title: Vacuolar proton pumps and aquaporins involved in rapid internode elongation of deepwater rice.
abstract: Rapid growth of the submerged shoots of deepwater rice is essential for survival during the rainy season. We investigated changes in the expression of vacuolar H(+)-ATPase (V-ATPase), H(+)-pyrophosphatase (V-PPase), and aquaporins under submerged conditions. The amounts of vacuolar proton pumps, which support the active transport of ions into the vacuoles, were maintained on a membrane protein basis in the developing vacuoles. Among the six isogenes of V-PPase, OsVHP1;3 was markedly enhanced by submersion. The gene expression of efficient water channels, OsTIP1;1, OsTIP2;2, OsPIP1;1, OsPIP2;1, and OsPIP2;2, was markedly enhanced by submersion. The increase in aquaporin expression might support quick elongation of internodes. The mRNA levels of OsNIP2;2 and OsNIP3;1, which transport silicic and boric acids respectively, clearly decreased. The present study indicates that internodes of deepwater rice upregulate vacuolar proton pumps and water channel aquaporins and downregulate aquaporins that allow permeation of the substrates that suppress internode growth.
authors.affiliation: Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Muto
authors.forename: Shoji
authors.initials: S
authors.lastname: Segami
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Hayashi
authors.forename: Junko
authors.initials: J
authors.lastname: Sakurai
authors.forename: Mari
authors.initials: M
authors.lastname: Murai-Hatano
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hattori
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Ashikari
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Maeshima
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D048430:Cell Shape; D018506:Gene Expression Regulation, Plant; D007101:Immersion; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism*; D012275:Oryza / Q000166:cytology / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D010539:Permeability; D018547:Plant Stems / Q000166:cytology / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology*
chemical_list: D020346:Aquaporins; D012333:RNA, Messenger; D025262:Vacuolar Proton-Translocating ATPases; D043564:Inorganic Pyrophosphatase