Abstract
Zostera marina is a kind of marine angiosperms (seagrasses), and lives under the sea throughout the life cycle stages. Here, we study plasma membrane aquaporins (PIPs) of Z. marina to reveal the water control mechanism of seagrass cells in seawater. Generally, aquaporins facilitate water flux across biomembranes as water channels, and more than 30 kinds of aquaporins exist in the plant genome. We successfully isolated two genes for PIPs (ZoPIP1 and ZoPIP2) from leaves of Z. marina. They may function as water channels because the functional domains (NPA motifs and transmembrane domains) were conserved in their predicted amino acid sequences. The expression of ZoPIPs was detected in leaves, inflorescence axes, roots, rhizomes, female flowers, male flowers, seeds and fruits, and seedlings. In leaves, the expression of ZoPIPs was increased during desiccation. The higher expression of ZoPIPs was also detected during seed germination than seed maturation. These suggest that ZoPIPs may be involved in unique physiological features of Z. marina to adapt to the marine environment.
