A new class of plant lipid is essential for protection against phosphorus depletion

Abstract

Phosphorus supply is a major factor responsible for reduced crop yields. As a result, plants utilize various adaptive mechanisms against phosphorus depletion, including lipid remodelling. Here we report the involvement of a novel plant lipid, glucuronosyldiacylglycerol, against phosphorus depletion. Lipidomic analysis of Arabidopsis plants cultured in phosphorus-depleted conditions revealed inducible accumulation of glucuronosyldiacylglycerol. Investigation using a series of sulfolipid sulfoquinovosyldiacylglycerol synthesis-deficient mutants of Arabidopsis determined that the biosynthesis of glucuronosyldiacylglycerol shares the pathway of sulfoquinovosyldiacylglycerol synthesis in chloroplasts. Under phosphorus-depleted conditions, the Arabidopsis sqd2 mutant, which does not accumulate either sulfoquinovosyldiacylglycerol or glucuronosyldiacylglycerol, was the most severely damaged of three sulfoquinovosyldiacylglycerol-deficient mutants. As glucuronosyldiacylglycerol is still present in the other two mutants, this result indicates that glucuronosyldiacylglycerol has a role in the protection of plants against phosphorus limitation stress. Glucuronosyldiacylglycerol was also found in rice, and its concentration increased significantly following phosphorus limitation, suggesting a shared physiological significance of this novel lipid against phosphorus depletion in plants.

A Bifunctional Glycosyltransferase from Agrobacterium tumefaciens Synthesizes Monoglucosyl and Glucuronosyl Diacylglycerol under Phosphate Deprivation

“…Enzyme assays revealed UDP-GlcUA as a sugar donor (29). GlcAD was recently also detected in plants, where it is probably synthesized by the SQD synthase SQD2 (35).…”

Anionic glycolipids related to glucuronosyldiacylglycerol inhibit protein kinase Akt

“…Glucuronosyldiacylglycerols (GlcADGs, figure 1) are unusual acidic glycoglycerolipids found in bacteria, 1 fungi, 2 algae 3 and in 15 some higher plants such as Arabidopsis thaliana and rice, 4 and only very recently their first synthesis has been reported. 5 Their presence in these photosynthetic organisms seems related to conditions of reduced phosphorous availability in which they replace phospholipids for their biological functions.…”

“…5 Their presence in these photosynthetic organisms seems related to conditions of reduced phosphorous availability in which they replace phospholipids for their biological functions. 4,6 GlcADGs 20 participate to this lipid remodelling as the better-known anionic sulfolipids, sulfoquinovosyldiacylglycerols (SQDGs, figure 1), 7,8 sharing also the same biosynthetic pathway, which requires a common SQDG synthase. 4 Differently from GlcADGs, in the last years both natural and synthetic sulfoquinovosylacylglycerols 25 have been tested for their antitumor, antiviral, anti-inflammatory, immunosuppressive and other bioactivities.…”

“…4,6 GlcADGs 20 participate to this lipid remodelling as the better-known anionic sulfolipids, sulfoquinovosyldiacylglycerols (SQDGs, figure 1), 7,8 sharing also the same biosynthetic pathway, which requires a common SQDG synthase. 4 Differently from GlcADGs, in the last years both natural and synthetic sulfoquinovosylacylglycerols 25 have been tested for their antitumor, antiviral, anti-inflammatory, immunosuppressive and other bioactivities. [9][10][11][12][13] This prompted us to prepare some SQDG analogues (figure 1) based on 2-O-β-Dglucosylglycerol, which were tested as inhibitors of tumorpromoters in cancer prevention studies.…”

Lipidomic analysis of soybean leaves revealed tissue-dependent difference in lipid remodeling under phosphorus-limited growth conditions

“…Some of them showed growth defects under P-limited conditions Okazaki et al 2013;Yu et al 2002). Recently, we have identified a novel plant glycoglycerolipid, glucuronosyldiacylglycerol (GlcADG), which inducibly accumulates in Arabidopsis and rice upon P limitation (Figure 1) (Okazaki et al 2013).…”