A variety of genetically modified (GM) crops have been developed in Korea. In these crops, the resveratrol-enriched transgenic rice plant (Agb0102) has moved ahead to generate the dossier for regulatory review process required for commercialization of GM crop. The resveratrol-enriched transgenic rice plant could be released to farmers for cultivation after national regulators have determined that it is safe for the environment and human health. Here, we developed a PCR-based DNA marker based on flanking sequences of transgene for the discrimination of resveratrol-enriched transgenic rice plant. This DNA markers will be useful for identifying of resveratrol-enriched transgenic rice plant, and can also be used to estimate transgene movement occurred by pollen transfer or seed distribution. Moreover, it is helpful for prompt screening of a homozygote-transgenic progeny in the breeding program.

In order to assess the substantial equivalence of two varieties of genetically modified rice, herbicide-tolerant Ab rice and the insect-resistant Bt rice, to the non-GM Dongjin-byeo cultivar. We analyzed the compositions and contents of the proximate, amino acids, minerals, fatty acids, vitamins, and anti-nutrients in their unpolished grains using t-test (p<0.05). A comparison of fatty acids compositions showed that the levels of stearic acid and arachidonic acid in Ab rice and those of myristic, palmitic, oleic, linoleic, and gadoleic acid in Bt rice were different significantly from the corresponding levels in Dongjin-byeo. Vitamin content did not differ between Bt and Dongjin-byeo, but the content of vitamins B1, B7, and E in Ab rice differed from that in Dongjin-byeo. Iron content in Ab and Bt rice was 2 times higher than that in Dongjin-byeo, although it was within the reference range set by Codex. The amount of the anti-nutrient trypsin inhibitor was 0.1 TIU/mg in the unpolished grain of all three rice varieties examined. Of the 47 components analyzed, 17 were significantly different among the three rice varieties; however, most of these differences were within the Codex reference range for commercial rice. Overall, it was confirmed that both Bt and Ab rice are substantially equivalent to the Dongjin-byeo and other commercial varieties of rice.

The β-carotene biofortified transgenic soybean was developed recently through Agrobacterium-mediated transformation using the recombinant PAC (Phytoene synthase-2A-Carotene desaturase) gene in Korean soybean (Glycine max L. cv. Kwangan). GM crops prior to use as food or release into the environment required risk assessments to environment and human health in Korea. Generally, transgenic plants containing a copy of T-DNA were used for stable expression of desirable trait gene in risk assessments. Also, information about integration site of T-DNA can be used to test the hypothesis that the inserted DNA does not trigger production of unintended transgenic proteins, or disrupt plant genes, which may cause the transgenic crop to be harmful. As these reasons, we selected four transgenic soybean lines expressing carotenoid biosynthesis genes with a copy of T-DNA by using Southern blot analysis, and analyzed the integration sites of their T-DNA by using flanking sequence analysis. The results showed that, T-DNA of three transgenic soybean lines (7-1-1-1, 9-1-2, 10-10-1) was inserted within intergenic region of the soybean chromosome, while T-DNA of a transgenic soybean line (10-19-1) located exon region of chromosome 13. This data of integration site and flanking sequences is useful for the biosafety assessment and for the identification of the β-carotene biofortified transgenic soybean.

The selectable marker-free rice plants containing mcry1Ac insecticidal gene isolated from Bacillus thuringiensis (Bt) were generated using a non-selection approach by Agrobacterium tumefaciens-mediated transformation. The nutritional composition of two lines of transgenic rice plants (RTB5 and RTB11) was compared with that of its non-transgenic counterpart. The results showed that, except for small differences in dietary fiber and some minerals, there was no significant difference between transgenic rice and conventional counterpart variety with respect to their nutrient composition. Most of measured levels of nutrients were within the range of values reported for other commercial cultivars, showing substantial equivalency. Therefore, the insertion of transgenes did not affect the nutritional composition of transgenic RTB5 and RTB11 rice grains.

