Project description:Plants take up nitrate in soils and utilize it both for nitrogen assimilation and as a signaling molecule. Thus, an essential role of nitrate in plants is triggering changes in gene expression patterns, including immediate induction of the expression of genes involved in nitrate transport and assimilation as well as several transcription factor genes and genes related with carbon metabolism and cytokinin biosynthesis and response. Recently we identified NIN-like proteins (NLPs) as transcription factors governing nitrate-inducible gene expression in Arabidopsis. Because of their similar DNA-binding property, nine NLP proteins may play redundant roles in controlling nitrate-regulated gene expression in Arabidopsis. The physiological roles of NLPs were therefore assessed by generating transgenic Arabidopsis plants expressing NLP6 fused to the transcriptional repression domain of SUPERMAN (SUPRD), which has an ability to convert transcriptional activators into transcriptional repressors. Our transcriptome analysis revealed that levels of nitrate-inducible expression of nitrate transporter genes (NRT1.1 and NRT2.1), nitrate reduction enzyme genes (NIA1, NIA2 and NIR1), the genes associated with ammonium assimilation (GLT1 for glutamine-2-oxoglutarate aminotransferase and ASN2 for asparagine synthetase), LBD37-39 transcription factor genes and genes encoding homologs of rice nitrate-inducible NIGT1 transcriptional repressor, were reduced in the NLP6-SUPRD lines. Furthermore, levels of nitrate-inducible expression of the genes associated with the oxidative pentose phosphate pathway (G6PD2 and G6PD3 for glucose-6-phosphate dehydrogenases, and 6-phosphogluconate dehydrogenase genes), cytokinin biosynthesis (IPT3) and signal transduction (A-type ARR genes), a gene encoding a Ser/Thr protein kinase associated with a calcineurin B–like calcium sensor (CIPK3) were also found to be largely decreased by reductions in NLP activity. Because induction folds by nitrate and reduction folds by decreases in the NLP activity were well proportional, the NLP activity appeared to be responsible for most of nitrate responsiveness of the genes whose expression occurs immediately after nitrate treatment.
Project description:bra-inra09-02_bioen_nitrogen - nitrate induction - nlp mutants - Short term nitrate induction kinetics in wildtype, nlp7-1, nlp7-3 and nlp6nlp7 - 10 days old seedling grown in liquid culture on 3mM nitrate wer starvec for N for 3 days and the kinetic for the resupply of nitrate was studied during a short kinetic (0,5, 10,20 minutes).
Project description:Plants take up nitrate in soils and utilize it both for nitrogen assimilation and as a signaling molecule. Thus, an essential role of nitrate in plants is triggering changes in gene expression patterns, including immediate induction of the expression of genes involved in nitrate transport and assimilation as well as several transcription factor genes and genes related with carbon metabolism and cytokinin biosynthesis and response. Recently we identified NIN-like proteins (NLPs) as transcription factors governing nitrate-inducible gene expression in Arabidopsis. Because of their similar DNA-binding property, nine NLP proteins may play redundant roles in controlling nitrate-regulated gene expression in Arabidopsis. The physiological roles of NLPs were therefore assessed by generating transgenic Arabidopsis plants expressing NLP6 fused to the transcriptional repression domain of SUPERMAN (SUPRD), which has an ability to convert transcriptional activators into transcriptional repressors. Our transcriptome analysis revealed that levels of nitrate-inducible expression of nitrate transporter genes (NRT1.1 and NRT2.1), nitrate reduction enzyme genes (NIA1, NIA2 and NIR1), the genes associated with ammonium assimilation (GLT1 for glutamine-2-oxoglutarate aminotransferase and ASN2 for asparagine synthetase), LBD37-39 transcription factor genes and genes encoding homologs of rice nitrate-inducible NIGT1 transcriptional repressor, were reduced in the NLP6-SUPRD lines. Furthermore, levels of nitrate-inducible expression of the genes associated with the oxidative pentose phosphate pathway (G6PD2 and G6PD3 for glucose-6-phosphate dehydrogenases, and 6-phosphogluconate dehydrogenase genes), cytokinin biosynthesis (IPT3) and signal transduction (A-type ARR genes), a gene encoding a Ser/Thr protein kinase associated with a calcineurin BM-bM-^@M-^Slike calcium sensor (CIPK3) were also found to be largely decreased by reductions in NLP activity. Because induction folds by nitrate and reduction folds by decreases in the NLP activity were well proportional, the NLP activity appeared to be responsible for most of nitrate responsiveness of the genes whose expression occurs immediately after nitrate treatment. Overall design: Gene expression in 3.5-day-old seedlings treated with or without 10 mM potassium nitrate was compared between the transgenic lines expressing a chimeric repressor form of NLP6 (NLP6-SUPRD) and the parental control line.
Project description:Arabidopsis mutants in the PMP/PNP oxidase PDX3 show abberant growth and development.RNA sequencing reveals strong induction of stress-related genes in pdx3, particularly those associated with biotic stress.
Project description:Plants modulate gene expression profile in response to nitrate through NIN-LIKE PROTEIN (NLP) transcription factors in order to promote nitrate uptake and utilization. Although there are 9 NLP proteins in Arabidopsis, NLP7 had attracted most of the attention. Here, we focused on NLP2, because the nlp2 and nlp7 knockout mutants displayed different phenotypes. To gain insight into genes whose expression was affected by the nlp2 mutation, we compared gene expression profiles in the wild-type Columiba and the nlp2 mutant that were treated with 10 mM KNO3 for 1 hour. Columbia and nlp2 that were treated with 10 mM KCl for 1 hour were used as controls. We found that nitrate induction of 6 genes was compromised only in the nlp2 mutant.
Project description:bra-inra09-02_bioen_nitrogen - nitrate induction - nlp mutants - Short term nitrate induction kinetics in wildtype, nlp7-1, nlp7-3 and nlp6nlp7 - 10 days old seedling grown in liquid culture on 3mM nitrate wer starvec for N for 3 days and the kinetic for the resupply of nitrate was studied during a short kinetic (0,5, 10,20 minutes). 26 dye-swap - gene knock out,time course
Project description:Autophagy mutants display early yellowing phenotype and major metabolic changes under both ideal and limiting nitrate supplies. We used Affymetrix microarrays to detail the global programme of gene expression underlying metabolic and cellular changes in autophagy mutants and wild type Arabidopsis rosettes grown under both low or high nitrate conditions. Fold changes data between mutants and wild type have been published (www.plantcell.org/cgi/doi/10.1105/tpc.114.124677)