Acyl-acyl carrier protein (ACP) thioesterase (TE) catalyze the hydrolysis of the thioester bond that links the acyl chain to the sulfhydryl group of the phosphopantetheine prosthetic group of ACP. This reaction terminates acyl chain elongation of fatty acid biosynthesis, and in plant seeds it is the biochemical determinant of the fatty acid compositions of storage lipids. A full-length cDNA of an acyl-ACP thioesterase, named CvFatB, was isolated from oil plant Cuphea viscosissima accumulating up to 90% caprylate (8:0) and caprate (10:0) in its seed oil. This cDNA contains a 1,245-bp open reading frame that encodes a protein of 415 amino acids. The deduced sequence also contains two essential residues (H317 and C352) for TE catalytic activity and a putative chloroplast transit peptide at the N-terminal. Overexpression of the CvFatB cDNA in Arabidopsis resulted in increased levels of saturated fatty acid, especially palmitate, and reduced levels of unsaturated fatty acids. The findings suggest that CvFatB from oil plant C. viscosissima can function as a saturated acyl-ACP TE and can potentially be used to diversify the fatty acid biosynthesis pathway to produce novel fatty acids.

The influences of ethylene inhibitors (AgNO3 and silver thiosulfate) and cytokinins (BAP and TDZ) on shoot regeneration from cotyledon and hypocotyl explants of B. napus cv. Youngsan were investigated. The presence of 50 μM Silver thiosulfate (STS) in shoot regeneration medium formed shoots at 60-68% after 3-4 weeks of culture, which was enhanced by 2-fold compared to that of Silver nitrate (AgNO3). Moreover, cotyledon explants were more regenerative than hypocotyls; shoots from cotyledon explants began to occur 4-5 days earlier than that of hypocotyl explants. TDZ at a concentration of 8-10 μM was effective for shoot regeneration, compared with BAP. Consequently, the optimal shoot regeneration response was observed in medium supplemented with 50 μM STS + 8 μM TDZ. In transmission electron microscopy (TEM) analysis, higher density of silver nanoparticles was shown to be accumulated widely inside the cell wall and plasmodesmata of regenerating leaf cultured in medium supplemented with AgNO3. By contrast, in the cell cultured in medium with STS, fine-grained deposits were partly observed in the surroundings of the cell wall.

The high quality of gene set is necessary to study the functional research of genes. Although perilla is cultivated as an oil crop and as a vegetable crop in Asian countries such as Korea, Japan, northeast China and Nepal, the reference genome is absent. To assembly perilla gene set, we sequenced the various tissues of perilla (Perilla citriodora) RNA-seq with Illumina HiSeq platform, generating 548,549,314 short reads. When de novo transcriptome assembly was performed with five samples, 86,396 and 38,413 transcripts were assembled as total and representative transcripts, respectively. Using 1,917,424 proteins at Phytozome ver. 9.1, we annotated the perilla assembled transcripts, and 66,139(76.55%) and 24,030(62.55%) transcripts showed the similarity with known plant proteins (E-value < 1e-10) as total and representative transcripts, respectively. Among the diverse molecular functions, we were interested in the regulatory components, such as transcription factor and transcription regulator. Using this data, we identified 499 transcripts annotated the putative transcription factor differentially expressed transcripts. 165 putative transcription factors were significantly expressed in perilla flower and 121 putative transcription factors in both leaf and flower. This study provides the perilla reference gene set and the understanding of the molecular regulation of transcription factor dependent on the tissue.

Citrus canker caused by Xanthomonas citri is a notorious disease affecting a decrease in fruit productivity and quality. Citrus export to USA is also prohibited by the disease. Therefore, development of citrus canker resistant variety is essential and exploitation of markers for molecular breeding is urgent. To develop DNA molecular markers, we performed whole genome resequencing for 8 varieties: 4 citrus canker resistant varieties including C. hybrid ‘Kioymi’ and 4 citrus canker susceptible varieties including C. iyo ‘Miyauchiiyokan’. In total, 642 polymorphic SNPs were detected between resistant and susceptible varieties. Of the 642 SNPs, 50 SNPs were preferably selected based on integrative genomics viewer. To apply the markers in a broad range of citrus variety, we performed genotyping with 6 other varieties very well known as citrus canker resistant and susceptible varieties in addition to previous mentioned 8 varieties. Three of the 50 SNPs were identified as a marker to distinguish citrus canker resistant varieties from susceptible varieties. Secondly, we developed molecular markers to apply for F1 lines crossed by ‘Kiyomi’ and ‘Miyauchiiyokan’. Of the 50 SNPs, we identified 2 SNP markers to distinguish between F1 resistant and susceptible lines. One of them is a resistance gene that plays a role in plant defense mechanism. In this study, we developed 5 molecular marker candidates possible to apply for molecular breeding to develop citrus canker resistant variety. We are working on development of candidate markers related to citrus canker.

