Alterations in seed development gene expression affect size and oil content of Arabidopsis seeds.

Seed endosperm development in Arabidopsis (Arabidopsis thaliana) is under control of the polycomb group complex, which includes Fertilization Independent Endosperm (FIE). The polycomb group complex regulates downstream factors, e.g.

A TIR-NBS protein encoded by Arabidopsis Chilling Sensitive 1 (CHS1) limits chloroplast damage and cell death at low temperature.

Survival of plants at low temperature depends on mechanisms for limiting physiological damage and maintaining growth. We mapped the chs1-1 (chilling sensitive1-1) mutation in Arabidopsis accession Columbia to the TIR-NBS gene At1g17610. In chs1-1, a single amino acid exchange at the CHS1 N-terminus close to the conserved TIR domain creates a stable mutant protein that fails to protect leaves against chilling stress.

Analysis of lipid content and quality in Arabidopsis plastids.

Chloroplasts of plants contain an intricate membrane system, the thylakoids, which harbor the complexes of the photosynthetic machinery. Chloroplasts are confined by two membranes, the inner and outer envelope. The major glycerolipids of chloroplasts are the glycolipids monogalactosyl diacylglycerol (MGD), digalactosyl diacylglycerol (DGD), and sulfoquinovosyl diacylglycerol (SQD).

Intersection of the tocopherol and plastoquinol metabolic pathways at the plastoglobule.

Plastoglobules, lipid-protein bodies in the stroma of plant chloroplasts, are enriched in non-polar lipids, in particular prenyl quinols. In the present study we show that, in addition to the thylakoids, plastoglobules also contain a considerable proportion of the plastidial PQ-9 (plastoquinol-9), the redox component of photosystem II, and of the cyclized product of PQ-9, PC-8 (plastochromanol-8), a tocochromanol with a structure similar to gamma-tocopherol and gamma-tocotrienol, but with a C-40 prenyl side chain. PC-8 formation was abolished in the Arabidopsis thaliana tocopherol cyclase mutant vte1, but accumulated in VTE1-overexpressing plants, in agreement with a role of tocopherol cyclase (VTE1) in PC-8 synthesis.

A salvage pathway for phytol metabolism in Arabidopsis.

Chlorophyll is the most abundant photosynthetic pigment in higher plants. During senescence, chlorophyll is hydrolyzed, resulting in the release of free phytol and chlorophyllide. Although the degradation of chlorophyllide has been studied in depth, the metabolic fate of phytol in plants is less clear.