Can digalactosyldiacylglycerol substitute for phosphatidylcholine upon phosphate deprivation in leaves and roots of Arabidopsis?

To explore the role of digalactosyldiacylglycerol (DGDG) in plants the dgd1 mutant of Arabidopsis thaliana was grown in the presence and absence of inorganic phosphate. Phosphate deficiency in the dgd1 mutant causes a strong decrease in all phospholipids accompanied by an increase in DGDG and sulpholipid. Moreover, a significant DGDG accumulation was found in roots upon phosphate deprivation as well. Our data indicate that DGDG accumulation upon phosphate deprivation is due to the activation of a specific eukaryotic dgd1-independent biosynthetic pathway. We propose that DGDG may substitute for phosphatidylcholine upon phosphate deprivation.