• Molecules and Cells
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• v.26 no.6
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• pp.595-605
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• 2008

Genome wide transcription analysis in response to stresses is essential to provide the basis of effective engineering strategies to improve stress tolerance in crop plants. In order to perform transcriptome analysis in Brassica rapa, we constructed a B. rapa oligo microarray, KBGP-24K, using sequence information from approximately 24,000 unigenes and analyzed cold ($4^{\circ}C$), salt (250 mM NaCl), and drought (air-dry) treated B. rapa plants. Among the B. rapa unigenes represented on the microarray, 417 (1.7%), 202 (0.8%), and 738 (3.1%) were identified as responsive genes that were differently expressed 5-fold or more at least once during a 48-h treatment with cold, salt, and drought, respectively. These results were confirmed by RT-PCR analysis. In the abiotic stress responsive genes identified, we found 56 transcription factor genes and 60 commonly responsive genes. It suggests that various transcriptional regulatory mechanisms and common signaling pathway are working together under the abiotic stresses in B. rapa. In conclusion, our new developed 24K oligo microarray will be a useful tool for transcriptome profiling and this work will provide valuable insight in the response to abiotic stress in B. rapa.

• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.590-600
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• 2017

A total of 447 accessions consisting of seven Brassica spp.; Brassica carinata (34), B. juncea (199), B. rapa subsp. dichotoma (18), B. rapa. subsp. oleifera (14), B. rapa subsp. rapa (36), B. rapa subsp. trilocularis (56) and B. alba subsp. alba (90) were studied for their morphological characters and fatty acid compositions. There was a wide variation for morphological traits, oil content and fatty acid composition among Brassica species. Seed number/silique and yield/plant were varied from 4.2 (B. alba) to 25.1 (B. rapa subsp. trilocularis) and from 170.7 g (B. rapa subsp. oleifera) to 351.9 g (B. juncea L. Czern.), respectively. Among Brassica species, B. rapa subsp. trilocularis exhibited the highest oil (29.2%), stearic (20.4%) and erucic acid (45.3%) content. B. carinata had the highest content of palmitic (5.2%), oleic (21.2%) and linolenic acid (11.1%). B. rapa subsp. dichotoma and B. rapa subsp. oleifera exhibited the highest content of linoleic (8.1%) and behenic (26.9%) acid, respectively. B. rapa subsp. trilocularis exhibited the highest (45.3%) erucic acid content and significant positive relationship was observed between oleic acid and linoleic acid. This variation of agronomic and fatty acid compositions in Brassica species can be utilized to develop new varieties.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.153-165
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• 2010

Brassica rapa is considered an ideal candidate to act as a reference species for Brassica genomic studies. Among the three basic Brassica species, B. rapa (AA genome) has the smallest genome (529 Mbp), compared to B. nigra (BB genome, 632 Mbp) and B. oleracea (CC genome, 696 Mbp). There is also a large collection of available cultivars of B. rapa, as well as a broad array of B. rapa genomic resources available. Under international consensus, various genomic studies on B. rapa have been conducted, including the construction of a physical map based on 22.5X genome coverage, end sequencing of 146,000 BACs, sequencing of >150,000 expressed sequence tags, and successful phase 2 shotgun sequencing of 589 euchromatic region-tiling BACs based on comparative positioning with the Arabidopsis genome. These sequenced BACs mapped onto the B. rapa genome provide beginning points for genome sequencing of each chromosome. Applying this strategy, all of the 10 chromosomes of B. rapa have been assigned to the sequencing centers in seven countries, Korea, UK, China, India, Canada, Australia, and Japan. The two longest chromosomes, A3 and A9, have been sequenced except for several gaps, by NAAS in Korea. Meanwhile a China group, including IVF and BGI, performed whole genome sequencing with Illumina system. These Sanger and NGS sequence data will be integrated to assemble a draft sequence of B. rapa. The imminent B. rapa genome sequence offers novel insights into the organization and evolution of the Brassica genome. In parallel, the transfer of knowledge from B. rapa to other Brassica crops would be expected.

• Molecules and Cells
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• v.23 no.2
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• pp.145-153
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• 2007

Elucidation of the roles of circadian associated factors requires a better understanding of the molecular mechanisms of circadian rhythms, control of flowering time through photoperiodic pathways, and photosensory signal transduction. In Arabidopsis, the APRR1 quintet, APRRs 1, 3, 5, 7, and 9, are known as central oscillator genes. Other plants may share the molecular mechanism underlying the circadian rhythm. To identify and characterize these circadian response genes in Brassica crops whose genome was triplicated after divergence from Arabidopsis, we identified B. rapa BAC clones containing these genes by BLAST analysis of B. rapa BAC end sequences against the five corresponding Arabidopsis regions. Subsequent fingerprinting, Southern hybridization, and PCR allowed identification of five BAC clones, one for each of the five circadian-related genes. By draft shotgun sequencing of the BAC clones, we identified the complete gene sequences and cloned the five expressed B. rapa circadian-associated gene members, BrPRRs 1, 3, 5, 7, and 9. Phylogenetic analysis revealed that each BrPRR was orthologous to the corresponding APRR at the sequence level. Northern hybridization revealed that the five genes were transcribed at distinct points in the 24 hour period, and Southern hybridization revealed that they are present in 2, 1, 2, 2, and 1 copies, respectively in the B. rapa genome, which was triplicated and then diploidized during the last 15 million years.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1528-1533
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• 2005

To evaluate the anti-hyperlipidemic effect of Brassica rapa L. and its major compound, $\beta$-sitosterol, the present study was undertaken, hypercholesterolemia was induced in rats with poloxamer-407, Triton WR-1339, 30% corn oil high cholesterol diet. The ethanol extract of Brassica rapa L. significantly decreased total cholesterol (TC), phospholipid, triglyceride at doses of 200 mg/kg, and $\beta$-sitosterol significantly exerted anti-hyperlipidemic activity at a dose of 15 mg/kg in rats with hyperlipidemia. Taken together, Brassica rapa L. and $\beta$-sitosterol can be useful agents for the prevention or treatment of hyperlipidemia.

