An important worldwide plant source of dietary protein and oil, modern breeding and improvement of soybean is suffered from a narrow cultivated germplasm relative to other crop species likely because of underuse of wild soybeans as breeding resources. SNP genotyping array is regarded as a promising tool for dissecting wild and cultivated germplasms to find important adaptive genes by high-density genetic mapping and genome-wide association studies (GWAS). Here, we present the establishment of a large soybean SNP array and its use for diversity analysis and high density linkage mapping. More than 4 million high-quality SNPs identified from 16 high-depth and 31 low-depth soybean genome resequencing data were used to select 180,961 SNPs for the AxiomÒ SoyaSNP array. Our validation analysis for a set of 222 diverse soybean lines showed that a total of 171,161markers were of good quality for genotyping. Of the converted SNPs, 82.6% 82.6% SNPs had a marker spacing of less than 9 kb and 17.4% SNPs greater than 9 kb with the 297 inter-SNP spacings of >100 kb and with 812 kb of the largest spacing, thereby suggesting that our array is likely suitable for GWAS of soybean germplasm. This array is being used to construct high-density genetic map in populations generated from intermatings of two cultivated and two wild soybeans, with an objective to confirm large structural variations of chromosomes using the ultra-high-density maps

The PepMoV has been considered the most frequently detected potyvirus. When it co-infects with CMV or PMMoV, it gives severe impact to total pepper harvest in Korea. Since F1 hybrid that resistant to PepMoV has not been developed, we have developed transgenic peppers using Agrobacterium-mediated transformation with a Hc-Pro gene of the PepMoV. A large number of GM peppers were tested for resistance to the PepMoV, and after consequent self-crossing up to T4 generation, a highly tolerant pepper to PepMoV called T20 was selected. So far, BC4F1 lines have been selected by back-crossing with 4 elite lines through a breeding program. Very recently, based on molecular analysis, we have selected another event, #10-2, which is also resistant to PepMoV. Horticultural difference was investigated for both GM lines, #T20 and 10-2, and no significance was found comparing to non-GM lines.

Unfavorable environmental stresses are major limiting factors that affect plant productivity. Plants perceive and respond adaptively to an abiotic stress condition, and the adaptive process is controlled mainly by phytohormone, consequently, changing in gene expression pattern. Transcriptional regulator ABF3 (Abscisic acid response element Binding Factor 3) mediating the ABA-responsive gene expression plays important roles in drought and temperature tolerance. Here, we report an event of drought tolerant GM gourd in which abf3 was inserted in the genome. For drought stress experiment, T0 plants were self-pollinated and back-crossed to select cultivars for drought stress experiment. The drought tolerant GM gourds were selected for last 3 years and have been crossed to get the several BC and T generation consecutively. In this year, BC3T1, F1 (Bak x GM gourd), BC1F1 and control plants were subjected to drought stress, that is no watering for 12 days and rehydration afterwards. The GM gourds showed high tolerance to drought while the non-transformed plants were totally dried. When the plants were subjected to rehydration, the GM bottle gourds were completely revived and recovered from the drought stress. Tolerance levels to drought of BC3T1, F1 (Bak x GM gourd) and BC1F1 were 92.5%, 50.0% and 65.0%, respectively.

Bt gene derived from the B. thuringiensis has been used for developing GM crops, and corn, cotton and soybean producing B. thuringiensis toxins have been on the market for last 17 years or so creating a huge GM seed industry. One of the notorious pests in brassica crops is diamondback moth (DBM). In order to protect the insect plague of crops from DBM, 4-5 billion dollars have been wasted annually for applying integrated measures in worldwide. Major prevention is use of pesticides that may build the contamination level of chemicals in the ground and this practice threats the environment and ecosystem. An alternative is to develop GM brassica crops and therefore we have developed GM cabbages resistant DBM using bt gene. Lots of T0 cabbages were tested for resistance and independent GM cabbages resistant to DBM were selected. Molecular analysis was conducted to find if GM cabbage holds one copy transgene and intergenic insertion. We found an independent GM cabbage and it contained a singly copy of the transgene without disturbing the insertion site. This one called C95 line with an status of event have been self-crossed for two generation (T2). Also we are working the development of GM cabbage with different vector that contains bar gene as a selection marker. So far 17 T0 cabbages have been obtained by bar selection.

