The biotrophic fungus Ustilago maydis causes smut disease on maize (Zea mays L.), which is characterized by immense plant tumours. To establish disease and reprogram organ primordia to tumours, U. maydis deploys effector proteins in an organ-specific manner. However, the cellular contribution to leaf tumours remains unknown. We investigated leaf tumour formation on the tissue- and cell type-specific level. Cytology and metabolite analysis were deployed to understand the cellular basis for tumourigenesis. Laser-capture microdissection was performed to gain a cell-type specific transcriptome of U. maydis during tumour formation. In-vivo visualization of plant DNA synthesis identified bundle sheath cells as the origin of hyperplasic tumour cells, while mesophyll cells become hypertrophic tumour cells. Cell type specific transcriptome profiling of U. maydis revealed tailored expression of fungal effector genes. Moreover, U. maydis See1 was identified the first cell type specific fungal effector, being required for induction of cell cycle reactivation in bundle sheath cells. Identification of distinct cellular mechanisms in two different leave cell types, and See1 as an effector for induction of proliferation of bundle-sheath cells, are major steps in understanding U. maydis-induced tumor formation. Moreover, the cell-type specific U. maydis transcriptome data is a valuable resource to the scientific community. Overall design: To analyze the cell type specific transcriptome of U. maydis during the indcution of plant tumors, transcriptomic profiling of U. maydis from LCM-dissected tumour cells was done. At 4 dpi, SG200 infected HTT cells, bundle sheath-derived HPT cells, and SG200?see1 infected HTT cells (?see1 HTT) were isolated. As controls, mesophyll and bundle sheath cells from mock treated leaf tissue of the same age were isolated.
Cell type specific transcriptional reprogramming of maize leaves during Ustilago maydis induced tumor formation.
Specimen part, Subject
View SamplesUsually starch is nearly depleted at the end of the night. To induce a gradual depletion of carbon, we have analysed the global response of transcripts during an extension of the night, where carbon becomes severely limiting from about four hours onwards.
Global transcript levels respond to small changes of the carbon status during progressive exhaustion of carbohydrates in Arabidopsis rosettes.
Specimen part
View SamplesPlants typically contain two different types of cell walls: a primary wall that is being deposited around all growing cells, and a secondary wall that is produced in cells with specialized functions once they have ceased to grow. In Arabidopsis, VND7 is a transcription factor that is sufficient to activate secondary cell wall synthesis. To artificially turn on the secondary cell wall synthesis, VND7 was fused to the activation domain of the herpes virus VP16 protein and the glucocorticoid receptor (GR) domain. Thus, the transgenic plants harbouring the constructs can then be treated with dexamethasone (DEX), a glucocorticoid derivative, to induce the secondary cell wall formation.
A Transcriptional and Metabolic Framework for Secondary Wall Formation in Arabidopsis.
Specimen part, Treatment
View SamplesTo investigate the response of Arabidopsis thaliana plants to non-freezing, cool temperatures, we subjected four week old plants to various chilling temperatures at defined times during the diurnal cycle to control for diurnal effects on transcription. From the same plants, metabolites and enzyme activities were measured as well. Interestingly a gradual change could be observed over a wide range of temperatures. Some of which could be attributed to the CBF program.
Multilevel genomic analysis of the response of transcripts, enzyme activities and metabolites in Arabidopsis rosettes to a progressive decrease of temperature in the non-freezing range.
Specimen part
View SamplesHow do the transcript levels of leaf-expressed genes change in a normal day-night cycle? The interest is in genes that are regulated by the circadian clock and the diurnal component (i.e. light, metabolite changes). Plants were grown on soil in a 12/12 h light/dark rythm at 20C day and night. 5 weeks after germination the rosettes of the non-flowering plants were harvested, 15 plants per sample. Plants were harvested at 6 timepoints every 4 hours beginning with the end of the night (still in darkness).
Sugars and circadian regulation make major contributions to the global regulation of diurnal gene expression in Arabidopsis.
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View SamplesCell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic organ fusions. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.
The FRIABLE1 gene product affects cell adhesion in Arabidopsis.
Specimen part
View SamplesPlant seeds prepare for germination already during seed maturation. We performed a detailed transcriptome analysis of barley grain maturation, desiccation and germination in two tissue fractions (endosperm/aleurone = e/a and embryo = em) using the Affymetrix barley1 chip.
Barley grain maturation and germination: metabolic pathway and regulatory network commonalities and differences highlighted by new MapMan/PageMan profiling tools.
No sample metadata fields
View SamplesComparative genomic analysis of nutrient response to NO3-, NH4+ or NH4+: NO3- in barley
Global transcriptional and physiological responses of Saccharomyces cerevisiae to ammonium, L-alanine, or L-glutamine limitation.
Age, Specimen part, Subject, Compound
View SamplesThe protrotophic laboratory strain CEN.PK113-7D (MAT a) and three knock-out strains snf1, snf4 and snf1snf4 were grown in laboratory fermentors with a working volume of 1 litre at dilution rate (D) of 0.10 per hour (in triplicate for each strain). At steady state, samples from each of the 12 continuous cultures were taken and cooled below 2 degree C within ten seconds by mixing 40% sample and 60% crushed ice.
Reconstruction of the yeast Snf1 kinase regulatory network reveals its role as a global energy regulator.
Sex
View SamplesA three-factor design was applied to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostat cultures of Saccharomyces cerevisiae.
Transcription factor control of growth rate dependent genes in Saccharomyces cerevisiae: a three factor design.
No sample metadata fields
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