Towards the cloning of GLY1

The Arabidopsis mutants designated gly1 exhibit a reduced carbon flux through the prokaryotic pathway that is compensated for by an increased carbon flux through the eukaryotic pathway. Biochemical approaches reveal that the gly1 phenotype cannot be explained by a deficiency in the enzymes of the prokaryotic pathway. The chemical complementation of the mutant phenotype by exogenous glycerol treatment of gly1 plants suggests a lesion affecting the glycerol 3-phosphate supply within the chloroplast. As an alternative to the biochemical study of the gly1 mutants we set out to map the GLY1 locus. The gly1 mutant being an EMS (ethyl methane sulphonate) mutant, we used a strategy based on the polymorphism existing between Arabidopsis ecotypes, here Columbia (gly1 background) and Landsberg erecta. We mapped gly1 on chromosome II. During the process of chromosome walking, the complete sequence of chromosome II was released, allowing us to make assumptions on candidate genes based on map location. We are currently sequencing the putative genes.