Abstract
We previously reported that transgenic Arabidopsis plants overexpressing Zinnia cytosolic glutathione reductase (GR) show retarded root formation and reduced number of root meristematic cells [Henmi et al. (2004) PCP suppl. s45]. This suggests that GR expression affects the rate of root formation. Using the GR-overexpressing and the T-DNA inserted cytosolic GR-knockout plants, we here verified the role of the glutathione redox state on the rate of root formation. On growth media containing GSSG, the rate of root formation of the knockout plants did not respond to GSSG, while that of wild-type plants was accelerated or suppressed by the various concentrations of GSSG. The response to GSSG was amplified in the GR-overexpressing plants, compared to wild-type plants. Considering these together with the short-root phenotype of the knockout plants, it is suggested that the glutathione redox state controlled via GR activity regulates the rate of root formation.
