Crops are exposed to various environmental stresses. These have been affecting the growth of crops, resulting in the severe loss of agronomic production in many countries. Therefore, development of new varieties of resistant crops is required to assure the desired productivity of crops in stress conditions. In this study, a putatively stress-related gene BrTSR53 was isolated from Brassica rapa. The BrTSR53 is 481 bp long and contains ORF region of 234 bp. The expression of BrTSR53 was determined by quantitative real-time PCR analysis. After 3 hr, the highest quantities of mRNA were revealed in cold and salt stress treatments. In drought stress treatments, there was the highest expression after 36 hr. Therefore, it was confirmed that the ORF in BrTSR53 should be a gene that confer increased resistance to B. rapa growing in different stress conditions. The ORF region of BrTSR53 gene was cloned into an expression vector, pYES-DEST52, and a new protein with molecular weight of 13 kDa was detected by western blot analysis. Also, stress tolerance tests showed that BrTSR53-ORF transgenic yeast exhibited increased resistance to the salt stresses compared with the control. In conclusion, the present data predicts that novel ORF in BrTSR53 can serve as an important genetic resource for abiotic stress resistance.

Secondary plant metabolites undergo several modification reactions, including glycosylation and physiological functions. Glycosylation, which is mediated by UDP-glycosyltransferase (UGT), plays a role in the storage of secondary metabolites and in defending plants against stress. In this study, a UDP-glucosyltransferase cDNA was isolated from Brassica rapa hereinafter referred to as BrUGT. It has a full-length cDNA of 1,236 bp that contains a single open reading frame of 834 bp which encodes a polypeptide of 277 amino acid residues with a calculated mass of 31.19 kDa. BLASTX analysis hits a catalytic domain of glycos_transf_1 super family (c112012) that belongs to the glycosyltransferases group 1 with tetratricopeptide (TPR) regions. UGT gene expression analysis showed high mRNA transcripts in pistil, followed by petal, seed and calyx of flower in Brassica rapa. Furthermore, we constructed a recombinant pFLCIII vector carrying the BrUGT gene under the control of ubiquitin promoter and NOS terminator and transformed into rice using Agrobacterium tumefaciens. The UGT overexpressing rice lines were then characterized at the physiological and molecular levels. To further understand the biological function of BrUGT, transcriptional profiling of the gene in transgenic rice lines under cold, salt, PEG, H2O2, ABA and drought stress condition is underway.

Glucosinolates of Brassica rapa collection from Korea genebank were measured to determine total glucosinolate content and their variation of diverse glucosinolates; Around 100 accessions representing the different morphotypes and geographical origin of Brassica rapa were analysed. The principal component analysis was performed to evaluate the differences among morphotypes using the profiles of 14 glucosinolates identified from the leaves. DMRT test and box plots showed the significant difference between total glucosinolates of subspecies. Most of turnip accessions had higher gluconilates compared to the other type accessions, Chinese cabbage and pak choi. These accessions will be used for GWAS study for glucosinolate. Now they are being finger-printed by genotyping by sequencing (GBS). Among these accession, we selected a turnip accession with high amount of glucosinolate, K0466 and two Chinese cabbage accession with low amount of glucosinolate, K0015 and K0621. To analyse quantitative traits loci (QTL) for glucosinolate synthesis, these three accessions were fixed through microspore culture. Finally, six homozygous lines were selected and were crossed each other to make F1 hybrids. We just harvested F2 seeds and transferred doubled haploid plants to pots. QTL analysis for glucosinolate will be performed these F2 and DH population.

UDP-glucose 4-epimerase (UGE) catalyzes the reversible conversion of UDP-glucose to UDP-galactose. To understand the biological function of UGE from Brassica rapa, the gene hereinafter referred to as was cloned and overexpressed into Japonica rice cv. Gopum. Transcriptional profiling showed that the is specific to stem of rice plant. Morphological evaluation of the overexpression lines revealed altered phenotype characters particularly in panicle length, number of productive tillers and filled spikelets which account for an increase in yield. This remarkable agronomic performance was ascribed to higher photosynthetic rate complemented with higher CO2 assimilation. Interestingly, BrUGE1 did not only improve plant fitness under optimal condition but also under water deficit stress. The enhanced drought tolerance may be due to the induction of soluble sugar which may act as osmolyte to compensate dehydration during drought stress.

