Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Science and Oceanography, Shenzhen University, Shenzhen, China.
College of Life Science, University of the Chinese Academy of Sciences, Beijing, China.
Plant Cell Rep. 2019 May;38(5):597-607. doi: 10.1007/s00299-019-02390-5. Epub 2019 Feb 6.
TuCAX1a and TuCAX1b improved Ca and Zn translocation and TuCAX1b enhanced Ca, Zn, Mn and Fe content when exposed to Cd; Cd translocation was inhibited under Ca and Zn. Cation/H antiporters (CAXs) are involved in the translocation of Ca and various metal ions in higher plants. In the present study, TuCAX1a and TuCAX1b, two cation/H antiporters, were isolated from the diploid wheat Triticum urartu, and their metal cation translocation functions investigated. TuCAX1a and TuCAX1b showed abundant tissue-specific expression in the internode and beard, respectively, and their expression levels were increased in shoots exposed to Cd, Zn and Ca. Plant phenotype analysis showed that overexpression of TuCAX1a and TuCAX1b could improve the tolerance of Arabidopsis to exogenous Ca and Zn. In the plant shoots and roots, the contents of Ca and Zn were higher than wild-type plants under Ca and Zn treatments, indicating that TuCAX1a and TuCAX1b can enhance Ca and Zn translocation. Ca, Zn, Mn and Fe contents showed higher accumulation in TuCAX1b-transgenic Arabidopsis shoots than in wild-type plants exposed to Cd, and the translocation of Cd was inhibited under Ca and Zn. Overall, the present study provides a novel genetic resource for improving the uptake of microelements and reducing accumulation of toxic heavy metals in wheat.
TuCAX1a 和 TuCAX1b 增强了 Cd 暴露下 Ca 和 Zn 的转运，TuCAX1b 增强了 Ca、Zn、Mn 和 Fe 的含量；Ca 和 Zn 抑制了 Cd 的转运。阳离子/H+反向转运蛋白（CAXs）参与高等植物中 Ca 和各种金属离子的转运。本研究从二倍体小麦普通小麦中分离出两个阳离子/H+反向转运蛋白 TuCAX1a 和 TuCAX1b，并研究了它们的金属阳离子转运功能。TuCAX1a 和 TuCAX1b 在节间和须根中分别表现出丰富的组织特异性表达，其表达水平在 Cd、Zn 和 Ca 处理的枝条中增加。植株表型分析表明，过表达 TuCAX1a 和 TuCAX1b 可以提高拟南芥对外源 Ca 和 Zn 的耐受性。在植物地上部和根部，Ca 和 Zn 处理下 Ca 和 Zn 的含量高于野生型植物，表明 TuCAX1a 和 TuCAX1b 可以增强 Ca 和 Zn 的转运。在 Cd 暴露下，TuCAX1b 转基因拟南芥地上部的 Ca、Zn、Mn 和 Fe 含量高于野生型植物，Ca 和 Zn 抑制了 Cd 的转运。总之，本研究为提高小麦对微量元素的吸收和减少有毒重金属积累提供了一种新的遗传资源。
