Overexpression of Forsythia intermedia pinoresinol lariciresinol reductase gene in Sesamum indicum increases secoisolariciresinol diglucoside content.

Abstract

Sesame (Sesamum indicum), an important oilseed crop, is well known for its therapeutic values. It is one of the richest sources of polyunsaturated fatty acids and health beneficiary lignans. However, nutraceutical potential is restricted due to the presence of secoisolariciresinol diglucoside (SDG), a potent anticarcinogen, in imperceptible amount (~ 0.03 mg/25 g of seeds). Consequently, a logical strategy was implemented to augment the SDG content in sesame by heterologous expression of the pinoresinol-lariciresinol reductase (Fiplr) gene from Forsythia intermedia. Four individual transgenic lines were generated by Agrobacterium-mediated transformation of pCAMBIA/Fiplr gene cassette into sesame and was further confirmed by PCR and Southern blot analyses. Among the Individual transgenic lines, PT₁1.1 was found to demonstrate ~ 3.5-fold higher expression of plr transcript in comparison to other transformants and untransformed control. PT₁1.1 plant also showed ~ twofold increased PLR enzyme activity that led to ~ threefold increased accumulation of SDG content as compared to that in untransformed control when confirmed by the HPLC analyses. Thus, the study suggests that the presently developed transgenic sesame line may have the better dietary prospect for people suffering particularly from estrogen-induced cancers and can emerge having significant medical implications.