To understand the molecular mechanism of leaf morphogenesis in rice, ethylmethane sulfonate (EMS) treated Ilpoom mutant line with semi-narrow and adaxially rolled leaf phenotype was identified. The leaf rolling character is said to be more advantageous under high temperature and heat stress, and play as one of the defensive mechanisms. The F1 plants, generated from a cross of Ilpoom and mutant, showed normal phenotype. Genetic analysis of its F2 population suggested that the mutation was controlled by a single recessive gene with segregation ratio of 3:1. Using F2 mapping population derived from a cross of Ilpoom mutant and Milyang23, each chromosomes were screened with STS markers by the bulked segregant analysis (BSA) method. The candidate region was detected to a long arm of chromosome 1 near the centromeric region. Fine mapping of the locus is currently conducted. Moreover, other morphological characterizations of the mutant plants were identified. Cytological analysis of the leaf suggested that deformation of the bulliform cells led to the smaller size and less number of the bulliform cells, and caused leaf rolling trait.

Radish (Raphanus sativus L.) is a widely-consumed root vegetable that is grown worldwide. To utilize the radish genetic resources for breeding research, we collected radish germplasms and evaluated their morphological and genetical characteristics. Here, phylogenetic relationship of 288 accessions were analyzed using 16 SSR markers and classified cytoplasm male sterility (CMS) types using cpDNA-based molecular markers. To create a collection of 288 accessions, 188 and 73 accessions were selected from RDA-Genebank (Korea) and NIAS-Genebank (Japan), respectively, after generation advancement for the accessions with low uniformity. In addition, 27 elite lines currently used for commercial radish breeding programs were included. In the result of phylogenetic analysis, 288 accessions were clustered into 5 major groups corresponding to the morphological traits and origins at the similarity coefficient value of 0.51. Analysis of CMS types revealed that majority of accessions were determined as DBRMF1 and DBRMF2 mitotypes, 15 accessions to Ogura and 4 accessions to DCGMS mitotypes. Further genetic analysis for radish germplasm will be valuable in assisting radish f1 hybrid breeding.

In order to assess the genetic diversity, phylogenetic relationships and population structure of Korean rice landraces, 76 accessions were estimated using agronomical traits and SSR markers. Among 11 agronomical traits, amylose content (AC) was the trait with the largest variance with values ranged from 4.9 to 28.39 %, while grain length (GL) was the lowest variance ranged from 4.4 to 5.9 cm. In the result of PCA, the first PC with Eigen value of 217.5 explained 60.3% of the total variance. Culm length (CL) was the variable with the largest positive loadings. Growth period (GP) was the positive variances, while AC was the negative variance. The second PC with Eigen value of 80.6 explained an additional 22.4% of the total variance. Growth period (GP) was variable with highest positive loading. Amylose content (AC) was variable with high positive, while CL was the negative variance. The 49 SSR markers produced a total of 473 alleles with an average of 9.6 alleles. The polymorphism information content (PIC) was in the range 0.11 to 0.93. The observed heterozygosity ranged from 0.12 to 0.39, with an average of 0.61. 76 rice accessions showed two subpoplations and three groups based on SSR markers. Group I and Gropu II appertained Pop-2 and Pop-1 subpopulation, respectively. They showed similar agronomical traits. Group III consisted 7 rice accessions predominantly appertained to Pop-1. These results provide insight into the characters of Korean rice landraces and help to improve our knowledge of rice breeding

