Molecular Biological Characteristics and Biosafety Assessment for β-carotene Biofortified Transgenic Rice

Sung-Dug Oh, Soo-Yun Park, Si Myung Lee, Kijong Lee, Soo-In Sohn, Soon Ki Park, and Tae-Hun Ryu* National Academy of Agricultural Science, Rural Development Administration, Jeonju, 560-500, Korea School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Korea Abstract : The β-carotene biofortified transgenic rice was developed by transforming rice cv. Nakdongbyeo with phytoene synthase (Psy) and carotene desaturase (Crt I) genes isolated from Capsicum and Pantoea. The aim of this study was to perform molecular characterization of rice transformants of T5-T7 generation harboring Psy and Ctr I genes driven by endosperm specific globulin promoter for biosafety evaluation of β-carotene biofortified transgenic rice. The structure and sequence of T-DNA in the transformation vector and the insertion sites, flanking sequences and generational stability of inserted T-DNA in transgenic rice lines were analyzed. The transformation vector consisted of right border, MAR gene, carotenogenic genes unit, herbicide resistance selectable marker unit, MAR gene and left border in sequential order. T-DNA was introduced at the position of 30,363,938-30,363,973 bp of chromosome No. 2 by adaptor-ligation PCR. Stable integration of T-DNA and stable expression of bar gene was confirmed in T5 to T7 generations. It was also confirmed that the backbone DNA of transformation vector containing antibacterial gene was not present in the genome of β-carotene biofortified transgenic rice. HPLC analysis confirmed that carotenoids were consistently detected through T5-T7 generations.