Project description:To explore the usefulness of Brachypodium distachyon for drought studies, a reproducible in soil drought assay was developed. Spontaneous soil drying led to a 45% reduction in leaf size, and this most mostly due to a decrease in cell expansion, whereas cell division remained largely unaffected by drought. To investigate the molecular basis of the observed leaf growth reduction, Brachypodium leaf 3 was dissected in three zones, namely the proliferation, expansion and mature zone, and subjected to transcriptome analysis using a Affymetrix whole-genome tiling array. This approach allowed us to highlight that transcriptome profiles of different developmental leaf zones respond differently to drought. Several genes and biological processes involved in drought tolerance were identified. Mainly, we observed an increased energy availability in the proliferation zone along with an upregulation of sterol synthesis that may influence membrane fluidity.
Project description:To explore the usefulness of Brachypodium distachyon for drought studies, a reproducible in soil drought assay was developed. Spontaneous soil drying led to a 45% reduction in leaf size, and this most mostly due to a decrease in cell expansion, whereas cell division remained largely unaffected by drought. To investigate the molecular basis of the observed leaf growth reduction, Brachypodium leaf 3 was dissected in three zones, namely the proliferation, expansion and mature zone, and subjected to transcriptome analysis using a Affymetrix whole-genome tiling array. This approach allowed us to highlight that transcriptome profiles of different developmental leaf zones respond differently to drought. Several genes and biological processes involved in drought tolerance were identified. Mainly, we observed an increased energy availability in the proliferation zone along with an upregulation of sterol synthesis that may influence membrane fluidity. 24 samples of Brachypodium leaf 3 harvested about 24 hours after the emergence of leaf 3, mild drought stress was performed for 2 biological replicates, severe drought stress and control condition was performed for 3 biological replicates. 3 developmental zones, namely the proliferation, expansion and mature zone, are dissected from leaf 3.
Project description:Centromeric repetitive DNA sequences are highly variable during evolution, which are the hub for genome stability in almost all the eukaryotic organisms. However, how centromeric repeat sequences diverge rapidly among closely related species and populations, and how polyploidy contributed to the diversity of centromere among co-evolved subgenomes are largely unknown. Here, we applied the Brachypodium system to investigate the track of centromere evolution within this taxa, and their adaptation to alloploidization process. Subgenome divergent centromeric satellite repeat were discovered in tetraploid B. hybridum, and this divergent was originated form their two diploid progenitors. Furthermore, differential sequences influence the association sites with CENH3 nucleosomes on the monomer satellite repeats, and positioning of CENH3 nucleosomes on the satellite DNA are stable in each subgenome after alloploidization. Only minor intrasubgenomic variations were observed on these satellite repeats from diploid to tetraploid in B. hybridum, and no evident intersubgenomic transfer of centromeric satellite repeats after alloploidization. Pan-genome analysis reveals that the general principle of centromere dynamic within the populations in Brachypodium genomes with different polyploidy level. Our results provide an unprecedented information regarding the genomic and functional diversity of centromeric repeat DNA during evolution.
Project description:ra15-03_oxpmt7-7 - acyltransferase brachypodium-arabidopsis - What biochemical function? What consequence on lignification when overexpressed in Arabidopsis thaliana? - Transcripts of Arabidopsis stem overexpressing an acyl transferase from Brachypodium are compared to wild type plants. The overexpression is under a specific promoter (C4H).
Project description:Brachypodium distachyon as an annual species that colonises broken ground is a highly appropriate model to define drought tolerance mechanisms. We have previously identified accessions exhibiting drought tolerance, high susceptibility and intermediate tolerance to drought; respectively, ABR8, KOZ1 and ABR4, from a screen of 138 genotypes. To define the mechanisms of tolerance, the responses to drought were assessed using transcriptomic and metabolomic approaches. Analysis of RNA-seq before and following drought suggested relatively few differentially expressed genes in ABR8. Linking these to gene ontology (GO) terms revealed an enrichment for biological processes related to “regulated stress response”, “plant cell wall” and “oxidative stress”. Interestingly, drought tolerance also appeared to correlate with pre-existing differences in gene expression linked to GO terms associated with the cell wall. These included glycoside hydrolases involved in cell wall remodelling, pectin methylesterases, expansins and a pectin acetylesterase. Metabolomic assessments of the same samples also indicated few statistically significant changes in ABR8 with drought. Instead, pre-existing differences in the cell-wall associated metabolites appeared to correlate with drought tolerance. Our data suggests two different modes/levels at which cell wall characteristics can play a role in conferring drought tolerance: (i) an active response mode/level which involves stress induced changes in cell wall features to help the plant cope with drought and (ii) an intrinsic mode in which innate differences in cell wall composition and architecture between genotypes are important in determining tolerance to drought stress. Both modes seem to contribute to the drought tolerance of ABR8. Identification of the exact mechanisms through which the cell wall confers drought tolerance will be important to fully exploit the contribution of the cell wall in the development of drought tolerant cereals and other grasses.
2019-04-10 | GSE126992 | GEO
Project description:Genomic Evolution of Drought Adaptive Stomata of Wild Cereals
Project description:ngs2020_04_hipath-differential expression analysis to hight co2 of the brachypodium distachyon-Analysis response of the Brachypodium distachyon to hight CO2 -treatment hight CO2
Project description:Deep sequencing of Brachypodium distachyon small RNA from panicles (flowers) was done to analyze the genome-wide distribution patterns of 1) total small RNA reads and loci, 2) 21 and 24 nucleotide repeat-normalized reads and 3) 21 and 24 nucleotide phased siRNA clusters relative to gene and transposable element density.