title: Simple, but not branched, plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves.
abstract: Leaves undergo a sink-source transition during which a physiological change occurs from carbon import to export. In sink leaves, biolistic bombardment of plasmids encoding GFP-fusion proteins demonstrated that proteins with an Mr up to 50 kDa could move freely through plasmodesmata. During the sink-source transition, the capacity to traffic proteins decreased substantially and was accompanied by a developmental switch from simple to branched forms of plasmodesmata. Inoculation of sink leaves with a movement protein-defective virus showed that virally expressed GFP, but not viral RNA, was capable of trafficking between sink cells during infection. Contrary to dogma that plasmodesmata have a size exclusion limit below 1 kDa, the data demonstrate that nonspecific "macromolecular trafficking" is a general feature of simple plasmodesmata in sink leaves.
authors.affiliation: Unit of Cell Biology, Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom. kopark@scri.sari.ac.uk
authors.forename: K J
authors.initials: KJ
authors.lastname: Oparka
authors.forename: A G
authors.initials: AG
authors.lastname: Roberts
authors.forename: P
authors.initials: P
authors.lastname: Boevink
authors.forename: S
authors.initials: S
authors.lastname: Santa Cruz
authors.forename: I
authors.initials: I
authors.lastname: Roberts
authors.forename: K S
authors.initials: KS
authors.lastname: Pradel
authors.forename: A
authors.initials: A
authors.lastname: Imlau
authors.forename: G
authors.initials: G
authors.lastname: Kotlizky
authors.forename: N
authors.initials: N
authors.lastname: Sauer
authors.forename: B
authors.initials: B
authors.lastname: Epel
mesh_terms: D001692:Biological Transport; D002244:Carbon / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D053830:Plant Viral Movement Proteins; D010947:Plants, Toxic; D017863:Potexvirus / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000378:metabolism; D014026:Nicotiana / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D008164:Luminescent Proteins; D010940:Plant Proteins; D053830:Plant Viral Movement Proteins; D012333:RNA, Messenger; D012367:RNA, Viral; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; D002244:Carbon