Ruud A. De Maagd

Ruud A. De Maagd
Wageningen University & Research | WUR · Wageningen Plant Research

MSc (Utrecht) PhD (Leiden)

About

135
Publications
19,231
Reads
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7,055
Citations
Citations since 2017
12 Research Items
2631 Citations
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Introduction
I am studying the transcriptional regulation of fruit development and ripening, in particular in -but not limited to- the model fleshy fruit of tomato. For more: https://www.wur.nl/en/Persons/dr.-RA-Ruud-de-Maagd.htm
Additional affiliations
July 1993 - present
Wageningen University & Research
Position
  • Senior Researcher
Description
  • Bacillus thuringiensis insecticidal toxins mode of action Transcriptional regulatory networks in fleshy fruit development and ripening
August 1991 - December 1992
Salk Institute for Biological Studies
Position
  • PostDoc Position
Description
  • Signal transduction in plant-pathogen interactions
July 1989 - July 1991
Leiden University
Position
  • PostDoc Position

Publications

Publications (135)
Article
Full-text available
In all fruit and vegetable crops, reduction in quality during postharvest storage leads to substantial losses of primary production with enormous economic consequences. Also in tomato, fruit shelf-life is an important quality trait. In this study a collection of tomato accessions, consisting of 92 S. lycopersicum landraces and old cultivars and sev...
Article
Full-text available
CRISPR-Cas-based genome editing allows for precise and targeted genetic modification of plants. Nevertheless, unintended off-target edits can arise that might confer risks when present in gene-edited food crops. Through an extensive literature review we gathered information on CRISPR-Cas off-target edits in plants. Most observed off-target changes...
Article
Full-text available
The timing of flowering and the inflorescence architecture are critical for the reproductive success of tomato (Solanum lycopersicum), but the gene regulatory networks underlying these traits have not been fully explored. Here we show that the tomato FRUITFULL-like (FUL-like) genes FUL2 and MADS-BOX PROTEIN 20 (MBP20) promote the vegetative-to-repr...
Article
The recent development of gene editing has generated a lot of excitement for the future of crop improvement. At a technical level, targeted gene modification through gene editing (GE) provides an opportunity to build on natural variation to target genetic changes for the creation of new varieties, crops, and market opportunities. Specialty crops, r...
Preprint
The timing of flowering and inflorescence architecture are critical for the reproductive success of tomato, but the gene regulatory networks underlying these traits have not been fully explored. Here we show that the tomato FRUITFULL-like (FUL-like) genes FUL2 and MADS-BOX PROTEIN 20 (MBP20) induce flowering and repress inflorescence branching by p...
Article
Full-text available
A tomato core collection consisting of 122 gene bank accessions, including landraces, old cultivars, and wild relatives, was explored for variation in several plant growth, yield and fruit quality traits. The resequenced accessions were also genotyped with respect to a number of mutations or variations in key genes known to underlie these traits. T...
Article
Full-text available
Tomato fruit ripening is regulated by transcription factors (TFs), their downstream effector genes, and the ethylene biosynthesis and signalling pathway. Spontaneous non-ripening mutants ripening inhibitor (rin), non- ripening (nor) and Colorless non-ripening (Cnr) correspond with mutations in or near the TF-encoding genes MADS- RIN, NAC-NOR and SP...
Article
The study of transcriptional regulation of tomato ripening has been led by spontaneous mutations in transcription factor (TF) genes that completely inhibit normal ripening, suggesting that they are 'master regulators'. Studies using CRISPR/Cas9 mutagenesis to produce knockouts of the underlying genes indicate a different picture, suggesting that th...
Article
Full-text available
Crossover formation during meiosis in plants is required for proper chromosome segregation and is essential for crop breeding as it allows an (optimal) combination of traits by mixing parental alleles on each chromosome. Crossover formation commences with the production of a large number of DNA double‐strand breaks, of which only a few result in cr...
