The ER within plasmodesmata

Abstract

The endoplasmic reticulum (ER) is an essential component of plasmodesmata, the membrane-lined pores that interconnect plant cells. The desmotubule which traverses the centre of a plasmodesma is formed from, and continuous with, the cortical ER. Whilst the exact role of the ER is only now being characterised, it is recognised that the ER is intimately involved in the transfer of molecules to and through plasmodesmata, providing a number of pathways for movement between cells as well as being implicated in the mechanisms that control transport. It is believed that molecules may be transported by passive flow within the desmotubule lumen, by diffusion along the inner desmotubule membranes or by specific attachment to the cytoplasmic face of the desmotubule followed by facilitated transport through the cytoplasmic sleeve. The ER is also involved in the formation of plasmodesmata either during cell division or when formed de novo across non-division walls. This chapter focusses on the role of the ER in plasmodesmatal formation and function. © Springer-Verlag Berlin Heidelberg 2006.