This study examined the total glucosinolate (GSL) and isothiocyanate (ITC) contents according to different processing conditions; fresh Kimchi cabbage (Brassica rapa L. ssp. pekinensis), salted Kimchi cabbage and kimchi (storage temperature 4℃ and 20℃) using two different cultivars (Bomatnorang and Chunkwang). Four GSL peaks representing gluconapin, glucobrassicanapin, glucobrassicin and 4-methoxyglucobrassicin were detected in Kimchi cabbage by HPLC and HPLC/MS analysis. The total GSL contents of fresh Kimchi cabbage of Bomatnorang and Chunkwang were 21.37±1.06 μg/g dry weight (DW) and 20.96±3.33 μg/g DW, respectively. After salting, the total GSL contents of salted Kimchi cabbage decreased by 39% and 52% in Bomatnorang and Chunkwang, respectively. Finally, the total GSL contents of kimchi after storage at 20℃ decreased by 83% and 56% in Bomatnorang and Chunkwang, respectively. The extracted ITC contents were analyzed by GC/MS. Three ITC peaks were detected in Kimchi cabbage representing 2-phenylethyl ITC, 3-butenyl ITC and 4-pentenyl ITC. The 2-phenylethyl ITC levels increased during the salting process but this generally fell during storage at 20℃ as kimchi. The 3-butenyl ITC levels of Kimchi cabbage according to processing decreased rapidly due to salting and then decreased slowly during storage as kimchi. The 4-pentenyl ITC of Kimchi cabbage was lost during the salting process. The results for the change in GSL and ITC contents during the kimchi making process will be used in the food industry.

Kimchi cabbage (known as Chinese cabbage) is one of the major vegetable in Korea. An inbred line ‘Wonkyo20042ho’, was developed by the National Institute of Horticultural & Herbal Science, RDA in South Korea. The first cross carried out using ‘Norang gwandong’ which had been introduced to Korea in 2007. During segrerating generations, bud pollination carried out using selected plants to fix genetic materials. ‘Wonkyo20042ho’ inbred line was finally selected by breeders from commercial companies at the field exhibition at 2011. The horticultural traits of ‘Wonkyo20042ho’ inbred line were as follows; half-open head, yellow inner leaf colour, and dark green outer leaf colour. The average head weight was 1899.2g, head width and height were 17.5cm and 27.9cm, respectively. Numbers of outer and internal leaves were 14.3 and 66.5, respectively. Harvest maturity was mid-late maturing type and average of seed yield for three years was 723 seeds. In addition, ‘Wonkyo20042ho’ inbred line showed resistance to clubroot disease (race 4 single spore isolation) and possessed thin leaves and small sized head.

Efficient infiltration of water through cell membranes is arbitrated by a family of transmembrane water channels called aquaporins (AQPs). Aquaporin belongs to a highly conserved group of membrane proteins called major intrinsic proteins that facilitate the transport of water and a variety of low molecular weight solutes across biological membranes,which is essential for plants to survive in stress conditions. This study identified 59 BrAQP genes from B. rapa database and Br135K microarray dataset, which was formed by applying low-temperature stresses to contrasting Chinese cabbage two inbreed lines, Chiifu and Kenshin. Based on phylogenetic analyses of BrAQPs revealed four distinct subfamilies, such as plasma membrane intrinsic proteins (PIP), tonoplast intrinsic proteins (TIP), NOD26-like intrinsic proteins (NIP), small basic intrinsic proteins (SIP) with aquaporin of Tomato and Arabidopsis thaliana. All BrAQP genes were firstly examined through homology study with existing biotic and abiotic stress resistance-related aquaporin genes of other plant species and found a high degree of homology. We selected PIP subfamily genes for expression analysis based on microarray data with high and differential transcript abundance levels and homology study with stress related aquaporin genes of other plant species. In our study, we characterized all B. rapa aquaporin genes and understanding the BrPIP subfamily gene function in plants under various environmental stimuli, the expressions of BrPIP genes under various abiotic stress conditions including cold, drought, salinity, water logging, ABA treatment and Fusarium oxysporum f. sp. Conglutinans infection were investigated by a quantitative real-time reverse transcription-PCR analysis. In our expression analysis, 4 BrPIP genes showed responsive expression against F. oxysporum f. sp. Conglutinans infection. The selected genes showed an organ-specific expression, and 12 out of 22 BrPIP genes were differentially expressed in Chiifu compared to Kenshin under cold stresses. Only 7 genes showed up regulation under drought stress and incase of salt stress 17 BrPIP genes were more responsiveness. Additionally, 18 BrPIP genes were up regulated by ABA treatment and all BrPIP genes showed down regulation under water logging stress. Together with expression and bioinformatic analyses, our results provides novel basis to allocate the stress-related biological function to each PIP gene.

