WRINKLED1 - A NOVEL, LOW-SEED-OIL MUTANT OF ARABIDOPSIS WITH A DEFICIENCY IN THE SEED-SPECIFIC REGULATION OF CARBOHYDRATE-METABOLISM

During oil deposition in developing seeds of Arabidopsis, photosynthat e is imported in the form of carbohydrates into the embryo and convert ed to triacylglycerols. To identify genes essential for this process a nd to investigate the molecular basis for the developmental regulation of oil accumulation, mutants producing wrinkled, incompletely filled seeds were isolated. A novel mutant locus, wrinkled1 (wri1), which map s to the bottom of chromosome 3 and causes an 80% reduction in seed oi l content, was identified. Wildtype and homozygous wri1 mutant plantle ts or mature plants were indistinguishable. However, developing homozy gous wri1 seeds were impaired in the incorporation of sucrose and gluc ose into triacylglycerols, but incorporated pyruvate and acetate at an increased rate. Because the activities of several glycolytic enzymes, in particular hexokinase and pyrophosphate-dependent phosphofructokin ase, are reduced in developing homozygous wri1 seeds, it is suggested that WRI1 is involved in the developmental regulation of carbohydrate metabolism during seed filling.