title: Metabolically engineered oilseed crops with enhanced seed tocopherol.
abstract: Tocochromanols (tocopherols and tocotrienols) are important lipid soluble antioxidants and are an essential part of the mammalian diet. Oilseeds are particularly rich in tocochromanols with an average concentration 10-fold higher than other plant tissues. Here we describe a systematic approach to identify rate-limiting reactions in the tocochromanol biosynthetic pathway, and the application of this knowledge to engineer tocochromanol biosynthesis in oilseed crops. Seed-specific expression of genes encoding limiting tocochromanol pathway enzymes in soybean increased total tocochromanols up to 15-fold from 320 ng/mg in WT seed to 4800 ng/mg in seed from the best performing event. Although WT soybean seed contain only traces of tocotrienols, these transgenic soybean accumulated up to 94% of their tocochromanols as tocotrienols. Upon crossing transgenic high tocochromanol soybean with transgenic high alpha-tocopherol soybean, the vitamin E activity in the best performing F2-seed was calculated to be 11-fold higher than the average WT soybean seed vitamin E activity.
authors.affiliation: Monsanto Company, 800 N. Lindbergh Boulevard, St. Louis, MO 63167, USA.
authors.forename: Balasulojini
authors.initials: B
authors.lastname: Karunanandaa
authors.forename: Qungang
authors.initials: Q
authors.lastname: Qi
authors.forename: Ming
authors.initials: M
authors.lastname: Hao
authors.forename: Susan R
authors.initials: SR
authors.lastname: Baszis
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Jensen
authors.forename: Yun-Hua H
authors.initials: YH
authors.lastname: Wong
authors.forename: Jian
authors.initials: J
authors.lastname: Jiang
authors.forename: Mylavarapu
authors.initials: M
authors.lastname: Venkatramesh
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Gruys
authors.forename: Farhad
authors.initials: F
authors.lastname: Moshiri
authors.forename: Dusty
authors.initials: D
authors.lastname: Post-Beittenmiller
authors.forename: James D
authors.initials: JD
authors.lastname: Weiss
authors.forename: Henry E
authors.initials: HE
authors.lastname: Valentin
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000502:physiology; D024861:Genetic Enhancement / Q000379:methods*; D012639:Seeds / Q000235:genetics* / Q000378:metabolism*; D013024:Soybean Oil / Q000737:chemistry / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism*; D024505:Tocopherols / Q000737:chemistry / Q000378:metabolism*
chemical_list: D013024:Soybean Oil; D024505:Tocopherols