Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic.
Plant Cell Environ. 2020 Oct;43(10):2460-2475. doi: 10.1111/pce.13831. Epub 2020 Aug 9.
Intracellular levels of Mg are tightly regulated, as Mg deficiency or excess affects normal plant growth and development. In Arabidopsis, we determined that phospholipase Dα1 (PLDα1) is involved in the stress response to high-magnesium conditions. The T-DNA insertion mutant pldα1 is hypersensitive to increased concentrations of magnesium, exhibiting reduced primary root length and fresh weight. PLDα1 activity increases rapidly after high-Mg treatment, and this increase was found to be dose dependent. Two lines harbouring mutations in the HKD motif, which is essential for PLDα1 activity, displayed the same high-Mg hypersensitivity of pldα1 plants. Moreover, we show that high concentrations of Mg disrupt K homeostasis, and that transcription of K homeostasis-related genes CIPK9 and HAK5 is impaired in pldα1. Additionally, we found that the akt1, hak5 double mutant is hypersensitive to high-Mg . We conclude that in Arabidopsis, the enzyme activity of PLDα1 is vital in the response to high-Mg conditions, and that PLDα1 mediates this response partially through regulation of K homeostasis.
细胞内镁的水平受到严格调控，因为镁缺乏或过多会影响正常的植物生长和发育。在拟南芥中，我们确定了磷脂酶 Dα1（PLDα1）参与了对高镁条件的应激反应。T-DNA 插入突变体 pldα1对高镁浓度敏感，表现出主根长度和鲜重减少。PLDα1 活性在高镁处理后迅速增加，并且这种增加是剂量依赖性的。两个携带 HKD 基序突变的品系，该基序对于 PLDα1 活性是必需的，表现出与 pldα1 植物相同的高镁敏感性。此外，我们表明高浓度的镁会破坏钾的稳态，并且与钾稳态相关的基因 CIPK9 和 HAK5 的转录在 pldα1 中受到损害。此外，我们发现 akt1、hak5 双突变体对高镁敏感。我们得出的结论是，在拟南芥中，PLDα1 的酶活性对于高镁条件的反应至关重要，并且 PLDα1 通过调节钾稳态部分介导这种反应。
