Transcription profiling of Cd-induced nitric oxide synthesis in Arabidopsis
ABSTRACT: Cadmium treatment induces slow but long lasting nitric oxide production in plant tissues. This NO production can be suppressed using the commonly used Nitric Oxide Synthase inhibitor L-NAME. This inhibitor tends to partially alleviate Cd toxicity. This effect is correlated with a strong diminution of Cd content in roots of plants treated both with Cd and L-NAME compared to roots from plants treated with Cd only. The main goal of this study is the identification of transcriptionnal changes caused by Cd-induced nitric oxide, and that could potentially result in enhanced Cd root accumulation.
Nitric oxide (NO) functions as a cell-signaling molecule in plants. In particular, a role for NO in the regulation of iron homeostasis and in the plant response to toxic metals has been proposed. Here, we investigated the synthesis and the role of NO in plants exposed to cadmium (Cd(2+)), a nonessential and toxic metal. We demonstrate that Cd(2+) induces NO synthesis in roots and leaves of Arabidopsis (Arabidopsis thaliana) seedlings. This production, which is sensitive to NO synthase inhibitors ...[more]
Project description:The study aims at determining the genes that are induced or repressed by cold in the suspension cells. It also aims at monitoring the effect of inhibitors of PLC (U73122 vs. U73343) and PLD (ethanol vs. tertiary butanol) on cold response at the transcription level. To answer this question we chose a pharmacological approach. We decided to use molecules that are going to inhibit PLC or PLD. For PLC we use U73122 and its inactive analog as a control; for PLD we used a primary alcohol (ethanol) and a tertiary alcohol (tert-butanol) as a control. We therefore extracted RNA after the following treatments:<br> 4 °C<br> 22 °C<br> 4 °C + 0.9% primary-ethanol<br> 4 °C + 0.9% tertiary-butanol<br> 4 °C + 60 micromolaire U73122<br> 4 °C + 60 micromolaire U73343<br> The exposure at 4 °C was 4 hours.
Project description:Functions of AtVDAC1 and its partner p26 in Arabidopsis thaliana. We previously showed that knock-out mutants impaired in AtVdac1 and p26 (AtVdac1 protein partner) are hypersensitive to salicylic acid: the root growth is more inhibited in response to 30 uM salicylic acid (SA) compared to the wild type. We want to know now which genes are up- or down-regulated in the mutants in control and SA conditions.<br> We want to compare the RNAm contents in the wild type, vdac1 and p26 mutants and, vdac1-p26 double mutant. One-week old plantlets were transferred for 2 hours on a fresh medium containing either 0 or 30uM salicylic acid.<br> Arabidopsis lines (WT, vdac1.1, p26.1, vdac1.1-p26.1) were grown in vertical position on ABIS medium (Lanquar et al., 2006). One week-old seedlings were transferred on a fresh ABIS medium containing either 0 or 30 uM salicylic acid. After 2 hours, the all seedlings were harvested. Three replicates were done; total RNAs from these 3 experiments were mixed together for the transcriptomic analysis.
Project description:Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana seedlings, under conditions of in vitro culture, a very high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors (Sulmon et al., 2004). The CATMA investigation will be useful to reveal the gene networks implicated in the mechanisms of xenobiotics tolerance. Seeds of Arabidopsis thaliana (ecotype Columbia) were surface-sterilized inbayrochlore/ethanol (1:1, v/v), rinsed in absolute ethanol and dried overnight. Germination and growth were carried out under axenic conditions in square Petri dishes. After seeds were sowed, Petri dishes were placed at 4 C for 48 h in order to break dormancy and homogenize germination, and then transferred to a control growth chamber at 22°C under a 16-h light period regime at 4500 lux for 4 weeks. Growth medium consisted of 0.8% (w/v) agar in 1x Murashige and Skoog (MS) basal salt mix (Sigma, St. Louis, MO, USA) adjusted to pH 5.7. After 4 weeks of cultivation on vertical plates plantlets were transferred on fresh medium complemented or not with atrazine 10 uM and with sucrose 80mM or mannitol 80 mM which were directly added during preparation of agar-MS media prior to sterilisation. Atrazine was sterilized by microfiltration through 0.2 um cellulose acetate filters (Polylabo, Strasbourg, France) and then axenically added to melted agar-MS medium prior to pouring into Petri dishes. Then plantlets were harvested after 24 hours of transfer and extracted for RNA.
