Genome-Wide Identification and Characterisation of Aquaporins in the Marine Higher Plant Zostera japonica and Their Response to the Intertidal Environment.

Zostera japonica mainly lives in the intertidal zone and is susceptible to fluctuations in abiotic stresses, making it an excellent natural model for studying plant response mechanisms in intertidal environments. Aquaporins (AQPs) play important roles in water uptake, growth and development, and stress regulation. However, studies on the functions of the AQPs of Z. japonica (ZjAQPs) in response to intertidal environments have not been reported. In this study, we identified 22 AQPs in Z. japonica. Phylogenetic analysis revealed that ZjAQPs can be divided into four subfamilies: PIP, TIP, NIP and SIP. Analysis of the cis-acting elements suggested that ZjAQPs may be responsive to stresses. The subcellular localisation of ZjAQPs in tobacco revealed that they functioned predominantly in the membrane system. Transcript expression revealed that ZjAQPs were specifically expressed in various tissues and presented complex responses to environmental variables. Furthermore, transgenic Overexpression in yeast and Arabidopsis revealed that ZjNIP2-1, ZjSIP2-3, ZjPIP1-3, and ZjTIP1-3 play pivotal roles in adaptation to drought and salinity stress. Unlike the AQP subfamily of other higher plants, NIPs and SIPs may play important roles in Z. japonica. The information provided here will help to understand the precise role of AQP in Z. japonica adaptation to intertidal environments.