Article
Full-text available
Tomato (Solanum lycopersicum) is a model for climacteric fleshy fruit ripening studies. Tomato ripening is regulated by multiple transcription factors together with the plant hormone ethylene and their downstream effector genes. Transcription Factors APETALA2a (AP2a), NON-RIPENING (NOR) and FRUITFULL (FUL1/TDR4 and FUL2/MBP7) were reported as maste...
Patent
The present invention provides means for inhibiting the bolting and flowering of a Beta vulgaris plant, including an isolated nucleic acid, which can be used to produce a transgenic Beta vulgaris plant, where bolting and flowering is inhibited after vernalization. Furthermore, the invention discloses vectors, transgenic and non-transgenic, non-bolt...
Article
Full-text available
Semi-polar metabolites such as flavonoids, phenolic acids, and alkaloids are very important health-related compounds in tomato. As a first step to identify genes responsible for the synthesis of semi-polar metabolites, quantitative trait loci (QTLs) that influence the semi-polar metabolite content in red-ripe tomato fruit were identified, by charac...
Article
In recent years, different Bacillus thuringiensis (Bt) toxin-encoding genes have been combined or 'stacked' in genetically modified (GM) crops. Synergism between Bt proteins may occur and thereby increase the impact of the stacked GM event on nontarget invertebrates compared to plants expressing a single Bt gene. On the basis of bioassay data avail...
Article
Fruit phenotype is a resultant of inherent genetic potential in interaction with impact of environment experienced during crop and fruit growth. The aim of this study was to analyze the genetic and physiological basis for the difference in fruit size between a small ('Brioso') and intermediate ('Cappricia') sized tomato cultivar exposed to differen...
Article
Tomato is one of the most cultivated vegetables in the world and an important ingredient of the human diet. Tomato breeders and growers face a continuous challenge of combining high quantity (production volume) with high quality (appearance, taste and perception for the consumers, processing quality for the processing industry). To improve the qual...
Chapter
Bacillus thuringiensis (or Bt, as it has become generally known) is one of the oldest and widely used biological control agents and has a long history of use. Bt and a number of related bacteria produce a variety of toxins, mostly—but not exclusively- localized in the parasporal crystals, which are, together with the spores themselves, the componen...
Article
Light affects plant growth through assimilate availability and signals regulating development. Effects of light on tomato fruit growth were studied using cuvettes with light emitting diodes providing white, red or blue light to individual tomato trusses for different periods during the day. Hypotheses tested were: 1) light-grown fruits are stronger...
Article
Full-text available
Fleshy fruits have evolved to be attractive to frugivores in order to enhance seed dispersal, and have become an indispensable part of the human diet. Here we review the recent advances in the understanding of transcriptional regulation of fleshy fruit development and ripening with a focus on tomato. While aspects of fruit development are probably...
Article
Full-text available
Background TCP proteins are plant-specific transcription factors, which are known to have a wide range of functions in different plant species such as in leaf development, flower symmetry, shoot branching, and senescence. Only a small number of TCP genes has been characterised from tomato (Solanum lycopersicum). Here we report several functional fe...
Article
Metabolomics separates and detects small molecules and helps determine the composition of plant materials. This makes it appear to be a possible contributor to environmental risk assessment (ERA) of transgenic plants. Here we argue that, despite important advances in the technology, limited annotation and our limited knowledge of the role of metabo...
Article
Full-text available
Expression of Bacillus thuringiensis delta-endotoxins has proven to be a successful stra-tegy for obtaining insect resistance in transgenic plants. Drawbacks of expression of a single resistance gene are the limited target spectrum and the potential for rapid adapta-tion of the pest. Hybrid toxins with a wider target spectrum in combination with ex...
Book
Genes expressing Bacillus thuringiensis (Bt) toxins have been incorporated into genetically modified (GM) plants to render these resistant to certain insect pests. Of particular interest have been the genes encoding Cry (Crystal) proteins, but also the gene encoding the vegetative insecticidal protein Vip3Aa has been incorporated into crop plants....
