Project description:Nitrate and other nitrogen metabolites can act as signals that regulate global gene expression in plants. Adaptive changes in plant morphology and physiology triggered by changes in nitrate availability are partly explained by these changes in gene expression. Despite several genome-wide efforts to identify nitrate-regulated genes, no comprehensive study of the Arabidopsis root transcriptome under contrasting nitrate conditions has been carried out. In this work, we employed the Illumina high throughput sequencing technology to perform an integrated analysis of the poly-A+ enriched and the small RNA fractions of the Arabidopsis thaliana root transcriptome in response to nitrate treatments. Our sequencing strategy identified new nitrate-regulated genes including 40 genes not represented in the ATH1 Affymetrix GeneChip, a novel nitrate-responsive antisense transcript and a new nitrate responsive miRNA/TARGET module consisting of a novel microRNA, miR5640 and its target, AtPPC3. This nitrate-responsive miRNA/target module might be involved in controlling carbon flux to assimilate nitrate into amino acids, suggesting that microRNAs can have both developmental and metabolic functions in the nitrate response of Arabidopsis roots.
Project description:Transcriptional profiling of an Fd-GOGAT1/GLU1 mutant in Arabidopsis thaliana reveals a multiple stress response and extensive reprogramming of the transcriptome Glutamate plays a central position in the synthesis of a variety of organic molecules in plants and is synthesised from nitrate through a series of enzymatic reactions. Glutamate synthases catalyse the last step in this pathway and two types are present in plants: NADH- or ferredoxin-dependent. Here we report a genome wide microarray analysis of the transcriptional reprogramming that occurs in leaves and roots of the A. thaliana mutant glu1-2 knocked-down in the expression of Fd-GOGAT1 (GLU1; At5g04140), one of the two genes of A. thaliana encoding ferredoxin-dependent glutamate synthase.
Project description:Purpose: Analyze changes in the transcriptome of Arabidopsis thaliana in response to chronic exposure to silver nitrate at 4 μg/mL concentration. Methods: mRNA was extracted from non-treated and silver nitrate-treated 14-day old Arabidopsis thaliana seedlings using the RNAeasy extraction kit (Qiagen). RNA-seq libraries (3 rep/treatment and 3 reps/control) constructed with the TruSeq Stranded mRNA Sample Preparation kit (Illumina) were paired-end sequenced (100-nt read length) on an Illumina Nova Seq6000 system. Reads were mapped to the A. thaliana TAIR10 reference genome sequence and transcript levels were analyzed using the softare CLC Genomics Workbench (version 20.0.4, Qiagen). Results: Chronic exposure of A. thaliana plants to silver nitrate caused a change in the abundance of transcripts: AT2G01520 and AT4G12550, but no measureable impact on the rest of the transcriptome. Conclusions: Exposure of A. thaliana to silver nitrate at 4 μg/mL has minor impact on the transcriptome.
Project description:Nitrate and other nitrogen metabolites can act as signals that regulate global gene expression in plants. Adaptive changes in plant morphology and physiology triggered by changes in nitrate availability are partly explained by these changes in gene expression. Despite several genome-wide efforts to identify nitrate-regulated genes, no comprehensive study of the Arabidopsis root transcriptome under contrasting nitrate conditions has been carried out. In this work, we employed the Illumina high throughput sequencing technology to perform an integrated analysis of the poly-A+ enriched and the small RNA fractions of the Arabidopsis thaliana root transcriptome in response to nitrate treatments. Our sequencing strategy identified new nitrate-regulated genes including 40 genes not represented in the ATH1 Affymetrix GeneChip, a novel nitrate-responsive antisense transcript and a new nitrate responsive miRNA/TARGET module consisting of a novel microRNA, miR5640 and its target, AtPPC3. This nitrate-responsive miRNA/target module might be involved in controlling carbon flux to assimilate nitrate into amino acids, suggesting that microRNAs can have both developmental and metabolic functions in the nitrate response of Arabidopsis roots. Arabidopsis thaliana wild-type Col-0 plants were grown in hydroponic nitrate-free medium with 0.5 mM ammonium succinate as the only N-source for two weeks and were treated with 5 mM KNO3, or 5 mM KCl as control, for 2 hours. Total RNA from two independent sets of plants (biological replicates) was extracted from roots, and poly-A+ enriched and sRNA fractions were used to construct libraries for Illumina sequencing.
Project description:Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. The presented model is a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. The Petri net formalism was used to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs were applied. Based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism, the core metabolism of Arabidopsis thaliana was formulated. Each reaction (transition) is experimentally proven. The complete Petri net model consists of 134 metabolites, represented by places, and 243 reactions, represented by transitions. Places and transitions are connected via 572 edges.