Project description:Seeds of Arabidopsis thaliana (ecotype Columbia) were surface-sterilized inbayrochlore/ethanol (1:1, v/v), rinsed in absolute ethanol and dried overnight. Germination and growth were carried out under axenic conditions in square Petri dishes. After seeds were sowed, Petri dishes were placed at 4°C for 48 h in order to break dormancy and homogenize germination, and then transferred to a control growth chamber at 22°C under a 16-h light period regime at 4500 lux for 4 weeks. Growth medium consisted of 0.8% (w/v) agar in 1x Murashige and Skoog (MS) basal salt mix (Sigma, St. Louis, MO, USA) adjusted to pH 5.7. After 4 weeks of cultivation on vertical plates plantlets were transferred on fresh medium complemented with atrazine 10 µM and with sucrose 80mM or mannitol 80 mM which were directly added during preparation of agar-MS media prior to sterilisation. Atrazine was sterilized by microfiltration through 0.2 µm cellulose acetate filters (Polylabo, Strasbourg, France) and then axenically added to melted agar-MS medium prior to pouring into Petri dishes. Then plantlets were harvested after 12, 24 and 48 hours of transfer and extracted for RNA. Plantlets grown on MS medium were harvested and extracted for RNA as control.
Project description:Does the ko of NIN7 leads to a differential expression in comparison to the wildtype. Can we repeat the results from the first experiment; and is there a difference between the two alleles? <br> Plants were harvested during the first 3 hours of light after 42 days growth on 0.2mM or 6mM nitrate in hydroponic condition (short day, 170 uE).
Project description:Does the NRT2.7 participate to the HATS?<br> We would like to understand the function of the AtNRT2.7 in nitrate transport under limiting and non limiting nitrate conditions.<br> Plants were harvested after 32 days for plants under high nitrogen nutrition and 42 days for low nitrogen nutrition. Plants were grown hydroponic condition (short day, 170 uE).
Project description:Whole seedlings of wild type (4d) and atm mutants (4d) have been analyzed after a gamma ray irradiation of 0.75h, 1.5h, 3h & 5h (time course). Roots of wt (4d), atm (3d) and atr (4d) mutants have been analyzed after a 1h irradiation.<br><br> Ataxia Telangiectasia Mutated (ATM), encodes a large protein with a phosphatidylinositol 3-kinase (PI3K)-like domain at the C terminus (reviewed by Rotman and Shiloh, 1998). PI3K-related proteins make up a large family of Ser-Thr protein kinases, numerous members of which are involved in the regulation of cell cycle progression, responses to DNA damage, and the maintenance of genomic stability (Hoekstra, 1997). AtATM plays an essential role in meiosis and in the somatic response to DNA damage in plants, similar to the function of ATM in mammals and other eukaryotes.<br>Ataxia telangiectasia-mutated and Rad3-related (ATR) plays a central role in cell-cycle regulation, transmitting DNA damage signals to downstream effectors of cell-cycle progression.
Project description:Transcriptomic study of a thioredoxin reductase knock-out mutant.<br> <br> Biological question :<br> Thioredoxins are small redox proteins implicated in crucial pathways of cell life. They are reduced by a conserved flavoprotein named NADPH-dependent thioredoxin reductase (NTR). In order to give an insight into the functions of the NTR/thioredoxin pathway in Arabidopsis, we have used a reverse genetic approch. Both NTR genes (NTRA and NTRB) have been inactivated in the double ntra ntrb mutant. T-DNA lines have been provided by the SALK library. Surprisingly, this mutant shows a limited phenotype suggested that some additional redox pathways are involved in compensating the inactivation of the NTR/thioredoxin pathway. In order to isolate compensatory genes that would be transcriptionally induced in the ntra ntrb mutant, we have performed this CATMA project.<br> <br> Seeds of the wild-type Col-0 ecotype and of the ntra ntrb homozygote double mutant were sowed in soil. Three replicates of lines were made (Col-0 1, 2 and 3 ntra ntrb 1, 2 and 3) : plants were put at different places of the greenhouse and grown at different times. Germination was synchronized by 4 days at 4C and plants were grown during 17 days, until they reached a 6 rosette leaves stage. Entire plants (30 plants per sample) were harvested, frozen in liquid nitrogen and stored at -80C until extraction.<br> <br>
Project description:Columbia Arabidopsis ecotype were grown hydroponically on 1 mM NH4NO3 as sole nitrogen source during 35 days under short days. Plants leaves were then sprayed with a seaweed extract or with water (control). Root and shoot samples were harvested separately 1 hour and 7 days after this spraying.
Project description:Effect of nicotianamine over-accumulation on the transcriptome of A. thaliana in standard condition and in response to nickel treatment<br> <br> After germination, plants were grown hydroponically for 6 weeks in classical nutrient solution (Marques et al, New Phytol, 2004, vol 164, pp 289-95) and then treated for 48 hours with 50 uM NiSO4 or with no nickel added for control.<br> <br> Biological question : Nicotianamine is a known metal chelator (of Mn, Fe, Zn, Ni, Cu) suspected to be involved in metal delivery and/or circulation in planta. This project aim at understanding the effect of the modulation of the nicotianamine content on the transcriptome of Arabidopsis thaliana in control hydroponic condition and in response to nickel treatment both at the root and at the leaf level.<br>