In Brassica as matter of seedling manner, they have the bilocular ovary and 20~28 seeds per silique after fertilization. Rarely some of B. juncea and yellow sarson (Brassica rapa ssp, tricolaris) have multilocular ovary. In this stdudy, the LP8 (YS-033, CGN06835) is shown tetralocular ovary as well as high seed yields. As microscope study for the different size of immature bud sections and we have known the floral meristem with already four locules in immature buds less size than 1mm of LP8. To identify of determining of tetralocular ovary formation, RNA-seq was carried out on the isolated RNA from less than 1mm and from 1mm of bud size respectively. By contrast tetralocular ovay and bilocular ovary, Chiifu is used. A total of 994 differentially expressed genes(DEGs) are detected in only LP8. Among the DEGs, we identify 18 DEGs in only immature buds of less size than 1mm. The expression patterns of 18 DEGs are validated by real time quantitative PCR and these genes are cloned and the sequence analyzed. At present, 12 candidated gene are analyzed by sequencing and there are detected by large fragment insertion as well as SNPs in sequence comparison to Chiifu. We will perform the genetic transformation of these DEG genes in Arabidopsis for relation between genes and tetralocular ovary. Our results will be helpful in understanding for mechanisms of tetraovular ovary in Brassica rapa.

Brassica rapa subspecies show morphological variability, containing vegetable types and oilseed types. The yellow sarson types(Brassica rapa ssp, tricolaris) have distinct morphology, yellow seeded and contain some lines with very unique character of tetralocular ovary. For genetic studies on tetralocular ovary related to high seed yields, we produced genetic segregation population with F2 and double haploid(DH) population. The yellow sarson LP8 (YS-033, CGN06835) with character of tetralocular ovary used as a maternal plant and crossed by LP21 of turnip rape type with bilocular ovary as paternal plant. We took on the microspore cultures on immature bud which is collected on sizing from 2mm to 3.2mm for DH population. The regenerations DH plants are analyzed by ploidy determination using flow cytrometer and selected on diploid plants. These regenerated DH and F2 plants are doing bud pollination and measuring the phenotype traits. Also, these populations will be used for identify of genetic locus relate to tetralocular ovary using genotyping by sequencing.

UDP-glucose 4-epimerase (UGE; EC 5.1.3.2) is an enzyme that plays an essential role in the interconverts UDP-D-glucose (UDP-Glc) and UDP-Dgalactose (UDP-Gal). Five members of the Chinese cabbage (Brassica rapa) UDP-glucose 4-epimerase gene family, designated BrUGE1 to BrUGE5, have been cloned and characterized. Quantitative PCR shows that the BrUGE1and BrUGE4 mRNA are most abundant among other BrUGE genes, accounting for more than 55% of total BrUGE transcripts in most of the tissues examined. All genes showed organ specific expression pattern, two of which (BrUGE1 and 4) actively responded after Pectobacterium carotovorum subsp. carotovorum infection, while four genes (BrUGE-1, -3, -4 and -5)were shown to respond considerably against salt, drought and abscisic acid (ABA) treatments. To better understand the function of the UGE gene, we constructed a recombinant pART vector carrying the BrUGE1 gene under the control of the CaMV 35S promoter and nos terminator and transformed using Agrobacterium tumefaciens. We then investigated BrUGE1 overexpressing rice lines at the physiological and molecular levels under biotic and abiotic stress conditions. Bioassay of T3 progeny lines of the transgenic plants in Yoshida solution containing 120 mM Nacl for 2 weeks, confirmed that the BrUGE1 enhances salt tolerance to transgenic rice plants. Also T3 progeny lines of the transgenic plants, when exposed to infection caused by Xanthomonas oryzae pv oryzae, showed tolerance to bacterial blight. These results showed that BrUGE1 can be used as potential genetic resource for engineering Brassica with multiple stress resistance.

