A hickory lysophosphatidic acid acyltransferase confers tolerance to multiple abiotic stresses via membrane lipid modulation

Abstract

With the continuous deterioration of the global environment, plants are facing various abiotic stresses that adversely affect plant growth and crop yield. In this study, we identified a lysophosphatidic acid acyltransferase gene CcLPAT2 from hickory that can increase plant oil content, and also found that its transcription is strongly induced by multiple abiotic stressors. However, the molecular mechanisms underlying the plant responses to multiple abiotic stressors are poorly understood. We demonstrated that CcLPAT2 localizes to the endoplasmic reticulum (ER) and contributes to the regulation of fatty acid metabolism, including changes in C18:1 and C18:2 levels, and membrane lipid composition, thereby promoting membrane integrity and stabilizing reactive oxygen species (ROS) homeostasis under stress conditions. Moreover, we found that the transcription factor CcMYB5 directly binds to the promoter of CcLPAT2 and promotes its expression under multiple abiotic stress conditions; interestingly, the expression of CcMYB5 is also induced by multiple abiotic stressors. Together, our genetic and biochemical analyses reveal a novel regulatory mechanism in which CcLPAT2-mediated changes in fatty acids and membrane lipids protect plant cells from abiotic stresses by reducing ROS accumulation and enhancing membrane stability.