Sacco C. de Vries

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 Single mesophyll cells in leaf explants of Dactylis glomerata L. (Dactylis) that were competent to form somatic embryos directly or through callus were identified by semi-automatic cell tracking. These competent cells were a subpopulation of small, isodiametric, cytoplasm-rich cells located close to the vascular bundles. Using whole mount in situ(More)
Programmed cell death (PCD) is a common host response to microbial infection [1-3]. In plants, PCD is associated with immunity to biotrophic pathogens, but it can also promote disease upon infection by necrotrophic pathogens [4]. Therefore, plant cell-suicide programs must be strictly controlled. Here we demonstrate that the Arabidopsis thaliana(More)
Auxin regulates numerous plant developmental processes by controlling gene expression via a family of functionally distinct DNA-binding auxin response factors (ARFs), yet the mechanistic basis for generating specificity in auxin response is unknown. Here, we address this question by solving high-resolution crystal structures of the pivotal Arabidopsis(More)
The carrot (Daucus carota L.) EP3 chitinase was shown to be essential for somatic embryo formation in a carrot mutant cell line. We identified the Arabidopsis thaliana (L.) Heynh. ortholog of the carrot EP3-3 chitinase gene, designated as AtEP3/AtchitIV and analyzed its expression in Arabidopsis by means of reverse transcription-polymerase chain reaction(More)
Leucine-rich repeat (LRR)-containing transmembrane receptor-like kinases (RLKs) are important components of plant signal transduction. The Arabidopsis thaliana somatic embryogenesis receptor-like kinase 1 (AtSERK1) is an LRR-RLK proposed to participate in a signal transduction cascade involved in embryo development. By yeast two-hybrid screening we(More)
Somatic embryogenesis of carrot (Daucus carota L.) is inhibited by the glycosylation inhibitor tunicamycin. This inhibition is reversible by the addition of correctly glycosylated glycoproteins which have been secreted into the culture medium. To identify the proteins responsible for complementation, glycoproteins present in the medium of embryo cultures(More)
An upward shift in the concentration of calcium present in the medium during somatic embryogenesis increased the number of embryos produced approximately two-fold. This was observed when embryogenic suspension cells grown in 2,4-D medium with the normal calcium concentration of 10−3 M were transferred to hormone-free medium containing 10−2 M calcium and(More)
A cell-tracking system was established to determine the capability of individual single suspension cells of carrot (Daucus carota L.) to develop into somatic embryos. When immobilised in phytagel, 127 out of 30 318 single suspension cells smaller than 22 μm in diameter developed into a somatic embryo. Single cells present at the start of the experiment were(More)
The regulation of a mRNA encoding a shoot-specific polypeptide from developing pea seedlings was studied and compared to the regulation of mRNAs encoding two major light-induced nuclear-encoded polypeptides, the small subunit of the ribulose 1,5 biphosphate carboxylase (ssRuBPCase) and a polypeptide of the light-harvesting chlorophyll a/b complex (LHCP). By(More)
Zygotic embryos of three Arabidopsis thaliana (L.) Heynh. mutants lacking an embryonic shoot apical meristem (SAM), shoot meristemless (stm), wuschel (wus) and zwille / pinhead (zll / pnh) were used as explants to establish embryogenic cell cultures. Somatic embryos of all three mutants showed the same mutant phenotypes as their zygotic equivalents. These(More)