Many viruses infect cucurbits. One of the well-known symptoms is mosaic disease. Those that cause mosaic are cucumber mosaic virus (CMV), squash mosaic virus (SqMV), watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV) and cucumber green mottle mosaic virus (CGMMV). WMV resistant GM squash was developed many years ago in the United States and it was on the market, but no further information was available by now pertinent to commercial aspect. Usually these viruses are not easily controlled by frequent applications of chemicals that target the insect as carriers of viruses. Therefore, it is necessary to develop commercial varieties possessing resistance against viral diseases. We have developed GM watermelon rootstocks called gongdae, using a coat protein gene of CGMMV as transgene. Those GM watermelon rootstocks showed highly resistant to CGMMV, and have been crossed to get the several BC and T generation. In order to obtain the virus resistant watermelon, watermelon lines were crossed to the selected GM watermelon rootstock. Here, we present the successful watermelon cultivars that show resistance to CGMMV. The resistance must have obtained by transferring the transgene from the GM watermelon rootstock to watermelon line

In Korea, CMV (cucumber mosaic virus) is the most frequently occurring virus with a single infection rate of 45%. However, a total occurrence of CMV by co-infection, either couple or multiple, with BBWV (broad bean wilt virus), PepMoV (pepper mottle virus) and PMMoV (pepper mild mottle virus) covers over 90% in the field cultivation of pepper. The PepMoV is transmitted by several aphid species, and it has been considered the most frequently detected potyvirus when it co-infects with CMV or PMMoV. Since F1 hybrid that resistant to PepMoV has not been developed, we have developed transgenic peppers using Agrobacterium-mediated transformation with a Hc-Pro gene of the PepMoV. A large number of T1 peppers were tested for resistance to the PepMoV, and T1 peppers tolerant of PepMoV were selected. After consequent self-crossing up to T4 generation, highly tolerant peppers to PepMoV were selected. So far, BC3F1 lines have been selected by back-crossing with 4 elite lines through a breeding program. The horticultural differences of the GM line comparing to inbred lines were investigated and no statistical significance between GM and non-GM lines was found. Based on molecular analysis, One of GM lines, 10-2, contained the transgene in the non-coding region indicating that this line would be a GM event.

Many viruses infect cucurbits. One of the well-known symptoms is mosaic disease. Those that cause mosaic are cucumber mosaic virus (CMV), squash mosaic virus (SqMV), watermelon mosaic virus (WMV), zucchini yellow mosaic virus (ZYMV) and cucumber green mottle mosaic virus (CGMMV). WMV resistant GM squash was developed many years ago in the United States and it was on the market, but no further information was available by now pertinent to commercial aspect. Usually these viruses are not easily controlled by frequent applications of chemicals that target the insect as carriers of viruses. Therefore, it is necessary to develop commercial varieties possessing resistance against viral diseases. We have developed GM watermelon rootstocks called gongdae, using a coat protein gene of CGMMV as transgene. Those GM watermelon rootstocks showed highly resistant to CGMMV, and have been crossed to get the several BC and T generation. In order to obtain the virus resistant watermelon, watermelon lines were crossed to the selected GM watermelon rootstock. Here, we present the successful watermelon cultivars that show resistance to CGMMV. The resistance must have obtained by transferring the transgene from the GM watermelon rootstock to watermelon line.

