Root gravitropism relies on a GSH-dependent reaction mediated by glutathione S-transferase in Arabidopsis thaliana

Abstract

We have reported that root gravitropism involves glutathione (GSH) and glutathione S-transferase (GST) in Arabidopsis root [Shiomi et al. (2005) PCP suppl. s171].
To examine how GSH participate in root gravitropism, we investigated the effects of GSH and buthionine sulfoxmine (BSO), an inhibitor of GSH synthesis, on wild-type root gravitropism. GSH and BSO reduced root gravitropism in a dose-dependent manner. However, dithiothreitol, a strong thiol reductant, did not influence root gravitropism in wild-type plants. Unlike wild-type plants, a T-DNA inserted mutant of H₂O₂ inducible GST did not show reduced root gravitropism in response to exogenous GSH. Taken together, it is suggested root gravitropism relies on GSH-dependent reaction mediated by H₂O₂-inducible GST.