Root aquaporins contribute to whole plant water fluxes under drought stress in rice (Oryza sativa L.) |
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| Authors: | Alexandre Grondin Ramil Mauleon Vincent Vadez Amelia Henry |
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| Affiliation: | 1. International Rice Research Institute, Crop Environmental Sciences Division, Metro Manila, Philippines;2. University of Nebraska‐Lincoln, Department of Agronomy and Horticulture, Lincoln, NE, USA;3. International Crops Research Institute for the Semi‐Arid Tropics, Patancheru, Andhra Pradesh, India |
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| Abstract: | Aquaporin activity and root anatomy may affect root hydraulic properties under drought stress. To better understand the function of aquaporins in rice root water fluxes under drought, we studied the root hydraulic conductivity (Lpr) and root sap exudation rate (Sr) in the presence or absence of an aquaporin inhibitor (azide) under well‐watered conditions and following drought stress in six diverse rice varieties. Varieties varied in Lpr and Sr under both conditions. The contribution of aquaporins to Lpr was generally high (up to 79% under well‐watered conditions and 85% under drought stress) and differentially regulated under drought. Aquaporin contribution to Sr increased in most varieties after drought, suggesting a crucial role for aquaporins in osmotic water fluxes during drought and recovery. Furthermore, root plasma membrane aquaporin (PIP) expression and root anatomical properties were correlated with hydraulic traits. Three chromosome regions highly correlated with hydraulic traits of the OryzaSNP panel were identified, but did not co‐locate with known aquaporins. These results therefore highlight the importance of aquaporins in the rice root radial water pathway, but emphasize the complex range of additional mechanisms related to root water fluxes and drought response. |
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| Keywords: | aquaporins plasma membrane intrinsic proteins azide root hydraulic conductivity sap exudation leaf water potential transpiration rate |
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