论文题目：ABA-activated low-nanomolar Ca2+–CPK signalling controls root cap cycle plasticity and stress adaptation
论文作者：Ziwei Lin, Ying Guo, Ruiyuan Zhang, Yiming Li, Yue Wu, Jen Sheen & Kun-hsiang Liu
论文摘要：Abscisic acid (ABA) regulates plant stress adaptation, growth and reproduction. Despite extensive ABA–Ca2+ signalling links, imaging ABA-induced increases in Ca2+ concentration has been challenging, except in guard cells. Here we visualize ABA-triggered [Ca2+] dynamics in diverse organs and cell types of Arabidopsis thaliana using a genetically encoded Ca2+ ratiometric sensor with a low-nanomolar Ca2+-binding affinity and a large dynamic range. The subcellular-targeted Ca2+ ratiometric sensor reveals time-resolved and unique spatiotemporal Ca2+ signatures from the initial plasma-membrane nanodomain, to cytosol, to nuclear oscillation. Via receptors and sucrose-non-fermenting1-related protein kinases (SnRK2.2/2.3/2.6), ABA activates low-nanomolar Ca2+ transient and Ca2+-sensor protein kinase (CPK10/30/32) signalling in the root cap cycle from stem cells to cell detachment. Surprisingly, unlike the prevailing NaCl-stimulated micromolar Ca2+ spike, salt stress induces a low-nanomolar Ca2+ transient through ABA signalling, repressing key transcription factors that dictate cell fate and enzymes that are crucial to root cap maturation and slough. Our findings uncover ABA–Ca2+–CPK signalling that modulates root cap cycle plasticity in adaptation to adverse environments.
众所周知，植物激素脱落酸（ABA）能够调节植物的生长、繁殖及逆境适应性。虽然ABA-Ca2+信号通路广泛存在，但是除了在保卫细胞中，可视化ABA诱导的Ca2+信号仍然具有挑战性。在本研究中，作者使用具有纳摩尔级别和大动态范围的遗传编码比率型Ca2+指示剂（CRS）可视化了ABA在不同器官和细胞类型中触发的Ca2+变化。具亚细胞器定位的CRS揭示了始于细胞质膜、到细胞质再到细胞核振荡的具时空分辨率的特异性Ca2+信号。ABA通过受体PYR/PYLs和SNRK2.2,2.3,2.6激活了纳摩尔级的Ca2+信号转导和CPK10,30,32蛋白激酶，从而调控根冠生长脱落周期。令人惊讶的是，与已知的盐胁迫诱导微摩尔级别Ca2+变化不同的是，盐刺激产生的ABA信号诱导了纳摩尔级Ca2+信号，并抑制决定细胞命运的关键转录因子以及对根冠成熟和脱落至关重要的酶。作者的研究揭示了ABA-Ca2+-CPK信号途径能够调节根冠周期的可塑性，以适应不利环境。
论文链接：https://www.nature.com/articles/s41477-024-01865-y