In spite of the overwhelming number of cysteine proteases in plants, only a few were substantially investigated. Papain-like cysteine proteases (PLCPs) are commonly implicated to disease immunity in some key pathosystems in plants, such as in tomato – Cladosporium fulvum, potato/tomato – phytopthora infestans, and Arabidopsis – Ralstonia solanacearum, among the few others. This study demonstrates the function of cysteine protease gene cloned form Brassica rapa (BrCP) related to resistance to Xanthomonas oryzae pv. oryzae in transgenic rice lines. The cysteine protease-encoding full-length cDNA was identified and characterized using web-based tools. The gene is 2,267 bp in size with an open reading frame of 1,365 bp that encodes predicted polypeptide of 455 amino acids. Blast analysis of the conserved domain of the gene confirmed its affinity to Peptidase_CIA family. Full-length cDNA of PLCP in Brassica rapa was then cloned and co-overexpressed in rice with HPT marker. Introgression of the gene was confirmed in the transformants through genomic PCR assay. RT-PCR analysis showed that the gene was constitutively expressed and present in all tissues. The overexpression rice lines exhibited an enhanced resistance when screened with four Korean Xoo isolates.

농작물은 다양한 외부 환경스트레스에 노출되어 있다. 환경스트레스는 작물의 성장에 영향을 주어 세계 각 지역의 농업 생산량을 심각하게 감소시키고 있다. 따라서 작물의 생산성을 높이기 위해서 다양한 환경스트레스에 내성이 강한 새로운 품종의 개발이 요구된다. 최근의 연구 동향은 환경스트레스 저항성 유전자를 작물에 도입시켜 환경 변화에 대한 저항성이 강한 작물을 개발하는 것이다. 본 연구에서는 배추의 저온, 고농도의 염과 건조 등의 환경스트레스에 대한 저항성 유전자로 추정되는 BrTSR53의 염기서열을 분석하였다. BrTSR53의 유전자의 총 길이는 481 bp이며 이중에서 ORF 부위는 234 bp이었다. 이 ORF의 염기서열 상동성을 분석한 결과 Arabidopsis에서 보고된 유전자와 유사한 것으로 나타났다. BrTSR53의 발현을 분석하기 위하여 quantitative real-time PCR을 실시하였다. 그 결과 배추를 고염 처리, 저온 처리하고 3시간 후에 가장 높은 mRNA 양을 보였으며, 건조 처리에서는 36시간 후에 발현량이 최대치를 보였다. 따라서 이 ORF는 환경스트레스에 대한 배추의 저항성 유전자임을 확인하였다. 그리고 BrTSR53 유전자를 효모발현 벡터인 pYES-DEST52에 삽입하고 western blot 분석법을 통해 효모에서 분자량이 약 13 kDa인 저항성 단백질의 발현을 확인하였다. 또한 BrTSR53 형질전환 효모는 염분 스트레스에 대한 저항성이 증가한 것으로 나타났다. 따라서 BrTSR53 유전자는 농작물의 환경스트레스 저항성을 높여줄 수 있는 주요한 유전자원으로 이용될 수 있다고 사료된다.

As the drought is getting worse, Lot of studies related to drought stress in plant have been conducted. Recently whole genome sequencing of Brassica rapa ssp which is important vegetable crop to East Asians has been completed to enable Omic research. It is known that the drought damages occur in the early stage of plant development. Here, we performed shotgun proteomics analysis of B. rapa to observe the morphological characters, monitor the expression patterns of the identified proteins during drought stress, and detect the proteins related to drought stress. The three week old B. rapa grown in density of single plant in a single pot were used. Drought stress were treated as that a single plant in soil was removed from the pot and the plant with soil was exposed to air and light without watering. Leaves were immediately harvested before drought treatment, 24hr after drought treatment, and 48hr after drought treatment. The protein expression patterns were monitored by a quantitative shotgun proteomics analysis. Extracted proteins were separated in 1D-SDS-PAGE then the gel sliced into seven pieces. Chopped gels were ingel-digested. Peptides were assigned to mass spectrometry (Q-Exactive). The ms/ms spectra were analyzed through Proteome Discoverer. By combining all of the identified proteins in the seven sliced gel samples, total B. rapa proteome reference map was completed. Protein expression patterns were investigated by comparing the quantity of protein. With shotgun proteomic approach, we evaluated the changes in the quantity and finally discovered the candidate proteins related with drought stress.

UDP-glucose 4-epimerase catalyzes the reversible conversion of UDP-glucose to UDP-galactose. The gene, named BrUGE1, isolated from a Chinese cabbage composes of a total length of 1,328 bp that contains a single open reading frame (ORF) of 1,056 bp which encodes a polypeptide of 351 amino acid residues with a calculated mass of 39.0 kDa. Expression analysis showed that BrUGE1 is tissue specific and highly expressed in stem of rice plant. Interestingly, BrUGE1 mRNA was highly accumulated by drought stress with significantly higher amount of soluble sugar. Morphological evaluation showed an increase in yield and yield components compared to the wild type. Moreover, a better growth performance on galactose as well as higher UGE1 expression was observed in transgenic rice lines than in wild type. In the Ubi-1::BrUGE1 lines, the increase of UGE1 expression was apparently sufficient to overcome the toxic effects of galactose. Taken together, the Ubi-1::BrGUE1 rice lines increased yield probably by increasing the rate of filled grains. The enhanced drought tolerance may be due to the induction of soluble sugar which may act as osmolyte to compensate dehydration during drought stress.

