Herbicide-tolerant plants have efficient biochemical pathways for detoxification of these molecules within the cell, with many cytoplasmic enzymes being involved in this process. In this study, the electrophoretic profiles of cytoplasmic proteins were evaluated in the leaves, stems, and roots of corn plants during the detoxification process after treatment with the herbicide mesotrione. At 15 days after planting, 192 grams per hectare (g ha-1) of mesotrione were administered post-emergence. Three or seven days after application (DAA), tissues were collected to perform cell fractionation and isolation of soluble proteins from the cytoplasm. Photosynthetic activity was analyzed as a physiological marker of the level of intoxication at different stages (1, 2, 3, 5, and 7DAA). While photosynthesis was inhibited in the first three days after spraying, there was no significant change on the fifth day. Biometric measurements were performed at seven DAA, and no significant differences were observed. Analysis of electrophoretic profiles of cytoplasmic proteins indicates higher expression of low molecular weight (~21-65kDa) proteins in leaves and stems for three days after mesotrione application. However, at seven days, we observed a recovery profile similar to the tissues of the plants not treated with herbicides. There was a reduction in the roots of herbicide-treated plants in protein biosynthesis for as long as three to seven DAA. These results suggest that changes in the electrophoretic profile of corn plant cytoplasmic proteins reflect the stage of tissue detoxification. Furthermore, even after proceedings have been established in shoots, the roots continue to show changes that indicate a longer mesotrione detoxification process for the root system.
phytotoxicity; corn; protein markers; weed control; herbicide metabolization
