Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
School of Science, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia.
Plant Physiol. 2020 Aug;183(4):1650-1662. doi: 10.1104/pp.20.00196. Epub 2020 Jun 18.
Calcium (Ca) signaling modulates sodium (Na) transport in plants; however, the role of the Ca sensor calmodulin (CaM) in salt tolerance is elusive. We previously identified a salt-responsive calmodulin (HvCaM1) in a proteome study of barley () roots. Here, we employed bioinformatic, physiological, molecular, and biochemical approaches to determine the role of HvCaM1 in barley salt tolerance. CaM1s are highly conserved in green plants and probably originated from ancestors of green algae of the Chlamydomonadales order. was mainly expressed in roots and was significantly up-regulated in response to long-term salt stress. Localization analyses revealed that HvCaM1 is an intracellular signaling protein that localizes to the root stele and vascular systems of barley. After treatment with 200 mm NaCl for 4 weeks, knockdown (RNA interference) lines showed significantly larger biomass but lower Na concentration, xylem Na loading, and Na transportation rates in shoots compared with overexpression lines and wild-type plants. Thus, we propose that is involved in regulating Na transport, probably via certain class I high-affinity potassium transporter (HvHKT1;5 and HvHKT1;1)-mediated Na translocation in roots. Moreover, we demonstrated that HvCaM1 interacted with a CaM-binding transcription activator (HvCAMTA4), which may be a critical factor in the regulation of in barley. We conclude that HvCaM1 negatively regulates salt tolerance, probably via interaction with HvCAMTA4 to modulate the down-regulation of and/or the up-regulation of to reduce shoot Na accumulation under salt stress in barley.
钙（Ca）信号调节植物中的钠（Na）转运；然而，钙传感器钙调蛋白（CaM）在耐盐性中的作用尚不清楚。我们之前在大麦（）根的蛋白质组研究中鉴定了一种对盐响应的钙调蛋白（HvCaM1）。在这里，我们采用生物信息学、生理学、分子和生化方法来确定 HvCaM1 在大麦耐盐性中的作用。钙调蛋白在绿色植物中高度保守，可能起源于绿藻门衣藻目的祖先。在根中主要表达，对长期盐胁迫有明显的上调。定位分析表明，HvCaM1 是一种细胞内信号蛋白，定位于大麦根中柱和维管束系统。在 200 mM NaCl 处理 4 周后，与过表达系和野生型植物相比，HvCaM1 敲低（RNA 干扰）系的生物量明显增大，但 shoot 中的 Na 浓度、木质部 Na 装载量和 Na 运输率较低。因此，我们提出 参与调节 Na 转运，可能通过根中某些 I 类高亲和力钾转运体（HvHKT1;5 和 HvHKT1;1）介导的 Na 转运。此外，我们证明 HvCaM1 与钙调蛋白结合转录激活因子（HvCAMTA4）相互作用，这可能是调节大麦中 的关键因素。我们得出结论，HvCaM1 负调节耐盐性，可能通过与 HvCAMTA4 相互作用来调节 的下调和/或 的上调，以减少大麦在盐胁迫下 shoot Na 的积累。
