Abnormal glycosphingolipid mannosylation triggers salicylic acid-mediated responses in Arabidopsis.

The Arabidopsis thaliana protein GOLGI-LOCALIZED NUCLEOTIDE SUGAR TRANSPORTER (GONST1) has been previously identified as a GDP-d-mannose transporter. It has been hypothesized that GONST1 provides precursors for the synthesis of cell wall polysaccharides, such as glucomannan. Here, we show that in vitro GONST1 can transport all four plant GDP-sugars.

Phylogenetic and biochemical evidence supports the recruitment of an ADP-glucose translocator for the export of photosynthate during plastid endosymbiosis.

The acquisition of photosynthesis by eukaryotic cells through enslavement of a cyanobacterium represents one of the most remarkable turning points in the history of life on Earth. In addition to endosymbiotic gene transfer, the acquisition of a protein import apparatus and the coordination of gene expression between host and endosymbiont genomes, the establishment of a metabolic connection was crucial for a functional endosymbiosis. It was previously hypothesized that the first metabolic connection between both partners of endosymbiosis was achieved through insertion of a host-derived metabolite transporter into the cyanobacterial plasma membrane.

A defect in carbohydrate metabolism ameliorates symptom severity in virus-infected Arabidopsis thaliana.

Altered starch accumulation is a characteristic biochemical symptom of virus infection in plants. To assess its biological importance, infection of Arabidopsis thaliana with Turnip vein-clearing virus, Cucumber mosaic virus or Cauliflower mosaic virus was investigated in plants grown under continuous illumination (under which there is no net breakdown of starch) and in pgm1 mutant plants lacking chloroplastic phosphoglucomutase, an enzyme required for starch biosynthesis. Virus-infected wild-type plants grown under continuous light exhibited more severe leaf symptoms, but no reduction in growth compared with plants grown under diurnal illumination.

Localisation and characterisation of cell wall mannan polysaccharides in Arabidopsis thaliana.

Polysaccharides containing beta-1,4-mannosyl residues (mannans) are abundant in the lignified secondary cell walls of gymnosperms, and are also found as major seed storage polysaccharides in some plants, such as legume species. Although they have been found in a variety of angiosperm tissues, little is known about their presence and tissue localisation in the model angiosperm, Arabidopsis thaliana (L.) Heynh.