Anion channel SLAH3 functions in nitrate‐dependent alleviation of ammonium toxicity in Arabidopsis |
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| Authors: | XIAOJIANG ZHENG KAI HE THOMAS KLEIST FANG CHEN SHENG LUAN |
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| Affiliation: | 1. College of Life Sciences, Sichuan University, Chengdu, China;2. Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA, USA;3. NJU‐NJFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China;4. Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China |
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| Abstract: | Slow anion channels (SLAC/SLAH) are efflux channels previously shown to be critical for stomatal regulation. However, detailed analysis using the β‐glucuronidase reporter gene showed that members of the SLAC/SLAH gene family are predominantly expressed in roots, in addition to stomatal guard cells, implicating distinct function(s) of SLAC/SLAH in the roots. Comprehensive mutant analyses of all slac/slah mutants indicated that slah3 plants showed a greater growth defect than wild‐type plants when ammonium was supplied as the sole nitrogen source. Ammonium toxicity was mimicked by acidic pH in nitrogen‐free external medium, suggesting that medium acidification by ammonium‐fed plants may underlie ammonium toxicity. Interestingly, such toxicity was more severe in slah3 mutants and, particularly in wild‐type plants, was alleviated by supplementing the media with micromolar levels of nitrate. These data thus provide evidence that SLAH3, a nitrate efflux channel, plays a role in nitrate‐dependent alleviation of ammonium toxicity in plants. |
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| Keywords: | growth nitrogen nutrients |
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