Abstract
Phosphorus is one of the most important nutrients and its deficiency induces several responses in plants. As one of the responses, glycolipid biosyntheses are activated during phosphate deprivation.
Monogalactosyldiacylglycerol (MGDG) is the most major lipid in thylakoid membranes of chloroplasts. In Arabidopsis, there are three MGDG synthases, which are classified into type A (MGD1) and type B (MGD2, 3). During phosphate deprivation, type B genes are activated particularly in roots. Whereas auxin efflux inhibitor inhibited the expression of type B genes in roots under phosphate-deprived condition, its expression was restored by auxin treatment, suggesting that under phosphate-deprived condition, auxin is necessary for the expression of type B genes in roots. In addition, we revealed that the induction of type B genes in that condition was inhibited by cytokinin treatment. Cytokinin may have antagonistic effects to auxin on type B expression under phosphate-deprived condition.
