Unlocking intercellular channels from cell wall biology to biophysics

Background
Plasmodesmata (PD) are the only intercellular channels linking the interiors of plant cells. PD allow cell-to-cell diffusion of small molecular weight factors such as hormones but are also regulated to control the movement of transcription factors and nucleic acids that are central to developmental events. PD extends across adjacent primary cell walls which offer physical constrictions on channel aperture by means of the cell wall glycan callose.
Objectives
This proposal aim to dissect the structures and functions of architectural components of cell walls around PD.
We will investigate how the cell wall glycan callose at the neck of PD is both integrated with the surrounding cell wall molecular architectures involving pectins, xyloglucans and cellulose microfibrils and also how modulations of callose levels (known to impact on PD transport) are orchestrated with the surrounding cell wall glycans to control PD mechanical properties.

Novelty and Timeliness
The project will identify novel cell wall components that contribute to PD regulation (together with callose). This knowledge will contribute to our understanding of the role of cell walls in regulating intercellular communication and signalling and highlight new targets that, in the long term, could be used to manipulate the transport of mobile proteins and RNAs opening applications in agriculture and crop development. Another aspect of the work will identify interactions between cell wall glycans that contribute to PD formation and function and that can also be involved in regulating the mechanical properties of these channels. Knowledge on interactions between cell wall glycans can be further exploited in the improvement or new development of biomimetic composites using cell wall polymers as raw materials
Experimental approaches:
-Immunolocalization
-Transport assays
- ELISA and epitope detection chromatography or EDC
- Mechanical testing in plant cell walls