AUTHOR=Guo Anhui , Hao Jianfeng , Su Ying , Li Bin , Zhao Nan , Zhu Meng , Huang Yi , Tian Baoming , Shi Gongyao , Hua Jinping 

TITLE=Two Aquaporin Genes, GhPIP2;7 and GhTIP2;1, Positively Regulate the Tolerance of Upland Cotton to Salt and Osmotic Stresses

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.780486

DOI=10.3389/fpls.2021.780486

ISSN=1664-462X

ABSTRACT=<p>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 <italic>AQP</italic> genes were identified in <italic>Gossypium hirsutum</italic> (AD<sub>1</sub>), <italic>Gossypium arboreum</italic> (A<sub>2</sub>), and <italic>Gossypium raimondii</italic> (D<sub>5</sub>), 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 <italic>GhPIPs</italic> and <italic>GhTIPs</italic> (PIP and TIP genes in <italic>G. hirsutum</italic>, respectively) in drought and salt stresses. <italic>GhPIP2;7</italic>-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 <italic>GhPIP2;7</italic> in salt tolerance of cotton. The <italic>GhTIP2;1</italic>-silenced cotton plants were more sensitive to osmotic stress. <italic>GhTIP2;1</italic>-overexpressed plants exhibited less accumulation of H<sub>2</sub>O<sub>2</sub> and malondialdehyde but higher proline content under osmotic stress. In summary, our study elucidates the positive regulatory roles of two <italic>GhAQPs</italic> (<italic>GhPIP2;7</italic> and <italic>GhTIP2;1</italic>) in salt and osmotic stress responses, respectively, and provides a new gene resource for future research.</p>