Article
Cry9Aa, produced by Bacillus thuringiensis is reported to be not active against Spodoptera exigua (beet armyworm). In this study we have cloned a new cry9Aa5 gene encoding a protoxin with increased activity against S. exigua as compared to Cry9Aa1. When aligned to Cry9Aa1, four amino acid substitutions in domain I and one substitution in the C-term...
Article
Full-text available
MADS-domain transcription factors have been shown to act as key repressors or activators of the transition to flowering and as master regulators of reproductive organ identities. Despite their important roles in plant development, the origin of several MADS-box subfamilies has remained enigmatic so far. Here we demonstrate, through a combination of...
Article
Full-text available
MicroRNAs (miRNAs) play important roles in plant development through regulation of gene expression by mRNA degradation or translational inhibition. Despite the fact that tomato (Solanum lycopersicum) is the model system for studying fleshy fruit development and ripening, only a few experimentally proven miRNA targets are known, and the role of miRN...
Chapter
Biological containment is the prevention or reduction in the spread of transgenes by modifying plant growth or development, most commonly through modification of reproductive characteristics. This review provides a summary of the current strategies for biological containment, including the use of both naturally occurring and engineered mechanisms....
Article
Full-text available
The pore-formation activity of monomeric and oligomeric forms of different Cry1 toxins (from Cry1A to Cry1G) was analyzed by monitoring ionic permeability across Manduca sexta brush border membrane vesicles. The membrane vesicles were isolated from microvilli structures, showing a high enrichment of apical membrane markers and low intrinsic K+ perm...
Article
Full-text available
Tomato (Solanum lycopersicum) contains two close homologs of the Arabidopsis thaliana MADS domain transcription factor FRUITFULL (FUL), FUL1 (previously called TDR4) and FUL2 (previously MBP7). Both proteins interact with the ripening regulator RIPENING INHIBITOR (RIN) and are expressed during fruit ripening. To elucidate their function in tomato,...
Article
Full-text available
Strigolactones are plant hormones that regulate both above- and belowground plant architecture. Strigolactones were initially identified as rhizosphere signaling molecules. In the present work, the tomato (Solanum lycopersicum) CAROTENOID CLEAVAGE DIOXYGENASE 8 (SlCCD8) was cloned and its role in rhizosphere signaling and plant physiology assessed...
Article
Studies on the transcriptional response to pathogens in the insect larval gut have shown the regulation of several genes after the infection. Repat (REsponse to PAThogens) genes were first identified in Spodoptera exigua midgut as being up-regulated in response to the exposure to Bacillus thuringiensis toxins and baculovirus. Recently, new members...
Article
Full-text available
Growth of tomato fruits is determined by cell division and cell expansion, which are tightly controlled by factors that drive the core cell cycle. The cyclin-dependent kinases (CDKs) and their interacting partners, the cyclins, play a key role in the progression of the cell cycle. In this study the role of CDKA1, CDKB1, and CDKB2 in fruit developme...
Article
Cry15Aa protein, produced by Bacillus thuringiensis serovar thompsoni HD542, in a crystal together with a 40 kDa accompanying protein, is one of a small group of non-typical, less well-studied members of the Cry family of insecticidal proteins, and may provide an alternative for the more commonly used Cry proteins in insect pest management. In this...
Article
Full-text available
Bacillus thuringiensis Cry toxins are used worldwide in the control of different insect pests important in agriculture or in human health. The Cry proteins are pore-forming toxins that affect the midgut cell of target insects. It was shown that non-toxic Cry1Ab helix α-4 mutants had a dominant negative (DN) phenotype inhibiting the toxicity of wild...
Article
Full-text available
Fruit ripening in tomato (Solanum lycopersicum) requires the coordination of both developmental cues as well as the plant hormone ethylene. Although the role of ethylene in mediating climacteric ripening has been established, knowledge regarding the developmental regulators that modulate the involvement of ethylene in tomato fruit ripening is still...
