Co-expression of Delta a' and Delta b subunits of Delta b-conglycinin in rice seeds and its effect on the accumulation behavior of the expressed proteins

• Published in: Transgenic research 2009-01, Vol.17 (6), p.819-827
• Main Authors: Motoyama, Takayasu, Okumoto, Yutaka, Tanisaka, Takatoshi, Utsumi, Shigeru, Maruyama, Nobuyuki
• Format: Article
• Language: English
• Subjects: Cysteine; Glutelin; Immunoelectron microscopy; Oryza sativa; Seeds; Soybeans
• ISSN: 0962-8819
• DOI: 10.1007/s11248-009-9359-8

A transgenic rice that produces both the Delta *a' and Delta *b subunits of Delta *b-conglycinin has been developed through the crossing of two types of transgenic rice. Although the accumulation level of the Delta *a' subunit in the Delta *a' Delta *b-transgenic rice was slightly lower than that in the transgenic rice producing only the Delta *a' subunit, the accumulation level of the Delta *b subunit in the Delta *a' Delta *b-transgenic rice was about 60% higher than that in the transgenic rice producing only the Delta *b subunit. Results from sequential extraction and gel-filtration experiments indicated that part of the Delta *b subunit formed heterotrimers with the Delta *a' subunit in a similar manner as in soybean seeds and that the heterotrimers interacted with glutelin via cysteine residues. These results imply that the accumulation level of the Delta *b subunit in the Delta *a' Delta *b-transgenic rice increases by an indirect interaction with glutelin. Immunoelectron microscopy revealed that the Delta *a' and Delta *b subunits are localized in a low electron-dense region of protein body-II (PB-II) and that Delta *a' homotrimers in the Delta *a' Delta *b-transgenic rice seeds seem to accumulate outside of this low electron-dense region.