TOR dynamically regulates plant cell–cell transport

The coordinated redistribution of sugars from mature “source” leaves to developing “sink” leaves requires tight regulation of sugar transport between cells via plasmodesmata (PD). Although fundamental to plant physiology, the mechanisms that control PD transport and thereby support development of ne...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2020-03, Vol.117 (9), p.5049-5058
Main Authors: Brunkard, Jacob O., Xu, Min, Scarpin, M. Regina, Chatterjee, Snigdha, Shemyakina, Elena A., Goodman, Howard M., Zambryski, Patricia
Format: Article
Language:English
Subjects:
Arabidopsis - embryology
Arabidopsis - genetics
Arabidopsis - metabolism
Arabidopsis Proteins - genetics
Arabidopsis Proteins - metabolism
Biological Sciences
Biological Transport
Carbohydrate Metabolism
Carbohydrates
Gene Expression Profiling
Gene Expression Regulation, Developmental
Gene Expression Regulation, Plant
Gene Knockdown Techniques
Gene Silencing
Genetic screening
Glucose
Leaves
Nicotiana - genetics
Nicotiana - metabolism
Phosphatidylinositol 3-Kinases - metabolism
Plant Cells - metabolism
Plant Leaves - growth & development
Plant Leaves - metabolism
Plant physiology
Plasmodesmata
Plasmodesmata - metabolism
Protein Transport
Rapamycin
Signal Transduction
Sugar
TOR protein
Transport
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Summary:The coordinated redistribution of sugars from mature “source” leaves to developing “sink” leaves requires tight regulation of sugar transport between cells via plasmodesmata (PD). Although fundamental to plant physiology, the mechanisms that control PD transport and thereby support development of new leaves have remained elusive. From a forward genetic screen for altered PD transport, we discovered that the conserved eukaryotic glucose- TOR (TARGET OF RAPAMYCIN) metabolic signaling network restricts PD transport in leaves. Genetic approaches and chemical or physiological treatments to either promote or disrupt TOR activity demonstrate that glucose-activated TOR decreases PD transport in leaves. We further found that TOR is significantly more active in mature leaves photosynthesizing excess sugars than in young, growing leaves, and that this increase in TOR activity correlates with decreased rates of PD transport. We conclude that leaf cells regulate PD trafficking in response to changing carbohydrate availability monitored by the TOR pathway.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1919196117