Arabidopsis Glutathione-S-Transferases and Function in Aliphatic Glucosinolate Biosynthesis.

Glutathione (GSH) conjugation with intermediates is required for the biosynthesis of glucosinolate (GSL) by serving as a sulfur supply. Glutathione-S-transferases (GSTs) primarily work on GSH conjugation, suggesting their involvement in GSL metabolism. Although several GSTs, including GSTF11 and GSTU20, have been recently postulated to act in GSL biosynthesis, molecular evidence is lacking. Here, we demonstrated that and play non-redundant, although partially overlapping, roles in aliphatic GSL biosynthesis. In addition, plays a more important role than , which is manifested by the greater loss of aliphatic GSLs associated with mutant and a greater number of differentially expressed genes in mutant compared to mutant. Moreover, a double mutation leads to a greater aggregate loss of aliphatic GSLs, suggesting that and may function in GSL biosynthesis in a dosage-dependent manner. Together, our results provide direct evidence that and are critically involved in aliphatic GSL biosynthesis, filling the knowledge gap that has been speculated in recent decades.