Responsive regulation of aquaporins in the plants exposed to abiotic stresses

Water is not only a necessary substrate synthesizing living matter in organisms, but also involves in the nutrient metabolism and the osmotic adjustment in the plant. Transmembrane transport of water in plants is mainly carried out by the water channel protein (AQPs) mediation. Therefore, based the overall level of plants or cell level, the moisture absorption and transport across the membrane system are essential guarantee for plant growth and development. In recent years, aquaporin, as a key factor regulating the water absorption and translation, has been widely focused in the research fields of plant nutrition and stress physiology at molecular level. This review described the mechanism of water transport involved by AQPs and the responsemechanism of the AQPs to abiotic stresses based on the kinds of structure, substrate specificity, gene expression and regulation mechanism of aquaporin in plants, and the physiological effects of water channel protein during plant growth process were better described, and functionally characterized the transport mechanism of water and osmotic adjustment as well as nutrient transport models regulated by channel protein. The responses of aquaporin proteins to the changes of environment factors such as the strength of light, drought and low temperature, were discussed accordingly. Study showed that the water channel protein obviously responded to the environmental changes by increasing or reducing the accumulation amounts of AQS expression, and aquaporin could realize an efficient transport of water in plants by maintaining certain specific structures and the transport of substrate specificity as well as adjusting the expression of target genes and post-translational modification processes. Importantly, aquaporin plays a positive role in maintianing an equilibrium of osmotic potentials by transport regulation of water and absorption of small molecule chemicals, which are involved in the physiological regulation and nutrient uptake in the plants. Aquaporin can not only enhance the tolerance of plant to drought and salt stress, but also to cold stress. Moreover, aquaporin could interact with proteins that responds to abiotic stresses, and regulate osmotic equilibrium in the plant cells to improve the adaptation ability of plant exposed to abiotic stresses. Responsive mechanism of water channel protein in the plants exposing to abiotic stresses should be further investigated in the coming exploration to provide scientific supports and molecular materials for application of aquaporin in molecular breeding.