Cysteine protease (CP) is one of the well-studied proteolytic enzymes in plants. This class of protease has been implicated in various physiological aspects of developmental stages in plants including seed germination, senescence, and disease immunity. A handful of studies assigned plants cysteine protease in different molecular battlefield under a few selected pathosystems, and initially extricated complex molecular mechanism of resistance. However, its potential use as an agent of resistance to diseases in rice has never been explored. This study demonstrates the function of CP specifically in rice - Xanthomonas oryzae pv. oryzae (Xoo) pathosystem. The CP -encoding full-length cDNA was cloned from Brassica rapa and transformed into japonica rice cv. ‘Gopumbyeo’. The gene was overexpressed under the control of CaMV35S promoter in pFLC vector. Blast analysis of the conserved domain of the gene confirmed its affinity to Peptidase_CIA family. RT-PCR analysis showed that the gene was constitutively expressed in all tissues tested. Regulation of rice resistance through cysteine protease activity is evident in overexpression lines which exhibited an enhanced resistance to four Korean Xoo isolates. Further analyses will be carried out to uncover the specific role of CP in rice-Xoo interaction.

Anthocyanins are responsible for vivid colors of flowers, fruits and vegetative tissues and biosynthesis of it is primarily controlled by several structural and regulatory genes. The regulatory mechanism of this pathway is still unknown. This study identified 19 transcription factors of Brassica rapa and investigated their regulatory function in anthocyanin biosynthesis pathway genes and cold and/or freezing tolerance in B. rapa. Expression analysis of these genes in the pigmented and non-pigmented portion of leaves of different lines of B. rapa revealed that BrMYB2-2 and BrTT8 showed responses contrasting with anthocyanin accumulation and cold stress. Sequences of these genes were analyzed and compared with similar gene sequences from other species and a high degree of homology with their respective functions was found. Co-regulated cis -elements were found in promoters of BrPAL1, BrCHS, BrF3H1, BrF3’H1, BrFLS, BrBAN, BrDFR8, BrANS1, and BrMYB2-2 and BrTT8 had binding sites of the promoters of those structural genes. Thus, the above results suggest the association of BrMYB2-2 and BrTT8 with regulation of anthocyanin biosynthesis pathway genes and cold and freezing stress tolerance and might be useful resources for development of cold resistant Brassica crops with desirable colors as well.

The TIFY family is composed of a plant-specific group of genes with diversity of functions. This family represents four subfamily of proteins viz. ZML, TIFY, PPD and JASMONATE ZIM-domain (JAZ) proteins. TIFY proteins especially, JAZ proteins have been reported to perform different biological processes, such as developmental and stresses and hormone responses in Arabidopsis and rice. However, there is no information about this family genes in Brassicaceae. This study identifies 36 TIFY genes in Brassica rapa, an economically important crop species from this family. An extensive in silico analysis through phylogenetic grouping, protein motif organization and intron-exon distribution also confirmed 4 subfamilies of BrTIFY proteins. Out of 35 BrTIFY genes, we identified 21 under JAZ subfamily besides 7 TIFY, 6 ZML and 2 PPD. An extensive expression profiling of 21 BrTIFY JAZs both in tissues and organs of B. rapa revealed differential expression patterns. Almost all the BrTIFY JAZs predominantly expressed in leaves and flower buds. Besides, in a flower stage specific expression analysis we observed 14 BrTIFY JAZs with constitutive expression patterns. This indicates BrTIFY proteins have a strong involvement in the development of B. rapa flowers. Our protein interaction study also reveals the strong association of these proteins with the fertility and defense processes of B. rapa. To elucidate the stress responsiveness of BrTIFY genes, we analyzed the low temperature-treated whole-genome microarray data set and found almost all the BrTIFY JAZs were having variable transcript abundance in two contrasting inbred lines of B. rapa. Subsequently, all 21 BrTIFY JAZs were validated in response to cold stress in the same two lines via qPCR, where 9 genes were found to show up- regulation. And, a high and differential qPCR expression pattern of all the BrTIFY JAZs was also recorded against JA. Additionally, BrTIFY JAZs were tested against salt, drought, Fusarium, ABA and SA treatments and a considerable number of genes were found to be induced. The extensive annotation and transcriptome profiling reported in this study will be useful for understanding the involvement of TIFY genes in stress resistance and different developmental functions, which ultimately provides the basis for functional characterization and exploitation of the candidate genes for genetic engineering of B. rapa.

