Soybean mosaic virus (SMV), a member of Potyviridae family, is one of the most typical viral diseases and results in yield and quality loss of cultivated soybean. Due to the depletion of genetic resources for resistance breeding, a trial of genetic transformation to improve disease resistance has been performed by introducing SMV-CP and HC-Pro gene by RNA interference (RNAi) method via Agrobacterium-mediated transformation. Transgenic plants were infected with SMV strain G5 and investigated the viral response. As a result, two lines (3 and 4) of SMV-CP(RNAi) transgenic plants and three lines (2, 5 and 6) of HC-Pro(RNAi) transgenic plants showed viral resistance. In genomic Southern blot analysis, most of lines contained at least one T-DNA insertion in both SMV-CP(RNAi) and HC-Pro(RNAi) transgenic plants. Subsequent investigation confirmed that no viral CP and HC-Pro gene expression was detected in two SMV-resistant lines of SMV-CP(RNAi) and three lines of HC-Pro(RNAi) transgenic plants, respectively. On the other hand, non-transgenic plants and other lines showed viral RNA expression. Viral symptoms affected seed morphology, and clean seeds were harvested from SMV-resistant line of SMV-CP(RNAi) and HC-Pro(RNAi) transgenic plants. In addition, strong viral gene expression was detected from seeds of SMV-susceptible non-transgenic plants and SMV-susceptible transgenic lines. When compared the viral resistance between SMV-CP(RNAi) and HC-Pro(RNAi) transgenic plants, soybean transgenic plants with the HC-Pro gene using RNAi strategy showed much stronger and higher frequency of viral resistance.

UGT72E3/2 gene encodes UDP-glycosyltransferase shown to glucosylate several phenylpropanoids such as syringin and coniferin. Syringin has effect of anti-stress and anti-fatigue. Korean soybean variety Kwangan was transformed with UGT72E3/2 gene. This gene was transformed into Kwangan using highly efficient soybean transformation system. This study used two promoters, beta-conglycinin promoter for seed-specific expression and 35s promoter for total expression. Transgenic plants were confirmed for gene introduction and their expression using PCR and RT-PCR. The analysis of syringin in transgenic plants was performed using HPLC. Currently, the confirmation of stable gene introduction with UGT72E3/2 gene is also performing by Southern blot analysis.

Bacillus thuringiensis(Bt) crystal protein (Cry1Ac) genes encode insecticidal δ-endotoxins that are widely used for the development of insect-resistant crops. Common soybean is a crop of economic and nutritious importance in many parts of the world. Korea soybean variety Kwangan was transformed with Bacillus thuringiensis(Bt) crystal protein genes. We transformed three difference Cry1Ac (Cry1Ac and two modified Cry1Ac) genes into Kwangan using highly efficient soybean transformation system. Transgenic plants with Bt crystal protein genes were confirmed for gene introduction and their expression using PCR, real-time PCR, and RT-PCR. We generated 30 independent lines of transgenic soybean plants. Analysis of the flanking sequences isolated by Inverse PCR revealed complex T-DNA insertion patterns and preferential integration of T-DNA into the intergenic spacer region of the soybean genome. We found 5 different intergenic transgenic soybean lines of soybean genome. Currently, the confirmation of stable gene introduction with Bt genes is also performing by southern blot analysis, physiology test, and agronomic characters are investigating.

