Effects of herbicidal chemicals on redox potentials of Arabidopsis thaliana root tip cells based on mt-roGFP1 probe

Objective The aim of this study was to investigate the effects of several commercial herbicides and the botanical herbicidal compound berberine and its analogues on the redox potential of Arabidopsis thaliana root tip cells.

Method A. thaliana transgenic plants marked with mitochondria targeted redox-sensitive green fluorescent protein were used as plant materials. The changes of cell redox potential in root cap, proximal meristem, transition zone and elongation zone were measured after being treated with different mass concentrations of herbicides for different time.

Result The redox potential of the proximal meristematic zone of A. thaliana root cells treated with commercial herbicides was the lowest. From the meristematic zone to the elongation zone, the redox potential gradually increased, showing a trend of being gradually oxidized. Among the tested commercial herbicides, the change rule of redox potential of photosystem II inhibitors (atrazine and hexazinone) was the most obvious, indicating that mt-roGFP1 fluorescent probe could respond better to photosystem II inhibitors. The effect of glyphosate, an amino acid biosynthesis inhibitor, on the redox potential of A. thaliana root tip cells showed an obvious dose-response manner. With the increase of mass concentration, the change of the redox potential also gradually increased, showing a positive correlation with R²=0.9956. After the treatment of berberine and its analogues, the redox potential of A. thaliana root tip cells in most treatment groups reached the maximum reduction value in the proximal meristematic zone, and was gradually oxidized from the meristematic zone.

Conclusion These results provide a basis for applying roGFP fluorescence probe technology to studying the mechanism of herbicidal compounds acting on root cell mitochondria.