Nitrogen deficiency-induced membrane lipid remodeling in plants: Physiological significance and membrane biophysical implications

This is the authors' abstract. We don't add key points for this paper.

Nitrogen (N) deficiency strongly affects plant growth by reducing chlorophyll formation, photosynthetic protein levels, carbon assimilation, and biomass production. Recent lipidomic studies show that N deficiency also changes membrane lipid balance across plastidic and extraplastidial compartments. These changes include chloroplast galactolipid remodeling, shifts in phospholipid balance, altered fatty-acid unsaturation, neutral lipid accumulation. However, these responses have mostly been studied separately in different species, organs, genotypes, and experimental conditions, which makes their physiological meaning difficult to compare. This review summarizes current evidence on N-deficiency-induced membrane lipid remodeling and places these findings into a cellular and membrane-level context. We discuss how N deficiency affects plastid membranes, especially chloroplast and thylakoid membranes, as well as non-plastid membranes. The review focuses on alterations in the monogalactosyldiacylglycerol to digalactosyldiacylglycerol (MGDG/DGDG) ratio, phosphatidylcholine to phosphatidylethanolamine (PC/PE) balance, linolenic acid content, double bond index (DBI), triacylglycerol (TAG) accumulation, and plastoglobule-associated lipid deposition. We also separate experimentally observed lipid changes from proposed membrane biophysical effects. Changes in membrane packing, fluidity, curvature, permeability, capacitance, and dielectric properties are discussed as possible effects of lipid remodeling. Overall, lipid remodeling may help membrane adjustment under mild or short-term N limitation. In contrast, strong galactolipid loss, reduced DBI, neutral lipid accumulation, and chloroplast damage may indicate progressive membrane turnover under prolonged or severe N deprivation. By connecting lipidomic evidence with membrane biophysics, this review can help future studies test how lipid remodeling is related to membrane stability, dielectric properties, and cellular damage under N deficiency.