Search results for "ARABIDOPSIS THALIANA"
showing 10 items of 126 documents
Biochemical quantitation of the eIF5A hypusination in Arabidopsis thaliana uncovers ABA-dependent regulation.
2014
The eukaryotic translation elongation factor eIF5A is the only protein known to contain the unusual amino acid hypusine which is essential for its biological activity. This post-translational modification is achieved by the sequential action of the enzymes deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). The crucial molecular function of eIF5A during translation has been recently elucidated in yeast and it is expected to be fully conserved in every eukaryotic cell, however the functional description of this pathway in plants is still sparse. The genetic approaches with transgenic plants for either eIF5A overexpression or antisense have revealed some activities related to t…
Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress
2011
Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic pl…
Identificació i caracterització de transportadors de coure d'alta afinitat d'Arabidopsis thaliana
2003
La tesi doctoral s'emmarca dins de l'àrea de la biologia molecular de plantes, incloent algunes consideracions de tipus fisiològic, i descriu la identificació i caracterització de 5 gens Arabidopsis que codifiquen proteïnes amb similitud estructural amb els transportadors de coure eucariotes de la família Ctr. Els resultats del treball s'han dividit en tres capítols. En el primer d'ells s'analitza a nivell teòric les seqüències dels polipèptids de la família COPT d'Arabidopsis, s'investiga la seua funcionalitat en un sistema d'expressió heteròleg i es caracteritza de forma global el perfil d'expressió dels gens de la família. En aquest apartat es mostra que COPT1 i COPT2 restableixen amb gr…
Temporal aspects of copper homeostasis and its crosstalk with hormones
2015
To cope with the dual nature of copper as being essential and toxic for cells, plants temporarily adapt the expression of copper homeostasis components to assure its delivery to cuproproteins while avoiding the interference of potential oxidative damage derived from both copper uptake and photosynthetic reactions during light hours. The circadian clock participates in the temporal organization of coordination of plant nutrition adapting metabolic responses to the daily oscillations. This timely control improves plant fitness and reproduction and holds biotechnological potential to drive increased crop yields. Hormonal pathways, including those of abscisic acid, gibberellins, ethylene, auxin…
Investigation of the physiological impact and the mode of action of the pyoverdine from Pseudomonas fluorescens on Arabidopsis thaliana : links with …
2015
Siderophores are strong iron chelators produced by bacteria under iron deficiency conditions. In the present work, we studied the impact of the siderophore pyoverdine, produced by the plant growth promoting rhizobacteria Pseudomonas fluorescens C7R12, on plant physiology from phenotypic to molecular effects with a specific focus on plant growth, immune response and iron homeostasis. Based on our analysis of the mode of action of the non-protein amino acid β-aminobutyric acid (BABA), a priming inducer in plants, we studied more specifically the functional link between iron homeostasis and plant immunity. Under iron deficiency, P. fluorescens excretes the iron free form of pyoverdine (apo-pyo…
Study of oligogalacturonides-triggered Nitric Oxide (NO) production provokes new questioning about the origin of NO biosynthesis in plants
2014
Addendum to: Rasul S, Dubreuil-Maurizi C, Lamotte O, Koen E, Poinssot B, Alcaraz G, et al. Nitric oxide production mediates oligogalacturonide-triggered immunity and resistance to Botrytis cinerea in Arabidopsis thaliana. Plant Cell Environ 2012; PMID:22394204; http://dx.doi. org/10.1111/j.1365-3040.2012.02505.x.; International audience; We investigated the production and function of nitric oxide (NO) in Arabidopsis thaliana leaf discs as well as whole plants elicited by oligogalacturonides (OGs). Using genetic, biochemical and pharmacological approaches, we provided evidence that OGs induced a Nitrate Reductase (NR)-dependent NO production together with an increased NR activity and NR tran…
The role of post-transcriptional modulators of metalloproteins in response to metal deficiencies
2021
Copper and iron proteins play a wide range of functions in living organisms. Metal assembly into metalloproteins is a complex process, where mismetalation is detrimental and energy-consuming to cells. Under metal deficiency, metal distribution is expected to reach a metalation ranking, prioritizing essential versus dispensable metalloproteins, while avoiding interferences with other metals and protecting metal-sensitive processes. In this review, we propose that posttranscriptional Modulators of Metalloprotein messenger RNA (ModMeR) are good candidates in metal prioritization under metal-limited conditions. ModMeR target high quota or redundant metalloproteins and, by adjusting their synthe…
Plant virus evolution under strong drought conditions results in a transition from parasitism to mutualism
2021
Environmental conditions are an important factor driving pathogens’ evolution. Here, we explore the effects of drought stress in plant virus evolution. We evolved turnip mosaic potyvirus in well-watered and drought conditions in Arabidopsis thaliana accessions that differ in their response to virus infection. Virus adaptation occurred in all accessions independently of watering status. Drought-evolved viruses conferred a significantly higher drought tolerance to infected plants. By contrast, nonsignificant increases in tolerance were observed in plants infected with viruses evolved under standard watering. The magnitude of this effect was dependent on the plant accessions. Differences in to…
S-Nitrosation of Arabidopsis thaliana Protein Tyrosine Phosphatase 1 Prevents Its Irreversible Oxidation by Hydrogen Peroxide
2022
Tyrosine-specific protein tyrosine phosphatases (Tyr-specific PTPases) are key signaling enzymes catalyzing the removal of the phosphate group from phosphorylated tyrosine residues on target proteins. This post-translational modification notably allows the regulation of mitogen-activated protein kinase (MAPK) cascades during defense reactions. Arabidopsis thaliana protein tyrosine phosphatase 1 (AtPTP1), the only Tyr-specific PTPase present in this plant, acts as a repressor of H2O2 production and regulates the activity of MPK3/MPK6 MAPKs by direct dephosphorylation. Here, we report that recombinant histidine (His)-AtPTP1 protein activity is directly inhibited by H2O2 and nitric oxide (NO) …
Comparison of global responses to mild deficiency and excess copper levels in Arabidopsis seedlings
2013
[EN] Copper is an essential micronutrient in higher plants, but it is toxic in excess. The fine adjustments required to fit copper nutritional demands for optimal growth are illustrated by the diverse, severe symptoms resulting from copper deficiency and excess. Here, a differential transcriptomic analysis was done between Arabidopsis thaliana plants suffering from mild copper deficiency and those with a slight copper excess. The effects on the genes encoding cuproproteins or copper homeostasis factors were included in a CuAt database, which was organised to collect additional information and connections to other databases. The categories overrepresented under copper deficiency and copper e…