Totally, 26 collections, 17 from Korea and 9 from China, were investigated for their sequences of 5S rDNA, especially the non-transcribed spacers (NTSs). Sequences of 5S rDNA were isolated by PCR using the primers, 5s-rRNA1 and 5s-rRNA2. Genomic DNA PCR produced single amplification of 300, 330, or 350 base pair fragments. Sequence analysis revealed that all inserts contained the part of 5S rDNA gene sequence and the full length of the NTS region. Three different sizes of the fragments were confirmed due to different size of NTS and their length were 300bp, 330bp and 350bp, respectively. Among 17 Korean foxtail millets tested, 14 collections showed single 300bp amplification. Longest fragment amplification, 350bp, was obtained only from the foxtail millet from China origin, even though 2 of them include 300bp fragment. CLUSTALW multiple alignments of 26 foxtail millets clearly revealed 4 areas with certain degree of sequence heterogeneity (region I, II, III, IV). Among 4 boxed areas, foxtail millet genotypes from China have distinct insertion especially in region III. Five of them have extra insertion of sequence and their additional sequences were either 45 or 48 base pair. Three Korean foxtail millets have 32 bp insertion. Other 8 Korean collections have short insert sequences (6 to 8 bp), 3 with 8 bp and 5 with 6 bp. In addition to insert, deletion sequences were also confirmed as major deletion was observed in region II of Chinese collection. The size of deletion was 7 bp long. According to phylogenic tree constructed using MEGA4 program, clear grouping was not revealed. To obtain more convincing results various collections from many countries should be obtained and analyzed to distinguish different germplasm from different origin.

Twenty two common millet (Panicum miliaceum L.) varieties collected from Korea, China and Russia were investigated for their phylogenetic relationship using 5S ribosomal DNA sequences with a hope to provide the basic information on their exact origin. Sequences of 5S rDNA were isolated by PCR. The primers, 5s-rRNA1 and 5s-rRNA2, were designed to isolate the complete NTS. Genomic DNA amplification produced two fragments with different length, 900 bp and 400 bp fragments, confirming the presence of two types of 5S rDNA repeats that differed from each other in the length of the NTS region. Amplified DNAs of 400 bp fragment were subcloned and used for further investigation. The obtained NTS sequences ranged from 200 to 300 bp and homology of sequences among plant materials was much higher than long repeat. CLUSTALW multiple aligment of 5S rDNA sequences from 22 different common millets revealed the clear difference by their origin. And critically different areas with insert or deletion were also confirmed. Those sequence difference seems to be used for discrimination of cultivars from different origin and use as molecular markers for origin identification. In phylogenic tree construction, the clear classification was shown where the genotypes from China and Russia is positioned together and stay away from domestic genotypes.

Bacillus thuringiensis (Bt) crystal protein genes encode insecticidal δ-endotoxins that are widely used for the development of insect-resistant crops. Common soybean is a crop of economic and nutritious importance in many parts of the world. Korea soybean variety Kwangan was transformed with Bacillus thuringiensis (Bt) crystal protein genes. These genes were transformed into Kwangan using highly efficient soybean transformation system. Transgenic plants with Bt crystal protein genes were confirmed for gene introduction and their expression using PCR, real-time PCR and RT-PCR. Currently, the confirmation of stable gene introduction with Bt genes is also performing by southern blot analysis and physiology test and agronomic characters are investigating.

Cry1Ac protein is known as one of toxin crystal proteins synthesized from Bacillus thuringenesis that plays a critical role for the insect resistance. Recently, cry1Ac genes have introduced into many plants in general and soybean as well. However, the gene expression of cry1Ac genes in transgenic plants remains low that need to be improved. Several mutations we reintroduced into the cry1Ac genes in order to enhance the insecticidal effect. In this study, the cry1Ac with mutant #2, #11 and #16 were transformed into Kwangan, a Korean soybean variety by using the “half-seed” method. The plant lets carrying modified cry1Ac genes were primarily selected on media containing Phosphinothricine (PPT), a bar selective agent and Basta leaf painting. Then, the presence of introduced genes in T0 plants and the gene expression were investigated by PCR, RT-PCR and Real-time PCR. PCR and RT-PCR analysis showed expression of bar and cry1Ac genes from tested transgenic soybean plants. The number of copy of bar gene ranged from 1 to 3 by Real-time PCR analysis. These results provided a fundamental back ground for our further experiments: Confirmation of the gene expression by Southern blot and identification of the function of modified cry1Ac by insect bioessays.

