Marc De Block

Marc De Block
IntrinsicCode

PhD

About

63
Publications
12,662
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Introduction
I have been retired since January 2020. Today I develop software for network visualization and analysis (https://www.intrinsic-code.eu) and I support scientific projects. The main focus is on developing network visualization algorithms and methods to analyze complex networks.

Publications

Publications (63)
Article
Full-text available
Two of the major pathways involved in induced defense of plants against pathogens include the salicylic acid (SA)- and jasmonic acid (JA)-mediated pathways that act mainly against biotrophs and necrotrophs, respectively. However, some necrotrophic pathogens, such as Botrytis cinerea, actively induce the SA pathway, resulting in cell death that allo...
Article
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Epigenetics offers important opportunities in breeding to improve the potential yield in a wide variety of crops. Starting from a pure breeder seed lot of a rice (Oryza sativa ssp. indica) inbred population, repeated testing for improved cellular respiration rates and energy use efficiency (EUE) over three generations identified performant epilines...
Article
Full-text available
Background Cytosine methylation in plant genomes is important for the regulation of gene transcription and transposon activity. Genome-wide methylomes are studied upon mutation of the DNA methyltransferases, adaptation to environmental stresses or during development. However, from basic biology to breeding programs, there is a need to monitor multi...
Article
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To increase both the yield potential and stability of crops, integrated breeding strategies are used that have mostly a direct genetic basis, but the utility of epigenetics to improve complex traits is unclear. A better understanding of the status of the epigenome and its contribution to the agronomic performance would help in developing approaches...
Patent
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Methods are provided to select plants and populations of epigenetically fixed crop plants with improved yield.
Patent
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Stress tolerance in plants and plant cells is achieved by using nucleotide sequences encoding enzymes involved in the NAD salvage synthesis pathway and/or the NAD de novo synthesis pathway e.g. for overexpression in plants.
Patent
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The invention provides for the use of isolated polynucleotides encoding maize poly (ADP-ribose) polymerase (PARP) proteins to identify endogenous PARP encoding genes or cDNAs from a plant and to produce plant cells and plants with high vigor.
Article
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To study the effect of short N-acetylglucosamine (GlcNAc) oligosaccharides on the physiology of plants, NodC of Azorhizobium caulinodans was expressed in Arabidopsis. The corresponding enzyme catalyzes the polymerization of GlcNAc and accordingly β-1,4-GlcNAc oligos accumulated in the plant. A phenotype characterized by difficulties in developing a...
Article
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This dialogue was held between the Guest Editors of the Special Issue on “Plant Transgenesis” of the Int. J. Dev. Biol. and Marc De Block. He was one of the first scientists worldwide to obtain transgenic plants transformed with the chimeric selectable marker genes encoding neomycin phosphotransferase and bialaphos that confer resistance against th...
Patent
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Methods and means are provided for the modification of the reactivity of plant cell walls, particularly as they can be found in natural fibers of fiber producing plants by inclusion of positively charged oligosaccharides or polysaccharides into the cell wall. This can be conveniently achieved by expressing a chimeric gene encoding an N-acetylglucos...
Article
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The aim of this paper is to establish a test method for the screening of bioengineered cotton fibers with an improved reactivity through the incorporation of positively charged nitrogen moieties. For this purpose a spectrophotometric method based on the absorption of a negatively charged dye (Acid Orange 7) is extensively studied. The processing pa...
Article
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Quantitative traits, such as size and weight in animals and seed yield in plants, are distributed normally, even within a population of genetically identical individuals. For example, in plants, various factors, such as local soil quality, microclimate, and sowing depth, affect growth differences among individual plants of isogenic populations. Bes...
Article
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The C4 grass Zea mays (maize or corn) is the third most important food crop globally after wheat and rice in terms of production and the second most widespread genetically modified (GM) crop, after soybean. Its demand is predicted to increase by 45% by the year 2020. In sub-Saharan Africa, tropical maize has traditionally been the main staple of th...
Article
