Ketelaar Group- Cellular polarity and dynamics

Ketelaar group - Cellular polarity and dynamics

Many answers to questions about plant development and functioning can be found within cells. Relevant cellular processes include the regulation of division plane, the direction of cell growth and polarization in response to internal and external signals. We aim to understand the cellular machinery that drives and executes these processes. To do so, a multidisciplinary approach is used in which physical, chemical and genetic factors are considered. To reduce complexity, we use several model species with simple body plans, the moss Physcomitrium patens and since recently the alga Ulva mutabilis.

The protonemal tissue of Physcomitrium patens has a 2 dimensional architecture and the behaviour of protonemal cells is highly predictable. In addition, the single layered protonemal tissue is ideal for high resolution, quantitative microscopy. Protonemal cells expand by tip growth, a highly polarized type of cell expansion. Since these cells function in exploring the environment, their growth direction is determined by a trade-off between internal polarity cues, provided by the microtubule cytoskeleton, and diverse external signals, including gravity and light. Understanding how polarity cues are transduced to the cell tip and how they are balanced against environmental signals to control the growth direction is one of the focus areas of the group.  

In a collaborative project with Francine Govers (PHP) and Joris Sprakel (PCC), we aim to understand how oomycete pathogens, particularly the notorious Phytophthora group, locate plants and get access to plant cells. In this project, we focus on both the weaponry of the pathogen and the defence machinery of plants. We study polarization and sensing mechanisms of the pathogen and polarized secretion as a cellular defence mechanism in plant cells, with the goal to find novel strategies to control Phytophthora pathogens.

Group members