Exogenous phosphatidylcholine treatment alleviates drought stress and maintains the integrity of root cell membranes in peach.

• Confirmed the alleviation of exogenous phosphatidylcholine on peach tree under drought stress. • Prove that exogenous phosphatidylcholine reduces root cell damage under drought stress. • Prove the positive effect of phosphatidylcholine on signal transduction under abiotic stress. • The first one used exogenous phosphatidylcholine to study on deciduous fruit trees. Phosphatidylcholine is a primary class of membrane lipids in most eukaryotes. In plants, the primary phosphatidylcholine biosynthetic pathway and its role in plant growth and development remain elusive due to lack of a mutant model with substantially decreased phosphatidylcholine content. In this study, we investigated whether the exogenous application of phosphatidylcholine can improve drought tolerance and reduce drought-induced damage to one-year-old peach (Prunus persica (L.) Batsch.). In this experiment, phosphatidylcholine was applied directly to the soil at concentrations of 200 mg/L, 500 mg/L, and 1000 mg/L to drought-stressed peach trees and at a concentration of 500 mg/L to control trees not subjected to drought stress. After these treatments, we assessed the net photosynthetic rate and chlorophyll content (i.e. SPAD values) of drought-stressed and unstressed trees. We found that trees sprayed with phosphatidylcholine resembled well-watered trees, but drought-stressed trees not supplemented with phosphatidylcholine showed a lower photosynthetic rate. In trees given sufficient water, the length and width of leaf stomata did not significantly differ regardless of whether plants were treated with phosphatidylcholine or not. However, untreated drought-stressed trees showed incompletely filled guard cells and low stomatal density relative to control trees. In addition, we also found that in drought-stressed trees exogenous phosphatidylcholine treatment resulted in significant increases in proline content as well as decreases in electrolyte leakage and the degree of damage to the cell membrane. Moreover, transmission electron microscopic observation of root cells of treated and untreated peach seedlings showed that phosphatidylcholine treatment protected the integrity of root cells in response to drought stress. Taken together, our results suggest that phosphatidylcholine treatment can improve the drought tolerance of young peach trees and can reduce the damage to cell membranes caused by drought stress. [ABSTRACT FROM AUTHOR]