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Transgenic plants with reduced poly(ADP-ribose) polymerase (PARP) levels have broad-spectrum stress-resistant phenotypes. Both Arabidopsis thaliana and oilseed rape (Brassica napus) lines overexpressing RNA interference-PARP constructs were more resistant to various abiotic stress treatments in laboratory and greenhouse experiments without negative...
Article
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Plants contain two genes that code for poly(ADP-ribose) polymerase (PARP): parp1 and parp2. Both PARPs are activated by DNA damage caused by, example reactive oxygen species. Upon activation polymers of ADP-ribose are synthesized on a range of nuclear enzymes using NAD(+) as substrate. Here, we show that in plants stresses such as drought, high lig...
Article
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Oilseed rape ( Brassica napus L.) genotypes with no or small petals are thought to have advantages in photosynthetic activity. The flowers of field-grown oilseed rape form a bright-yellow canopy that reflects and absorbs nearly 60% of the photosynthetically active radiation (PAR), causing a severe yield penalty. Reducing the size of the petals and/...
Article
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The DEFORMED ROOTS AND LEAVES1 (DRL1) gene is single copy in the Arabidopsis genome, and based on overall amino acid similarity and conservation of functional domains, the DRL1 protein is homologous with yeast TOT4/KTI12. TOT4/KTI12 associates with Elongator, a multisubunit complex that binds the RNA polymerase II transcription elongation complex....
Article
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At present, there is no general laboratory assay described that allows quantification of the yield potential of plant lines obtained in breeding or research programmes. The only way to evaluate the performance of a plant line is by greenhouse and field trials over several years on different locations. In this paper, an in vitro physiological method...
Article
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Reporter genes are commonly used m prokaryotes and eukaryotes to measure promoter activity of a gene of interest Transgenic organisms have to be generated by transformation with a chimertc gene consisting of the respective promoter and the coding sequence of the reporter gene. The activity of promoters can be studied by gene fusions without interfe...
Article
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 Nuclear male sterility within Triticum aestivum is considered as the ideal basis for the development of a hybridization system for wheat. We engineered nuclear male sterility in wheat by introducing the barnase gene under the control of tapetum-specific promoters derived from corn and rice. A biolistic-mediated transformation method, based on the...
Article
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An assay which allows the identification of plant lines or tissue cultures with an altered metabolism versus the control lines, will be described. The principles of the fitness assay are: Explants (calli, leaf disks,...) are put in media containing niacinamide and ascending salt concentrations. Niacinamide functions as an inhibitor of poly(ADP-ribo...
Article
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In situ enzyme histochemistry is a powerful method to help unravel the biochemical complexity of a plant. It permits the study of the biochemical functions of a single cell type without removing those cells from their normal biological context. This chapter describes a modification of the enzyme histochemical methods. This method is based on the pr...
Article
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In a study to optimize the use of the bar gene as a selectable marker gene in plant transformation, the selection mechanism of phosphinothricin in vitro was studied. It was found that tissues with a high anabolic activity were more sensitive to the toxicity of ammonium than tissues with a low anabolic activity. However, tissues with a low anabolic...
Article
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In Arabidopsis, mutation at PFL causes pointed first leaves, reduced fresh weight and growth retardation. We have cloned the wild-type PFL gene by T-DNA tagging, and demonstrate that it complements the mutant phenotype. PFL codes for ribosomal protein S18, based on the high homology with rat S18 and on purification of S18-equivalent peptides from p...
Article
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A nonradioactive RNA-RNA in situ hybridization method using digoxigenin-labeled probes is described. The visualization of hybrids is done using the indoxyl-nitro blue tetrazolium alkaline phosphatase reaction. The addition of polyvinyl alcohols of high molecular weight (40-100 kDa) to the reaction medium enhances the alkaline phosphatase reaction a...
Article
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Cytological and histochemical analyses were performed on developing anthers of wild-type, transgenic male-sterile and fertility-restored Brassica napus plants. Male sterility resulted from the expression of the barnase gene under the control of the tobacco-derived tapetumspecific promoter pTA29. Fertility was restored to male sterile plants by expr...
Article