Bt gene derived from the B. thuringiensis has been used for developing GM crops, and corn, cotton and soybean producing B. thuringiensis toxins have been on the market for last 16 years or so creating a huge GMO industry. One of the notorious pests in brassica crops is diamond backmoth (DBM). In order to protect the insect plague of crops from DBM, 4-5 billion dollars have been wasted annually for applying integrated measures in worldwide. Major prevention is use of pesticides that may build the contamination level of chemicals in the ground and this practice threats the environment and ecosystem. An alternative is to develop GM brassica crops and therefore we have developed GM cabbages resistant DBM using bt gene. Lots of T0 cabbages were tested for resistance and independent GM cabbages resistant to DBM were selected. Molecular analysis was conducted to find GM cabbage to hold one copy transgene and intergenic insertion. We found two independent GM cabbages as an event and those have been self-crossed for two generation. Also we are working the development of GM cabbage with different vector that contains bar gene as a selection marker.

Soybean is one of the most important crop plants used for seed protein and oil content that has undergone substantial phenotypic and physiological changes during domestication. Thanks to the advent of the next-generation sequencing platforms, genome sequences of many major crop plants including soybean and maize have been unraveled. We have resequenced the genomes of 10 cultivated soybean and 6 accessions of their wild progenitors (Glycine soja) selected from the Korean soybean germplasm to >15 × raw data coverage. We have investigated genome-wide variation patterns in soybean and obtained millions of high-quality single nucleotide polymorphisms (SNPs). Further analyses of the extracted SNPs including population structure analysis, introgressions, linkage disequilibrium, and reduction of diversity are ongoing in order to provide an unprecedented opportunity to finely resolve the domestication history of cultivated soybean. At the same time, we have conducted a comparison study between the Williams 82 soybean reference genome sequence and a genetic map. Here, I will present our current analysis status of the soybean genome resequencing data. Then, I present our recent progresses in the understanding of dynamic genetic features of soybean chromosome revealed by comparison of genetic and sequence-based physical maps in which we have used a portion of our resequencing data to substantiate putative introgression region detected during the construction of a genomewide soybean genetic map.

Soybeans X soybeans mosaic virus (SMV) strains interactions affected plant growth and seed transmission. Strain virulence of SMV depended on host cultivars. Kwangankong and Tawonkong were susceptible to G7H and G5 strains, causing mosaic symptoms. The distribution patterns of two SMV strains in soybean plants inoculated with G7H, G5 and G7H/G5 sets were investigated by RT-PCR/RFLP analysis. In the first treatment, two primary leaves in a single plant were infected with both strains by means of one strain per leaf. The leaves of Kwangankong and Tawonkong at V2, V4 and V6 stage were doubly infected with the two strains and the upper leaves than those had only G7H strain. Secondly, the two soybeans were inoculated with G7H, and 24 h after followed by the other strain inoculation. The leaves of V6 and V8 stages in all infected plants showed mosaic symptoms caused by G7H, and there was no detection of G5 strain. In contrast, the reverse treatment with G5 and G7H induced different results. Pre-inoculated G5 strain detected in every stage besides G7H strain. Host X SMV strain compatibility influenced seed coat mottling, yield, plant height, number of pod per plant. G7H had a seed mottling rate of 98.5% in Kwangankong, while G5 had an incidence of seed mottling of 1.4% in the same cultivar. G5 was more virulent to Kwangankong and had a lower affinity for infecting soybean seed mottling. Additional inoculation of G7H protected soybean yield and growth from G5-inducing loss in Kwangankong.

Transgenic plants that over express virus coat protein genes have attracted particular interest from researchers, by virtue of their tolerance to virus infection. The transgenic watermelon rootstock analyzed in this study was established by introducing CGMMV coat protein (cp) under the control of CaMV 35S promoter and NOS terminator (Park et al., (2005) Plant Cell Rep. 24: 350-6). The primary objective of this study was to determine the copy number and integration site of the transgene element, in order to develop detection techniques required for monitoring of the transgenic watermelon rootstock. The Southern blot analysis indicated that a single copy of CGMMV-cp gene was inserted into the genome of transgenic watermelon rootstock. We also identified the genomic sequences flanking the integration site of the transgene by inverse PCR analysis. In an effort to find a sequence usable as an internal positive control for the screening of the watermelon and watermelon rootstock, we found that the Sat and DIP-1 genes appears as one copy within their genomes and is watermelon rootstock- and watermelon-specific. The information of the integrated site and the internal positive control sequence was used to establish a new event-specific PCR-based detection method. In addition, mRNA and protein expression level of the transgene in the transgenic watermelon rootstock and grafted watermelon were investigated. The expression of both mRNA and protein of CGMMV-CP was not detected in the transgenic watermelon rootstocks and watermelons, suggesting that the movement of transgene products from transgenic rootstock to watermelon does not occur at our detection level.

