Proteomics as a Toolbox to Study the Metabolic Adjustment of Trees During Exposure to Metal Trace Elements

Kjell Sergeant, Jenny Renaut, and Jean-Francois Hausman Abstract Although trees form an important part of the global environment, the use of proteomics in the study of environmental adaptation of trees, and specifically in the study of heavy metal exposure, is currently limited. This lack of proteomics studies is mainly due to the characteristics of trees making them difficult species to work with but can also partially be attributed to the limited genetic information that is available for most...

Auxin and Heavy Metal Stress

Among the nonessential heavy metals, cadmium (Cd) is the most well studied compound. It is mainly released into the environment by anthropogenic activities and its emissions have been estimated to be in the range of 30,000 t per annum (Sanita di Toppi and Gabrielli 1999). As Cd is highly toxic its over-accumulation in plants results in growth reductions and death. Environmental pollution with Cd is of great concern since its accumulation in the food chain may eventually affect human health....

Organic Acids Nicotianamine Amino Acids and Phytates

Organic acids (OAs) have been associated with metal hyperaccumulation and tolerance in a range of plant species and have been proposed as important cellular ligands for Zn, Cd and Ni (Salt et al. 1999 Kupper et al. 2004). The carboxylic acids known to be present in high concentrations in the cell vacuoles of photosyn-thetic tissues include citric, isocitric, oxalic, tartaric, malic, malonic and aconitic (Callahan et al. 2007). Many studies have implied that these acids play a role in...

Phytochelatins

To protect themselves from the toxicity of metal ions, plant cells have developed a mechanism to inactivate metal ions thus preventing enzymatic and structural proteins (Kneer and Zenk 1992). This mechanism consists of the biosynthesis of a set of iso-peptides PCs with varying chain lengths such as (y-Glu-Cys)n-Gly where n 2-11 (Fig. 1). PCs (or cadystins) were first discovered in fission yeast Schizosaccharomyces pombe exposed to Cd (Murasugi et al. 1981) and then in many plants (Grill et al....

References

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Phytohormone Signaling Pathways

The accumulation of H2O2 driven by plasma membrane NADPH-oxidases are thought to induce the formation of lipid peroxides (i.e., fatty acid radicals orFA-OO Neil et al. 2002). This oxidative process, together with the activity of several classes of lipoxigenases, generate oxylipins, which are precursors of jasmonate (JA Turner et al. 2002 Foreman et al. 2003). Several short-term experiments have shown that heavy metals can induce the overexpression of several genes encoding LOXs. Thus, the...

Introduction

As a consequence of the industrial revolution there is an enormous and increasing demand for heavy metals that leads to highly anthropogenic emission into the biosphere (Ayres 1992). Apart from some emissions into the atmosphere in the form of dust particles or gases, these heavy metals stay largely in the aquatic and soil phases of this planet. Contamination also occurs extensively or locally even under natural environmental conditions where there are no directly connected human activities....

Auxin and Essential Metals

Among the essential micronutrients, transition metals such as copper, iron, and manganese (Cu, Fe, Mn) are important cofactors in metalloproteins, for example in peroxidases, oxidases, and superoxide dismutases. Free Cu2+ or Fe3+ catalyse the formation of hydroxyl radicals (OH*) via the Fenton reaction. OH is highly reactive and leads to unspecific oxidative degradation. Therefore, the intracellular levels of free Cu or Fe have to be kept low to avoid triggering the Fenton reaction inside the...

Localization of Heavy Metals in Cells and Tissues of Different Plant Organs

Rejective Way Silicon Uptake

As shown in Fig. 2, general mechanisms for detoxification and accumulation of heavy metals in plants are the distribution of the metals to apoplastic compartments Fig. 2 Possible metal localization and presence of major metal-binding ligands in a model plant with a standard root, stem and shoot system. In each organ, tissues and cells are conventionally divided into apoplasic and symplastic sites. The former including xylem (sap) in the conductive tissues of each organ, and rizosphere connected...

Cadmium Toxicity in Plants

Although cadmium toxicity in many plant species has been reported by several authors Clemens 2006 Sandalio et al. 2009 the mechanisms of its toxicity are not yet well understood. Recent experiments reveal, however, that there is a relationship between metal stress, redox homeostasis and antioxidant capacity Sharma and Dietz 2009 and that the cellular redox state is important in the determination of metal phytotoxicity Cuypers et al. 2011 . Cadmium is able to induce different effects on plants....