Flavonoids and total polyphenols are important secondary plant metabolites, as they play a role in reducing the oxidative stress caused by ROS In this study, we investigated for flavonoid contents, total polyphenol contents, and antioxidant activities in 27 accessions from 10 Vicia species. Among 27 vicia accessions, NAC17 (V. monantha) and NAC14 (V. hyrcanica) had the highest total flavonoid (1.42 ± 0.09 mg/g) and total polyphenol (124.2 ± 0.5 μg/GAE mg) contents, respectively. In four flavonoids, naringenin showed the highest concentrations in Vicia species. The DPPH and ABTS were the range from 0.2 (NAC24, V. sativa subsp. nigra) to 18.5 (NAC13, V. faba) μg/ASC mg and 19.1 (NAC7, V. cracca) to 253.4 (NAC13, V. faba) μg/Trolox mg, respectively. Among the 10 Vicia species, V. monantha and V. hyrcanica had the highest flavonoid (1.31 ± 0.09 mg/g) and total polyphenol (116.5 ± 2.0 μg/GAE mg) contents, respectively. The highest antioxidant activity was detected in V. faba. These results will expand the flavonoid database and provide information on Vicia species valuable for development of functional foods or feed-additives resources.

Citrus canker caused by Xanthomonas citri pv. citri is one of economically important diseases in the citrus industry. The devastating bacterial disease results in unattractive quality and a significant reduction in fruit production. Citrus growers and industry in Korea has been struggling with the serious disease causing the prohibition of export market. Korea also became the top import market for oranges. The development of markers linked to citrus canker resistance is strongly needed. In this study, we investigated molecular markers between ‘Kiyomi’ (Citrus unshiu ｘ C. sinensis), a resistant cultivar, and Natsudaidai (C. natsudaidai), a susceptible cultivar. To develop markers, we focused on structural variation (copy number variation, CNV, and presence/absence variation, PAV). It has been well documented that CNV and PAV of defense-related genes are associated with resistant cultivars. Using a read depth approach following next-generation sequencing, we performed genome-wide analysis of CNV and PAV in two varieties. As a result, 633 genes showing at least two times difference between the mapping reads from two varieties and 61 genes showing presence of the mapping reads in only either one of them were screened. Visual inspection using the Integrative Genomics Viewer (IGV) was performed and experimental validation is being investigated. Interestingly, one of PAV candidates showed polymorphism in ‘Kiyomi’ and ‘Natsudaidai’ as well as other resistant and susceptible cultivars. Our results suggest a necessity for the detection of structural variation and indicate that the candidates may be useful for molecular breeding for citrus canker resistance and understanding disease resistance mechanism.

Single nucleotide polymorphisms (SNPs) are the most abundant variation in plant genomes. As DNA markers, SNPs are rapidly replacing simple sequence repeats (SSRs) and sequence tagged sites (STSs) markers, because SNPs are more abundant, stable, easy to automation, efficient, and increasingly cost-effective. We developed a 96-plex indica/japonica SNP genotyping set for genetic analysis and molecular breeding in rice using Fluidigm platform. Informative SNPs for indica/japonica populations were selected from 1536 Illumina SNPs and 44K Affymetrix SNP chip data of Rice Diversity and our resequencing data sets. Selected SNPs were evenly distributed across 12 chromosomes and average physical distance between adjacent SNP markers was 4.38Mb. We conducted genetic diversity analysis of 49 Bangladesh germplasm and check varieties to test a 96-plex indica/japonica SNP genotyping set we developed. High-throughput Fluidigm SNP genotyping system will serve a more efficient and valuable tool for genetic diversity analysis, DNA fingerprinting, quantitative trait locus (QTL) mapping and background selection for crosses between indica and japonica in rice. This work was supported by a grant from the Next-Generation BioGreen 21 Program (Plant Molecular Breeding Center No. PJ008125), Rural Development Administration, Republic of Korea.

