Ma Qing, Tang Ren-Jie, Zheng Xiao-Jiang, Wang Suo-Min, Luan Sheng
State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730020, PR China; Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA, 73072, USA.
Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA, 73072, USA.
Biochem Biophys Res Commun. 2015;468(1-2):59-65. doi: 10.1016/j.bbrc.2015.10.164. Epub 2015 Nov 6.
Calcium (Ca(2+)) serves as a critical messenger in a number of adaptation and developmental processes. In plants, CBL family represents a unique group of calcium sensors that decodes calcium signals. Several CBL members have been functionally characterized in the model plant Arabidopsis thaliana, but the role of CBL7 remains unknown. Here, we report that CBL7 is involved in the regulation of low-nitrate response in Arabidopsis. Expression of CBL7 was predominant in the root of young seedlings and substantially induced by nitrate starvation. Cbl7 mutant was more inhibited in root growth upon nitrate starvation compared to the wild-type. Interestingly, the growth arrest of cbl7 under low-nitrate conditions relied on acidic pH. Further analyses revealed that expression of two high-affinity nitrate transporter genes, NRT2.4 and NRT2.5, was down-regulated in cbl7 under nitrogen-starvation condition. Accordingly, the cbl7 mutant plants retained lower nitrate content than wild-type plants under low-nitrate condition. Taken together, our results uncover a novel role of CBL7 in the response to nitrate deficiency in Arabidopsis.
钙（Ca(2+)）在许多适应和发育过程中充当关键信使。在植物中，CBL家族代表了一组独特的钙传感器，可解码钙信号。几个CBL成员已在模式植物拟南芥中得到功能表征，但CBL7的作用仍不清楚。在此，我们报道CBL7参与拟南芥低硝酸盐响应的调控。CBL7在幼苗根部表达占主导，且在硝酸盐饥饿时显著诱导表达。与野生型相比，Cbl7突变体在硝酸盐饥饿时根生长受到更大抑制。有趣的是，cbl7在低硝酸盐条件下的生长停滞依赖于酸性pH。进一步分析表明，在氮饥饿条件下，两个高亲和力硝酸盐转运蛋白基因NRT2.4和NRT2.5在cbl7中的表达下调。因此，在低硝酸盐条件下，cbl7突变体植株的硝酸盐含量低于野生型植株。综上所述，我们的结果揭示了CBL7在拟南芥对硝酸盐缺乏响应中的新作用。
