PfPAH1-1 gene enhances plant tolerance to low phosphate stress by modulating cell membrane lipid remodeling

Phosphate (Pi) is an essential macroelement for plant survival, and Pi deficiency triggers membrane lipid remodeling that promotes the conversion of phospholipids to galactolipids. Perilla frutescens is a traditional food and medicinal plant, widely used in food, pharmaceutical, and industrial sectors. Importantly, Perilla seed oil is rich in polyunsaturated fatty acids (PUFAs) and are considered an ideal source of healthy vegetables oils for humans. However, Perilla is highly vulnerable to low Pi stress, which affects product quality. Phosphatidic acid phosphohydrolase (PAH) mediated membrane lipid remodeling is an essential adaptation mechanism to low Pi stress in plants. In this study, we developed PfPAH1-1 overexpression lines of the model plant tobacco (Nicotiana tobaccum) and low plant algal (Chlamydomonas reinhardtii) to analyze the expression profile and lipid accumulation dynamics of the PfPAH1-1 gene under low Pi stress. It was found that the transgenic plants showed reduced amounts of malondialdehyde (MDA) content compared to the nontransgenic plants, indicating a reduced lipid peroxidation required to maintain membrane stability. Protein metabolism of PfPAH1-1-overexpressing plants was less affected, while the degree of starch degradation was greatly, the soluble sugar content increased, and more carbon flux was modulated into lipid. Furthermore, PfPAH1-1 had improved the pathway of phospholipid hydrolysis and glycolipid biosynthesis, and the membrane lipid remodeling process was positively regulated. Collectively, these findings offer a foundation for exploring the molecular regulatory mechanism of the PfPAH1-1 gene in lipid synthesis under Pi stress, demonstrating that its key function in membrane lipid remodeling significantly improve the resistance ability of Perilla to the stress of adversity.