본 연구는 계절별 절임배추의 품질 균일화를 위한 기초 자료를 제공할 목적으로 저온 저장 중 물리화학적, 미생물학적 및 관능적 품질 특성 조사하였다. 전반적으로 계절별(봄배추, 여름배추, 가을배추 및 월동배추) 절임배추의 제조 직후 pH는 저장 초기 계절별 시료 간 차이를 보이다가 저장 후반에는 시료 간 차이가 없었다. 적정산도는 가을 절임배추가 비교적 낮은 산도를 보였고, 가용성 고형분 함량은 월동배추가 비교적 높은 함량을 보였으며, 미생물 균수는 여름배추가 가장 높은 균수를 보였다. 관능검사의 경우 계절별 절임배추의 외관의 변화 냄새와 맛 특성 변화도 계절별 시료에 따라 차이가 있었고, 관능적 품질 특성 항목간의 상관관계 분석결과 유의적으로 양 또는 음의 상관성을 보이는 품질 특성이 많아서 절임배추 저장 중에 한 개의 품질 특성만 변화하는 것이 아니라 여러 가지 특성이 함께 변화한다는 것을 확인할 수 있었다. 한편 계절별 절임배추 전반적인 품질 특성의 주성분 분석 결과 첫 번째 주성분(F1)과 두 번째 주성분(F2)는 전체 데이터의 51.98%와 14.23%의 설명력을 보여 주었고, 총설명력은 66.21%였다. 계절별로 월동배추는 F1상의 위쪽, 봄배추는 중간, 나머지 시료는 F2상의 아래쪽에 분포하였고, 저장기간에 따라서는 F1상의 왼쪽에 저장 일수가 적은 절임배추 시료가 오른쪽에는 저장 일수가 많은 시료가 위치하였다. 본 연구 결과 계절별 절임배추의 품질 특성이 제조 직후부터 저장 중에도 계속 시료 간 품질 차이가 뚜렷하게 있음을 확인하였다. 그러므로 품질이 균일화된 절임배추를 연중 소비자에게 제공하기 위해서 계절별 절임배추의 품질 특성과 저장 중의 차이를 고려하여 고품질의 절임배추 제조와 품질을 유지할 수 있는 연구 및 계절별 저장 절임배추를 이용한 김치 제조 연구가 지속되어야 한다고 판단된다.

본 연구는 유채-MS를 이용하여 배추와 순무 등을 화분친으 로 활용 잎의 모용이 없는 유채 잎에 배추와 순무의 엽색과 엽형 을 도입하여 소비자가 선호하는 새로운 형질을 갖춘 엽채소의 작출 가능성을 검토하고자 실시하였다. 교배효율에 영향을 미 치는 인공수분 후 주두 위에서의 화분발아나 화분관 신장은 유 채-MS와 배추간 종간 교배 조합에서 유채-MS와 순무간 종간 교잡보다 빠르게 진행되었으며, 유채-MS와 배추간 종간교잡 에서의 결협율이 90.6%로 유채-MS와 순무의 교배 결협율 67.3% 보다 23.3% 정도 높게 나타났으며, 협당결실립수는 각각 15.5립, 11.6립으로 나타나 유채-MS와 배추간의 종간교잡 효 율이 높았다. 유채-MS와 배추의 종간교잡 F1 잡종의 표현형질 의 특성은 주로 모계인 유채와 비슷하였으며 엽색은 밝은 녹색 으로 양친의 중간형을 나타냈고 모용은 적게 분포되어 있었으 며 엽수는 10.2매, 엽장은 27.5 ㎝, 엽폭은 14.0 ㎝로 잎의 길이 와 넓이가 유채에 비하여 커졌다. 유채-MS와 순무의 종간교잡 F1 잡종의 엽수는 9.6매, 엽장은 21.6 ㎝, 엽폭은 10.6 ㎝로 잎의 크기, 형태 및 결각 등은 양친의 중간형을 나타냈으며 엽색은 모 본인 유채와 비슷하거나 좀 더 짙은 녹색이었고, 모용이 잎의 앞 과 뒷면에 존재하였다.

