PROBLEM TO BE SOLVED: To fine out a water-channel gene that can control the water permeability in cells from a halophilious plant and to provide use thereof. SOLUTION: The water channel gene originates from sea fennel as a halophilious plant. This water channel gene can control the expression of the water channel gene depending on the environment as the water channel gene can grow even in the presence of a high concentration of salts. This invention additionally provides the water channel protein formed by expressing the channel gene, a vector into which the channel gene is inserted, a host that is used for introducing the water channel gene into the vector and a transformant prepared by introducing the water-channel gene into the eukaryocyte cells.
