Early transcriptional responses of Arabidopsis thaliana to ammonium and nitrate deprivation
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ABSTRACT: Identification of the earliest transcriptional responses of adult Arabidopsis plant roots towards N-deprivation. Hydroponically grown Plants (35 days old) were 5 days adapted to nitrate or ammonium,respectively, as sole N-source to detect N-form specific transcripts. 24 Samples: 2 Pre-Treatments (5 Day adaptation to 3mM Ammonium/Nitrate) x 3 sampling time-points (0min, 15 min, 180 min) x 3 independent replications per time-point + 6 additional controls (2 x 15min, 1x 180min per Pre-Treatment)
Project description:This work aims to study the effect of the elevated CO2 concentration on the tomato plant response to the toxicity provoked by ammonium nutrition. Tomato plants (Solanum lycopersicum L. cv. Agora Hybrid F1, Vilmorin®) were grown for 4 week with 15 mM of nitrogen, supplied as nitrate or ammonium, at ambient or elevated CO2 conditions (400 ppm or 800 ppm). Transcription profiling by array was carried out in roots for the four growth conditions assayed and gene expression comparisons were done between N sources and CO2 conditions: i) genes differentially expressed in response to the atmospheric CO2 concentration (800 ppm vs 400 ppm CO2) under nitrate or ammonium nutrition; ii) genes differentially expressed in response to the N source (ammonium vs nitrate) under ambient or elevated condition. 3 biological replicates for each growth condition were analysed.CO2).
Project description:Plants aquire nitrogen from the soil, most commonly in the form of either nitrate or ammonium. Unlike ammonium, nitrate must be reduced (with NADH and ferredoxin as electron donors) prior to assimilation. Thus, nitrate nutrition imposes a substantially greater energetic cost than ammonium nutrition. Our goal was to compare the transcriptomes of nitrate-supplied and ammonium-supplied plants, with a particular interest in characterizing the differences in redox metabolism elicited by different forms of inorganic nitrogen. We used microarrays to compare the short-term transcriptional response to either nitrogen supply or ammonium supply in Arabidopsis roots. Genes upregulated or downregulated by nitrate only, ammonium only, or both ammonium and nitrate were identified and analyzed. Arabidopsis thaliana (Col-0) plants were grown hydroponically until they reached growth stage 5.10. They were then transferred to a nitrogen-free medium for 26 hr and then supplied with 1 mM nitrate or 1 mM ammonium. RNA isolation (and subsequent microarray analysis) was performed on root tissue isolated just before nitrogen supply (time 0) and at 1.5 hr and 8 hr after nitrogen supply (1.5 hr nitrate, 8 hr nitrate, 1.5 hr ammonium, 8 hr ammonium).
Project description:Although urea is the most used nitrogen fertilizer worldwide, little is known on the capacity of crop plants to use urea per se as a nitrogen source for development and growth. To date, the molecular and physiological bases of its transport have been investigated only in a limited number of species. In particular, up to date only one study reported the transcriptomic modulation induced by urea treatment in the model plant Arabidopsis (MM-CM-)rigout et al., 2008 doi: 10.1104/pp.108.119339). In maize, one of crops using huge amount of urea, only a physiological characterization of uptake and assimilation of the N-source has been conducted. General aim of the present work was the comprehension of the molecular basis of urea uptake and assimilation in maize plants, using a transcriptomic approach. In addition, the work focused on the possible interactions between the two main N-sources, conceivably occurring concomitantly in the soil, urea and nitrate. 5 dd-old maize plants were treated for 8 hours with nutrient solution containing nitrogen in form of urea; nitrate; urea and nitrate; or not exposed to any form of nitrogen. Three different biological replicates were used for each sample repeating the experiment three times. All samples were obtained pooling roots of six plants.
Project description:This study was conducted to investigate the changes in gene expression that occurs with the silencing of GmbHLHm1. GmbHLHm1 is a membrane localised DNA binding transcription factor that is important for nodule development. Its activity is linked to ammonium transport. 7 samples
Project description:This work aims to study wether the increment of the atmospheric carbon dioxide (CO2) concentration, in the context of climate change, will potentially allow plants to better face ammonium nutrition. Tomato (Solanum lycopersicum L.) plants were grown for 4 week with 15 mM of nitrogen, supplied as nitrate or ammonium, in conditions of ambient (aCO2, 400 ppm) or elevated CO2 (eCO2, 800 ppm) atmosphere. Transcription profiling by array was carried out in leavesfor the four growth conditions assayed and gene expression comparisons were done between N sources and CO2 conditions: i) genes differentially expressed in response to the atmospheric CO2 concentration (eCO2 vs aCO2) under nitrate or ammonium nutrition; ii) genes differentially expressed in response to the N source (ammonium vs nitrate) at aCO2 or eCO2. 3 biological replicates for each growth condition were analysed.