본 연구는 계절별 배추 원료의 최적 절임 조건 및 저장성 연구를 위한 기초 자료 제공을 위하여 계절별 절임배추의 물리화학적 및 미생물학적 특성 조사와 이들 특성의 상관성을 조사하였다. 계절별(봄배추, 여름배추, 가을배추 및 겨울배추) 절임배추의 pH와 적정산도의 경우 가을배추 시료가 6.02±0.04와 0.15±0.01%로 다른 계절의 절임배추 시료보다 pH는 약간 높고 적정산도는 약간 낮았다. 가용성 고형분 함량은 월동배추가 7.76±0.39%로 가장 높았고, 염도 함량은 계절별로 유의적인 차이가 없었다. 총균수의 경우 여름배추가 다른 계절의 배추보다 유의적으로 많은 균수가 있었고 색도는 유의적인 차이가 없었다. 조직감의 경우 경도(firmness)는 봄배추가 가장 높은 4.92±0.06 kgf였고, 단단한 정도(hardness)는 여름 배추가 11.71±0.53 kgf로 가장 높게 측정되었다. 한편 계절별 절임배추의 품질 특성간 상관관계를 분석한 결과 계절별 절임배추와 가용성 고형분 함량, 경도와 1% 유의수준 유의적인 상관성이 있었다. 또 주성분 분석 결과 첫 번째 주성분(F1)과 두 번째 주성분(F2)는(은) 전체 데이터의 각각 35.59%와 27.28%의 설명력을 보여 주었고, 총설명력은 62.87%였다. 주성분 F1은 계절, 밝기, 가용성 고형분 함량, 배추 두께, 총균수와 젖산균 수였고, 주성분 F2는 절임배추의 피크 개수였다. 계절별 절임배추의 품질 특성을 바탕으로 계층적 군집분석 결과 봄배추, 여름배추 그리고 가을과 월동 배추로 3그룹으로 나뉘었다. 이상의 결과에서 계절별 절임배추의 경우 물리화학적 및 미생물학적 품질 특성에 차이가 있음을 확인하였고, 품질 균일화와 고품질의 절임배추를 연중 생산하기 위해서는 각 계절별 배추의 품질 특성과 절임 적성에 관한 많은 연구가 필요하다고 사료된다.

We investigated the genetic diversity and structure of the 239 fixed lines with 47 simple sequence repeat (SSR) and 109 NGS-generated SNP markers evenly distributed in B. rapa genome. Phylogenetic analysis classified the vegetable fixed lines to four subgroups, with the three types forming a separate and relatively farther cluster. Population structure analysis identified four sub-populations corresponding to geographic origin and morphological traits, and revealed extensive admixture. The vegetable B. rapa fixed lines successfully developed in our study would be valuable materials for multinational B. rapa diversity resources establishment. Understanding the genetic diversity and population structure could be useful for utilization of the representing genetic variation and further genetic and genomic analysis.

Plant bZIP transcription factors play crucial roles in biological processes. In this study, 136 putative bZIP transcription members were identified in Brassica rapa. The bZIP family can be divided into nine groups according to the specific amino acid rich domain in Brassica rapa. To screen the cold stress responsive BrbZIP genes, we evaluated whether the transcription patterns of the BrbZIP genes were enhanced by cold treatment in the inbred lines, Chiifu and Kenshin, by microarray data analysis and qRT-PCR. The expression level of six genes increased significantly in Kenshin, but these genes were unchanged in Chiffu. Additionally, homo- and hetero-dimerization test between selected bZIP proteins indicated the Bra020735 is a key regulator in cold response. These findings suggest that the six genes that encoded proteins containing N-rich regions might be involved in cold stress response. These results presented herein provide valuable information regarding the molecular basis of the bZIP transcription factors and their potential function in regulation growth and development, particularly in cold stress response.