Bacterial blight is a serious problem of rice in irrigated and rainfed lowlands. It is caused by Xanthomonas oryzae pv. oryzae (Xoo) which is represented by many pathotypes, making it difficult to control. Plant proteases are important players in immunity acting either in the execution of attack, in signaling cascade or in perception of invader. This study demonstrates the response of cysteine protease (CP) upon interaction with the pathogen. The cysteine protease encoding full-length cDNA was identified and characterized using web-based tools. Conserved domain of the gene revealed its affinity to Peptidase_CIA family. The full-length cDNA of CP in Brassica rapa was then cloned and overexpressed in rice. Insertion of gene was verified in the transformants through PCR assay. Spatiotemporal expression of the gene was performed in transgenic rice. To evaluate the resistance of CP-overexpression lines to Xoo, transgenic plants were inoculated with two races of Xoo. In planta analysis of enzymatic activity of CP was also performed before and after infection by the pathogen.

This study investigated the quality characteristics between spring cultivars of Kimchi cabbage(Brassica rapa L. ssp. pekinesis). We measured the weight, length, width, formation index, midrib thickness and moisture contents of fresh Kimchi cabbage for characteristics of growth. And we analyzed the free sugar, amino acid, organic acid, mineral, pectin and cellulose contents of fresh Kimchi cabbage. The hardness and firmness were measured for texture of fresh Kimchi cabbage. The weight of 'K-power' cultivar was the highest than other cultivars. The ‘Jeongsang’ cultivars was the thinnest midrib thickness in cultivars, but it was not significantly different. The free sugar levels of spring cultivars was the highest in ‘Chunkwang’. Malic acid content of ‘Jeongsang’ was significantly different among spring cultivars. Also amino acid content of ‘K-power’ and ‘Chunkwang’ were significantly different among spring cultivars Mineral content in ‘K-power’ and ‘Bomaknorang’ were greater than that of other cultivars. Especially Na, Ca and Mg contents of ‘K-power’ and ‘Bomaknorang’ were higher four times than that of other cultivars. Pectin content of ‘Jeongsang’ was higher than that of other cultivars, but it was not significantly different. Hardness and Firmness were not significantly different among spring cultivars.

Calcium-binding proteins, like calcineurin B-like (CBL) proteins, represent important roles in plant calcium signaling. Calcium signals mediate a multitude of plant responses to external stimuli and regulate a wide range of physiological processes including pathogens, abiotic stresses and hormones. These proteins form a complex network with their target kinases being the CBL-interacting protein kinases (CIPKs). CBL genes play vital roles in multiple abiotic stress response pathways whereas some of these are more specifically involved in mediating ABA signaling. In this study, we collected 17 CBL genes designated as B. rapa CBL (BrCBL) from the Brassica database and analyzed the sequences. In comparison analysis, these genes showed high homology with published CBL genes of other species. An organ specific expression of these genes was observed in different organs of chinese cabbage plants. In addition, six BrCBL genes showed responsive expression after cold and drought stress treatments at certain time courses. All these data revealed that these CBL genes might be useful resources in developing abiotic stresses resistance Brassica.

The C-repeat/dehydration-responsive element binding transcription factors (CBF/DREBs) are involved in an important pathway for abiotic stress-response in plants. We have identified CBF/DREB1 gene family from Brassica rapa whole genome sequence and designated them as BrDREB1s. They contain conserved nucleus localization signal, AP2/EREBP domain, and CBF/DREB1 signature, as other known plant CBF/DREB1s. By comparative genomics, we found that nine of ten BrDREB1 genes were present in seven macro-synteny blocks co-linear to four Arabidopsis counterpart blocks and also genomic organizations of their flanking regions were very similar to those for co-linear Arabidopsis CBF/DREB1 genes. In particular, three genes, BrDREB1A, BrDREB1B1, and BrDREB1C1, were closely located within a 59 kb genomic sequence, which was similar to that of their Arabidopsis counterpart genes. However, the genomic regions of those BrDREB1 genes contained additional sequences, compared to their co-linear regions in A. thaliana. The expression of BrDREB1 genes under abiotic stresses were examined by searching microarray database and by RT-PCR analysis. All of eight genes tested were highly up-regulated during cold treatment and some of them were also responsive to salt, drought, and ABA treatment. Taken together, these results indicate that CBF/DREB1-mediated stress signaling pathway is also functioning in B. rapa. On the other hand, differences in genomic organization and gene number for CBF/DREB1 are thought to cause different response to stress between B. rapa and A. thaliana. In this presentation, we will introduce more detailed results for CBF/DREB1 gene family in B. rapa.

