Project description:Expression of the EXS domain of PHO1 in the Arabidopsis thaliana pho1 mutant leads to improved shoot growth in comparison to the parental pho1 mutant. We have used RNAseq to study the gene expression profile in the roots and shoots of the pho1 mutant, two independent transgenic lines of pho1 expressing the EXS domain of PHO1 (lines EXS32 and EXS34) as well as a pho1 mutant transformed with the full length PHO1 gene (complemented line).
Project description:Plant cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes involved in Cys biosynthesis and located in different subcellular compartments. These enzymes are made up of a complex variety of isoforms resulting in different subcellular Cys pools. To unravel the contribution of cytosolic Cys to plant metabolism, we characterized the knockout oas-a1.1 and osa-a1.2 mutants, deficient in the most abundant cytosolic OASTL isoform in Arabidposis thaliana. Total intracellular Cys and glutathione concentrations were reduced, and the glutathione redox state was shifted in favour of its oxidized form. Interestingly, the capability of the mutants to chelate heavy metals did not differ from that of the wild type, but the mutants have an enhanced sensitivity to Cd. With the aim of establishing the metabolic network most influenced by the cytosolic Cys pool, we used the ATH1 GeneChip for evaluation of differentially expressed genes in the oas-a1.1 mutant grown under non-stress conditions. The transcriptomic footprints of mutant plants had predicted functions associated with various physiological responses that are dependent on reactive oxygen species and suggested that the mutant was oxidatively stressed. To further elucidate the specific function(s) of the OAS-A1 isoform in the adaptation response to cadmium we extended the trasncriptome experiment to the wild type and oas-a1.1 mutant plants exposed to Cd. The comparison of transcriptomic profiles showed a higher proportion of genes with altered expression in the mutant than in the wild type, highlighting up-regulated genes identified as of the general oxidative stress response rather than metal-responsive genes. Wild type and oas-a1.1 mutant plants were grown hydroponically and, after a two-week acclimation period, the roots and shoots were harvested separately. Total RNA was then prepared and analyzed using the Affymetrix-Arabidopsis ATH1GeneChip array. Three biological replicates were performed for each sample. We made two different comparisons to classify the differently expressed genes in the mutant plant: oas-a1.1 roots versus wild-type roots and oas-a1.1 shoots versus wild-type shoots. Hydroponically-grown wild type and oas-a1.1 mutant plants were further treated with 50µM CdCl2 and 18h-treated-roots and 24h-treated-shoots were harvested. Total RNA was then prepared and analyzed using the Affymetrix-Arabidopsis ATH1GeneChip array. Three biological replicates were performed for each sample. Different comparisons were performed as follows: 18h Cd-treated wild type roots versus untreated wild type roots; 24h Cd-treated wild type shoots versus untreated wild type shoots; 18h Cd-treated oas-a1.1 roots versus untreated oas-a1.1 roots; 24h Cd-treated oas-a1.1 shoots versus untreated oas-a1.1 shoots; 18h Cd-treated oas-a1.1 roots versus 18h Cd-treated wild type roots; 24h Cd-treated oas-a1.1 shoots versus 24h Cd-treated wild type shoots
Project description:Reduced glutathione (GSH) is required for cell cycle initiation and auxin-regulated root meristem development. Transcriptome profiling of the roots and shoots of the root meristemless 1 (rml1) mutant, which has about 3% of the wild type GSH, revealed a divergent auxin and strigolactone response linked to the arrest of the cell cycle. Plants of the rml1 mutant and Columbia-0 ecotype were harvested and separated into roots and shoots, then RNA extraction and Affymetrix Agronomics Tiling Array were performed.
Project description:Lateral roots (LRs) are formed post-embryonically and contribute to root architecture formation in vascular plants. LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16) is a key transcription factor to initiate LR formation functioning redundantly with related LBD members. To identify primary downstream targets of LBD16, we engineered a transgenic line with inducible LBD16 activity by expressing a fusion protein of LBD16 and rat glucocorticoid receptor (GR) under the regulation of its own regulatory region (gLBD16-GR) in the lbd16-1 lbd18-1 lbd33-1 mutant. Here we identified primary response genes of LBD16 from transcriptome analysis.
Project description:Reduced glutathione (GSH) is required for cell cycle initiation and auxin-regulated root meristem development. Transcriptome profiling of the roots and shoots of the root meristemless 1 (rml1) mutant, which has about 3% of the wild type GSH, revealed a divergent auxin and strigolactone response linked to the arrest of the cell cycle.
Project description:We analyzed global transcriptional changes in both shoots and roots of root-flooded Arabidopsis seedlings by microarrays. We also interpreted the significance of the systemic communication between roots and shoots by functional classification of affected genes. We performed genetic analysis with an ethylene signaling mutant, ein2-5, to correlate systemic flooding responses with ethylene signaling. We identified a class of genes that were up- or downregulated in shoots, but not affected in roots, under hypoxic conditions. A comprehensive managing program of carbohydrate metabolism was observed, providing an example of how systemic communications might facilitate the survival of plants under flooding. A proportion of long-distance hypoxic regulation was altered in ein2-5.
Project description:Gene expression profiles of drought-stressed roots and shoots was performed at 0, 1, 3, 5, 7 and 9 days were analyzed using the custom microarray Agilent-034592.
Project description:BCKGROUND: New modes of action are needed for herbicides. The flavonoid synthesis intermediate t-chalcone causes apoptosis-like symptoms in roots and bleaching of shoots of Arabidospsis, suggesting a unique mode of action as a phytotoxin. RESULTS: Using RNA-Seq, transcriptome changes were monitored in Arabidopsis seedlings during the first 24 h of exposure (at 1, 3, 6, 12 and 24 h) to 21 μM t-chalcone (I50 dose), examining effects on roots and shoots separately. Expression of 892 and 1000 genes was affected in roots and shoots, respectively. According to biological function, many of the affected genes were transcription factors and genes associated with oxidative stress, heat shock proteins, xenobiotic detoxification, ABA and auxin biosynthesis, and primary metabolic processess. These are secondary effects found with most phytotoxins. Potent phytotoxins usually act by inhibiting enzymes of primary metabolism. KEGG pathway analysis of transcriptome results from the first 3 h of t-chalcone expsoure indicated several potential primary metabolism target sites for t-chalcone. Of these, p-hydroxyphenylpyruvate dioxygenase (HPPD) and tyrosine amino transferase were consistent with the bleaching effect of the phytotoxin. Supplementation studies with Lemna paucicostata and Arabidiopsis supported HPPD as the target, although in vitro enzyme inhibition was not found. CONCLUSIONS: t-Chalcone is possibly a protoxin that is converted to a HPPD inhibitor in vivo.