Enhancement of seed phytosterol levels by expression of an N-terminal truncated Hevea brasiliensis (rubber tree) 3-hydroxy-3-methylglutaryl-CoA reductase.

摘要: Summary Dietary intake of phytosterols (plant sterols) has been shown to be effective in reducing blood cholesterol levels, thereby the risk cardiovascular disease. Phytosterols are most commonly sourced from vegetable oils, where they present as minor components. We report here generation transgenic tobacco seeds substantially enhanced phytosterol content by expression a modified form one key sterol biosynthetic enzymes, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR). The constitutive an N-terminal truncated Hevea brasiliensis HMGR (t-HMGR), lacking membrane binding domain, seed activities 11-fold, leading increases total 2.4-fold. Seed-specific t-HMGR levels 3.2-fold, 1.36% dry weight or 3.25% oil. 4-desmethylsterols were increased 2.2-fold, whilst certain intermediates, particular cycloartenol and 24-ethylidene lophenol, also accumulated. additional tissue was fatty acid esters. Constitutive leaf 10-fold, representing 1.8% weight, sequestered, acyl ester form, cytoplasmic ‘oil droplets’. These studies establish enzyme controlling overall flux into biosynthesis pathway tissue, but accumulation intermediates suggests slow steps pathway. N-truncated activity generated novel phytosterol-enriched raw materials that may provide basis new sourcing opportunities for this important class cholesterol-lowering actives.