title: Root aquaporins contribute to whole plant water fluxes under drought stress in rice (Oryza sativa L.).
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.
authors.affiliation: International Rice Research Institute, Crop Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines.|University of Nebraska-Lincoln, Department of Agronomy and Horticulture, Lincoln, NE, 68583, USA.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Grondin
authors.affiliation: International Rice Research Institute, Crop Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Ramil
authors.initials: R
authors.lastname: Mauleon
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru, 502 324, Andhra Pradesh, India.
authors.forename: Vincent
authors.initials: V
authors.lastname: Vadez
authors.affiliation: International Rice Research Institute, Crop Environmental Sciences Division, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Amelia
authors.initials: A
authors.lastname: Henry
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D001386:Azides / Q000633:toxicity; D032461:Chromosomes, Plant / Q000235:genetics; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D012275:Oryza / Q000033:anatomy & histology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D053147:Plant Exudates / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism*; D018526:Plant Transpiration / Q000187:drug effects; D019655:Quantitative Trait, Heritable; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D014867:Water / Q000378:metabolism*
chemical_list: D020346:Aquaporins; D001386:Azides; D053147:Plant Exudates; D010940:Plant Proteins; D012333:RNA, Messenger; D014867:Water
keywords: aquaporins; azide; leaf water potential; plasma membrane intrinsic proteins; root hydraulic conductivity; sap exudation; transpiration rate