Journal Article

Overexpression of a Wheat Aquaporin Gene, <i>TaAQP8</i>, Enhances Salt Stress Tolerance in Transgenic Tobacco

Wei Hu, Qianqian Yuan, Yan Wang, Rui Cai, Xiaomin Deng, Jie Wang, Shiyi Zhou, Mingjie Chen, Lihong Chen, Chao Huang, Zhanbing Ma, Guangxiao Yang and Guangyuan He

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 53, issue 12, pages 2127-2141
Published in print December 2012 | ISSN: 0032-0781
Published online November 2012 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcs154
Overexpression of a Wheat Aquaporin Gene, TaAQP8, Enhances Salt Stress Tolerance in Transgenic Tobacco

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  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

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Aquaporin (AQP) proteins have been shown to transport water and other small molecules through biological membranes, which is crucial for plants to combat salt stress. However, the precise role of AQP genes in salt stress response is not completely understood in plants. In this study, a PIP1 subgroup AQP gene, designated TaAQP8, was cloned and characterized from wheat. Transient expression of TaAQP8–green fluorescent protein (GFP) fusion protein revealed its localization in the plasma membrane. TaAQP8 exhibited water channel activity in Xenopus laevis oocytes. TaAQP8 transcript was induced by NaCl, ethylene and H2O2. Further investigation showed that up-regulation of TaAQP8 under salt stress involves ethylene and H2O2 signaling, with ethylene causing a positive effect and H2O2 acting as a negative factor. Overexpression of TaAQP8 in tobacco increased root elongation compared with controls under salt stress. The roots of transgenic plants also retained a high K+/Na+ ratio and Ca2+ content, but reduced H2O2 accumulation by an enhancement of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities under salt stress. Further investigation showed that whole seedlings from transgenic lines displayed higher SOD, CAT and POD activities, increased NtSOD and NtCAT transcript levels, and decreased H2O2 accumulation and membrane injury under salt stress. Taken together, our results demonstrate that TaAQP8 confers salt stress tolerance not only by retaining high a K+/Na+ ratio and Ca2+ content, but also by reducing H2O2 accumulation and membrane damage by enhancing the antioxidant system.

Keywords: Antioxidant enzyme; Aquaporin; Reactive oxygen species; Salt stress tolerance; Wheat

Journal Article.  8823 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

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