Ramie (Boehmeria nivea L. Gaudich.) is a hardy perennial herbaceous plant of the Urticaceae family and has been grown as a fiber crop in several countries including Korea for many centuries. Ramie leaves also have been traditionally used as a major ingredient of a type of rice cake called ‘Song-pyun’ in the Southwest area of Korea, especially Yeong-Gwang province. Despite its economic importance, the molecular genetics of ramie have not been studied in detail yet. Genetic resources of ramie were widely collected from domestic local sites by Bioenergy Crop Research Center (RDA) and Yeong-Gwang Agricultural Technology Center. For the systematic and efficient management of the genetic resources, we developed microsatellite molecular markers of ramie. To do this, we generated microsatellite-enriched genomic DNA libraries using magnetic bead hybridization selection method. 216 contigs containing microsatellite repeat motif were generated using nucleotide sequences of 376 clones from the libraries. Primer sets were designed from the flanking sequences of the repeat motif. Finally, we selected 26 microsatellite markers, possibly showing polymorphism among the genetic resources. Results on the genotype analysis of the ramie genetic resources using the microsatellite markers will be presented.

To determine the expression levels of genes related to the salt stress response in rice, gene expression profiles were investigated through microarray analysis using the rice mutant line Till-II-877. There were no significant changes in physiological response under salt stress of the mutant increased less than that in the WT. The intensity of gene expression was analyzed and compared between the wild type and mutant lines using a microarray. Among the most significantly affected pathways, α-linolenic acid metabolism and linoleic acid metabolism (in lipid metabolism), fructose and mannose metabolism and glycolysis-gluconeogenesis (in carbohydrate metabolism), cysteine and methionine metabolism (in amino acid metabolism), and carbon fixation (in the energy metabolism of photosynthetic organisms) showed changes in gene expression levels under salt stress. These results further our understanding of the effects of salt stress in rice and may aid in the development of salt-tolerant rice cultivars.

Soluble sugar content in soybean seed is an important quality attribute for soyfood and feed. Usually, soluble sugars comprise 6 to 17% of total dry wt. in mature soybean seeds. In this study, 414 soybean mutant lines induced by gamma-ray were screened by colormetric assay, FACE (Fluorophore-assisted carbohydrate electrophoresis), and GC-MS to identify the change of soluble sugar contents. Among 414 soybean mutant lines, 12 mutant lines derived from three different soybean cultivars (Hwanggum, Paldal, and Bangsa) showed higher level of soluble sugar content compared to their original cultivars. However, 5 mutant lines derived from soybean landrace KAS 636-15 showed lower level in the colormetric assay. In FACE, 17 soybean mutant lines selected by colormetric assay also showed different band intensity compared with their original cultivars. However, there were no different soluble sugar patterns between soybean original cultivars and mutant lines. Finally, the variations of soluble sugar content in 17 soybean mutant lines were confirmed by using GC-MS. These mutant lines will be used for genetic study to find mutations of genes related soluble sugar biosynthesis.

Recently, detection of esophageal diverticula by neck ultrasonography has been increasing. In particular, esophageal diverticula near the thyroid gland can be diagnosed as thyroid nodule on ultrasonography. To date, 13 cases of ultrasonographic features of Killian-Jamieson (K-J) diverticula have been reported. We report on four cases of K-J diverticula and discuss clinical characteristics, including ultrasonographic findings, in comparison with previously reported cases. Awareness of ultrasonographic finding of esophageal diverticula, a hypoechoic nodule containing echogenic foci found in the posterolateral aspect of the thyroid, is most important for making a differential diagnosis of K-J diverticulum from a thyroid nodule.

Next generation sequencing (NGS) approaches can also be useful tool for characterization of organelle genomes. We generated chloroplast (CP) genome sequences of two Korean ginseng cultivars, Chunpoong and Yunpoong, based on reference-guided assembly using whole genome NGS data. We used 0.5x of P. ginseng genome NGS reads to assemble CP genome. Of the NGS reads used, about 6% were mapped to the reference CP genome with mean coverage of 94x due to high copy number of CP genome in plant cell. CP genomes of the two cultivars were predicted to be 156,248 bp and 156,355 bp in length and showed about 0.1% differences at nucleotide level, compared to reference CP genome sequenced from P. ginseng (Acc.no. NC_006290), whereas difference between CP genomes of the two cultivars is very rare. In this study, we developed the molecular marker to perform taxon identification and also to elucidate phylogenetic relationship among Korean ginseng cultivars. Now, we are analyzing the CP genomes of other P. ginseng cultivars together with other Panax species including American ginseng and Panax related species.