Project description:Tieguanyin (TGY) and Shuixian (SX) cultivars of Camellia sinensis were selected to explore the mechanism underlying the accumulation of the rare earth element lanthanum through proteomics. Roots and fresh leaves of TGY and SX with low- and high-accumulation potential for lanthanum, respectively, were studied; 845 differentially expressed proteins (DEPs) were identified. Gene ontology analysis showed that the DEPs are involved in redox processes and related to molecular functions, such as defense and oxidative stress reactions, catalytic activity, and metal ion binding. Kyoto Encyclopedia of Genes and Genomes metabolic pathway analysis showed that DEPs were associated with glutathione (GSH) and α-linolenic acid metabolism, plant pathogen interaction, and oxidative phosphorylation. Thirty-seven proteins in the GSH metabolism pathway showed significant differences, of which 18 GSH S-transferases show differential expression patterns in the root system.The expression multiples of GST (TEA004130.1) and GST (TEA032216.1) in T1L and T0L were 6.84 and 4.06, respectively, which were significantly higher than those in S1L and S0L. The lanthanum-induced activation of the GSH-related antioxidant defense system may cause the difference in TGY and SX. The LOX2.1 (TEA011765.1) and LOX2.1 (TEA011776.1 expression ratios) in the α-linolenic acid metabolic pathway were 2.44 and 6.43 in T1R and T0R, respectively, which were significantly higher than those in S1R snd S0R. The other differential proteins were also sig-nificantly upregulated in TGY leaves.The synthesis of specific substances induces lantha-num-associated defense responses in TGY, which is of great significance for the stability of its yield.
Project description:The metabolic response of maize source leaves to low nitrogen supply was analyzed in maize seedlings by parallel measurements of transcriptome and metabolome profiling. Inbred lines A188 and B73 were cultivated under controlled growth chamber conditions and supplied with either sufficient (15mM) or limiting (0.15mM) nitrate supply. Leaf lamina material was harvested at day 20 and day 30 after germination with the fifth and sixth leaf representing the main source leaf respectively. Four replicates were collecetd from individual plants for each combination of genotype, growth stage and nitrogen treatment. The leaf material was frozen, homogenised and aliquoted for transcriptome and metabolome analysis. The molecular data was further supplemented by phenotypic characterisation of the maize seedlings under investigation. Limited availability of nitrogen caused strong shifts in the metabolite profile of leaves. The transcriptome was less affected by the nitrogen stress but showed strong genotype and age dependent patterns. Nitrogen starvation initiated the selective down-regulation of processes involved in nitrate reduction and amino acid assimilation; ammonium assimilation related transcripts on the other hand were not influenced. Carbon assimilation related transcripts were characterized by high transcriptional coordination and general down-regulation under low nitrogen conditions. Nitrogen deprivation caused a slight accumulation of starch, but also directed increased amounts of carbohydrates into the cell wall and secondary metabolites. The decrease in N availability also resulted in accumulation of phosphate and by strong down-regulation of genes usually involved in phosphate starvation response, underlining the great importance of phosphate homeostasis control under stress conditions. Maize inbred lines A188 and B73 were cultivated in pots containing nutrient poor peat soil under the controlled conditions of a growth chamber. The plants were fertilized with modified Hoagland solutions containing either 15mM (high N) or 0.15mM nitrate (low N). Source leaf lamina were harvested at day 20 and day 30 after start of germination for parallel analysis of transcriptome and metabolome profiles. The molecular data is further supplemented by phenotypic characterization of the maize seedlings under investigation.
Project description:Rice seedlings grown on a hydroponic set-up depleted of nitrogen were supplemented with 5mM of nitrate, 5mM of ammonium, 2.5mM of ammonium-nitrate or with a negative control (potassium nitrate). Samples were harvested immediately after treatment and over an 8 points time-course up to 48h after treatment. Roots and shoots were harvested separately.
Project description:Date palm (Phoenix dactylifera) cultivar Khalas was drought treated and two tissues (root and shoot) were compared to control conditions by RNAseq.