Abstract：Aquaporins(AQPs) are ancient channel proteins localized in biological membranes and facilitating water transport through cell membranes rapidly. Aquaporins play an important role in plant development. A gene encoded aquaporin was isolated from cotton (Gossypium hirsutum) fiber and named GhAQP2 (GenBank accession No.: KJ920936). The full length of GhAQP2 composed three introns and four exons, and contained a open reading frame of 837 bp encoding 279 amino acids. Analysis of multiple alignment and phylogenetic tree showed that GhAQP2 shared the highest identity with NtPIP2; 1(86%) and belonged to PIP2 protein family. Semi-quantitative RT-PCR was used to investigate the expression profile of GhAQP2 in different tissues and fibers from different days post-anthesis. The results showed that GhAQP2 was preferentially expressed in cotton fiber, and the transcript level increased along with fiber development and maintained at high abundance in fiber cells at 6 to 18 days post anthesis, after which time it gradually decreased. The GhAQP2 was transformed into tobacco (Nicotiana tobacum) suspension BY-2 cells to preliminary analyze the gene function. Overexpression of GhAQP2 in BY-2 cells led to cell shape significantly changed from round to long strip, and the cell state changed from aggregating to loose. All our results manifested that GhAQP2 may have important effect on the elongation of cotton fiber cell.
