Project description:ngs2020_19_arimnet-barley responses to nitrate limitation-What are the molecular mechanisms taking place in barley under nitrate limitation?-Barley were grown on sand under 0.5 mM nitrate (Low nitrate= LN) or 5 mM nitrate (high nitrate = HN)
Project description:Anthropogenic activities have dramatically increased the inputs of reactive nitrogen (N) into terrestrial ecosystems, with potentially important effects on the soil microbial community and consequently soil C and N dynamics. Our analysis of microbial communities in soils subjected to 14 years of 7 g N m-2 year-1 Ca(NO3)2 amendment in a Californian grassland showed that the taxonomic composition of bacterial communities, examined by 16S rRNA gene amplicon sequencing, was significantly altered by nitrate amendment, supporting the hypothesis that N amendment- induced increased nutrient availability, yielded more fast-growing bacterial taxa while reduced slow-growing bacterial taxa. Nitrate amendment significantly increased genes associated with labile C degradation (e.g. amyA and xylA) but had no effect or decreased the relative abundances of genes associated with degradation of more recalcitrant C (e.g. mannanase and chitinase), as shown by data from GeoChip targeting a wide variety of functional genes. The abundances of most N cycling genes remained unchanged or decreased except for increases in both the nifH gene (associated with N fixation), and the amoA gene (associated with nitrification) concurrent with increases of ammonia-oxidizing bacteria. Based on those observations, we propose a conceptual model to illustrate how changes of functional microbial communities may correspond to soil C and N accumulation.
Project description:RNA-seq was performed on shoot and root from 42 day-old plants of nlps mutants and WT grown on sand under non-limiting nitrate supply (5mM).
Project description:cea06-01_uranyl_nitrate - time course uranyl nitrate response - Dynamic analyses of transcriptomic response to urany l nitrate - Plants are grown on sand and transfert in hydroponic culture during 2 days and then expose or not to 50uM uranyl nitrate at pH 4.5 in water or only to water at pH 4.5. Roots and leaves were collected independently after 2h, 6h and 30h of treament. Keywords: organ comparison,time course,treated vs untreated comparison
Project description:cea06-01_uranyl_nitrate - time course uranyl nitrate response - Dynamic analyses of transcriptomic response to urany l nitrate - Plants are grown on sand and transfert in hydroponic culture during 2 days and then expose or not to 50uM uranyl nitrate at pH 4.5 in water or only to water at pH 4.5. Roots and leaves were collected independently after 2h, 6h and 30h of treament. Keywords: organ comparison,time course,treated vs untreated comparison 20 dye-swap - CATMA arrays
Project description:Nitrogen (N) fertilization is essential to maximize crop production. However, around half of the applied N is lost to the environment causing water and air pollution and contributing to climate change. Understanding the natural genetic and metabolic basis underlying plants N use efficiency is of great interest to reach an agriculture with less N demand and thus, more sustainable. The study of ammonium (NH4+) nutrition is of particular interest, because it mitigates N losses due to nitrate (NO3-) leaching or denitrification. In this work, we performed gene expression analysis in the root of the model plant for C3 grasses Brachypodiyum distachyon, reference accession Bd21, grown with exclusive NH4+ or NO3- supply.
Project description:Because nitrogen (N) nutrition is a key determinant of plant growth, we explored the role of N availability in grafted grapevine development. Vitis vinifera cv. Cabernet Sauvignon was grafted on two rootstock genotypes known to confer high (1103 Paulsen, 1103P) and low (Riparia Gloire de Montpellier, RGM) vigour. One-year-old plants were cultivated in sand-filled pots in a greenhouse and irrigated with the control nutrient solution for 15 days of acclimation (1.6 mM N). At the end of the acclimation period (0 days post treatment (dpt)), the plants were divided in two groups of 5 plants per combination and irrigated with nutrient solutions varying only in their nitrate concentration (0.8 mM (Nitrate -) and 2.45 mM (Nitrate +)). Roots were harvested at 15 and 60 dpt. Gene expression profiling was done using the Nimblegen whole genome array with 3 biological replicates per condition to analyze the combined effect of N treatment and rootstock genotype on gene expression.
Project description:Nitrate is both an important nutrient and a critical signaling molecule that regulates plant metabolism, growth, and development. Although several components of the nitrate signaling pathway have been identified, the molecular mechanism of nitrate signaling remains unclear. Here, we showed that the growth-related transcription factors HBI1 and its three closest homologs (HBIs) positively regulate nitrate signaling in plants. HBI1 is rapidly induced by nitrate through NLP6 and NLP7, which are master regulators of nitrate signaling pathway. Mutations in HBIs result in the reduced effects of nitrate on plant growth and approximately 22% nitrate-responsive genes no longer to be regulated by nitrate. HBIs increase the expression levels of a set of antioxidant genes to reduce the accumulation of reactive oxygen species (ROS) in plants. Nitrate treatment induces the nuclear localization of NLP7, whereas such promoting effects of nitrate are significantly impaired in the hbi-q and cat2cat3 mutants, which accumulate high levels of H2O2. These results demonstrate that HBI-mediated ROS homeostasis regulates nitrate signal transduction through modulating the nucleocytoplasmic shuttling of NLP7. Overall, our findings reveal that nitrate treatment reduces the accumulation of H2O2, and H2O2 inhibits nitrate signaling, thereby forming a feedback regulatory loop to regulate plant growth and development.