Abstract
Aquaporins are membrane proteins which facilitate water movement in plants. We've already identified 33 rice aquaporin genes from the database and showed their organ specific expression patterns. To clarify the possible role of each aquaporin member in water movement in rice plants, we conducted (1) expression analysis at protein level using specific peptide antibodies and (2) analysis of water permeability of each aquaporin member. OsPIP2;1 and OsTIP1;1 were expressed both in leaf blades and roots, while OsTIP2;1 was only in roots. Several aquaporin members were localized in endodermis, rhizodermis, exodermis, vascular bundles or cortex, but distribution patterns were different among aquaporin members. Analysis of water channel activities revealed that OsPIP2;1, OsPIP2;2, OsPIP2;3, OsPIP2;4, OsPIP2;5, OsTIP1;1 and OsTIP2;1 had high water permeabilities, while OsPIP1;1 and OsPIP1;2 did not. From these results, we will discuss the function of each aquaporin members.
