From Tolerance to Acute Metabolic Deregulation: Contribution of Proteomics To Dig into the Molecular Response of Alder Species under a Polymetallic Exposure

<i>Alnus</i> spp. are actinorhizal trees commonly found in wet habitats and able to grow effectively in soil slightly contaminated with metal trace- elements. Two clones belonging to two <i>Alnus</i> species, namely, <i>A. incana</i> and <i>A. glutinosa</i>, were grown in hydroponics and exposed for 9 weeks to a Cd + Ni + Zn polymetallic constraint. Although responding by a similar decrease in total biomass production, the proteomic analysis associated with the study of various biochemical parameters including carbohydrate and mineral analyses revealed that the two clones have a distinct stress-responsive behavior. All parameters indicated that the roots, the organ in direct contact with the media, are more affected than the leaves. In fact, in <i>A. glutinosa</i> the response was almost completely confined to the roots, whereas many proteins change significantly in the roots and in the leaves of the treated <i>A. incana</i>. In both clones, the changes affected a broad range of metabolic processes such as redox regulation and energy metabolism and induced the production of pathogenesis-related proteins. In particular, changes in the accumulation of bacterial proteins that were not identified as coming from the known symbionts of <i>Alnus</i> were reported. Further investigation should be performed to identify their origin and exact role in the plant response to the polymetallic exposure tested here

Peptides from βPG identified in <i>Arabidopsis</i>, cannabis and maize.

<p>Peptides from βPG identified in <i>Arabidopsis</i>, cannabis and maize.</p

Identified peptides and sequence coverage for the contig 53836 (AGED database).

<p>The upper panel shows the identified peptides, mainly based on a database search of the dataset ft2011092714 (<a href="http://dx.doi.org/10.6084/m9.figshare.100494" target="_blank">http://dx.doi.org/10.6084/m9.figshare.100494</a>)[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171990#pone.0171990.ref019" target="_blank">19</a>]. Peptides uniquely found in in-house datasets are indicated in red. The lower panel shows the translated contig, it contains two sequences coding for different βPG homologs. The signal- and propeptide (residue 1–110) as well as the two C-terminal BURP–domains are indicated in italics. The identified peptides are underlined and the repetitive tetrapeptide FxxY with modified phenylalanine in red. Those phenylalanine residues that were identified as not modified are indicated in blue. The proline that is reproducibly found to be oxidized is in green. Similar observations were done for other contigs.</p

MS/MS spectrum of the precursor at m/z 1548.6924.

<p>The peptide was identified as SFNEGTDKFTGYGK from the Cannabis sativa polygalacturonase non-catalytic protein (NCBI EST database GI:156080210). The upper panel shows the MS/MS spectrum with y- and b-ions indicated respectively in red and green. The one-letter code is used for the amino acids and dF indicates a didehydrophenylalanine. The lower spectra illustrate the specificity of the modification. While no mass shift is observed for the Phe closest to the N-terminus, illustrated by the lack of secondary peak at 233 for the b2-ion shown in the left panel, the more C-terminal Phe is completely modified as illustrated for the y6- and b9-fragment in the central and right lower panel.</p

Physiological and Proteomic Responses of Different Willow Clones (<i>Salix fragilis</i> X <i>alba</i>) Exposed to Dredged Sediment Contaminated by Heavy Metals

<div><p>High biomass producing species are considered as tools for remediation of contaminated soils. Willows <i>(Salix spp.)</i> are prominent study subjects in this regard. In this study, different willow clones <i>(Salix fragilis x alba)</i> were planted on heavy-metal polluted dredging sludge. A first objective was assessment of the biomass production for these clones. Using a Gupta statistic, four clones were identified as high biomass producers (HBP). For comparison, a group of four clones with lowest biomass production were selected (LBP). A second objective was to compare metal uptake as well as the physiological and proteomic responses of these two groups. All these complementary data's allow us to have a better picture of the health of the clones that would be used in phytoremediation programs. Cd, Zn, and Ni total uptake was higher in the HBPs but Pb total uptake was higher in LBPs. Our proteomic and physiological results showed that the LBPs were able to maintain cellular activity as much as the HBPs although the oxidative stress response was more pronounced in the LBPs. This could be due to the high Pb content found in this group although a combined effect of the other metals cannot be excluded.</p> </div