Search results for "Arabidopsis Thaliana"
showing 10 items of 126 documents
Screening for Solute Transporters in Plant Photosynthetic Membranes
2008
As compared to chloroplast envelope transporters, the field of thylakoid transporters is largely unexplored. There is evidence for several transport activities in the plant thylakoid membrane, but only a copper P-type ATPase and an ATP/ADP carrier have been so far identified at the gene level in Arabidopsis thaliana. Using in silico analyses, we have predicted the existence of approximately 15 thylakoid transporters, including phosphate transporters and cation channels. For experimental validation, we have used peptide- specific antibodies and functional analyses in heterologous system. These novel data are highly relevant to understand the transport network of the thylakoid membrane and it…
Polyamine Oxidase 5 loss-of-function mutations in Arabidopsis thaliana trigger metabolic and transcriptional reprogramming and promote salt stress to…
2017
The family of polyamine oxidases (PAO) in Arabidopsis (AtPAO1-5) mediates polyamine (PA) back-conversion, which reverses the PA biosynthetic pathway from spermine, and its structural isomer thermospermine (tSpm), into spermidine and then putrescine. Here, we have studied the involvement of PA back-conversion in Arabidopsis salinity tolerance. AtPAO5 is the Arabidopsis PAO gene member most transcriptionally induced by salt stress. Two independent loss-of-function mutants (atpao5-2 and atpao5-3) were found to exhibit constitutively higher tSpm levels, with associated increased salt tolerance. Using global transcriptional and metabolomic analyses, the underlying mechanisms were studied. Stimul…
Copper and iron homeostasis inArabidopsis: responses to metal deficiencies, interactions and biotechnological applications
2007
Plants have developed sophisticated mechanisms to tightly control the acquisition and distribution of copper and iron in response to environmental fluctuations. Recent studies with Arabidopsis thaliana are allowing the characterization of the diverse families and components involved in metal uptake, such as metal-chelate reductases and plasma membrane transporters. In parallel, emerging data on both intra- and intercellular metal distribution, as well as on long-distance transport, are contributing to the understanding of metal homeostatic networks in plants. Furthermore, gene expression analyses are deciphering coordinated mechanisms of regulation and response to copper and iron limitation…
Deregulated High Affinity Copper Transport Alters Iron Homeostasis inArabidopsis
2020
The present work describes the effects on iron homeostasis when copper transport was deregulated in Arabidopsis thaliana by overexpressing high affinity copper transporters COPT1 and COPT3 (COPTOE). A genome-wide analysis conducted on COPT1OE plants, highlighted that iron homeostasis gene expression was affected under both copper deficiency and excess. Among the altered genes were those encoding the iron uptake machinery and their transcriptional regulators. Subsequently, COPTOE seedlings contained less iron and were more sensitive than controls to iron deficiency. The deregulation of copper (I) uptake hindered the transcriptional activation of the subgroup Ib of basic helix-loop-helix (bHL…
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…
Activation of the plant plasma membrane H+ -ATPase. Is there a direct interaction between lysophosphatidylcholine and the C-terminal part of the enzy…
1996
The antagonistic effects of the fungal toxin beticolin-1 and of L-alpha-lysophosphatidylcholine (lysoPC) were investigated on the plasma membrane H+-ATPase of the plant Arabidopsis thaliana (isoform 2) expressed in yeast, using both wild-type enzyme (AHA2) and C-terminal truncated enzyme (aha2delta92). Phosphohydrolytic activities of both enzymes were inhibited by beticolin-1, with very similar 50% inhibitory concentrations, indicating that the toxin action does not involve the C-terminal located autoinhibitory domain of the proton pump. Egg lysoPC, a compound that activates the H+-ATPase by a mechanism involving the C-terminal part of the protein, was found to be able to reverse the inhibi…
Ions channels/transporters and chloroplast regulation.
2015
International audience; Ions play fundamental roles in all living cells and their gradients are often essential to fuel transports, to regulate enzyme activities and to transduce energy within and between cells. Their homeostasis is therefore an essential component of the cell metabolism. Ions must be imported from the extracellular matrix to their final subcellular compartments. Among them, the chloroplast is a particularly interesting example because there, ions not only modulate enzyme activities, but also mediate ATP synthesis and actively participate in the building of the photosynthetic structures by promoting membrane-membrane interaction. In this review, we first provide a comprehen…
Arabidopsis Serine Decarboxylase 1 (SDC1) in Phospholipid and Amino Acid Metabolism
2018
Arabidopsis thaliana serine decarboxylase 1 (SDC1) catalyzes conversion of serine to ethanolamine, the first reaction step of phosphatidylcholine and phosphatidylethanolamine biosynthesis. However, an involvement of SDC1 in amino acid metabolism remains elusive despite that serine is the substrate of SDC1. Here, we showed that SDC1 localizes in mitochondria although phosphatidylcholine and phosphatidylethanolamine are known to be produced in the endoplasmic reticulum (ER). Moreover, we found that overexpression of SDC1 decreased levels of amino acid compounds derived from mitochondrial tricarboxylic acid cycle. These results suggest that mitochondria-localized SDC1 plays an important role i…
Establishment of tools for investigating pyoverdine impact on iron homeostasis and plant defense responses
2013
Iron, the fourth major element in the Earth crust, is essential for growth and development of living organisms. However, due to its low solubility in the soil, it is weakly available for plants and micro-organisms. To efficiently assimilate iron, living organisms have evolved specific strategies. In plants such as Arabidopsis thaliana three trans-membrane proteins are involved in iron assimilation while in bacteria such as Pseudomonas fluorescens iron is taken up from the soil thanks to molecules displaying high affinity for iron called siderophores. It has been recently shown that pyoverdine, the major siderophore of the beneficial bacterium Pseudomonas fluorescens, is assimilated by A. th…
The phosphorylated pathway of serine biosynthesis is essential both for male gametophyte and embryo development and for root growth in Arabidopsis.
2013
This study characterizes the phosphorylated pathway of Ser biosynthesis (PPSB) in Arabidopsis thaliana by targeting phosphoserine phosphatase (PSP1), the last enzyme of the pathway. Lack of PSP1 activity delayed embryo development, leading to aborted embryos that could be classified as early curled cotyledons. The embryo-lethal phenotype of psp1 mutants could be complemented with PSP1 cDNA under the control of Pro35S (Pro35S:PSP1). However, this construct, which was poorly expressed in the anther tapetum, did not complement mutant fertility. Microspore development in psp1.1/psp1.1 Pro35S:PSP1 arrested at the polarized stage. The tapetum from these lines displayed delayed and irregular devel…