Figure 1.

Submergence induces PLDα1- and PLDδ-derived PA accumulation, which triggers the nuclear localization of RAP2.12. A, Amounts of membrane lipids (PG, PC, PE, PI, PS, and PA) in the rosettes of 4-week-old WT Col-0 plants under light submergence treatment (Sub) and after recovery (R) for the indicated times. B, Various PA and PE species in the rosettes of 4-week-old WT, pldα1, pldδ, and pldα1 pldδ plants before light submergence treatment (air) and after 2 days of submergence treatment (submergence). C, Exogenous application of PA, but not PC, PE, or PS, induces the translocation of RAP2.12-GFP from the plasma membrane to the nucleus. Detached leaves of 3-week-old RAP2.12-GFP transgenic plants were treated with 50-µM liposomes prepared from PA, PC, PE, or PS (natural lipid mixtures purified from soy, Avanti Polar Lipids) for 3 h. Leaves similarly treated with dilution buffer were set as mock controls (Mock). The GFP fluorescence was detected by confocal microscopy. Red arrows indicate nuclear signal induced by PA application. Bars, 20 μm. All experiments were performed on three biological replicates with similar results. Values represent means ± sd (n = 4) of four independent technical replicates, and each replicate was collected from the rosettes of at least seven plants. Asterisks with “H” or “L” indicate significantly higher or lower levels than in control plants (A) or in WT (B) at each time point (*P < 0.05, **P < 0.01 by Student’s t test).