The Alfin-like transcription factor family is one of the important gene families in eukaryotic plants. They are involved in many biological processes, such as lignocellulosic wall biosynthesis, meristem development, metabolite transport, and responses to biotic and abiotic stresses. But the regulatory mechanism of these genes involved in stresses responses is still unrevealed. In this study, we identified a total of 16 Alfin-like genes from Brassica rapa database. The 16 putative Alfin-like proteins were divided into four groups (group I-IV) based on structural and phylogenetic analyses. Accordingly, this study analyzed stress resistance-related functions of all B. rapa Alfin-like (BrAL) genes through a homology study with existing biotic and abiotic stress resistance-related Alfin-like genes of other plant species and found a high degree of similarity with them. Subsequently, these genes were further investigated by real-time quantative PCR under cold, salt and drought stresses and after infection with Fusarium oxysporum f. sp. conglutinans in B. rapa. These genes showed an organ specific expression and all genes differentially expressed in Chiifu compared to Kenshin under cold stress. Ten and seven BrALs responded highly in Kenshin compared to Chiifu under salt and drought stresses respectively. In addition, six BrAL genes showed responsive expression after Fusarium oxysporum f. sp. conglutinans infection in B. rapa. Interestingly, four BrAL genes showed responses against both biotic and abiotic stress factors. Thus, our result provides a useful reference data set as the basis for functional analysis and utilization in the resistance molecular breeding of B. rapa.

Chinese cabbage is one of most important vegetable crop in Eastern Asian countries including Korea. Because Chinese cabbage is a leafy vegetable, genetic research with respect to the leaf morphology is important. In this research, we have used two inbred lines of Chinese cabbages (Kenshin and RCBr) and generated recombinant lines having various leaf morphology. In F2 population of Kenshin X RCBr, leaf shape showed very dramatic variations with normal distribution in terms of leaf size, petiole length, leaf margin and etc. Microarray with a 135K DNA chip (version 3) integrated 2 sets of total Chinese cabbage genes. Biological process of candidate genes was classified into transcription factor, genes encoding kinase activity protein, protein folding related genes, oxidation-reduction process genes. Putative leaf-morphology-related genes were 142 that are involed in phytohormone pathway genes, cell proliferation & cell elongation related genes and genes controlling leaf morphogenesis etc. These genes are further classified to phytohormone signaling-associated genes (SAUR44, PIN2, CPK6, RDUF2), leaf development regulating genes (DWF4, CUC2, TCP15, BLH4, NGA4), and cell division and cell growth related genes (ILP1, TCTP, EMB1027).

Flavonoids are divided into several structural classes, including anthocyanins, which provide flower and leaf colors and other derivatives with diverse roles in plant development and interactions with the environment. This study characterized four Anthocyanidin Synthase (ANS) genes of Brassica rapa, a structural gene of anthocyanin biosynthetic pathway, and investigated their association with cold and freezing tolerance in B. rapa. Sequences of these genes were analyzed and compared with similar types of gene sequences of other species and found a high degree of homology with their respective functions. In the organ specific expression analysis, these genes showed expression only in the colored portion of leaves of different lines of B. rapa. On the other hand, BrANS genes also showed differential expression with certain time course of cold stress treatment in B. rapa. Thus, the above results suggest probable association of these genes with anthocyanin biosynthesis and cold and freezing tolerance and might be useful resources for developing cold resistant Brassica crops with desirable colors as well. The present work may help explore the molecular mechanism that regulates anthocyanin biosynthesis and its response to abiotic stress at the transcriptional level in plants.

