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: Copper (Cu) is an essential micronutrient for plants. However, excess amounts of Cu are toxic and result in a wide range of harmful effects on the physiological and biochemical processes of plants. Cell wall has a crucial role in plant defense response to toxic metals. To date, the process of cell wall response to Cu and the detoxification mechanism have not been well documented at the proteomic level.PLoS ONE 01/2014; 9(10):e109573. · 3.53 Impact Factor
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ABSTRACT: Copper (Cu) accumulation in soils is becoming a major environmental problem. Elsholtzia splendens, a Cu-tolerant plant growing in Cu mine areas, can accumulate high levels of Cu. This study develops a systematic method of detecting the intracellular localization and different chemical forms of Cu to comprehensively understand the mechanisms involved in Cu tolerance and detoxification of E. splendens. Various chemical forms of Cu were absorbed by E. splendens, the highest proportion of which was stored in its cell walls (68 %) and vacuoles (42 %). Most of the Cu in the roots, stems and leaves were extracted by 2 % hydrate acetic acid (HAc) in controls. The distribution characteristics of Cu, particularly in the roots, were closely related to the Cu tolerance of E. splendens. In addition, the binding capacity of Cu to soluble salts or proteins decreased and its binding capacity to insoluble oxalate increased with the increasing Cu supply. These results indicated that Cu ions were integrated with compounds of low bioavailable, such as undissolved phosphate or oxalate, which contributed to the metal tolerance and detoxification of E. splendens. Cluster analysis, based on Cu abundance levels, reveals that correlations exist between the chemical forms of Cu and their intracellular locations, which in turn indicates a relationship between their migration activity and toxicity.Biological Trace Element Research 07/2014; · 1.31 Impact Factor
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ABSTRACT: Differential expression of soluble proteins was explored in roots of metallicolous (M) and non-metallicolous (NM) plants of Agrostis capillaris L. exposed to increasing Cu to partially identify molecular mechanisms underlying higher Cu tolerance in M plants.Plants were cultivated 2 months on perlite with a CuSO4 (1–30 μM) spiked-nutrient solution. Soluble proteins extracted by the TCA/acetone procedure were separated with 2-DE (linear 4–7 pH gradient). After CCB staining and image analysis, 19 proteins differentially expressed were identified using LC-MS/MS and ESTs databases.At supra-optimal Cu exposure (15–30 μM), glycolysis was likely altered in NM roots with increased production of glycerone-P and methylglyoxal based on over-expression of Triosephosphate Isomerase and Fructose bisphosphate aldolase. Changes in Tubulins and higher expressions of 5-methyltetrahydropteroyltriglutamatehomocysteine methyltransferase and S-Adenosylmethionine synthase respectively underpinned impacts on the cytoskeleton and stimulation of ethylene metabolism. Increased L-methionine and S-Adenosylmethionine amounts may also facilitate production of nicotianamine, which complexes Cu, and L-cysteine, needed for metallothioneins and GSH. In M roots, the increase of [Cu/Zn] Superoxide dismutase suggested a better detoxification of superoxide, when Cu exposure rose. Higher Cu-tolerance of metallicolous plants would rather results from simultaneous cooperation of various processes than from a specific mechanism.This article is protected by copyright. All rights reservedProteomics 05/2014; · 4.43 Impact Factor