Research Scientist Tienen, Belgium
Since October 2013
Genetic engineering: Developing new gene editing technologies in sugar beet protoplasts using TALEN and CRISPR/Cas9. As such, new traits can be developed in sugar beet with the aim to increase the genetic potential of elite sugar beet varieties.
Post-doctoral Fellow Leuven, Belgium
May 2013 --- September 2013
The aim of this project was to further investigate the trehalose metabolism in Arabidopsis (see Ph thesis), but limited to one cell type only, namely the stomatal guard cells. In order to enable this research, a new system for studying metabolites within stomates needed to be established.
PhD student Leuven
January 2009 --- May 2013
The role of the Arabidopsis trehalase and the trehalose-6-phosphate phosphatases during drought stress, growth and development
Trehalose is a nonreducing disaccharide linking two glucose units in an a,a-1,1 configuration. It is a common sugar in bacteria, fungi and yeast, where it functions as a carbon source and stress protectant. The major trehalose biosynthesis pathway involves two consecutive enzymatic reactions mediated by trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). The intermediate compound trehalose-6-phosphate (T6P) has recently emerged as a growth regulator and a coordinator of the plant metabolism. Plants contain only small amounts of trehalose but encode large families of trehalose biosynthesis genes. In contrast, Arabidopsis contains only one trehalase enzyme, AtTRE1, which hydrolyzes trehalose into glucose.
In this PhD project, I analyzed the Arabidopsis TPPs and trehalase to gain more insight in the role of the trehalose metabolism during plant growth, development and drought stress. AtTPPA-J gene expression assays in Arabidopsis suggest that the regulation of the TPPs is highly specific in response to altered sugar availability and light conditions. Arabidopsis TPPs, possible regulators of T6P levels, seem to control specific processes in plant development. AtTPPB expression levels are negatively correlated with leaf size and cell division, while AtTPPA and AtTPPG execute redundant roles during the differentiation of trichoblast and atrichoblast cells in the root.
Ectopic expression of trehalose biosynthesis genes in plants has been used in the past to increase trehalose synthesis, thereby hoping to generate stress tolerant plants. The abiotic stress tolerance of the plants improved but the trehalose levels remained low. Trehalase, the only known plant enzyme able to degrade trehalose, might be responsible for these suppressed trehalose levels. Arabidopsis plants modified in AtTRE1 expression were generated to test this assumption and were subjected to drought stress. AtTRE1-overexpressing plants contain reduced trehalose levels but recover better after drought stress, whereas Attre1 mutants display increased trehalose contents and a drought-susceptible phenotype. Water-retaining capacities of the AtTRE1-modified plants were consistent with the drought stress phenotypes. In addition, ABA-mediated stomatal closure is impaired in Attre1 mutants, while AtTRE1 overexpressors are hypersensitive towards ABA in their guard cells. Consistent with this finding are the altered leaf temperatures of AtTRE1-modified plantlets during in vivo drought stress experiments. All these data support that overexpression of AtTRE1 enhances drought stress tolerance in Arabidopsis and suggest an important role for trehalase in the control of stomatal regulation in the drought stress response.
A link between AtTRE1 and lateral root development was found in the Attre1-3OE mutant. This T-DNA insertion mutant contains a CaMV 35S element in the 3’ end of the AtTRE1 promoter, resulting in the overexpression of AtTRE1 and the disruption of two cis-acting elements. It is hypothesized that the design of the AtTRE1 promoter in the Attre1-3OE mutant is responsible for a deregulated overexpression of AtTRE1 upon auxin signaling, leading to a twisted root phenotype and the tendency for early lateral root formation.
AtTRE1 overexpression is related with a decreased leaf area and leaf epidermal cell number. AtTRE1 overexpressors show the tendency to accumulate less UDP-glucose and sugar phosphates, while the opposite trend is seen in Attre1 mutants. In addition, AtTRE1 influences the transition to flowering, since early and late flowering phenotypes are observed in AtTRE1-modified plants. AtTRE1 expression patterns suggest a role for AtTRE1 in phloem loading/unloading processes and seed development.
Scientific Collaborator Leuven, Belgium
September 2008 --- January 2009
Project: Induced protein aggregation as a tool for the validation of antifungal target genes in the pathogen Candida albicans
Research Scholar Vero Beach, FL, United States
September 2007 --- July 2008
Project: Purifying and sequencing of the Trypsin Modulating Oostatic Factor (TMOF) Receptor in the midgut of Aedes Aegypti
Creative thinkingAnalytical thinkingInterest in knowledgeEfficiency
Cell biology Biochemistry R&D Scientific writingWestern BlottingTransfectionTeam ManagementStudy protocolsSDS-PAGERT-PCRReport Writingrecombinant DNA technologyDNAFluorescence Microscopygas chromatographygrant writing and designHPLCIn VitroLIMSMetabolismGeneticsRNAGene Editing
Ph.D. in Biology from KULeuven in 2013
Master in Bioengineering from KULeuven in 2007