Thellungiella halophila ThPIP1 gene enhances the tolerance of the transgenic rice to salt stress

Aquaporin proteins were demonstrated to play an important regulatory role in transporting water and other small molecules. To better understand physiological functions of aquaporins in extremophile plants, a novel ThPIP1 gene from the Thellungiella halophila was isolated and functionally characterized in the transgenic rice. Data showed that the ThPIP1 protein encoded 284 amino acids, and was identified to be located on the plasma membrane. The expression of ThPIP1 gene in the shoots and roots of T. halophila seedlings were induced by high salinity. The transgenic rice overexpressing ThPIP1 gene significantly increased plants tolerance to salt stress through the pathway regulating the osmotic potentials, accumulation of organic small molecules substances and the ratio of K+/Na+ in the plant cells. Moreover, split-ubiquitin yeast two-hybrid assay showed that ThPIP1 protein specifically interacted with ThPIP2 and a non-specific lipid-transfer protein 2, suggesting that ThPIP1 probably play a key role in responding to the reactions of multiple external stimulus and in participating in different physiological processes of plants exposed to salt stress.