Clubroot, caused by a soil borne fungus Plasmodiophora brassicae Woronin, is a common disease of cabbages and other plants belonging to the genus Brassica, which is the most extensively cultivated vegetable crops worldwide. This present study was to evaluate the utilization possibility of SNP primers, which we designated as molecular markers linked to disease resistance based on B. rapa genome, it may be possible to apply them to B. oleracea, and to survey SNP marker related to clubroot resistance of cabbages. In total, 425 SNP markers can be applied to B. oleracea were selected from 8,000 SNP markers based on B. rapa genome linked to disease resistance. New 123 SNP markers of them were designed to be analysed to High Resolution Melt (HRM), and tested for clubroot resistance using 6 cabbage varieties, including 3 clubroot resistances (YR Chunrok, YR Dongjanggun, and Grandmart Cabbage) and 3 susceptibilities (Chungam-45, Bogam-1, and Junggam-21). Of them, 118 SNP primers amplified cabbage genomic DNA using HRM analysis, suggesting that it is possible to apply SNP markers based on B. rapa genome to B. oleracea. A total of 4 candidate SNP markers related to clubroot resistance were detected at 80.2℃ of melt temperature in BRS6, 79.2℃ in BRS18, 82.2℃ in BRS79, and at 84.4℃ in BRS114, respectively. These results provide valuable information that can be used for the utilization of the genus Brassica genome study and breeding for clubroot resistance in cabbages.

For genetic mapping studies, biparental segregating populations are often useful, however recombination is limited, giving rise to large genomic regions under QTL, and one can only study alelles present in both parents. In Wageninegn UR, a core collection is being developed representing all Brassica rapa morphotypes and geographic origins. As most B. rapa accessions are heterozygous and heterogeneous, we started a project to fix the collection through microspore culture. The resulting Diversity Fixed Foundation Set will be an interesting resource for association mapping studies, which have as advantage that they present the allelec variation present in the collection, and for mapping studies recombination is increased. Nineteen accessions of eight subspecies of Brassica rapa were used for microspore culture to developdoubled haploid lines. Eight morphotypes were represented: 3 Chinese cabbage, 2 Chinese turnip cabbage, 3 Pak choi, 5 Turnip, 3 Broccolleto, 1 Mizuna, 1 Komatsuna and 1 Turnip greenfrom the 19acessions examined, embryos were obtained for 13, representing six subspecies (Komatsuna and Turnip Green had no response). The embryo yields differed significantly between these 13 accessions. We regenerated normal plants from 10 accessions that survived more than 4 weeks in the soil using microspore culture. Nine accessions flowered after 4 weeks vernalization at 5℃ and seeds were harvested from 5 accessions. From a Mizuna, we obtained 3791 seeds from one plant and total 7318 seeds were harvested from 5 accessions representing 4 subspecies(Chinese cabbage, Chinese turnip cabbage, Pak choi, Mizuna). At present, we carry out experiment for obtain more seeds and induce embryos from the other plant materials.

Miniature inverted- repeat transposable elements are expected to play vital role in evolution of genes and genome of major eukaryotic organisms. However, there have been little reports on MITEs in B. rapa, a polyploidy model genome. We identified 13 novel MITE families in B. rapa genome by computational approach. Out of 13 MITEs families three, eight and two were classified under stowaway-like, tourist-like and hAT super families based on their unique structural characteristics. We characterized the members of 13 MITE families from the available 256 Mbp from whole genome draft sequences of B. rapa. We found ech MITE has high copiy number ranges from 14 to 977 which are distributed randomly along all the chromosomes. We also found more than 40% of the MITE members were associated with genes and gene rich regions. Furthermore, the polymorphism due to insertion and non-insertion of MITEs analysis suggest that MITEs are active in the genome. As, such the newly identified MITEs will provide a foundation for the further analysis of roles of MITEs in gene and genome evolution.

We have identified ATTIRTA1 transposon, a kind of mariner-type DNA transposon from Brassica rapa genome. A total of 811 inverted-terminal repeat, ITR consisting of the both terminal on ATTIRTA1 transposon were found from B. rapa v1.1 sequence. Among them 616 ITR were paired by two in each transposon, indicating three quarters of the transposon exists in original form. Around 10 percentage of the transposon, 82 ITR was located in gene, expecially only in intron. Using these ATTRRTA1, we developed a display system modified from AFLP technique and applied for this system to analyze genetic diversity of Korea Brassica rapa core collection. The collection includes 220 accessions representing the different morphotypes and geographical origin. The analysis of population structure revealed five subgroups and the clustering patterns matched well with their morphological traits. ATTIRTA1 transposon display seems useful marker system for studying genetic relationships. Presently we have profiled the components and contents of glucosinolate in the core collection to analyze genome wide association. This collection will be helpful to identify agriculturally desirable traits from other supspecies.