Simple, but not branched, plasmodesmata allow the nonspecific trafficking of proteins in developing tobacco leaves.
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.
Oparka
K J
KJ
Unit of Cell Biology, Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom. kopark@scri.sari.ac.uk
Roberts
A G
AG
Boevink
P
P
Santa Cruz
S
S
Roberts
I
I
Pradel
K S
KS
Imlau
A
A
Kotlizky
G
G
Sauer
N
N
Epel
B
B
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
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