Data
Full-text available
Sequence of the primers employed for quantitative RT-PCR. (0.01 MB PDF)
Data
Differentially expressed ESTs in the Xen-R colony when compared to the FRA colony (Xen-R columm) and their relative change in expression in the FRA colony when exposed to the B. thuringiensis-based product, Xentari™ (FRA-E columm). (0.02 MB PDF)
Article
Full-text available
Bacillus thuringiensis is the most effective microbial control agent for controlling numerous species from different insect orders. The main threat for the long term use of B. thuringiensis in pest control is the ability of insects to develop resistance. Thus, the identification of insect genes involved in conferring resistance is of paramount impo...
Data
On Jul 19, 2011 this sequence version replaced gi:239809561.
Article
Full-text available
Cry15Aa protein, produced by Bacillus thuringiensis serovar thompsoni HD542 in a crystal together with a 40-kDa accompanying protein, is one of a small group of nontypical, less well-studied members of the Cry family of insecticidal proteins and may provide an alternative for the more commonly used Cry proteins in insect pest management. In this pa...
Patent
The invention relates to the field of quality testing of fresh plant-based and mushroom based products. Methods, carriers and kits for determining the quality stage are provided.
Article
Insect larvae spend most of their time eating and the digestive tract is the most crucial barrier for the entrance of many pathogens. In our study, suppression subtractive hybridization (SSH) was used to compare Spodoptera exigua midgut gene expression between larvae exposed to the Bacillus thuringiensis Cry1Ca toxin and non-exposed insects. Based...
Chapter
The application of transgenic approaches in chrysanthemum for fundamental research and to solve some of the breeding and cultivation problems has resulted in the past decade in an array of reports covering aspects of flower color and flowering time, plant architecture, and resistance to abiotic stress, viruses, fungi, and insects. This review summa...
Article
Solubilized protoxins of nine Cry1 and one hybrid Cry1 delta-endotoxin from Bacillus thuringiensis were tested for their activity against larvae of the codling moth (Cydia pomonella L). Cry1Da was the most toxic, followed by Cry1Ab, Cry1Ba, and Cry1Ac, while Cry1Aa, Cry1Fa, Cry1Ia, and SN19 were still less active. Cry1Ca and Cry1Cb showed no activi...
Article
We report the cloning of a cDNA from TcAG, an AG (Arabidopsis thaliana MADS-box C-type transcription factor gene AGAMOUS) homologue from cocoa (Theobroma cacao L.). TcAG was in the cocoa flower expressed primarily in stamens and ovaries, comparable to AG in Arabidopsis. Additionally, we found that TcAG is also expressed in the fruit (pod) wall and...
Article
Full-text available
Many Bacillus thuringiensis crystal proteins, particularly those active against lepidopteran insects, have carboxy-terminal extensions that mediate bipyramidal crystal formation. These crystals are only soluble at high (>10.0) pH in reducing conditions such as generally found in the lepidopteran midgut. Most of the Colorado potato beetle (CPB)-acti...
Article
Full-text available
The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armigera larvae reared on Cry1Ac, Cry1Ab, or Cry2Ab toxin...
Article
Full-text available
The pore-formation activity of monomeric and oligomeric forms of different Cry1 toxins (from Cry1A to Cry1G) was analyzed by monitoring ionic permeability across Manduca sexta brush border membrane vesicles. The membrane vesicles were isolated from microvilli structures, showing a high enrichment of apical membrane markers and low intrinsic K(+) pe...
Article
A novel chymotrypsin which is expressed in the midgut of the lepidopteran insect Spodoptera exigua is described. This enzyme, referred to as SeCT34, represents a novel class of chymotrypsins. Its amino-acid sequence shares common features of gut chymotrpysins, but can be clearly distinguished from other serine proteinases that are expressed in the...
