The expression pattern and activity of Zea mays plasma membrane aquaporins highlight their central role in the control of the cell membrane water permeability
(2008)
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- Authors
- Supervisors
- Chaumont, François
- Abstract
- Because of their absolute dependence on water and their need to deal with a challenging environment, plants have to tightly adjust their water balance. This can be achieved through different mechanisms but in the short term, the role of aquaporins is currently believed to be determinant. Aquaporins (AQPs) are major integral proteins (MIP) that allow water or small solutes to cross membranes. They provide plants with means to rapidly and reversibly alter their membrane water permeability in order to give the most fitted response to the environmental cues. Our work aimed at studying the expression pattern and activity of Zea mays plasma membrane aquaporins (ZmPIPs). RT-PCR and immunodetection approaches as well as biophysical measurements were performed in parallel to characterize the expression levels, cellular localization and activity of ZmPIPs in maize seedlings. We found that all ZmPIP genes except ZmPIP2;7 were expressed in maize plantlets, although to different extents. In roots and leaves of 7 day-old plants, expression was dependent on the developmental stage of the tissue, with, in general, an increase in expression in differentiating elongated tissues and a steady state or even a decrease in more mature tissues. Interestingly, this variation of expression could be correlated to changes in the cell membrane water permeability. Diurnal expression of ZmPIPs in roots and leaves was also investigated and their transcript and protein level was found to be higher during the first hours of the light period than at night. Finally, the root cell water permeability of transgenic plants partially down-regulated in ZmPIP expression through RNA silencing decreased significantly, highlighting the key role of ZmPIP aquaporins in the control of cell water permeability. Altogether, the data obtained during this work point out to ZmPIPs as major regulators of cell membrane water permeability in maize plants.
- Affiliations
Citations
Hachez, C. (2008). The expression pattern and activity of Zea mays plasma membrane aquaporins highlight their central role in the control of the cell membrane water permeability. https://hdl.handle.net/2078.5/124080