Project description:Cyanide is stoichiometrically produced as a co-product of the ethylene biosynthesis pathway, and it is detoxified by the b-cyanoalanine synthase enzyme. The molecular and phenotypical analysis of T-DNA insertional mutants of the mitochondrial b-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates, but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin. Hydroxocobalamin not only recovers the root phenotype of the mutant, but also the formation of ROS at the initial step of the root hair tip. Transcriptional profile analysis of the cys-c1 mutant reveals that cyanide accumulation acts as a repressor signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip, as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial b-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development. Using Affymetrix ATH1 GeneChips, we performed a comparative transcriptomic analysis of roots of the cys-c1 and wild type plants. Total RNA was extracted from roots of 14-days-old plants grown under identical conditions on MS medium (three biological replicates for each genotype), and these samples were used to prepare complementary RNA and and analyzed using the Affymetrix-Arabidopsis ATH1GeneChip array.
Project description:Cyanide is stoichiometrically produced as a co-product of the ethylene biosynthesis pathway, and it is detoxified by the b-cyanoalanine synthase enzyme. The molecular and phenotypical analysis of T-DNA insertional mutants of the mitochondrial b-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates, but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin. Hydroxocobalamin not only recovers the root phenotype of the mutant, but also the formation of ROS at the initial step of the root hair tip. Transcriptional profile analysis of the cys-c1 mutant reveals that cyanide accumulation acts as a repressor signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip, as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial b-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development.
Project description:Sequence-specific transcription factor WRKY75 is highly responsive to reactive oxygen species on transcriptional level in the rosettes of Arabidopsis thaliana. In addition, it acts in developmental responses, acquisition of nutrients, and in stress responses. In the root, WRKY75 is a repressor of root hair formation, it regulates the phosphate starvation response, and the response to certain pathogens. In order to find the target genes of WRKY75, the effects of estradiol-inducible overexpression of WRKY75 on transcriptome was studied using RNA-seq.
Project description:Phosphate (Pi) deficiency alters root hair length and frequency as a means of increasing the absorptive surface area of roots. Three partly redundant single R3 MYB proteins, CAPRICE (CPC), ENHANCER OF TRY AND CPC1 (ETC1) and TRIPTYCHON (TRY), positively regulate the root hair cell fate by participating in a lateral inhibition mechanism. To identify putative targets and processes that are controlled by these three transcription factors (TFs), we conducted transcriptional profiling of roots from Arabidopsis thaliana wild-type plants, and cpc, etc1 and try mutants grown under Pi-replete and Pi-deficient conditions using RNA-seq.
Project description:Sequence-specific transcription factor WRKY75 is highly responsive to reactive oxygen species on transcriptional level in the rosettes of Arabidopsis thaliana. In addition, it acts in developmental responses, acquisition of nutrients, and in stress responses. In the root, WRKY75 is a repressor of root hair formation, it regulates the phosphate starvation response, and the response to certain pathogens. In order to find the target genes of WRKY75, the effects of estradiol-inducible overexpression of WRKY75 on transcriptome was studied using RNA-seq. Two independent inducible WRKY75 overexpressor lines (N2102362 and N2102363) were treated with estradiol for 3 hours and four biological replicates, five plant per replicate, were used for RNA-seq. As a control, wild type Col-0 was treated with estradiol or water for 3 hours and three biological replicates, five plant per replicate, were used for RNA-seq.
Project description:Several fungi have been reported to form intimate bonds with plants. These close mutual relationships can provide physiological benefits to the interacting organisms, including the improvement of nutrient assimilation or enhanced stress tolerance. The root-colonizing fungus Fusarium sp. strain K-23 is known to successfully colonize tomato roots. Previous studies highlighted the promotion of plant biomass production and stress tolerance of tomato plants infected with the K-23. However, up to data, nothing is known about the effect of this fungus on the model plant Arabidopsis thaliana. We here report the comparative analysis of the effect of mock- and K-23-infected wild-type Arabidopsis plants (Col-0) in the abscence and presence of moderate salt stress conditions (50 mM NaCl). Our data provide evidence for a profound effect of K-23 on root hair elongation through the activation of a regulatory network that includes several plant hormones. Intriguingly, the fungus suppresses gibberellic acid biosynthesis which, in turn, promotes root hair elongation.
Project description:ra04-07_pgpr - profiling of the root architecture response to phyllobacterium - Experiment 1 : Which genes are up- or down-regulated in Arabidopsis thaliana cultivated in vitro with increased lateral root development in response to Phyllobacterium STM196 inoculation. Experiment 2 : Which genes are up- or down-regulated during the ISR triggered by a rhizobacteria, in comparison with those affected by a pathogenic interaction. Experiment 3 : which genes are specifically induced or repressed in Arabidopsis thaliana by inoculation of the soil with a PGPR vs a bacteria that has the ability to trigger nodule formation in a Legume. - Seeds of wild-type Arabidopsis thaliana (ecotype Columbia) were surface-sterilized and sawn on agar mineral medium (see below). 4 days after storage in the dark at 4degreeC, seedling were cultivated 6 days in a growth chamber (16 h daily, 20-22degreeC) and then transferred on a fresh agar mineral medium inoculated or not with Phyllobacterium STM196 (2.108 cfu/ml). 6 days later, root and leaves were collected, froze on liquid nitrogen and stored at -80degreeC. Keywords: treated vs untreated comparison
Project description:The aim of this project is to exploit a shot gun proteomic analysis to better characterize Arabidopsis thaliana rhd2 mutant. The mutant shows a loss of function mutation in RBOHC, a gene encoding NADPH oxidase implicated in root hair elongation.