Korean soybean variety Kwangan was transformed with ORE7 gene using highly efficient soybean transformation system. The gene is known to exhibit a delayed leaf senescence phenotype in Arabidopsis. To confirm phenotypic characterization of leaf senescence for non-transgenic (NT) and transgenic plants, we transplanted T1 transgenic lines 7, 9, 14 and 15 together with two negative controls (NT and EV) in greenhouse. As a result, line 15 showed dramatic phenotypic characterization of yield increase and senescence delay. In addition, to investigate the agriculture traits for transgenic plants with leaf senescence delaying, T2 transgenic lines and two negative controls were transplanted on GMO fields in Ochang and harvested T3 seeds (2010). Most transgenic lines showed higher total seed weigh than NT. Especially, total seed weight of line 15 was increased by about 180% and 120% compared with the NT and EV, respectively. Therefore, we carried out the second field experiments with T3 transgenic line 15 and NT in Ochang (2011). A total of 117 transgenic plants were divided into two groups, senescence delaying (64 out of 117 plants) and increased yield (53 out of 117 plants), by transcript level of ORE7 gene. Interestingly, among increased yield plants, total seed weight of each 7 plants were increased by more than 200% compared with NT.

Korean soybean variety Kwangan was transformed with coat protein (CP), helper component-proteinase (HC-Pro), and ABRE binding factor 3 (ABF3) genes using highly efficient soybean transformation system. Among these genes, CP and HC-Pro were transformed using RNAi technology. Transgenic plants with CP were confirmed for gene introduction and their expression using PCR, real-time PCR, RT-PCR, Southern blot, and Northern blot. To investigate the response of viral infection with CP, T1 plants were inoculated with SMV-infected leaves and confirmed the existence of mosaic symptom in both leaves and seeds. Two transgenic lines with CP were highly resistant to SMV with clear leaves and seeds while SMV-susceptible lines showed mosaic symptom with seed mottling. The transcript levels of T1 plants with CP were also determined by northern blot, suggesting that SMV-resistant T1 plants did not show viral RNA expression whereas SMV-susceptible T1 plants showed viral RNA expression. Currently, the response of viral infection with HC-Pro is investigating to produce SMV-resistant soybean transgenic plants, and the physiological experiment with ABF3 is also carrying out to produce drought-tolerant soybean transgenic plants.

Wild rice might have previously unidentified genes important for disease resistance and stress tolerance in response to biotic and abiotic stresses. A set of subtractive library was constructed both from leaves of wild rice plants, Oryza grandiglumis (CCDD, 2n=48), treated with fungal elicitor and from wounded leaves. A partial fragment that was homologous to PR10 genes from other plant species was identified via suppression subtractive hybridization and cDNA macroarray. The obtained full-length cDNA sequence (OgPR10) contains an open reading frame of 480 bp nucleotide, encoding 160 amino acids with a predicted molecular mass of 16.944 kDa and an isoelectric point (pI) of 4.91. The multiple alignment analyses showed the higher sequence homology of OgPR10 with PR10 genes identified in rice plants at amino acid level. The OgPR10 mRNA was not expressed by treatment with wounding, jasmonic acid, and salicylic acid, but markedly expressed in leaves treated with protein phosphatase inhibitors cantharidin and endothall, and yeast extract. In addition, the expression of OgPR10 mRNA was induced within 72 h after treatment with probenazole, one of well-known chemical elicitors, and reached the highest level at 144 h. Heterologous expression of OgPR10 caused growth inhibition and seedling lethality in E. coli and Arabidopsis, respectively. Chemically induced OgPR10 expression with glucocorticoid-mediated transcriptional induction system further reconfirmed its lethality on Arabidopsis seedling. In addition, OgPR10-expressing rice plants, Oryzae sativar were resistant against the infection of rice blast fungus, Magnaporthe grisea. These results indicate that OgPR10 is involved in probenazole- and microbe associated molecular patterns-mediated disease resistance responses in plants and is a potential gene for developing disease resistance crop plants.