Project description:Transcriptional profiling in the shoot after SHR induction by DEX. We used Affymetrix ATH1 microarrays to identify new target genes of SHR and the effect of SHR on growth and development of the Arabidopsis shoot system by global transcriptome analysis.
Project description:To obtain detailed information about gene expression during stamen development in Arabidopsis thaliana, we compared, by microarray analysis, the gene expression profile of wild-type inflorescences to those of the floral mutants apetala3, sporocyteless/nozzle, and male sterile 1, in which different aspects of stamen formation are disrupted. These experiments led to the identification of groups of genes with predicted expression at early, intermediate and late stages of stamen development. Additional experiments aimed at characterizing gene expression specifically during microspore formation. To this end, we compared the gene expression profiles of wild-type flowers of distinct developmental stages to those of the male sterile 1 mutant. Computational analysis of the datasets derived from this experiment led to the identification of genes that are likely involved in the control of key developmental processes during microsporogenesis. Keywords: mutant comparison, developmental series
Project description:In Arabidopsis, jasmonate is required for stamen and pollen maturation. Mutants deficient in jasmonate synthesis, such as opr3, are male-sterile but become fertile when jasmonate is applied to developing flower buds. We have used ATH1 oligonucleotide arrays to follow gene expression in opr3 stamens for 22 hours following jasmonate treatment. In these experiments, a total of 821 genes were specifically induced by jasmonate and 480 repressed. Comparisons with data from previous studies indicate that these genes constitute a stamen-specific jasmonate transcriptome, with a large proportion (70%) of the genes expressed in the sporophytic tissue but not in the pollen. Bioinformatics tools allowed us to associate many of the induced genes with metabolic pathways that are likely up-regulated during jasmonate-induced maturation. Our pathway analysis led to the identification of specific genes within larger families of homologues that apparently encode stamen-specific isozymes. Extensive additional analysis of our dataset identified 13 transcription factors that may be key regulators of the stamen maturation processes triggered by jasmonate. Two of these transcription factors, MYB21 and MYB24, are the only members of subgroup 19 of the R2R3 family of MYB proteins. A myb21 mutant obtained by reverse genetics exhibited shorter anther filaments, delayed anther dehiscence and greatly reduced male fertility. A myb24 mutant was phenotypically wild type, but production of a myb21 myb24 double mutant indicated that introduction of the myb24 mutation exacerbated all three aspects of the myb21 phenotype. Exogenous jasmonate could not restore fertility to myb21 or myb21 myb24 mutant plants. Together with the data from transcriptional profiling, these results indicate that MYB21 and MYB24 are induced by jasmonate and mediate important aspects of the jasmonate response during stamen development. Keywords: Time course analysis
Project description:Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. The presented model is a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. The Petri net formalism was used to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs were applied. Based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism, the core metabolism of Arabidopsis thaliana was formulated. Each reaction (transition) is experimentally proven. The complete Petri net model consists of 134 metabolites, represented by places, and 243 reactions, represented by transitions. Places and transitions are connected via 572 edges.
Project description:Transcriptional profiling of the vegetative part of Arabidopsis comparing wild type with the shr scl23 scr triple mutant. The latter is produced by crossing the strong null alleles of shr (shr-2), scl23 (scl23-1) and scr (scr-5). The goal was to determine the effects of the GRAS transcription factors SHR, SCL23 and SCR on growth and development of the Arabidopsis shoot system by global transcriptome analysis.
Project description:Transcriptional profiling of root part comparing wild type with scl3 mutant and SCL3 OE. We used Affymetrix ATH1 microarrays to determine the effect of GRAS transcription factor SCL3 on growth and development of Arabidopsis root system by global transcriptome analysis and to identify new regulators in the regulatory pathway.