This document summarizes research on profiling gene expression of glutathione S-transferases (GSTs) in sorghum lines with different tolerances to the herbicide s-metolachlor. Through a genome-wide association study, the researchers identified two sorghum lines with high and low tolerance. They designed primers for two GST genes associated with tolerance and measured expression levels at 8 and 12 hours after treatment. Preliminary results show a correlation between basal expression of one GST gene and tolerance, but not the other. Further research is needed to identify additional genes involved in the safener-induced detoxification pathway.