Ectopic Expression of , a Plasma Membrane Intrinsic Protein Gene from the Halophyte , Enhances Drought and Salt-Alkali Stress Tolerance in Arabidopsis.

Aquaporins are channel proteins that facilitate the transmembrane transport of water and other small neutral molecules, thereby playing vital roles in maintaining water and nutrition homeostasis in the life activities of all organisms. , a seashore and mangrove-accompanied halophyte with strong adaptability to adversity in tropical and subtropical regions, is a good model for studying the molecular mechanisms underlying extreme saline-alkaline and drought stress tolerance in leguminous plants. In this study, a PIP2 gene () was cloned from , and its expression patterns and physiological roles in yeast and heterologous expression systems under high salt-alkali and high osmotic stress conditions were examined. The expression of at the transcriptional level in was affected by high salinity and alkali, high osmotic stress, and abscisic acid treatment. In yeast, the expression of enhanced salt/osmotic and oxidative sensitivity under high salt/osmotic and HO stress. The overexpression of in could enhance the survival and recovery of transgenic plants under drought stress, and the seed germination and seedling growth of the (over-expression) lines showed slightly stronger tolerance to high salt/alkali than the wild-type. The transgenic plants also showed a higher response level to high-salinity and dehydration than the wild-type, mostly based on the up-regulated expression of salt/dehydration marker genes in plants. The reactive oxygen species (ROS) staining results indicated that the transgenic lines did not possess stronger ROS scavenging ability and stress tolerance than the wild-type under multiple stresses. The results confirmed that is involved in the response of to salt and drought, and primarily acts by mediating water homeostasis rather than by acting as an ROS transporter, thereby influencing physiological processes under various abiotic stresses in plants.