Research Projects

The following paragraphs provide an introduction to current projects; for more detailed information, please visit the pages.


A         Phosphate: essential for food security and sustainable agriculture

Phosphate is essential for agriculture, but is a limiting, non-renewable resource.  Much phosphate currently applied to crops is wasted and pollutes the environment before plants can absorb it.  To promote food security and sustainable agriculture, it is paramount to better understand the mechanisms that control growth behavior in response to low phosphate and to increase the efficiency with which crops assimilate and use phosphate.  One important strategy of plants to increase their capacity to acquire phosphate is to alter the growth patterns of their root systems in low phosphate: We want to understand how this happens, so we can manipulate it to make root systems more efficient in nutrient uptake.  We have started to identify key processes in root growth control in low phosphate, and are now aiming to further study these and initiate transfer of this knowledge to crops.


B         Growth control in response to DNA damage

In all eukaryotes cell cycle progression is arrested for the duration of the DNA repair process.  As plants are constantly exposed to UV and other radiation that damage their DNA, their growth capacity is reduced.  In animal systems, arrest of cell cycle progression occurs at different checkpoints and involves cyclin-dependent kinase inhibitors and the reversible phosphorylation of crucial cell cycle regulators.  We have discovered a novel mechanism that arrests cell growth in response to DNA damage.  Further research is required to understand how this mechanism interacts with repair and other mechanisms to control growth.  Ultimately, we aim to enhance crop growth capacity by judicious exploitation of this knowledge.  

Plants that cannot arrest cell division after suffering DNA damage are much more susceptible to accumulate mutations, visible here in a mutated sector of this plant.





C         Stem cells and cell differentiation in plants

The meristems at the growing tips of roots and shoots contain stem cells and their immediate progeny, so-called transit amplifying cells.  The progression from stem cells to differentiated cells that transient amplifying cells undertake is a gradual process: involving an initial phase of rapid cell divisions followed by the loss of mitosis and cell division at the meristem boundary.  Nonetheless, a modified cell cycle persists in these post-mitotic cells, manifested by several rounds of genome duplication (endoreplicating cells) that proceed concomitantly with cellular differentiation. Mitotic exit is of great importance for plant growth control: in plants that experience environmental stress, cells prematurely lose the capacity to divide, thereby reducing growth capacity following a stress episode.  Likewise, differentiated plant cells in general lack the capacity to resume proliferation, and therefore cells that express the metabolic networks for the production of high value chemicals (pharmaceuticals) cannot be cultivated.  This is because most cultured plant cells lose their differentiation state (which is critical for their ability to produce pharmaceuticals) rapidly.  We are interested to identify the mechanisms by which the differentiated state is reversed (reprogrammed) in regenerating plants and what the impediments are to proliferation in differentiated cells.  We have developed new tools to isolate and enrich plant protoplasts, and are studying the mechanisms of de-differentiation with the aim to use plant cells in the future as the basis for a new biotechnological industry.