Phospholipase Dα1 Acts as a Negative Regulator of High Mg2+-Induced Leaf Senescence in Arabidopsis

Abstract

Magnesium (Mg2+) is a macronutrient involved in essential cellular processes. Its deficiency or excess is a stress factor for plants, seriously affecting their growth and development and therefore, its accurate regulation is essential. Recently, we discovered that phospholipase Dα1 (PLDα1) activity is vital in the stress response to high-magnesium conditions in Arabidopsis roots. This study shows that PLDα1 acts as a negative regulator of high-Mg2+-induced leaf senescence in Arabidopsis. The level of phosphatidic acid produced by PLDα1 and the amount of PLDα1 in the leaves increase in plants treated with high Mg2+. A knockout mutant of PLDα1 (pldα1-1), exhibits premature leaf senescence under high-Mg2+ conditions. In pldα1-1 plants, higher accumulation of abscisic and jasmonic acid (JA) and impaired magnesium, potassium and phosphate homeostasis were observed under high-Mg2+ conditions. High Mg2+ also led to an increase of starch and proline content in Arabidopsis plants. While the starch content was higher in pldα1-1 plants, proline content was significantly lower in pldα1-1 compared with wild type plants. Our results show that PLDα1 is essential for Arabidopsis plants to cope with the pleiotropic effects of high-Mg2+ stress and delay the leaf senescence.

Silencing a dehydration‐responsive element‐binding gene enhances the resistance of plants to a phloem‐feeding herbivore

“…AtWRKY33 in Arabidopsis , the homolog of OsWRKY33, negatively and positively, respectively, regulates the biosynthesis of ABA and ethylene (Li et al, 2012; Liu et al, 2015). AtPLDα1 , the homolog of OsPLDα1 whose expression can be directly activated by OsDREB1A (Huo et al, 2016), acts as a negative regulator of JA and ABA accumulation in Arabidopsis (Kocourková et al, 2021). In addition, the overexpression of AtDREB1A , the ortholog of OsDREB1A , suppressed the expression of genes related to JA biosynthesis in Arabidopsis but enhanced the transcription of those related to ethylene biosynthesis (Li et al, 2017).…”

Identification of phospholipase Ds and phospholipid species involved in circadian clock alterations using CRISPR/Cas9-based multiplex editing of Arabidopsis

“…They can be activated differently in response to diverse stimuli, and these differences account for the highly dynamic nature of PA contents and compositions depending on environmental conditions (Hong et al, 2016;Ali et al, 2022;Deepika and Singh, 2022;Kolesnikov et al, 2022). This is evidenced by, in addition to early studies, recent reports showing a rapid accumulation of PA by PLDα1 in response to magnesium stress and rhizobium infection, β2 during hypoxia, δ under heat and osmotic stress, and ε and ζ2 in nitrogen and phosphate deficit, respectively, with a few specific PA molecular species contributing to the accumulation of total PA in some cases (Su et al, 2018;Premkumar et al, 2019;Song et al, 2020;Kocourková et al, 2021;Liu et al, 2021;Zhang et al, 2021;Kim et al, 2022;Yao et al, 2022 a and b). Not only for plants to cope with unfavorable conditions, PLDs are also required for normal physiological processes mediated by their direct interaction with effector proteins, regulation of cytoskeletal dynamics and vesicle trafficking, and membrane remodeling and degradation (Hong et al, 2016;Deepika and Singh, 2022).…”

Phosphatidic Acid in Plant Hormonal Signaling: From Target Proteins to Membrane Conformations

“…These changes are made possible by various phospholipases, lipid kinases and phosphatases. The generation of signaling PA occurs via the activation of phospholipase D (PLD), which cleaves structural membrane lipids (e.g., phosphatidylcholine) to generate PA and free headgroups (e.g., choline) [ 10 , 11 , 12 , 13 ] ( Figure 1 ). Signaling PA can also be produced by the phosphorylation of diacylglycerol (DAG, Figure 1 ) in a reaction catalyzed by diacylglycerol kinase (DGK) [ 14 , 15 , 16 ].…”