Ectopic Expression of <i>CrPIP2;3</i>, a Plasma Membrane Intrinsic Protein Gene from the Halophyte <i>Canavalia rosea</i>, Enhances Drought and Salt-Alkali Stress Tolerance in Arabidopsis

• Main Authors: Jiexuan Zheng, Ruoyi Lin, Lin Pu, Zhengfeng Wang, Qiming Mei, Mei Zhang, Shuguang Jian
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: International Journal of Molecular Sciences
• Subjects: plasma membrane intrinsic proteins; salt-alkali; drought; <i>Canavalia rosea</i>
• Online Access: https://www.mdpi.com/1422-0067/22/2/565
• ISSN: 1661-6596; 1422-0067

Aquaporins are channel proteins that facilitate the transmembrane transport of water and other small neutral molecules, thereby playing vital roles in maintaining water and nutrition homeostasis in the life activities of all organisms. <i>Canavalia rosea</i>, a seashore and mangrove-accompanied halophyte with strong adaptability to adversity in tropical and subtropical regions, is a good model for studying the molecular mechanisms underlying extreme saline-alkaline and drought stress tolerance in leguminous plants. In this study, a PIP2 gene (<i>CrPIP2;3</i>) was cloned from <i>C. rosea</i>, and its expression patterns and physiological roles in yeast and <i>Arabidopsis thaliana</i> heterologous expression systems under high salt-alkali and high osmotic stress conditions were examined. The expression of <i>CrPIP2;3</i> at the transcriptional level in <i>C. rosea</i> was affected by high salinity and alkali, high osmotic stress, and abscisic acid treatment. In yeast, the expression of <i>CrPIP2;3</i> enhanced salt/osmotic and oxidative sensitivity under high salt/osmotic and H₂O₂ stress. The overexpression of <i>CrPIP2;3</i> in <i>A. thaliana</i> could enhance the survival and recovery of transgenic plants under drought stress, and the seed germination and seedling growth of the <i>CrPIP2;3 OX</i> (over-expression) lines showed slightly stronger tolerance to high salt/alkali than the wild-type. The transgenic plants also showed a higher response level to high-salinity and dehydration than the wild-type, mostly based on the up-regulated expression of salt/dehydration marker genes in <i>A. thaliana</i> plants. The reactive oxygen species (ROS) staining results indicated that the transgenic lines did not possess stronger ROS scavenging ability and stress tolerance than the wild-type under multiple stresses. The results confirmed that <i>CrPIP2;3</i> is involved in the response of <i>C. rosea</i> to salt and drought, and primarily acts by mediating water homeostasis rather than by acting as an ROS transporter, thereby influencing physiological processes under various abiotic stresses in plants.