Article
Full-text available
Nature Biotechnology journal featuring biotechnology articles and science research papers of commercial interest in pharmaceutical, medical, and environmental sciences.
Article
Full-text available
Agrobacterium-mediated genetic transformation was applied to produce beet armyworm (Spodoptera exigua Hübner) resistant tropical shallots (Allium cepa L. group Aggregatum). A cry1Ca or a H04 hybrid gene from Bacillus thuringiensis, driven by the chrysanthemum ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (Rubisco SSU) promoter, alon...
Article
We investigated the role of domain III of Bacillus thuringiensis delta-endotoxin Cry1Ac in determining toxicity against Heliothis virescens. Hybrid toxins, containing domain III of Cry1Ac with domains I and II of Cry1Ba, Cry1Ca, Cry1Da, Cry1Ea, and Cry1Fb, respectively, were created. In this way Cry1Ca, Cry1Fb, and to a lesser extent Cry1Ba were ma...
Article
Full-text available
Insecticidal toxins from Bacillus thuringiensis bind to receptors on midgut epithelial cells of susceptible insect larvae. Aminopeptidases N (APNs) from several insect species have been shown to be putative receptors for these toxins. Here we report the cloning and expression analysis of four APN cDNAs from Spodoptera exigua. Suppression Subtractiv...
Article
Full-text available
Several mutants of the Bacillus thuringiensis Cry1Ca toxin affected with regard to specific activity towards Spodoptera exigua were studied. Alanine was used to replace single residues in loops 2 and 3 of domain II (mutant pPB19) and to replace residues 541-544 in domain III (mutant pPB20). Additionally, a Cry1Ca mutant combining all mutations was...
Article
Twelve Cry proteins from Bacillus thuringiensis Berliner were tested in bioassays on cacao plantations in Indonesia for activity against the larvae of cocoa pod borer (Conopomorpha cramerella (Snellen)), an insect pest of the cacao tree. Through the damage caused by their feeding, the larvae of cocoa pod borer cause the pods of the cocoa tree to ri...
Article
Full-text available
Twelve Cry1 and two Cry9 delta-endotoxins from Bacillus thuringiensis were tested for their activity against black cutworm ( Agrotis ipsilon). A. ipsilon was not susceptible to many toxins, but three toxins had significant activity. Cry9Ca was the most toxic, followed by Cry1Aa and Cry1Fb. Hybrids between these three active proteins were made by in...
Article
Monoterpene cyclases are the key enzymes in the monoterpene biosynthetic pathway, as they catalyze the cyclization of the ubiquitous geranyl diphosphate (GDP) to the specific monoterpene skeletons. From Citrus limon, four monoterpene synthase-encoding cDNAs for a beta-pinene synthase named Cl(-)betaPINS, a gamma-terpinene synthase named ClgammaTS,...
Article
Complete cDNA sequences were obtained for ribosomal protein (rp) L15 and eukaryotic initiation factor eIF2alpha from the lepidopteran insect Spodoptera frugiperda, and for elongation factor eEF2 from S. exigua. The presence of a 5' terminal oligopyrimidine (TOP) tract classified the lepidopteran rpL15 transcript as a TOP mRNA. For eEF2, two types o...
Article
Complete cDNA sequences were obtained for ribosomal protein (rp) L15 and eukaryotic initiation factor eIF2α from the lepidopteran insect Spodoptera frugiperda, and for elongation factor eEF2 from S. exigua. The presence of a 5′ terminal oligopyrimidine (TOP) tract classified the lepidopteran rpL15 transcript as a TOP mRNA. For eEF2, two types of tr...
Article
Expression of Bacillus thuringiensis delta-endotoxins has proven to be a successful strategy for obtaining insect resistance in transgenic plants. Drawbacks of expression of a single resistance gene are the limited target spectrum and the potential for rapid adaptation of the pest. Hybrid toxins with a wider target spectrum in combination with exis...