Further evidence that mutations in UGT74S1 alter SDG lignan glucoside profiles in EMS flax mutant lines

Flax glycosyltransferase UGT74S1 was recently found to sequentially catalyze secoisolariciresinol (SECO) monoglucoside (SMG) and diglucoside (SDG) formation in vitro using the aglycone precursor SECO. However, whether this gene is unique in achieving this glucosylation process in planta is not clear. We developed and characterized a flax EMS mutant population using reverse and forward genetics to assess loss-of-function in UGT74S1. EMS lines carrying missense or nonsense mutations and showing altered lignan profiles were identified. Ampliseq sequencing using a panel of 10 genes encountered in the lignan biosynthetic pathways was performed in EMS lines displaying altered lignan profiles. The data will be reported and discussed in connection with the putative roles for UGT74S3 and UGT74S4, two closely related genes to UGT74S1.