Content of key nutrients and anti-nutrients of the insect-resistant transgenic rice (Btt12R) developed in Korea that contains a cryIIIA insecticidal gene was compared with those of its non-transgenic counterpart (Oryza sative L. cv. Nakdongbyeo). Grains of Btt12R, its parent cultivar, and two commercial rice plants (cv. Yeonganbyeo and Hwaseongbyeo) grown in the adjoining fields under the same environmental conditions and field management were used for this study. Among the analyzed 47 nutrients (8 proximates, 17 amino acids, 8 fatty acids, 9 minerals, and 5 vitamins) and two anti-nutrients (trypsin inhibitors and phytic acid), although the levels of 17 components differed between Nakdongbyeo and Btt12R, all of the measured values from Btt12R were within the ranges of values observed in the two typical Korean varieties and commercial rice provided by the OECD. These results confirm that the nutritional quality of rice grains was not affected by the insertion of the cryIIIA gene.

In recent years, novel plant breeding techniques (NPBTs) have emerged, and safety assessment of the novel plant(s) generated using the NPBTs has drawn the attention of many stakeholders. The notable characteristics of the novel plants are as follows: firstly, it is almost impossible to distinguish from the natural mutations in the conventional counterparts, because site-directed nuclease (SDN) and oligonucleotide-directed mutagenesis (ODM) could introduce short indel(s) in the targeted region(s) of the chromosomes. Secondly, the genome constitution of novel plants is almost identical to that of their conventional counterparts, eventually becoming indistinguishable by the introduction of only unmodified gene(s) from sexually compatible species to the target host plant. Thirdly, it is possible to generate new plants that have the desired traits, but without introducing genes. These plants will have some modified bases in their genome by selecting null-segregant(s) from heterozygous transgenic plants or by other epigenetic methods. The Organisation for Economic Co-operation and Development (OECD) and many countries developing genetically modified organisms (GMOs) have concluded that novel plants developed using SDN, ODM, cisgenesis, intragenesis, or null-segregant techniques are treated in the same manner as non-genetically modified (GM) plants or may even have less strict risk assessments depending on the case. Additionally, grafting and agro-infiltration are methods that can be used to avoid or reduce the burden of current strict GMO risk assessment. The risk assessments of some of the novel plants have already been performed and those of commercially important plants are expected to be performed in the near future. Hence, it is necessary to develop a competitive and practical NPBT that can mitigate the concern and revulsion toward GMOs in Korea.

The purpose of this study was to characterize the T-DNAs introduced into the transgenic OsCK rice, as part of a biosafety evaluation. Choline Kinase (CK) gene is upregulated in the transgenic OsCK rice. We identified the insertion sites, flanking sequences, structures and sequences of the inserted T-DNAs. Based on the adaptor-ligation PCR, we found that the right border of the T-DNA was inserted at position no. 129971, on BAC clone OSJNBa0014J14 of chromosome 10. The flanking sequences of the left border region of the T-DNA (which was later identified as a region harboring a 1-kb long deleted sequence), could not be identified by various PCR-based trials. However, it was finally identified with whole-genome shotgun sequencing, using an Illumina sequencer. The result indicated that one of the T-DNAs was inserted into the CaMV 35S promoter region, whereas the other T-DNA was introduced at position 128947 on OSJNBa0014J14 clone, with an inverse orientation. During the insertion process, a 1024-bp-long chromosome sequences flanked by the right border of the T-DNA region was deleted. A 370-bp long left border region and 199-bp long right border region corresponding to the matrix attachment region (MAR) sequences of the T-DNA were also deleted. Collectively, these results indicate that whole-genome shotgun sequencing is a useful tool to reveal the detailed sequences and structures of the introduced T-DNAs, especially in the case of multiple T-DNA insertions. The expenses incurred on genome sequencing can be easily compensated by minimizing the time and efforts invested in conventional molecular analyses.