title: Transfer and targeted overexpression of γ-tocopherol methyltransferase (γ-TMT) gene using seed-specific promoter improves tocopherol composition in Indian soybean cultivars.
abstract: Soybean oil contains high levels of tocopherols which are an important source of vitamin E in human diet. The conversion of γ- to α-tocopherol catalyzed by γ-tocopherol methyltransferase (γ-TMT) is found to be the rate limiting factor in soybean which influences the tocopherol composition. Using Agrobacterium-mediated transformation, we overexpressed the γ-TMT gene of Perilla frutescens under the control of the seed-specific promoter vicillin in cultivar Pusa 16. Transgene integration and expression was confirmed in five independently transformed GUS positive soybean plants by polymerase chain reaction (PCR), Southern hybridization, and reverse transcriptase-PCR (RT-PCR). High-performance liquid chromatography (HPLC) analysis showed that overexpression of Pf-γ-TMT resulted in efficient conversion of γ-tocopherol to α-tocopherol and concomitant increase in seed α-tocopherol content in RT-PCR positive plants. The protocol was successfully applied to three more cultivars PK 416, Gujarat soybean 1, and VL soya 1 in which seeds of transformed plants showed elevated level of α-tocopherol than wild-type seeds.
authors.affiliation: Department of Biotechnology & Genetic Engineering, School of Biotechnology, Bharathidasan University, Tiruchirappalli, 620024, Tamil Nadu, India.
authors.forename: Muthukrishnan
authors.initials: M
authors.lastname: Arun
authors.forename: Kondeti
authors.initials: K
authors.lastname: Subramanyam
authors.forename: Jeevaraj
authors.initials: J
authors.lastname: Theboral
authors.forename: Ganeshan
authors.initials: G
authors.lastname: Sivanandhan
authors.forename: Manoharan
authors.initials: M
authors.lastname: Rajesh
authors.forename: Gnanajothi
authors.initials: G
authors.lastname: Kapil Dev
authors.forename: Balusamy
authors.initials: B
authors.lastname: Jaganath
authors.forename: Markandan
authors.initials: M
authors.lastname: Manickavasagam
authors.forename: Shanmugam
authors.initials: S
authors.lastname: Girija
authors.forename: Andy
authors.initials: A
authors.lastname: Ganapathi
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013025:Glycine max / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D024505:Tocopherols / Q000378:metabolism*
chemical_list: D008780:Methyltransferases; C047259:gamma-tocopherol methyltransferase; D024505:Tocopherols