title: Genetic modification of the soybean to enhance the β-carotene content through seed-specific expression.
abstract: The carotenoid biosynthetic pathway was genetically manipulated using the recombinant PAC (Phytoene synthase-2A-Carotene desaturase) gene in Korean soybean (Glycine max L. cv. Kwangan). The PAC gene was linked to either the β-conglycinin (β) or CaMV-35S (35S) promoter to generate β-PAC and 35S-PAC constructs, respectively. A total of 37 transgenic lines (19 for β-PAC and 18 for 35S-PAC) were obtained through Agrobacterium-mediated transformation using the modified half-seed method. The multi-copy insertion of the transgene was determined by genomic Southern blot analysis. Four lines for β-PAC were selected by visual inspection to confirm an orange endosperm, which was not found in the seeds of the 35S-PAC lines. The strong expression of PAC gene was detected in the seeds of the β-PAC lines and in the leaves of the 35S-PAC lines by RT-PCR and qRT-PCR analyses, suggesting that these two different promoters function distinctively. HPLC analysis of the seeds and leaves of the T(2) generation plants revealed that the best line among the β-PAC transgenic seeds accumulated 146 µg/g of total carotenoids (approximately 62-fold higher than non-transgenic seeds), of which 112 µg/g (77%) was β-carotene. In contrast, the level and composition of the leaf carotenoids showed little difference between transgenic and non-transgenic soybean plants. We have therefore demonstrated the production of a high β-carotene soybean through the seed-specific overexpression of two carotenoid biosynthetic genes, Capsicum phytoene synthase and Pantoea carotene desaturase. This nutritional enhancement of soybean seeds through the elevation of the provitamin A content to produce biofortified food may have practical health benefits in the future in both humans and livestock.
authors.affiliation: Department of Genetic Engineering, Dong-A University, Busan, Republic of Korea.
authors.forename: Mi-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Jae Kwang
authors.initials: JK
authors.lastname: Kim
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jung Hun
authors.initials: JH
authors.lastname: Pak
authors.forename: Jai-Heon
authors.initials: JH
authors.lastname: Lee
authors.forename: Doh-Hoon
authors.initials: DH
authors.lastname: Kim
authors.forename: Hong Kyu
authors.initials: HK
authors.lastname: Choi
authors.forename: Ho Won
authors.initials: HW
authors.lastname: Jung
authors.forename: Jeong-Dong
authors.initials: JD
authors.lastname: Lee
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Chung
authors.forename: Sun-Hwa
authors.initials: SH
authors.lastname: Ha
mesh_terms: D060054:Agrobacterium / Q000235:genetics; D019883:Alkyl and Aryl Transferases / Q000235:genetics; D016166:Free Radical Scavengers / Q000378:metabolism; D015870:Gene Expression; D005818:Genetic Engineering / Q000379:methods*; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D009928:Organ Specificity; D010840:Phytosterols / Q000378:metabolism; D010858:Pigmentation / Q000235:genetics; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000235:genetics; D012639:Seeds / Q000235:genetics* / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism*; D024505:Tocopherols / Q000378:metabolism; D014170:Transformation, Genetic; D019076:Transgenes / Q000235:genetics; D019207:beta Carotene / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D016166:Free Radical Scavengers; D010840:Phytosterols; D011994:Recombinant Proteins; D019207:beta Carotene; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D024505:Tocopherols