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

Kristýna Kroumanová,Daniela Kocourková,Tereza Podmanická,Jan Martinec,Michal Daněk

doi:10.3389/fpls.2021.770794

Kristýna Kroumanová, Daniela Kocourková + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2021.770794

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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.

Highlights

Magnesium (Mg2+) is a macronutrient involved in essential cellular processes such as photosynthesis, nucleic acid and protein synthesis, energy metabolism, etc. (Guo et al, 2016)
Shoot expression of β-amylases BAM1 and BAM2 was impaired in pldα1-1 compared with WT under high Mg2+ treatment (Figures 4J,K). These results demonstrate that Mg2+, K+, and P homeostasis, starch metabolism and proline accumulation are altered in pldα1-1 shoots of Arabidopsis seedlings grown under high-Mg2+ conditions
In our previous work (Kocourková et al, 2020) we found that pldα1 plants have shorter roots under high Mg2+ conditions compared to WT

Summary

Introduction

Magnesium (Mg2+) is a macronutrient involved in essential cellular processes such as photosynthesis, nucleic acid and protein synthesis, energy metabolism, etc. (Guo et al, 2016). Magnesium (Mg2+) is a macronutrient involved in essential cellular processes such as photosynthesis, nucleic acid and protein synthesis, energy metabolism, etc. (Guo et al, 2016). On the contrary, its excess is a stress factor for plants, seriously affecting plant growth and development. Accurate regulation of intracellular magnesium level is essential. The knowledge of the mechanisms activated in Mg2+ deficiency is relatively good. The mechanisms associated with the regulation of cellular Mg2+ under high-Mg2+ conditions are less known. High concentrations of Mg2+ together with low concentrations of Ca2+ occur, for example, in serpentine soils. High-magnesium water and soils have been considered as an emerging environmental and food security issues (Qadir et al, 2018). For non-adapted plants, high-Mg2+ conditions are strongly inhibitory to growth

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