Long- and short-term phosphate deprivation in bean roots: Plasma membrane lipid alterations and transient stimulation of phospholipases

Implication of phospholipase D in response of Hordeum vulgare root to short-term potassium deprivation

“…PtBut is a relative measure of PLD activity due to the unique ability of this enzyme to transfer its phosphatidyl group to an alcohol forming phosphatidylalcohol (Munnik, 2001;Navari-Izzo et al, 2006). In agreement with Navari-Izzo et al (2006) and Russo et al (2007) on the basis of the concomitant increase in PLD activity and the decrease in some membrane PL and, in particular, in the PC content (Fig. 3), we can hypothesize that PC could have served as substrate for PA formation.…”

“…K + limitation was quickly sensed by the root system since PA accumulation was measured as early as 2 h after the transfer of plants in -K medium. The higher amount of PA in comparison with PtBut (12.4 and 5.9 mol% of the total PL, respectively) could derive, besides via PLD, via the PLC/DAG kinase pathway as suggested by Testerink and Munnik (2005) and Russo et al (2007) or as intermediate in the biosynthesis of GL and PL.…”

“…PA is considered a second messenger in response to multiple environmental stresses, i.e. hyperosmotic stress (Munnik et al, 2000), symbiotic interactions (Den Hartog et al, 2001), copper excess (Navari- Izzo et al, 2006;Sgherri er al., 2007), and phosphate deprivation (Russo et al, 2007). In vivo and in vitro studies in suspension cultured rice cells, Yamaguchi et al (2004) demonstrated that PLD is activated by H 2 O 2 and this activation involves a protein tyrosine kinase.…”

“…Recently, it has been demonstrated that phospholipase D (PLD, EC 3.1.4.4), besides its catabolic function, has critical roles in cell signalling cascades (Meijer and Munnik, 2003;Navari-Izzo et al, 2006;Russo et al, 2007;Sgherri et al, 2007). This enzyme hydrolyzes structural phospholipids at the terminal phosphate diester bond, leading to the formation of phosphatidic acid (PA) and a free head group such as choline, in the case of phosphatidylcholine (PC, Zhang et al, 2003).…”

Pseudomonas syringaeBetT Is a Low-Affinity Choline Transporter That Is Responsible for Superior Osmoprotection by Choline over Glycine Betaine

“…Choline can also be liberated from phosphatidylcholine through the action of phosopholipases such as phospholipase D (1). Members of the large and diverse phospholipase D family are widely distributed across plant species (reviewed in reference 4), with distinct members activated during growth (1) or in response to environmental stresses, such as nutrient deprivation (52), wounding (53), and infection by microorganisms (14,46). The biosynthesis and degradation processes that yield choline contribute to the ubiquity and relative abundance of choline within plants (67).…”