Abstract
Plants control water movement in response to various environmental changes. Changes in amounts and activities of aquaporins are important for a rapid regulation of water movement under stress conditions. The objective of this study is to clarify the role of individual rice aquaporin under stress conditions. Among 33 rice aquaporins, we focused mainly on 13 members that expressed well in roots and leaf blades. Correlations between aquaporin amounts and water-related osmotic, transpirational and nitrogen stresses were analyzed. Although mRNA levels of OsPIP1;1 and OsPIP2;1 in roots showed less changes under these stresses, OsPIP2;4 and OsPIP2;5 dramatically changed in a similar manner in transpiration or bleeding sap volume changes. We also examined aquaporin amounts at protein level, phosphoryated state, localization in tissues and water transport activities. Based on these results, role of each aquaporin will be discussed.
