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Regulation of Arabidopsis leaf hydraulics involves light-dependent phosphorylation of aquaporins in veins.
- Source :
-
The Plant cell [Plant Cell] 2013 Mar; Vol. 25 (3), pp. 1029-39. Date of Electronic Publication: 2013 Mar 26. - Publication Year :
- 2013
-
Abstract
- The water status of plant leaves depends on the efficiency of the water supply, from the vasculature to inner tissues. This process is under hormonal and environmental regulation and involves aquaporin water channels. In Arabidopsis thaliana, the rosette hydraulic conductivity (Kros) is higher in darkness than it is during the day. Knockout plants showed that three plasma membrane intrinsic proteins (PIPs) sharing expression in veins (PIP1;2, PIP2;1, and PIP2;6) contribute to rosette water transport, and PIP2;1 can fully account for Kros responsiveness to darkness. Directed expression of PIP2;1 in veins of a pip2;1 mutant was sufficient to restore Kros. In addition, a positive correlation, in both wild-type and PIP2;1-overexpressing plants, was found between Kros and the osmotic water permeability of protoplasts from the veins but not from the mesophyll. Thus, living cells in veins form a major hydraulic resistance in leaves. Quantitative proteomic analyses showed that light-dependent regulation of Kros is linked to diphosphorylation of PIP2;1 at Ser-280 and Ser-283. Expression in pip2;1 of phosphomimetic and phosphorylation-deficient forms of PIP2;1 demonstrated that phosphorylation at these two sites is necessary for Kros enhancement under darkness. These findings establish how regulation of a single aquaporin isoform in leaf veins critically determines leaf hydraulics.
- Subjects :
- Aquaporins genetics
Arabidopsis genetics
Arabidopsis metabolism
Arabidopsis Proteins genetics
Biological Transport
Cell Membrane genetics
Cell Membrane metabolism
Darkness
Mesophyll Cells metabolism
Osmosis
Phosphorylation
Plant Leaves genetics
Plant Leaves radiation effects
Plant Transpiration
Plants, Genetically Modified genetics
Plants, Genetically Modified metabolism
Plants, Genetically Modified radiation effects
Protein Isoforms genetics
Protein Isoforms metabolism
Water metabolism
Aquaporins metabolism
Arabidopsis radiation effects
Arabidopsis Proteins metabolism
Gene Expression Regulation, Plant
Light
Plant Leaves metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1532-298X
- Volume :
- 25
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Plant cell
- Publication Type :
- Academic Journal
- Accession number :
- 23532070
- Full Text :
- https://doi.org/10.1105/tpc.112.108456