. Interestingly, cold stress increased the STRP nuclear content, promoting its association with chromatin, thus suggesting that STRP may exert a protective role under stressed conditions. Results obtained suggest a role for STRP in plant protection against cold and salt stress, proposing this protein as a multitasking regulator acting at different levels in the response mechanisms to abiotic stresses in Arabidopsis.

Biography:

Dr. Sabina Visconti graduated in Chemistry from the Sapienza University of Rome. She achieved a PhD in Cellular and Molecular Biology, at the University of Rome Tor Vergata in 1999 and from 2000 to 2005 had postdoctoral fellowships in the laboratory of plant physiology at the same university. Since 2005 she is an assistant professor in Plant Physiology and Biotechnology at the University of Rome Tor Vergata. Sabina Visconti’s research activity focused on the study of signal transduction pathways and the molecular mechanisms of plant response to abiotic and biotic stresses. She is author of more than 50 oral and poster presentations at national and international congresses, and of 28 articles published in international peer-reviewed journals.