PLASMODESMATA - INTERCELLULAR CHANNELS FOR MACROMOLECULAR TRANSPORT IN PLANTS

Plasmodesmata are special intercellular organelles that establish cyto plasmic and endomembrane (endoplasmic reticulum and nuclear envelope) continuity throughout most of the plant body. Microinjection studies h ave provided direct proof that plasmodesmata facilitate the cell-to-ce ll trafficking of viral movement proteins and nucleic acids. Evidence is now accumulating that plant-encoded proteins, including transcripti on factors, also move from cell to cell on this endogenous macromolecu lar trafficking pathway. The picture that is emerging is that the prog ramming of plant development may involve this supracellular network fo r the effective delivery of one form of information molecule.