Mg deficiency interacts with the circadian clock and phytochromes pathways in Arabidopsis

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Changes in the Proteome of Medicago sativa Leaves in Response to Long-Term Cadmium Exposure Using a Cell-Wall Targeted Approach

Accumulation of cadmium (Cd) shows a serious problem for the environment and poses a threat to plants. Plants employing various cellular and molecular mechanisms to limit Cd toxicity and alterations of the cell wall structure were observed upon Cd exposure. This study focuses on changes in the cell wall protein-enriched subproteome of alfalfa (Medicago sativa) leaves during long-term Cd exposure. Plants grew on Cd-contaminated soil (10 mg/kg dry weight (DW)) for an entire season. A targeted approach was used to sequentially extract cell wall protein-enriched fractions from the leaves and quantitative analyses were conducted with two-dimensional difference gel electrophoresis (2D DIGE) followed by protein identification with matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time of flight (TOF/TOF) mass spectrometry. In 212 spots that showed a significant change in intensity upon Cd exposure a single protein was identified. Of these, 163 proteins are predicted to be secreted and involved in various physiological processes. Proteins of other subcellular localization were mainly chloroplastic and decreased in response to Cd, which confirms the Cd-induced disturbance of the photosynthesis. The observed changes indicate an active defence response against a Cd-induced oxidative burst and a restructuring of the cell wall, which is, however, different to what is observed in M. sativa stems and will be discussed

Didehydrophenylalanine, an abundant modification in the beta subunit of plant polygalacturonases

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The Effects of Salinity on the Anatomy and Gene Expression Patterns in Leaflets of Tomato cv. Micro-Tom.

peer reviewedSalinity is a form of abiotic stress that impacts growth and development in several economically relevant crops and is a top-ranking threat to agriculture, considering the average rise in the sea level caused by global warming. Tomato is moderately sensitive to salinity and shows adaptive mechanisms to this abiotic stressor. A case study on the dwarf tomato model Micro-Tom is here presented in which the response to salt stress (NaCl 200 mM) was investigated to shed light on the changes occurring at the expression level in genes involved in cell wall-related processes, phenylpropanoid pathway, stress response, volatiles' emission and secondary metabolites' production. In particular, the response was analyzed by sampling older/younger leaflets positioned at different stem heights (top and bottom of the stem) and locations along the rachis (terminal and lateral) with the goal of identifying the most responsive one(s). Tomato plants cv. Micro-Tom responded to increasing concentrations of NaCl (0-100-200-400 mM) by reducing the leaf biomass, stem diameter and height. Microscopy revealed stronger effects on leaves sampled at the bottom and the expression analysis identified clusters of genes expressed preferentially in older or younger leaflets. Stress-related genes displayed a stronger induction in lateral leaflets sampled at the bottom. In conclusion, in tomato cv. Micro-Tom subjected to salt stress, the bottom leaflets showed stronger stress signs and response, while top leaflets were less impacted by the abiotic stressor and had an increased expression of cell wall-related genes involved in expansion

A Study on the Use of the Phyto-Courier Technology in Tobacco Leaves Infected by <i>Agrobacterium tumefaciens</i>

Climate change results in exceptional environmental conditions and drives the migration of pathogens to which local plants are not adapted. Biotic stress disrupts plants’ metabolism, fitness, and performance, ultimately impacting their productivity. It is therefore necessary to develop strategies for improving plant resistance by promoting stress responsiveness and resilience in an environmentally friendly and sustainable way. The aim of this study was to investigate whether priming tobacco plants with a formulation containing silicon-stabilised hybrid lipid nanoparticles functionalised with quercetin (referred to as GS3 phyto-courier) can protect against biotic stress triggered by Agrobacterium tumefaciens leaf infiltration. Tobacco leaves were primed via infiltration or spraying with the GS3 phyto-courier, as well as with a buffer (B) and free quercetin (Q) solution serving as controls prior to the biotic stress. Leaves were then sampled four days after bacterial infiltration for gene expression analysis and microscopy. The investigated genes increased in expression after stress, both in leaves treated with the phyto-courier and control solutions. A trend towards lower values was observed in the presence of the GS3 phyto-courier for genes encoding chitinases and pathogenesis-related proteins. Agroinfiltrated leaves sprayed with GS3 confirmed the significant lower expression of the pathogenesis-related gene PR-1a and showed higher expression of peroxidase and serine threonine kinase. Microscopy revealed swelling of the chloroplasts in the parenchyma of stressed leaves treated with B; however, GS3 preserved the chloroplasts’ mean area under stress. Furthermore, the UV spectrum of free Q solution and of quercetin freshly extracted from GS3 revealed a different spectral signature with higher values of maximum absorbance (Amax) of the flavonoid in the latter, suggesting that the silicon-stabilised hybrid lipid nanoparticles protect quercetin against oxidative degradation

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

Magnesium maintains the length of the circadian period in Arabidopsis

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