배추속은 전세계적으로 재배되는 중요한 경제작물을 포함하고 있으며, 종의 진화 및 배수성 연구를 위해 학문적으로 중요한 가치를 가지고 있다. 그러나 대부분의 작물이 교잡육종을 통해 종자를 생산하기 때문에 고정 계통을 육성하는 데 많은 시간과 노력이 필요하다. 이러한 문제점을 해결하기 위하여 인위적인 방법으로 반수체 식물체를 유도하여 형질이 고정된 계통을 단시간에 육성함으로써 연구 및 육종 소재로 활용할 수 있는 다양한 기내배양법이 시도되었다. 본 논문에서는지금까지 배추속 작물에서 시도된 기내배양법의 연구현황을살펴보고 반수체 생산에 영향을 미치는 요인들을 조사하여 효율적인 반수체 생산 기술에 대한 정보를 제공하고자 하였다.

Chrysanthemum is one of the most popular and economically important ornamental plants due to its huge diversity in growing habits, wide range of colors, and different patterns of flower. In the present study, we conducted the karyotype analysis in four naturally occurring genotypes of Chrysanthemum boreale. Karyotype studies based on the fluorescence in situ hybridization (FISH) using 5S and 45S rDNAs. Four chrysanthemum genoteyps showed an aneuploid chromosome number of 2n=18+2 (111016 and 111021) or a diploid of 2n=18 (121001 and 121002). All the genoteyps had the same karyotype formula of 14 metacentrics and 4 submetacentrics. In 111016, the chromosome length during somatic metaphase ranged from 3.11 ± 0.26 μm (shortest) to 3.94 ± 0.20 μm (longest), with a total length of 32.94 μm. The chromosome length at the mitotic metaphase ranged from 3.11 to 6.46 μm, with a total length of 32.94 μm in 111016 and 51.05, 32.81, and 46.00 μm in 111021, 121001, and 121002, respectively. The 5S rDNA and 45S rDNA signals recorded different in all four wildly grown genotypes of C. boreale. This information can be useful in cultivar improvement, as well as in elucidation of the evolution of the chrysanthemum.

In the genus Chrysanthemum, repetitive DNA sequences, the dominant part of a genome, are still to be elucidated. To explore the matter, the present study applied fluorescent in situ hybridization (FISH) to the mitotic metaphase chromosome of Chrysanthemum boreale with C0t DNA as probes. Based on DNA re-assotiation kinetics, three kinds of C0t DNA exhibiting different degrees of repetitive nature were fractionated and used as FISH probes to map the repetitive sequences. Signals from all C0t DNAs were successfully observed but their coverage on the chromosomes was different among C0t-1, C0t-10, and C0t-100. C0t-1 FISH signals resulted to have its intensity on the telomeric region and were also dispersed on both chromosome arms except for some distal regions. In C0t-10, signals were observed in all parts of the chromosome with greater intensity around pericentromeric regions. FISH with C0t-100 DNA was observed in bright signals all over the chromosome. Signals of C0t FISH found in this study covered the regions where ribosomal DNAs and telomeric repeats of C. boreale have been distributed (previous report), thus signifying their repetitive attributes. The present results could enhance the efficiency of studying genomes, chromosomes and repetitive sequences of C. boreale and subsequently hasten the realization of the genetic scheme of Chrysanthemum.

The Asteraceae/Compositae family is one of the biggest families in flowering plants and has more than 23000 species including the economically important lettuce, sunflower, and chicory as well as the agronomic weeds. With its significance and the progress in sequencing technology, its species have been subjected to the genome sequencing project worldwide. Although chrysanthemum is an important plant in the floricultural industry, however, it has been less studied at the level of genomics, compared with other species in the Asteraceae. There were only several reports on comparative analysis of transcriptome for chrysanthemum. Actually, the genome of Chrysanthemum species is known to be gigantic and complex with diverse status ranging from diploid to decaploid. Since the cultivated and commercial chrysanthemum exhibits hexaploid genome, we decided to select the diploid species with smaller genome as a material for reference genome sequencing. Thus, we launched a genome sequencing project with C. boreale which was previously reported to be diploid by cytogenetic analysis. We constructed sequencing libraries with insert size 300bp and 500bp and sequenced them from the paired end in 100bp read length with Illumina’s HiSeq platform. After quality checking, we preprocessed raw reads by removing duplicated reads and trimming reads with low quality value. Kmer frequency analysis with the cleaned reads showed that the genome is heterozygous, highly repetitive and gigantic, ranging from 2.9Gb to 5.8Gb. The cleaned reads were further subjected to error correction and primary assembly with SOAPdenovo2. Here, we’ll report the result of Kmer frequency analysis and genome assembly.

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.

Fluorescence in situ hybridization (FISH) is a powerful tool for the detection of DNA sequences in the specific region of the chromosomes. As well as for the integrated physical mapping, FISH karyotype analysis has to be preceded. The detailed karyotypes of two onion cultivars, which are resources for onion genome sequencing project (‘Eumginara’ and ‘Sinsunhwang’), were constructed based on triple color fluorescence in situ hybridization (FISH) using 5S rDNA, 45S rDNA, and tandem repeat sequence. All used our materials showed 2n=2x=16 with x=8 as basic chromosome number. 5S rDNAs were located on 4 loci in one pair of interstitial region of short arm chromosome in both onion cultivars. Two pairs of 45S rDNAs were positioned in distal region of short arm chromosome in ‘Eumginara’. Otherwise 5 loci of 45S rDNAs were located in distal region of two pairs of short arm chromosome in ‘Sinsunhwang’. Among them, two signals of 45S rDNAs were co-localized in distal part of short arm and long arm chromosome, respectively. In case of tandem repeat sequence was detected on telomeric region of 8 pairs of chromosomes except on 45S ribosomal DNA sites. These results will provide a valuable background for physical mapping and help to further more understand the genome sequencing project in Allium cepa.

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.

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.