Engineering Flax with the GT Family 1 Solanum sogarandinum Glycosyltransferase SsGT1 Confers Increased Resistance to Fusarium Infection

The aim of this study was to engineer a flax with increased resistance to pathogens. The approach was based on the recent analysis of the Solanum sogarandinum-derived glycosyltransferase (UGT) protein, designated SsGT1 (previously called 5UGT). On the basis of enzyme studies, the recombinant SsGT1 is a 7-O-glycosyltransferase, the natural substrates of which include both anthocyanidins and flavonols such as kaempterol and quercetin. Because flavonoids act as antioxidants and glycosylation increases the stability of flavonoids, it has been suggested that the accumulation of a higher quantity of flavonold glycosides in transgenic plants might improve their resistance to pathogen infection. Flax overproducing SsGT1 showed higher resistance to Fusarium infection than wild-type plants, and this was correlated with a significant increase in the flavonoid glycoside content in the transgenic plants. Overproduction of glycosyltransferase in transgenic flax also resulted in proanthocyanin, lignan, phenolic acid, and unsaturated fatty acid accumulation in the seeds. The last is meaningful from a biotechnological point of view and might suggest the involvement of polyphenol glycosides in the protection of unsaturated fatty acids against oxidation and thus improve oil storage. It is thus suggested that introduction of SsGT1 is sufficient for engineering altered pathogen resistance in flax.