Walking the back alleys: a modelling study of symplastic transport
- Event time: 1:00pm
- Event date: 22nd October 2012
- Speaker: Eva Deinum (FOM Institute AMOLF Amsterdam)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
How to become a full-sized plant? The answer is a ongoing growth process of continuous adaptation to the environment, from fertilization till death. When and where new parts are formed is controlled by interacting signals such as plant hormones. To understand how they control development, it is essential to understand how they move through tissues. We will discuss here an often ignored, but potentially very important mode of signal propagation in plants.
For one key developmental plant hormone, auxin, the transport systems are well characterized and many studies have focussed on this hormone and its role in development. However, for several other important signals, very little is known about their transport mechanism(s). Fortunately, all sufficiently small molecules can move diffusively through plasmodesmata: narrow channels connecting neighbouring cells. This so called (non-targeted) symplastic transport has been mostly ignored in previous modelling studies, although mutants defective in plasmodesmatal control often show severe developmental phenotypes, including early stage lethality.
Using a combined analytical and numerical approach we have studied the physical properties of signal propagation by purely symplastic transport. Although we were interested in tissue level phenomena, a subcellular description was essential for a correct incorporation of the biological processes involved.
We then zoom in to the (electron) microscopic scale and try to derive key parameters for the tissue model from a consideration of hindered diffusion through individual plasmodesmata. This microscopic derivation allows us to directly assess the importance of different plasmodesmatal features on a signal's behaviour at the tissue level and show how the particle size dependence at this level propagates in a highly nonlinear way to the tissue level.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..