Two Aquaporin Genes, and , Positively Regulate the Tolerance of Upland Cotton to Salt and Osmotic Stresses.

Aquaporins (AQPs) facilitate the transport of water and small molecules across intrinsic membranes and play a critical role in abiotic stresses. In this study, 111, 54, and 56 candidate genes were identified in (AD), (A), and (D), respectively, and were further classified into five subfamilies, namely, plasma intrinsic protein (PIP), tonoplast intrinsic protein (TIP), nodulin 26-like intrinsic protein (NIP), small basic intrinsic protein (SIP), and uncategorized X intrinsic protein (XIP). Transcriptome analysis and quantitative real-time PCR (qRT-PCR) revealed some high-expression and (PIP and TIP genes in , respectively) in drought and salt stresses. -silenced plants decreased in the chlorophyll content, superoxide dismutase (SOD) activity, and peroxidase (POD) activity comparing the mock control (empty-vector) under 400 mM NaCl treatment, which indicated a positive regulatory role of in salt tolerance of cotton. The -silenced cotton plants were more sensitive to osmotic stress. -overexpressed plants exhibited less accumulation of HO and malondialdehyde but higher proline content under osmotic stress. In summary, our study elucidates the positive regulatory roles of two ( and ) in salt and osmotic stress responses, respectively, and provides a new gene resource for future research.