• Journal of Plant Biotechnology
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• v.35 no.4
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• pp.317-327
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• 2008

Phytocystatins, which are inhibitors of plant cysteine peptidases, are involved in the regulation of protein turnover and in the defense against insect pests and pathogens. Extensive searches in the Brassica rapa genome allowed the prediction of at least eight different phytocystatin genes on seven chromosomes in the B. rapa genome. Structure comparisons based on alignments of the all BrCYS ($\underline{B}$. $\underline{r}apa$ $phyto{\underline{cys}}tatin$) proteins using the CLUSTALW program revealed conservation of the three consensus motifs known to interact with the active site of cysteine peptidases. According to the phylogenetic analysis based on the deduced amino acid sequences, the eight BrCYS proteins were divided into several clusters related to the orthologous phytocystatin. The predicted three-dimensional structure models of the eight BrCYS proteins demonstrate that all of these proteins are similar to the reported crystal structure of oryzacystatin-I (OC-I). Digital northern and RT-PCR analyses indicated that the eight BrCYS genes exhibit different expression patterns in B. rapa tissues and respond differently to abiotic stimuli. The differences in gene structure and expression between the eight BrCYS genes suggest that these proteins may play diverse physiological roles in B. rapa and may interact with cysteine peptidases through different mechanisms.

• Molecules and Cells
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• v.22 no.3
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• pp.300-307
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• 2006

Brassica rapa ssp. pekinensis (Chinese cabbage) is an economically important crop and a model plant for studies on polyploidization and phenotypic evolution. To gain an insight into the structure of the B. rapa genome we analyzed 12,017 BAC-end sequences for the presence of transposable elements (TEs), SSRs, centromeric satellite repeats and genes, and similarity to the closely related genome of Arabidopsis thaliana. TEs were estimated to occupy 14% of the genome, with 12.3% of the genome represented by retrotransposons. It was estimated that the B. rapa genome contains 43,000 genes, 1.6 times greater than the genome of A. thaliana. A number of centromeric satellite sequences, representing variations of a 176-bp consensus sequence, were identified. This sequence has undergone rapid evolution within the B. rapa genome and has diverged among the related species of Brassicaceae. A study of SSRs demonstrated a non-random distribution with a greater abundance within predicted intergenic regions. Our results provide an initial characterization of the genome of B. rapa and provide the basis for detailed analysis through whole-genome sequencing.

• Korean Journal of Pharmacognosy
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• v.35 no.3 s.138
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• pp.259-263
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• 2004

Twelve constituents were isolated from the MeOH extract of the root of Brassica campestris L. ssp rapa. They were identified as linoleic acid methylester (1), palmitic acid (2), ${\beta}-sitosterol$ (3), 1-methoxyindole-3-acetonitrile (4), indole-3-acetonitrile (5), linolenic acid (6), goitrin (7),4-hydroxycinnamyl alcohol (8), coniferyl alcohol (9), p-coumaroylglucose (11) and feruloylglucose (12), on the basis of spectral data respectively.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.42-46
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• 2008

The community size of culturable heterotrophic bacteria and community level physiological profiles (CLPP) in the rhizosphere of Brassica rapa subsp. pekinensis (Chinese cabbage) were analyzed in two different sites. The average community size of culturable heterotrophic bacteria ranged between $2.65\times10^6CFU\;g^{-1}$ soil (Suwon) and $3.75\times10^6CFU\;g^{-1}$ soil (Yesan), whereas those of bulk soils ranged between $2.45\times10^6CFU\;g^{-1}$ soil (Suwon) and $2.97\times10^6CFU\;g^{-1}$ soil (Yesan). The average functional richness of Suwon rhizoshpere was 90.8, whereas that of Yesan rhizosphere was 154.1. High level of correlation was found between the community size and functional richness. The most actively utilized substrates in both rhizospheres were adonitol, L-asparagine, D-gluconic acid, L-glutamic acid and D-galacturonic acid. Clear differences were seen in the utilization patterns between the two sites. Differences were also observed for the patterns of bulk soils between the two sites, although D-raffinose and D-mannose were found as the commonly utilized substrates.

• Molecules and Cells
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• v.23 no.3
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• pp.349-356
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• 2007

Simple Sequence Repeats (SSRs) represent short tandem duplications found within all eukaryotic organisms. To examine the distribution of SSRs in the genome of Brassica rapa ssp. pekinensis, SSRs from different genomic regions representing 17.7 Mb of genomic sequence were surveyed. SSRs appear more abundant in non-coding regions (86.6%) than in coding regions (13.4%). Comparison of SSR densities in different genomic regions demonstrated that SSR density was greatest within the 5'-flanking regions of the predicted genes. The proportion of different repeat motifs varied between genomic regions, with trinucleotide SSRs more prevalent in predicted coding regions, reflecting the codon structure in these regions. SSRs were also preferentially associated with gene-rich regions, with peri-centromeric heterochromatin SSRs mostly associated with retrotransposons. These results indicate that the distribution of SSRs in the genome is non-random. Comparison of SSR abundance between B. rapa and the closely related species Arabidopsis thaliana suggests a greater abundance of SSRs in B. rapa, which may be due to the proposed genome triplication. Our results provide a comprehensive view of SSR genomic distribution and evolution in Brassica for comparison with the sequenced genomes of A. thaliana and Oryza sativa.