Deciphering the structure and function of the last unknown major plant organelle - Plasmodesma
EMSL Project ID
60368
Abstract
Plant tissues exhibit a symplasmic organization; the individual protoplasts are connected to their neighbors via cytoplasmic bridges that extend through pores in the cell walls. These bridges may have diameters of a micrometer or more, as in the sieve pores of the phloem, but in most cell types they are smaller. Historically, botanists referred to cytoplasmic bridges of all sizes as plasmodesmata. The meaning of the term began to shift when the transmission electron microscope (TEM) became the preferred tool for studying these structures. Today, a plasmodesma is widely understood to be a ‘nano-scale’ pore. Surprisingly, despite their essential role in plant performance, structural and functional studies on plasmodesmata are rare and were mostly conducted several decades ago. Despite the fact that plasmodesmata are central to the organism’s integrity, our understanding of these nanoscopic channels is poor and suffers from methodological limitations. This is exemplified by the fact that available EM images appear to reveal plasmodesmal pore structures that are much smaller than the tracer molecules known to diffuse through these pores. In general, transport processes in pores that have dimensions in the size range of the transported molecules are governed by different physical parameters than transport process in the macroscopic realm. This can lead to unexpected effects, as experience in nanofluidic technologies demonstrates. We will apply cutting edge sample preparation technology (Cryo-FIB/SEM) and Cryo-Electron Tomography to reveal the in situ structure of plasmodesmata. We will combine this with functional studies of molecule movement through plasmodesmata utilizing minimal invasive diffusional injection micropipettes and live cell imaging at both EMSL and WSU. The combination of structural and functional data will allow us to fundamentally refine current models.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2022-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Team Members