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The DNA delivery systems which are routinely used to introduce genes into crop plants are Agrobacterium tumefaciens, electroporation and particle bombardment. The differences and similarities between these different transformation techniques are outlined. The influence of the cell biological approach, and more specifically the impact of the state o...
Article
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Male fertility was restored to genetically engineered male sterile oilseed rape plants. Male sterile plants that express a chimaeric ribonuclease gene in the anther tapetal cell layer were crossed with male fertile plants that were transformed with a chimaeric tapetal-cell-specific ribonuclease-inhibitor gene. F1 progeny expressing both genes are r...
Article
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An in-situ enzyme histochemical method is described that preserves the tissue and cell structure as well as the enzyme activities. Flower buds at different developmental stages from wild-type and transgenic Brassica napus plants, the latter containing the GUS gene under the control of a tapetum-specific promoter, were used as starting material. The...
Article
This chapter explains the use of the bar gene as a selectable marker in plant transformation, as a screenable marker in tissue culture and plant breeding, and as a reporter gene in plant molecular biology. The bar gene has served as a useful assayable marker gene in plant molecular biology. To guarantee correct translation initiation in plants, an...
Article
Plants can be transformed by using Agrobacterium-based T-DNA vectors or by direct uptake of DNA. However, for the selection of transformed cells or tissues, selectable marker genes are required. This chapter describes the use of the bialaphos resistance gene as a selectable marker in plant transformation, as a screenable marker in tissue culture an...
Chapter
Glufosinate and bialaphos are non-selective herbicides which act by inhibiting glutamine synthetase. A gene which confers resistance to bialaphos (bar) was isolated from Streptomyces hygroscopicus, the organism which produces bialaphos. The gene was shown to encode a phosphinothricin acetyl transferase. Using Agrobacterium-mediated Ti plasmid trans...
Article
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Hypocotyl explants of threeBrassica napus varieties were infected with two nopaline typeAgrobacterium strains each carrying a distinct disarmed T-DNA containing different selectable markers. Selection was done for only one of the markers, after which the regenerated plants were screened for the presence of the second marker. High co-transformation...
Article
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Tissue culture conditions and transformation have been established for both aspen and poplar. The use of previously described culture conditions resulted in shoot tip necrosis in the shoot cultures and necrosis of stem and leaf explants. Shoot tip necrosis could be overcome by buffering the medium with 2-(N-morpholino)ethanesulfonic acid and Ca-glu...
Article
The attempts to manipulate organelle DNA of higher plants have not yet been succesfull. Although some Agrobacterium mediated and direct gene transfer experi-ments suggested that chloroplasts of Nicotiana tabacum could be transformed, these experiments could not be reproduced. New transformation techniques have emerged: laser-injection, microinjecti...
Article
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An efficient and largely genotype-independent transformation method for Brassica napus and Brassica oleracea was established based on neo or bar as selectable marker genes. Hypocotyl explants of Brassica napus and Brassica oleracea cultivars were infected with Agrobacterium strains containing chimeric neo and bar genes. The use of AgNO(3) was a pre...
Article
We have explored the possibility of producing large amounts of biologically active peptides as part of chimeric plant seed storage proteins, the 2S albumins. A portion of an Arabidopsis thaliana 2S albumin gene, encoding a region of the protein whose sequence is not highly conserved among different species, was replaced by sequences encoding the ne...
Article
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We have analysed two herbicide resistant transgenic tobacco (Nicotiana tabacum) and four potato (Solanum tuberosum) lines under field conditions. These lines resulted from Agrobacterium mediated transformation of tobacco and potato leaf discs with chimeric bar genes encoding phosphinothricin acetyl transferase (PAT). Greenhouse tests have demonstra...
Article
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Leaves of the in vitro grown potato cultivars 'Bintje', 'Berolina', 'Desiree', and 'Russet Burbank' were wounded and co-cultivated with Agrobacterium strains having chimeric bar and nptII genes on a disarmed T-DNA. Each leaf from these cultivars formed numerous calli on kanamycin-containing medium, and almost all calli regenerated shoots. For 'Russ...
Article
The transfer of foreign DNA to plant cells can be achieved in a variety of ways that are described in several chapters of this manual. This chapter describes the various selectable and screenable marker genes that are presently used in plant transformation experiments. Screenable markers have been widely used in gene constructs to study the regulat...