MADS-box transcription factor (TF), primarily involved in the floral organ specification with other several aspects of plant growth and development. Whole genome survey of B. rapa revealed 167 MADS-box genes and categorized into MIKCc, MIKC*, Mα, Mβ and Mγ groups based on phylogeny, protein motif structure and exon-intron organizations. MIKCc group belongs 89 genes, which is the highest in number than in any other crops till date. The MIKCc group has further classified into 13 sub-families. In case of chromosomal localization, remarkably 57 MIKCc type MADS-box genes were found in the duplicated segments of B. rapa genome, whereas only 4 M-type genes have resulted from tandem duplications. Besides floral and vegetative tissue expression we also identified MADS-box genes with their male and female gametophyte specific expression in different stages of flower bud development. Furthermore, from a low temperature treated whole genome microarray data set 19 BrMADS genes were found to show variable transcript abundance in two contrasting double haploid lines of B. rapa. Subsequently, the responsive genes were investigated under three abiotic stresses where they showed differential and corresponsive expression patterns. An extensive annotation and transcriptome profiling undertaken in this study might be useful for understanding the involvement of MADS-box genes in stress resistance besides their growth and developmental functions, which ultimately will provide the basis for functional characterization and exploitation of the candidate genes in the genetic engineering study of B. rapa

Shaggy-like kinases (SKs), also known as Glycogen synthase kinase 3 (GSK3) proteins, play many important roles in cellular signaling in animals, fungi and amoebae. In particular, SKs participate in key developmental signaling pathways and also regulate the cytoskeleton. SKs -encoding genes are also present in all land plants and in algae, raising questions about possible ancestral functions in eukaryotes. Unlike in animals and Dictyostelium, land plant SKs are encoded by relatively large multi-gene families whose members share high sequence similarity. Along with the studied 10 ASKs (Arabidopsis shaggy-like kinases) indicate that plant SK proteins are actively implicated in hormonal signalling networks during development as well as in biotic and abiotic stress responses. In this study, 18 BrSKs are identified from Chinese cabbage, and they are classified into four groups according to the classification of Arabidopsis. The characterization, classification, gene structure and phylogenetic construction of BrSK proteins are performed. Distribution mapping shows that BrSKs are absented in A02 and A10 chromosome. 8 orthologous gene pairs are shared by Chinese cabbage and Arabidopsis. The expression patterns of BrSK genes exhibit differences in five tissues based on RNA-seq data in public data base. Specially, BrSKβ-1 and BrSKβ-2 show floral buds specifically expressed, which indicate that BrSKβ may play a key role during flower or pollen development. We deomonatrated that suppresion of Arabdiopsis orthology of BrSKβ impaired the late pollen in Arabidopsis plants. Taken together, our analyses provided insights into the characterization of the BrSK genes in Chinese cabbage, providing foundation of further functional studies of those genes. [This work was supported by a grant from the Next-Generation BioGreen 21 Program (the Next-Generation Genomics Center No. PJ008118), Rural Development Administration, Republic of Korea]

Flavonoids including anthocyanins provide flower and leaf colors and other derivatives that play diverse roles in plant development and interactions with the environment and dihydroflavonol 4-reductase (DFR) is part of an important step in the flavonoid biosynthesis pathway of anthocyanins. This study characterized 12 DFR genes of Brassica rapa and investigated their association with anthocyanin coloration, cold and freezing tolerance in several genotypes of B. rapa. Sequences of these genes were analyzed and compared with DFR gene sequences from other species and a high degree of homology was found. Constitutive expression of them in several pigmented and non-pigmented lines of B. rapa showed a correlation with anthocyanin accumulation only for BrDFR8 and 9. Conversely, BrDFR genes also showed responses to cold and freezing stress treatment in B. rapa. BrDFRs were also shown to be regulated by two transcription factors, BrMYB2-2 and BrTT8, contrasting with anthocyanin accumulation and cold and freezing stress. Thus, the above results suggest the association of these genes with anthocyanin biosynthesis and cold and freezing stress tolerance and might be useful resources for development cold and/or freezing resistant Brassica crops with desirable colors as well. The findings presented here may also help explore the molecular mechanism that regulates anthocyanin biosynthesis and its response to abiotic stress at the transcriptional level in plants.