J. G. Schmidt

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The male gametophyte (or pollen) plays an obligatory role during sexual reproduction of higher plants. The extremely reduced complexity of this organ renders pollen a valuable experimental system for studying fundamental aspects of plant biology such as cell fate determination, cell-cell interactions, cell polarity, and tip-growth. Here, we present the(More)
In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization(More)
The objective of this study was to identify barley leaf proteins differentially regulated in response to drought and heat and the combined stresses in context of the morphological and physiological changes that also occur. The Syrian landrace Arta and the Australian cultivar Keel were subjected to drought, high temperature, or a combination of both(More)
Tailoring carotenoids by plant carotenoid cleavage dioxygenases (CCDs) generates various bioactive apocarotenoids. Recombinant CCD1 has been shown to catalyze symmetrical cleavage of C(40) carotenoid substrates at 9,10 and 9',10' positions. The actual substrate(s) of the enzyme in planta, however, is still unknown. In this study, we have carried out RNA(More)
Upon irradiation with elevated light intensities, the ice plant (Mesembryanthemum crystallinum) accumulates a complex pattern of methylated and glycosylated flavonol conjugates in the upper epidermal layer. Identification of a flavonol methylating activity, partial purification of the enzyme, and sequencing of the corresponding peptide fragments revealed a(More)
Botrytis cinerea is a phytopathogenic fungus infecting a number of crops (tomatoes, grapes and strawberries), which has been adopted as a model system in molecular phytopathology. B. cinerea uses a wide variety of infection strategies, which are mediated by a set of genes/proteins called pathogenicity/virulence factors. Many of these factors have been(More)
The discovery of a plume of water vapour and ice particles emerging from warm fractures ('tiger stripes') in Saturn's small, icy moon Enceladus raised the question of whether the plume emerges from a subsurface liquid source or from the decomposition of ice. Previous compositional analyses of particles injected by the plume into Saturn's diffuse E ring have(More)
One of the spectacular discoveries of the Cassini spacecraft was the plume of water vapour and icy particles (dust) originating near the south pole of Saturn's moon Enceladus. The data imply considerably smaller velocities for the grains than for the vapour, which has been difficult to understand. The gas and dust are too dilute in the plume to interact, so(More)
The higher plant Arabidopsis (Arabidopsis thaliana) has eight genes potentially coding for small ubiquitin-related modifier (SUMO) proteins. However, two well-expressed isoforms differ from fungal and animal consensus in a conserved glutamine (Gln) residue situated four residues from the carboxyl terminus. We tested deviations in this position in the(More)
Cation- and S-adenosyl-L-methionine (AdoMet)-dependent plant natural product methyltransferases are referred to as CCoAOMTs because of their preferred substrate, caffeoyl coenzyme A (CCoA). The enzymes are encoded by a small family of genes, some of which with a proven role in lignin monomer biosynthesis. In Arabidopsis thaliana individual members of this(More)