Identification, phylogeny, and transcript profiling of aquaporin genes in response to abiotic stress in Tamarix hispida

Aquaporins belong to the highly conserved major intrinsic protein family and are involved in the transcellular membrane transport of water and other small solutes. However, there has been little work on cloning aquaporin (AQP) family genes and characterizing their functions in plants under various environmental stimuli. In this study, a total of 18 full-length AQP genes were identified in Tamarix hispida, a woody halophyte. Sequence analysis showed that most of these AQP proteins have six transmembrane domains connected by five loops. Phylogenetic analysis revealed that the members of the AQP family can be divided into four groups based on their structural characteristics, including plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), NOD26-like intrinsic proteins (NIPs), and small basic intrinsic proteins (SIPs). Furthermore, the expression profiles of AQP genes were analyzed in the roots, stems, and leaves under salinity, drought, heavy metal, and abscisic acid (ABA) treatments using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. The results demonstrated that the AQP were involved in abiotic stress responses, indicating that they play important roles in response to abiotic stress and are involved in ABA-dependent stress-signaling pathways. These data will be useful to elucidate the complexity of the AQP gene family and the molecular mechanisms of abiotic stress tolerance.