Abstract
We have shown that transient accumulation of GSSG is required for the tracheary element (TE) differentiation in Zinnia experimental system, and then performed further study on it. RT-PCR analysis on the gene expressions involved in the glutathione-related metabolism indicated transient increase in the gene expression levels of dehydroascorbate reductase and decrease in those of glutathione reductase (GR) before secondary thickening of cell walls. These suggest that co-operative expression of these genes facilitates GSSG accumulation. To investigate whether GSSG accumulation is essential for differentiation in planta, we generated transgenic Arabidopsis plants overexpressing Zinnia-derived GR. Transgenics showed retarded root formation, indicating that the accumulation of GSSG is necessary to facilitate the formation of roots as well as TEs. It has been suggested that cell division control involves glutathione, but our results suggest that glutathione also regulates cell differentiation.