Most soybean cultivars have ovate leaflets, although a few cultivars have narrow or lanceolate leaflets. Narrow leaflet cultivars tend to have more seeds produced per pod than ovate leaflet cultivars, suggesting that the narrow leaflet trait is tightly linked to or cosegregating with the trait controlling number of seeds produced per pod (nspp). The objective of this study was to construct a high resolution map of a chromosomal region controlling narrow leaflet trait and nspp in soybean. A BC3F2 population from a cross between 'Sowonkong' and 'V94-5152' was used. Sowonkong have narrow leaflet and 4-seeded pod and V94-5152 have ovate leaflet and do not have 4-seeded pod. The plants of F2 populations showed a segregation ratio of 3:1 of ovate leaflet to narrow leaflet and then leaflet genotypes were obtained from F2:3 population of each F2 individual. The narrow leaflet-containing plants showed Sowonkong-like pod trait and the ovate leaflet-containing plants V94-5152-like pod trait. The results suggested that, in our mapping population, a single gene controls inheritance of the narrow leaflet character and the narrow leaflet trait is tightly linked to or co-segregating with the trait controlling nspp. Subsequently, we mapped the narrow leaflet locus near Sat_105, Satt270 and SM315 on soybean linkage group I that corresponds with the previously known ln locus. Work is ongoing to construct a fine molecular genetic linkage map on this MLG I region and to find a linkage relationship between ln and nspp. Our results should facilitate further elucidation for the relationship between ln/nspp and yield.

Proanthocyanidins and anthocyanins derived from the phenylpropanoid pathway most likely play a protective function from pathogens and UV light exposure within the plant and, in addition, act as signal molecules in plant-microbe interactions. The metabolites are now attracting attention because of the medicinal and nutritional values due to their antioxidant properties and flavors. Three independent loci (I, R, and T) control pigmentation of the seed coats determined by proanthocyanidins and anthocyanins in soybean (Glycine max). The I locus controls distribution of anthocyanin and proanthocyanidin pigments, which in its dominant form exhibits homology-dependent gene silencing leading to a yellowish seed coat. The R and T genes determine the anthocyanin and proanthocyanidin products and specific seed coat color such as black, imperfect black, brown, or buff. The I and T loci have been cloned. The objectives of this study were to develop PCR-based molecular markers cosegregating with the genetic loci controlling the biosynthesis of these interesting metabolites using public soybean EST and genomic sequence data and is to develop molecular markers to establish a marker-assisted selection scheme for these natural products-related traits. A population of 112 F11 recombinant inbred lines generated by an interspecific cross between a Glycine max line 'Hwangkeumkong' and a G. soja Siebold & Zucc. line ‘IT182932' was used to construct a frame map consisting of 20 soybean linkage groups. The frame map contains over 300 SSR, RAPD and transposon markers. PCR-based molecular markers cosegregating with the I and T loci that control pigmentation of the seed coats determined by secondary metabolites derived from the flavonoid pathway including anthocyanins and proanthocyanidins in soybean have been developed. We have developed three SSR cosegregating with the I locus and one codominant STS and one SNP markers cosegregating with the T locus. So far, we have developed SSR, SNP, and STS markers cosegregating with the I locus and with the T locus. Work is in progress to develop markers cosegregating with other genetic loci. The markers will facilitate markers-assisted selection of seed coat colors in molecular breeding programs.