Chapter
Phosphinotricin (PPT) is a new non-selective contact herbicide. It is an analogous of glutamate and acts as an irreversible inhibitor of the plant glutamine synthetase. The compound is obtained by chemical synthesis (BastaR, Hoechst AG) or naturally produced by some microorganisms as part of a tripeptide antibiotic — e.g. the tripeptide bialaphos f...
Article
Full-text available
Phosphinothricin (PPT) is a potent inhibitor of glutamine synthetase in plants and is used as a non-selective herbicide. The bar gene which confers resistance in Streptomyces hygroscopicus to bialaphos, a tripeptide containing PPT, encodes a phosphinothricin acetyltransferase (PAT) (see accompanying paper). The bar gene was placed under control of...
Chapter
Reproducible methods, allowing the introduction of defined DNA fragments in the plant nuclear genome, are presently available (see previous chapters in this volume) and are contributing significantly to the experimental analysis of the gene structure-function relationships governing regulated gene-expression in plants.
Article
A chimeric gene consisting of the promoter region of the nopaline synthase gene (Pnos) fused to the coding sequence of the chloramphenicol acetyltransferase gene (cat gene) of Tn9 was introduced by co-cultivation in tobacco protoplasts followed by selection with 10 mug/ml chloramphenicol. The chloramphenicol-resistant plants derived from these sele...
Article
Full-text available
Chimeric genes comprised of the nopaline synthase promoter and bacterial coding sequences specifying resistance to kanamycin, chloramphenicol or methotrexate, were inserted into the non-oncogenic Ti plasmid vector pGV3850 by recombination (through homologous pBR322 sequences present in the chimeric gene constructs and pGV3850). These co-integrates...
Chapter
The soil bacterium Agrobaeterium tumefaciens can infect almost all dicotyledonous plants (Braun 1978, 1982). As a result of the infection, the wound tissue proliferates as a neoplastic growth, commonly referred to as a crown gall tumor. Once induced, the tumor no longer requires the presence of the bacteria to grow, and can be cultivated in vitro a...
Chapter
Agrobacterium tumefaciens has long been proposed as a vector for the introduction of genetic material into plant cells. Recently, this natural gene transfer system has been modified to allow the transfer of any foreign gene of interest to plant cells in a simple and efficient manner. We will describe some of the new Agrobacterium vectors currently...
Article
Full-text available
Opine synthases are enzymes produced in dicotyledonous plants as the result of a natural gene transfer phenomenon. Agrobacteria contain Ti plasmids that direct the transfer, stable integration and expression of a number of genes in plants, including the genes coding for octopine or nopaline synthase. This fact was used as the basis for the construc...
Chapter
Full-text available
A chimeric gene was constructed consisting of the promoter of the nopaline synthase gene of Agrobacterium tumefaciens and the structural gene of the aminoglycoside phosphotransferase derived from the transposon Tn5 (APH(3′)II) gene). This chimeric gene was recombined into the T-DNA of Agrobacterium. This plasmid was introduced into plant cells by m...
Chapter
Mutagenesis through the insertion of transposons has proved to be an invaluable technique for mapping the genes of complex plasmids1. No selection for a mutant phenotype has to be devised, but a straightforward selection for the antibiotic resistance markers, encoded by the transposon, is sufficient to identify the presence of a mutant plasmid.
Article
The structure of the cointegrate plasmids formed by fusion of RP4 and the tumour-inducing plasmid (pTi) of Agrobacterium tumefaciens was analyzed. In all of the nine independently isolated pTi::RP4 cointegrates, the integration occurred at the same site on the RP4 genome. Moreover, a 1.2 Md (1750 bp) RP4 sequence (IS8) was directly repeated at both...
Article
We have employed the P type plasmid RP4 and the transposons Tn1 and Tn7 to isolate insertion and deletion mutations in the nopaline Ti-plasmid pTiC58. Mutations that inactivate all known Ti phenotypes have been located on the physical map. Most importantly, we have positioned several regions involved in the determination of oncogenicity. They corre...
Article
Full-text available
Agrobacterium tumefaciens is a gram-negative bacterium with the unique capacity to induce neoplasmic transformations in dicotyledonous plants. Recently, both the mechanism and the biological significance of this transformation have been elucidated. Agrobacterium tumefaciens strains contain a large extrachromosomal DNA plasmid (the Ti-plasmid). This...
Article
A pTiB6S3::RP4 cointegrate and a pTiC58::RP4 cointegrate plasmid were isolated. They are formed by the covalent linkage of the respective pTiB6S3 and pTiC58 plasmids of Agrobacterium tumefaciens and of the RP4 factor. They carry the genetic markers of both parental molecules, and these markers are transferred as a unit under the same circumstances...

Projects

Projects (2)
Project
Develop graph algorithms for: - visualization of networks - analysis of networks