Proteomic characterization of copper stress response in Elsholtzia splendens roots and leaves.
ABSTRACT Elsholtzia splendens is generally considered as a Cu-tolerant and -accumulating plant species, and a candidate for phytoremediation of Cu-contaminated soils. To better understand the Cu tolerance/accumulation mechanisms in E. splendens, proteomic analysis was performed on E. splendens roots and leaves exposed to 100 muM CuSO(4) for 3 and 6 days. After 6 days of treatment, Cu accumulation in roots increased much more than that in leaves. SDS-PAGE analysis showed that the proteins changed more intensively in roots than did in leaves upon Cu stress. Two-dimensional gel electrophoresis (2-DE) and image analyses found that 45 protein spots were significantly changed in roots, but only six protein spots in leaves. The abundance of protein spots mostly showed temporal changes. MALDI-TOF MS and LTQ-ESI-MS/MS were used to identify the differently expressed protein spots. The identified root proteins were involved in various cellular processes such as signal transduction, regulation of transcription and translation, energy metabolism, regulation of redox homeostasis and cell defense. The leaf proteins were mainly degraded fragments of RuBisCo and antioxidative protein. The roles of these proteins in Cu tolerance/accumulation were discussed. The resulting differences in protein expression pattern suggested that redirection of root cellular metabolism and redox homeostasis might be important survival mechanisms of E. splendens upon Cu stress.
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ABSTRACT: Withania somnifera L. seedlings were grown in half-strength MS (Murashige and Skoog) basal medium for 4 weeks and then transferred to full-strength MS liquid medium for 3 weeks. The sustainable plants were subcultured in the same medium but with different concentrations (0, 25, 50, 100 and 200 μM) of Cu for 7 and 14 days. The growth parameters (root length, shoot length, leaf length and total number of leaves per plant) showed a declining trend in the treated plants in a concentration dependant manner. Roots and leaves were analyzed for protein profiling and antioxidant enzymes [catalase (CAT, EC 188.8.131.52), superoxide dismutase (SOD, EC 184.108.40.206) and guaiacol peroxidase (GPX, EC 220.127.116.11)]. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of crude protein extracts showed the appearance of some new proteins due to Cu treatment. In plant samples grown with 25 and 50 μM of Cu, a rapid increase in antioxidant activities were noticed but at higher concentration (100 and 200 μM) the activities declined. Isoforms of CAT, SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and concentration specific new isoforms were noticed during the study. Isoforms of the antioxidant enzymes synthesized due to Cu stress may be used as biomarkers for other species grown under metal stress.Physiology and Molecular Biology of Plants 01/2013;
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ABSTRACT: Plant acclimation to stress is associated with profound changes in proteome composition. Since proteins are directly involved in plant stress response, proteomics studies can significantly contribute to unravel the possible relationships between protein abundance and plant stress acclimation. In this review, proteomics studies dealing with plant response to a broad range of abiotic stress factors--cold, heat, drought, waterlogging, salinity, ozone treatment, hypoxia and anoxia, herbicide treatments, inadequate or excessive light conditions, disbalances in mineral nutrition, enhanced concentrations of heavy metals, radioactivity and mechanical wounding are discussed. Most studies have been carried out on model plants Arabidopsis thaliana and rice due to large protein sequence databases available; however, the variety of plant species used for proteomics analyses is rapidly increasing. Protein response pathways shared by different plant species under various stress conditions (glycolytic pathway, enzymes of ascorbate-glutathione cycle, accumulation of LEA proteins) as well as pathways unique to a given stress are discussed. Results from proteomics studies are interpreted with respect to physiological factors determining plant stress response. In conclusion, examples of application of proteomics studies in search for protein markers underlying phenotypic variation in physiological parameters associated with plant stress tolerance are given.Journal of proteomics 02/2011; 74(8):1301-22. · 5.07 Impact Factor
Conference Paper: Iterative multiuser detection for space-time coded synchronous CDMA[Show abstract] [Hide abstract]
ABSTRACT: Multiuser detectors for trellis space-time coded synchronous CDMA, operating in the presence of independent Rayleigh fading are considered. The joint optimal maximum likelihood (ML) multiuser detector, which can be implemented as a Viterbi algorithm, is derived for such space-time coded systems. A suboptimal, low complexity iterative space-time multiuser detector based on interference cancellation and the turbo principle is also derived. Simulations show that this latter method achieves performance competitive with the single user bound for space-time coded systemsVehicular Technology Conference, 2001. VTC 2001 Fall. IEEE VTS 54th; 02/2001